DISEASES OF THE MAMMARY GLANDS Animals that suckle their young are known as mammalia. They are provided with special organs or glands called mammas (collectively known as the udder, the milk-vessel, or milk bag) which secrete the milk intended for the support of the young animal for some time after birth. They differ in size, contour, and situa tion with the species, and their number varies from one to five or six pairs. Mammals possess ing several pairs have them arranged in a row on either side of the inferior median line of the body, beginning near the posterior aspect of the abdomen and stretching well over the chest. The number of pairs is closely related to the number of young brought forth—from one pair in the mare to five or six pairs in the sow. The mammas are present in both sexes, and are rudimentary in early life, but while no material change takes place in them in the male, they become developed with age in the female, under going special enlargement during gestation until they attain their maximum size imme diately after parturition. As the close of the suckling period approaches, they diminish in size through the collapse of the gland tubules, and eventually return almost to their original dimensions, though it is usually possible to tell by the appearance of the glands and teats whether an animal has been suckled.
Anatomical Construction of the Mamma. This is essentially the same in all mammals. The skin which covers and protects the mammEe is soft and fine, and in supporting the tissue proper of the gland it is assisted by a subcutane ous covering of thin elastic tissue which sends processes into the glandular elements or paren chyma, forming partitions between the chief lobes. Fatty tissue is present more or less, according to the condition of the animal, between the glands and the skin. Each gland has a separate envelope of elastic tissue which enables it to undergo considerable enlargement in volume without injury, and so long as the envelope is uninjured it prevents communication between the mammm.
Imperfections of the elastic envelope are often demonstrated during the inflation of the udder when treating cows for milk - fever. The glandular tissue or parenchyma is arranged like a bunch of grapes. The chief lobes are made up of smaller lobules composed of the milk secreting cells and minute ducts. When drops of milk form in the milk-cells or acini they gravitate into the small connecting milk-ducts, which, by union with others, form the milk duct for each lobe. Eventually the numerous milk-ducts coalesce and, converging to the centre of the gland, form the galactophorous or milk sinuses to which the secretion is carried. From the milk-sinuses proceed the excretory or teat canals, which run parallel in a straight course to the free extremity of the teat, where they emerge, each orifice being provided with a sphincter composed of circular bundles of muscular and elastic connective tissue which involuntarily prevents the escape of the milk and is only rendered patent by pressure from above or suction. The teats are the organs by means of which the young suck the milk from the milk-sinuses above. They are covered with skin devoid of hair and have, at their base, numerous small glands that secrete sebaceous matter which protects the delicate integument of the teats.
Mammm of the Cow.The cow's udder is situated in the inguinal region and consists of two halves—a right and a left—lying side by side and easily separable. Each half is sub divided into an anterior and a posterior gland, so that the udder consists of four separable glands or quarters. The anatomical divisions between the front and back quarters are not so well defined as that dividing the two halves of the organ. The teats vary in length and bulk, being too small in some families of Ayr shires, while in some shorthorn and cross-bred cows they are unduly large, indicating extension of the milk-sinus almost to the extremity of the teat. Two small supernumerary teats are occasionally met with on the posterior aspect of the gland. They are often imperforate and have no superimposed gland tissue. But in some cases gland-tissue does exist, and the teats are more developed and yield a few drops of milk. In rare instances this part is the seat of induration, and the extent of the gland-tissue present is indicated by a flat, bun-like swelling in which the teat is centrally placed. The circular muscular fibres, round the orifice of the teat, which form the valve or sphincter at the point of the teat, are well developed in the cow. The"blood supply"to the udder is carried by the two mammary arteries, each of which penetrates its own side of the organ on its upper surface and,;dividing into two, sends one branch to the anterior and one to the posterior quarter. A deep set of veins accompanies the mammary arteries, while others, which collect the blood superficially, unite to form the large sub abdominal or milk veins. The degree of develop ment of the milk veins is held by many to be an index of a cow's milk-producing capacity. The udder has a well - developed system of lymphatic vessels, all of which empty into the supramammary glands, two in number, one on either side, situated near the perineum, in a cavity above the posterior quarter of the organ and outside of its elastic envelope. The nerve supply is from the two mammary nerves— anterior and posterior—but little is known regarding their disposition and endings.
Mammm of the Mare.These are two in number, placed side by side in the same part of the inguinal region that the scrotum occupies in the male. When active, each gland is hemi spherical in shape and is separated from its fellow by a shallow fissure. Ligaments of fibro elastic tissue connect and support them to the abdominal wall. The skin is soft and black, and is covered by fine hairs which disappear towards the teats. The teats are conical in shape and are pierced by two or more orifices, which give exit to the milk from the two or more milk-sinuses situated above and whose cavities freely communicate with each other.
Mammm of the Goat and Ewe.These animals have only two maramm and they are situated in the inguinal region. Though somewhat similar in shape in both animals and having well-developed conical teats with a single canal, the glands and teats of the goat are greater in volume than those of the ewe, and the teats point slightly forward.
Mamma of the Bitch.The bitch has usually ten mammze, arranged longitudinally in two rows, one on each side of the median line; two of them are pectoral, two abdominal, and one inguina1. The milk-sinuses are absent or ill developed and the truncated teats have several orifices.
The Cat has two pectoral and two abdom inal marnmm on each side.
Mamma of the Sow.The sow has ten or twelve arranged as in the bitch. Each gland is circumscribed by a depression, the teats are not well developed, and they have several orifices.
Secretion of Milk.As the age of puberty approaches considerable development of the mammze occurs, causing increase of volume through the bifurcation of ducts and additions to their minute structure. As gestation advances the enlargement of the gland is progressive, vascularity is increased, and the milk vesicles become bigger and more numerous. These actual changes in the glands cause consider able swelling in their substance and cedema of the surrounding tissues, and shortly before parturition the secretion of milk commences. When the young animal is born the cavities in the glands become fully distended. The first milk is called the"colostrum,"which is an alkaline, light yellow fluid of creamy con sistence, and rich in proteid. The colostrum is intended as, and serves the purpose of, a purgative which effectively clears the meconium out of the intestinal canal of the newly-born animal. The volume of the glands is main tained during the active period of lactation, and when the secretion of milk lessens and eventually ceases, the glands return almost to their normal size.
Anomalies of Function. - Many writers have put on record instances of virgin animals show ing evidence of mammary activity by some increase in the size of the mammy and the secretion of milk for a time. In human medicine it has occasionally been observed that some milk is present in the breasts of newly-born infants; similarly in equine medicine many observers have noted mammary activity in newly-born fillies. Smith, of saw a foal one day old whose mammae were swollen and hard. After rubbing the gland one pint of milk was drawn off. The glands remained active for ten to twelve days and on the ninth day cestrum occurred in the foal as well as in the mother. of Tedbury, records that a shire filly was born with fully-developed manurm and teats one inch long. Each gland yielded half a pint of milk, which was micro scopically the same as that secreted by its mother. We know of no recorded case in which lactation has been seen in the newly-born of any other species. Many cases are on record, however, in which animals that never were mated have shown mammary activity and acted as foster-mothers. Neurotic virgin bitches, kept as pets and not allowed to bear young, sometimes acquire the habit of licking the parts, beget lactation, and lick up the exud ing milk. We know of such a case in a Scotch terrier bitch, four years old, whose bed is con stantly wet and noisome. This phenomenon, when it does occur, is usually seen twice a year in bitches. The records of many cases of this kind show that such animals have often usurped the place of the actual mother and successfully reared her progeny. Still more common is it to meet with cases where animals that have been mated and failed to conceive have ex hibited some degree of function in the mammm, and secreted milk at the time when parturition would have been due if they had fallen pregnant. This anomaly in every species is encouraged if the mamnm be manipulated or the teats suckled by a young animal. When it is desired to treat this condition the patient should be purged and put on short rations. She should be isolated from other animals, old and young, and the mamirm and teats should be painted over daily or oftener with a nauseous and bitter liquid, such as a strong solution of aloes.
Agalactia.Agalactia or absence of milk in the udder is occasionally met with in cows and mares after parturition, and may be temporary or permanent. Often met with after abortion, it is also occasionally seen after normal preg nancy, especially in mares that have only been bred from late in life or that have not been pregnant for a number of preceding years. In such it is sometimes due to physiological dis turbance in the function of the mamnm that is difficult to account for, and then the glands are small, and there is an absence of the usual plumpness and tenderness on manipulation. But more often defective secretion of milk is the result of previous disease or of existing chronic disease of the udder itself, or is due to grave pathological conditions of important organs associated with debility, anaemia, and emaciation. It is common after difficult par turition when the animal remains exhausted and feverish for a number of days, and if recovery is protracted the function of the udder may fail to be established until the end of a subsequent pregnancy, In grossly mismanaged dairy herds agalactic conditions may be very prevalent.
In such a case where our advice was sought at a time when a dozen cows were recently calved, we found the animals so ill nourished and weak from insufficient and improper food that they were almost"dry"when they should have been in full flow. Failure to secrete milk may be due to atrophy or wasting of the substance of the mammas, the result of former disease, and it sometimes occurs in cows with a great appearance in whose enormously large and indurated udders it would seem that the func tion if not the entire structure of the milk secreting cells had been destroyed by the undue pressure to which they were subjected by the unyielding and over-developed intercellular tissue of the organs.
Treatment. Success depends altogether on the cause of the defect. If the mammas seem healthy and are only faulty in size and activity they should be massaged twice or thrice daily with a little spirit and olive-oil. The diet should be changed to sloppy, nourishing, cooked food, including draff; warm milk may also be allowed, and in this way many temporary cases are quickly overcome. If functional activity is delayed, recourse may be had to drugs that have the reputation of stimulating the milk-secreting cells, e.g. fennel, caraway, aniseed, juniper, and sulphur. These should be mixed in equal quan tities and two tablespoonfuls of the mixture given once or twice a day in food or administered in a pint of stout.
Anomalies of Development.Absence of the inammce (amastia) is exceedingly rare and only found in association with grave developmental defects, e.g. in complete hermaphroditism. M. Sanson mentions the case of a cow and Lafour one of a mare that suffered from the defect.
Absence of the teats (microthelia) is also rare.' Joachim da Costa, Veterinary Hospital, Khair pur State, Sind, reports the case of a four-year old cow that had no teats but only four round coloured spots showing the seat of the nipples. No openings were apparent, but below each spot could be felt a finger-like process. He made incisions over each spot, exposing the processes, and removed the milk by a teat-tube. He does not state whether the exposed pro cesses were capable of being milked by hand or suckled thereafter.
Imperforate Teats (Congenital).An imper forate state of the teat is occasionally seen in animals whose mammas and teats seem normal in appearance, and the fault, usually confined to one teat, is only discerned when a first attempt is made to milk the animal. (Acquired stenosis of the teat canal, the result of accident or disease, is more common. (See p.1034.) Here we are only concerned with the defect as it is seen in primiparw.) It may be located at the point of the teat or near to the top of the teat canal, or the teat canal may be entirely obliterated.
Symptoms and Diagnosis. The diagnosis is easy, for, when an attempt is made to milk the teat, not a drop can be drawn off, and if the cow is suckling her calf the owner's attention is attracted by the swollen state of the quarter. When the fault is at the point, the teat is ballooned and an examination reveals the absence of an orifice. If the imperforation is located at the top of the teat it is, in most cases, due to the presence of a delicate membrane' which prevents the entrance of the milk into the teat canal, and in this case as well as in complete obliteration of the teat canal, the teat is undistended and feels more or less solid.
Prognosis. The outlook is hopeful unless in cases of obliteration of the canal of the teat.
Treatment. When there is no orifice and the teat is filled with milk it should be grasped with the left hand so as to distend the canal to its extremity, which should then be pierced by a small sterile trocar held in the right hand, and when this is withdrawn a sterile milk-tube is inserted and the milk drawn off. Thereafter the teat is steeped in a weak solution of an anti septic in a cup and, after drying, an aseptic bougie is put in position to keep the orifice patent. This is repeated after each milking until the perforation wound has healed and a permanent orifice has resulted. When a par tition of membrane is present higher up in the teat, it is usually capable of being pierced by an upward thrust of a pointed silver teat-tube, through which the milk immediately flows. There is little danger of wounding the mammary tissue by this procedure, as the milk-sinus above is distended with secretion, and it is desirable to make some lateral movement with the metal tube to enlarge the puncture and break down the delicate curtain. The teat may then be suckled or milked by hand, and there is usually no untoward result if aseptic precautions are taken. When the teat canal is completely obliterated nothing should be done, and if there be no interference the congestion and swelling of the gland soon subside and complete atrophy or wasting results.
Injuries of the Mamma3.These are roughly divisible under two heads: bruises and wounds. Both types of injury are common in all domestic animals that spend a large part of their time in the open, and the danger is greatest to those that have largely - developed and pendulous mammas. In herbivora the quality of the field hedges or fencing and the nature of the ground surface are factors that often predispose to injuries of the udder.
Bruises or Contusions. The udders of the cow, goat, and ewe are much subject to bruises on account of their great development and the risks attached to unrestrained grazing in the company of many neighbours. The posterior pair of mammw in bitches and sows that have bred several litters often hang so low that they are liable to and on occasion are the seat of bruising. When subjected to blows of any kind the maminm are more apt to suffer con tusion when fully distended and firm, so that they offer a comparatively unyielding impact to the stroke or blow. By butting with the head, the sucking call may bruise the udder of its mother. More frequent causes are contact with blunt stakes when jumping fences, blows from the horns of other animals, kicks, etc. We have occasionally seen the udder of a paralysed, prone cow bruised by a tramp from its neigh bour, when insufficient care was taken in turning the latter out to water. Bruising of the udder is occasionally met with in dairy cows on board ship during stormy weather, and animals sub jected to railway journeys are often the victims of treads on teats and udders.
Symptoms. There may be only a slight dis coloration of the skin and a little local swelling, or there may be considerable exudation of blood subcutaneously, and if the blow has been very severe the mammary tissue may be injured, when blood extravasation penetrates more or less deeply into the gland. In such cases the secretion from the quarter may be mixed with blood for several days, and there is considerable pain and swelling. Sometimes a subcutaneous clot of blood is formed without any marked dis integration of the glandular tissue as indicated by the absence of discoloration of milk from the quarter. An Ayrshire cow, not in full milk, failed to negotiate a hedge and the front of her left fore quarter came into contact with a square-edged post. Seen immediately after wards, her udder showed only a linear excoria tion five inches long, but very soon a round tumour, eight inches in diameter, appeared, indicating subcutaneous haemorrhage.
Segue e. When the bruise is severe and is followed by painful swelling and deep dis coloration, a slough may separate after some days. Injury to the gland-tissue is often fol lowed by inflammation which tends to end in abscess formation. Mastitis occurs all the more readily if the skin is broken and precautions have not been taken to prevent the entrance of bacteria, or when, in the absence of a lesion to the integument, the acini have been injured and so rendered incapable of resisting the attack of udder-contained organisms, hitherto held in check, that so often exist in the mammm of cows belonging to a herd in which cases of mammitis are of common occurrence.
Treatment. Slight contusions need no treat ment. In more severe cases the part should be cleansed with an antiseptic solution, dried, and then thickly smeared with a layer of lukewarm cataplasma kaolin and glycerine, covered with a layer of cotton-wool, and if necessary a sus pensory bandage should be applied. This should be renewed every twelve hours till pain subsides, when the part may be gently massaged with a mild stimulating liniment. The teat of the affected quarter should be drawn four times a day or oftener if the milk is in any way altered.
Wounds. Animals possessed of pendulous udders—the cow, goat, and ewe—are most com monly the subjects of lesions in this region. Cows that have the habit of jumping fences are specially liable, and forcible contact with large thorns, sharp stakes, taut and barbed wires produces a variety of lesions from scratches to deep penetrating or lacerated wounds that sometimes involve the teat to the escape of milk, or it may be almost torn off and need amputation. When the horns of animals given to goring their neighbours are unduly pointed or sharpened through contact with the wall, they are capable of producing ugly excoriation of the integument and actual piercing of the udder tissue. Other causes include improper bedding containing sharp substances, bites from dogs, etc., and wounds are sometimes caused maliciously or otherwise by utensils used in the cow-shed. Wounds involving the teat canal or the milk-sinus, allowing the escape of milk, seldom heal satisfactorily and a fistula often results. All wounds of the udder are serious, especially when the organ is functionally active, because of their liability to become soiled through con tact with dirty floors or bedding. Deep punc tured wounds are often followed by gangrene more or less extensive. In a case of this kind, a penetrating wound caused by a horn-gore, little attention was given to the cow's injury, and gangrene resulted. After the dead portion was thrown off the cow was in good health, but the lesion left presented an unusual appear ance, compared to that seen when a slough has separated in cases of non-traumatic gangrenous mammitis. Instead of the usual granulating wound, there hung from the lesion from eight to ten red bleeding stumps—some of them branched—varying in length from three to ten inches, and in diameter from I of an inch to one inch. When operating on the stumps by liga ture and excision it was seen that a healthy blood-vessel formed the nucleus of each, and was clothed by rapidly - growing granulation tissue or proud flesh, which had bled freely through contact with the inner aspect of the hock. It was evident that the less resistant tissues of the part had become dead and sloughed off before complete involution of its nutrient vessels had taken place.
Treatment. It is in most cases bad practice to stitch up wounds of the udder, especially the part from which milk escapes. The wound should be cleansed with weak antiseptic solu tions, loose shreds of tissue should be clipped off, and after drying with a clean cloth the surface of the lesion may be painted with car bolized glycerine (1 in 16) or a solution of iodine, or dusted over with boric acid to which a little iodoform may be added. No bedding should be allowed, and the floor under the udder should be scrupulously cleansed and disinfected as often as necessary.
Milk Fistulae. When a teat is injured during lactation and the teat canal or milk-sinus is exposed, the constant escape of milk interferes with complete healing and a fistula results. In dry animals, with careful treatment, such wounds often heal perfectly. Fistula of a hind teat is occasionally seen in primiparm. The history usually is that when the young calf was examined the teat was seen to be branched or had a small supernumerary teat attached near its base, which the owner had snipped off with a pair of scissors after deciding to rear the animal. Fistulae originating from this cause are invariably encircled by more or less firm tissue —the base of the amputated appendage. When a deep-rooted wart on the teat is removed by the common practice of plucking it off with the fingers, the resulting wound may ulcerate and penetrate to the teat canal. Milk fistulae are usually located somewhere in the teat, but the opening is sometimes in the udder near to the base of the teat. If the aperture is large, the milk is continually trickling away, soiling the floor and making it noisome. When smaller, there may be very little escape of milk for six or eight hours after each milking, but when the teat is drawn two streams of milk proceed from it and it is usually impossible to direct both into the milk-pail. The slightest handling of the udder usually starts the flow of milk from a fistula, or when the dripping is constant, increases it. A fistulous teat constitutes un soundness in a dairy cow. It is a serious defect, not only because it is a nuisance and causes material loss of milk, but because it is a per manent predisposition to mammitis through the teat being continually wet with secretion. The wet teat has every opportunity to become soiled when the cow lies down, bacteria grow readily on the film of milk, and it may be presumed that the ordinary fistula is a less effective bar to bacterial invasion of the udder than the normal orifice at the point of the teat.
Treatment. No surgical measures need be attempted during lactation, because the secre tion and unavoidable discharge of milk make healing impossible. Operation may be tried when the cow is quite dry and is likely to remain so for a few months. The animal is cast and a perpendicular incision is made over the fistula, exposing the teat canal. The hardened or cicatricial tissue of the fistula is curetted away, and after drying the wound one or two deep silk sutures are inserted closing the mucous membrane of the canal, and thereafter the skin wound is closed by four or five stitches. The part should then be painted over several times with flexible collodion and an aseptic bougie of some length inserted into the canal. The animal's bed should be kept scrupulously clean, and, if necessary, a new bougie is inserted after two days. Unfortunately, these operations are not always successful, especially in the case of old fistulae. If an operation is inadvisable, cows with a lacteal fistula should be put on grass to foster one or two calves and then be fattened for slaughter.
Teat Sores. The integument of the teats is liable to mechanical injury, but the great majority of cases of"sore teats"are of the nature of chaps and fissures or cracks. All young animals and thin-skinned cows are espe cially liable to these conditions. Sore teats are very troublesome, as they render the animal fidgety and difficult to milk, and if suckling a calf the attentions of the latter are resented.
Causes. In newly-calved queys and fine skinned animals the delicate integument of the teats is liable to break and become fissured through failing to support the friction of hand milking or suckling, and doubtless the milk or mixture of milk and saliva usually left on the teats has a macerating effect on the cells of the epidermis. Cows, when suckling calves affected with"thrush of the mouth,"are often the victims of teat sores. The skin of the teat is at first tender, and if not carefully looked after, the alternate distension of it before, and relaxa tion after, milking soon cause cracks to appear. When left wet with milk, etc., the wrinkled parts of the empty teat present a soapy appear ance through shedding of superficial cells that have undergone maceration and been cast off. One or more sores in the form of cracks may result in this way, and they readily extend in depth and length under the irritation of the milking process. The season of the year in fluences the production of sore teats. The con dition is most common and troublesome during the wet periods of spring and autumn when there is slight frost during the night, and when many cows are calving and the animals are at grass.
Symptoms. Before the formation of a fissure the skin of the part about to break is red and tender, and the lesion is often made during milking, the hand of the milker being a little blood-stained. A superficial crack gives little pain, but when it deepens and widens under the necessary manipulation of milking, infection of the wound is common and the teat becomes inflamed, tumefied with inflammatory exudate, hot, and very painful. When in this condition it is a difficult matter to get the cow milked by hand or suckled. If the point of the teat is involved the gravity of the case is much in creased, the orifice becomes sealed with coagul ated discharge that needs removal before the secretion can be drawn off, and not infrequently, owing to incomplete removal of the contents of the quarter and extension of infection up the teat canal, an acute attack of mammitis supervenes and septicmmic sequelm often follow.
Prognosis. This is favourable if the point of the teat remains healthy. But in some cases, even in the absence of implication of the sphinc ter, the teat becomes so infiltrated with in flammatory swelling that proper milking is impossible, and, by a process of extension into the prejudiced mammary tissue, the quarter becomes"weeded." Treatment. — Preventive measures embrace cleanliness, keeping the animal comfortable and free from draughts, drying the teats after milking and smearing them with a little gly cerine, lard, or a mixture of lard and beeswax, lanoline, or lead liniment. These measures are most essential in primiparm and fine-skinned animals at the commencement of lactation. When cracks have formed, the affected teats, after milking, should be steeped in a cupful of a weak solution of Jeyes' fluid, lysol, or other antiseptic, and then dried with a clean cloth or absorbent cotton-wool. Thereafter, the parts should be smeared with one of the following dressings: Liq. plumbi sabacet. fortis 3ij. Glycerin or ol. ohm 3xvi.
M. ft. lin.
Or 4 Ac. oath. 3i. Glycerin Oj.
M. ft. lin.
or dry dressings may be used, dusting the parts with boric acid or a combination of boric acid and iodoform. Zinc ointment, to which a few drops of carbolic acid have been added, serves well for superficial sores. Indolent sores should be lightly touched with nitrate of silver, and healing of deep fissures is hastened by the use of wet dressings. A suitable piece of plain or boric lint is steeped in water that has previously been boiled, and after applying it to the teat it is covered by a piece of jaconet or other water proof material held in position by two light rubber bands. If it be evident, notwithstanding the use of suitable dressings, that healing is not making headway because of the want of rest to the parts caused by milking, the use of a teat syphon becomes imperative, provided the milk shows no change in its character. This procedure gives rest to the lesions, and they heal readily under proper care.
(1) The papular or nodular stage is charac terized by the presence on the teats and skin of the udder of little firm red nodules, giving the teats a"shotty"feeling. The nodules increase in size and arrive at (2) The Vesicular Stage. The vesicles are formed by the exudation of lymph; the smaller ones coalesce to some extent, forming larger vesicles comprised of several lymph-containing compartments. The head of the vesicle is pale yellow and depressed or umbilicated, and this is thought to be due to the binding effect of the unmacerated borders of the primary vesicles that have grouped together. The lymph in the vesicles, of which there may be from two to six on each teat, soon changes and the eruption assumes the (3) Pustular Stage. The vesicle has now become a pustule, greyish in colour, the con tents being turbid and purulent. The centre of the pustule is more or less rounded, having lost the pitted appearance of the vesicular stage, and around it there is a red zone of congestion (hyperemia). The pustules gradually dry and reach (4) The siccative stage, when crusts are formed under which the regeneration of tissue gradually takes place. The crust is then thrown off and, if the papillary layer has been involved, a slightly depressed scar is left. It is not often that the eruption passes through these regular stages on the teats, for the vesicles are often broken by the hands of the milker, secondary infection occurs, and the sores assume a hemorrhagic type often associated with much infiltration and tumefaction of the teat. It is also by the hands of the milkers that infection is carried to other cows, and not uncommonly the milkers become inoculated themselves and are incapacitated for a few days by sore hands and sickness.
Differential Diagnosis of Specific Teat Erup tions.The vesicles met with on the teats in foot-and-mouth disease, instead of being multi 'ocular and pitted as in cow-pox, have a single cavity with no central depression. Again, in cow-pox there is an absence of the marked con stitutional disturbance, the characteristic lesions of the mouth and feet, and the rapid spread of disease to non-milking members of the herd and to oxen, pigs, sheep, etc., so typical of foot-and mouth disease. In rinderpest an eruption is occasionally seen on the udder and teats which does not closely resemble that of cow-pox, while the highly infectious, febrile, and fatal nature of the disease readily serves to distinguish the two affections. Again, in malignant catarrh there is no difficulty. The teat eruption is lenticular in character, so that it cannot be mistaken for cow-pox, while the early appearance of gross mouth lesions, accompanied by high fever and grave signs of ill-health in malignant catarrh, are in marked contrast to the almost imper ceptible symptoms of constitutional disturbance in most cases of cow-pox. In eruptions due to streptococcal infection pustules are directly formed which vary in size, and some of them end in small abscesses which ripen and burst, leaving ulcerating sores. In varicella or false cow-pox the eruption more closely resembles variola. The vesicles are, however, directly formed, there being no papular or"shotty"stage: they are small and rounded, or flat, but never umbilicated. It is rarely that any of them become pustules, the rule being that the small vesicles simply dry up and throw off a thin crust like a broad flake of bran, leaving no scar. In October 1909, eruptive disease of the teat closely resembling varicella occurred in a herd of seventy milch cows near to a large town, and our advice was sought because the medical officer of health threatened to stop the milk supply. Every cow in the herd became infected, the eruption passed through its course in seven days, except in a few cows in which it became irregular (which was doubtless the result of teat stripping causing bursting of the vesicles and allowing secondary infection), the cows maintained their health, and there was no appreciable drop in their yield of milk. Micro scopical examination of the contents of a freshly opened vesicle revealed diplococci, which readily grew in pure culture when sown on artificial media. The medical officer's apprehension of danger was based on the fact that, coincident with this outbreak, an epidemic of septic sore throat occurred in many of the houses receiving the suspected milk supply, and it was also asserted that diplococci were constantly re covered from the throats of human patients. However, an examination of the cows in five other dairies distributing milk in the same quarter disclosed that several of the animals in three of these herds were showing the identical eruption present in the herd whose milk they proposed to ban. Fortunately, no case of sore throat occurred among the milkers nor in the family of the owner, all of whom consumed the raw milk every day, and we pleaded successfully that the human infection was more likely to be due to the pre vailing bad weather—which was cold, wet, and stormy—than to bovine infection, since, at the time, throat affections were quite common in many other districts.
Precautionary Measures for Eruptive Diseases of the Teats. Milkers should wear clean gar ments, wash and disinfect their hands before going on duty, and as often as is necessary during milking. The udder and teats of every cow should be swabbed with a cloth wet with anti septic solution and then dried. Similar swab bing and drying of the udder should take place after milking, and the teats of thin-skinned and newly-calved cows, especially heifers, should be smeared with some bland emollient dressing. When eruptive disease does appear, isolate the affected, and detail for them a special milker, who should not approach the healthy animals, since the spread of the disease is mainly by the hands of the milkers. If it is not possible to house the affected animals separately or to supply for them a special attendant, they should at least be moved to one end of the byre and be milked last, the affected teats receiving suitable treatment. Infective eruptions often originate with the introduction into the herd of young cows commencing lactation, so they should be housed separately for some time.
Abnormal Conditions of the Interior of the Teat—Relaxed Sphincter. Cases are occasion ally met with in cows with apparently normal mammae in which the sphincters of the teats— usually the hind ones—are so incompetent that milk begins to escape (lactorrhcea) before the cavities of the glands are fully distended with secretion. This incompetence may be due to weakness dependent on insufficient development of the circular elastic and muscular fibres of the sphincter or to an over-patent state of the orifice itself. In either case there is an absence of proper resistance to the pressure exerted by the milk when it collects in the milk-sinus, considerable loss of secretion results, and this creates a nuisance on the floor of the stall. Cows defective in this respect are"free"to milk, the secretion flowing in a thick stream from the teat, and for economical and sanitary reasons it is obvious that they should be emptied more frequently than is usual with normal animals. If detailed to suckle young, a cow that drips milk should have two calves to ensure the complete use of her secretion. If she has only one sucker, and is a heavy milker, the attention given by the young animal to one teat is accompanied by much escape of milk from one or more of the other teats. In other cases it may be necessary to supplement the function of the weak sphincter by applying a circular rubber band to the point of the teat, by blocking the orifice with a sterile bougie, or, in less needful cases, by painting collodion over the orifice. Relaxation of the sphincter is fre quently seen in prize-bred milch cows and is often due to the repeated overstocking that is practised to put them in full bloom for exhibition. It constitutes at all times a predisposition to mammitis.
Constriction of the Sphincter.This condition is more common than its antithesis (relaxation of the sphincter), and there are few large com mercial herds that do not include one or two cows that are"stiff to milk"owing to a con tracted state of the sphincter and smallness of the orifices of the teats. It is usually met with in long-teated, cross-bred animals whose teats when the hour for milking arrives are distended with secretion down to the point, and it would seem that in such cases unusual development and competence of the mechanism responsible for the retention of the milk existed by special design on the part of nature. Constriction of the sphincter is easily diagnosed, for even a strong milker has considerable difficulty in with drawing the milk, which issues in a thin thread like stream. Unfortunately, the condition often gets worse, for the extreme pressure which it is necessary to exert on the teat during milking has the sinister effect of hardening the valve and the atresia becomes more complete.
Treatment. Surgical measures used to be commonly practised, but in our hands they have proved worse than useless. They consisted in dividing the sphincter with a single- or double edged instrument—the"bistouri cache."The immediate result was always good, but when the small wounds made had healed the defect was usually more pronounced than before. Bene ficial results are obtained only by the use of bougies for the possible dilatation of the orifice, care being taken not to bruise the inner lining. Bougies for this purpose should be light, and the best ones are made of aluminium or hollow silver, like a tapering blind teat-tube, or of bone. A piece of coloured thread should be attached to the end of the bougie that protrudes from the teat when it is to be left in position for some time, as it sometimes falls out. The coloured thread facilitates its recovery from the bedding, and after being sterilized it is again fit for use if its surface is smooth and uninjured. In some cases a suitable set of milk catheters is made use of to save the difficulty of hand-milking, but their constant use requires the exercise of great care and antiseptic precautions.
Adventitious Growths in the Interior of the Teat.These vary in size, shape, and position, and the relative obstruction occasioned by them may be partial or complete. Their character and position can be judged by palpating the teat and introducing a teat-tube as a sound. Sometimes the obstruction consists of a warty like growth or granulation attached to one side of the sinus, while in other cases there is a pro nounced circle of thickened mucous membrane which readily develops further under the irrita tive effect of milking into a complete diaphragm beyond which no milk can pass. In certain families possessed of narrow, supple teats, this insidious circle of thickening develops during the first lactation period, and when it exists in one teat traces of commencing growth are usually discernible in some of the other teats.
Symptoms. When the obstruction is only partial, milk can be drawn off slowly in a thin stream, but the milking of the teat becomes progressively more difficult until complete obstruction takes place, the seat of obstruction marking the limit of distension of the teat by the accumulated secretion. In the absence of surgical interference and bacterial infection the pent-up secretion distends the sinus to its utmost capacity, the quarter becomes congested, tense, swollen, and painful to pressure, but very soon secretion is suspended, the contents of the gland become absorbed, and the quarter shrinks into a state of functional inactivity.
Treatment. In our experience it is courting disaster to adopt surgical measures of any kind for the relief of partial or complete obstruction due to the presence of adventitious growths on the teat lining that have appeared during the lactation period. When the milk can no longer be drawn off by hand it should be allowed to accumulate and produce the desirable results referred to above. The most careful use of sounds, grooved needles, quills, catgut, milking needles, etc., for dilating the canal can only give relief by causing lesions, and the almost invariable result is an acute attack of mammitis. Similar remarks apply to the use of even specially designed instruments by means of which warty granulations can be cut away. If the case be left to nature while the milk is still unaltered, the cow, though the quarter is lost, suffers little in health, whereas after the most careful surgical interference there is a certain risk of mammitis and possibly gangrene.
Obstruction by Calculus. — Lacteal calculi, composed of lime salts and casein, occasionally form in the milk-sinus and cause intermittent obstruction. They can be distinguished from granulation outgrowths by their extensive freedom of movement under palpation. If small, it may be possible to evacuate the calculus by manipulation, while larger ones may be capable of being broken down by pressure exerted on them through the teat and removed with the milk without causing material injury to the mucous membrane. If this is not prac ticable, extraction by incision is the only resort.
Inflammation of the Skin of the Udder in the Region of the Groin.A scalded condition of the skin of the udder in this region is more common than is generally supposed, and calls for remark. The udder integument is thinner and more delicate here than elsewhere, especially in cows, amply protected as it is from injury by the great width of the thighs. The cases of dermatitis in this location which we have seen have been almost confined to animals recently calved, whose mammee were so large as to compel a straddling pose and gait in order to avoid painful compression of the organ between the thighs. Mild cases often escape notice entirely, and, owing to failure on the part of owners to examine the groins of cows whose immense udders impinge on the inner aspect of the thighs over a large area, it often hap ens that in one or both groins the entire surfac of contact has become acutely inflamed and we ing, emitting a putrid odour and presenting in the deep cleft between the organ and the leg the appearance of a huge traumatism.
Causes. The chief"predisposing"factor is the highly-congested and enlarged state of the udder at the period of parturition, while the intimate contact of the thighs prevents lateral expansion of the organ and totally inhibits ventilation of air. Moreover, in some recently calved cows the cedema that accompanies the hyperaemic condition of the gland at this period is such that when the leg is abducted the impress of the thigh is seen to be deeply marked on its broadSide."Exciting"factors comprise erup tions on the skin of the udder, soiling of the parts with genital discharges, mud, or grit, and excessive exercise causing undue chafing of the opposed surfaces.
Symptoms. The animal is disinclined to move and walks with a straddling gait. At rest she stands with hind feet as wide apart as possible, and, failing to rid herself of discomfort when standing, she is often recumbent. But the state of the groin is seldom recognized until betrayed by the odour and presence of blood-coloured discharge on the udder and thigh beyond their border of contact.
Treatment. (a) Preventive. Cows about to calve or newly-calved should have limited exercise only. To prevent groin mischief and other more serious results they should be taken to and from marts in suitable cattle-floats. The groin of every straddling cow should he care fully and repeatedly examined, especially after traversing muddy roads, and the region should be washed with soap and water, dried, and dressed with an emollient. The tail and hind parts of the cow should be disinfected daily.
(b) Curative. Keep the cow in the stall on a well-bedded floor. Empty the udder four or five times a day, to reduce if possible the con tact of the abraded surfaces. Bathe and cleanse the parts twice a day with warm water con taining a little bicarbonate of soda, dry with a soft clean cloth, and apply oxide of zinc ointment or lead liniment, or dust the parts well with either boric acid and starch (1 in 6), or oxide of zinc and starch in similar proportions. If called for, the surfaces may occasionally he dressed with a weak astringent solution of alum, zinc sulphate, or acetate of lead.
Inflammation of the Mamma The inflammatory diseases of the udder— technically known as mammitis or mastitis— are more commonly referred to as garget, udder clap, weed, or downfall of the udder. All cases of mammitis can readily be classified as acute, subacute, or chronic in type according to the intensity of the morbid changes in the affected gland and the degree of systemic disturbance that is present. But other classifications are permissible though more or less 'open to criti cism. These are chiefly based on the mode of infection, the character of the causal organisms, or the morbid anatomy of the affected gland. In all its forms the disease is essentially con tagious, and is specifically dependent on the presence in the mammee of pathogenic bacteria which have gained an entrance by the teat canal, or through lesions of the integument, or have arrived in a centrifugal way from pre-existing centres of disease within the body of the animal. The responsible organisms vary in virulence and produce a type of disease in keeping with their pathogenic properties. But the suscepti bility of the animal is also an important factor, and this is accentuated when influences that undermine the power of the tissues to resist attack have been in operation. In like manner the infectivity of the disease is dependent on the same causes, and is most pronounced when the attack is acute in type and associated with high fever. Infection is carried mainly by the hands of milkers, the danger of atmospheric dispersion being remote. Although mammitis received the attention of writers as far back as the early part of last century and was recog nized as a serious disease of milch stock, it received no consideration from the bacterio logical standpoint until 1875, when Dieckerhoff, in the Veterinary Journal, described an attack of septic mammitis, which he concluded was caused by a septic ferment. Two years later Zurn considered the disease contagious and not due to generally accepted causes, and at the same time Franck, of Munich, held the view that udder inflammation was chiefly caused by putrid matter, and he demonstrated the truth of his conclusions by injecting the morbid secretion of an affected udder into the teat of a sound gland. thereby setting up mammitis in twenty-four hours. His theory received much support soon afterwards from Nocard, Mollereau, Kitt, Bang, and many other continental bac teriologists, who found special organisms in the contents of the diseased organs, which they cultivated artificially, and by injecting the cultures into healthy glands induced mammitis similar in type to the original cases. It is doubt less true that, long before the light of bacterio logical investigation was shed on the etiology of the disease, outbreaks were experienced in many countries, and they must have proved puzzling to observers of limited outlook, who habitually attributed the occurrence of udder troubles solely to what are now known to be contribu tory or predisposing causes, e.g. chills, exposure to cold and draughts, errors in diet, faulty con struction or ventilation of the cow-shed, ineffi cient milking, etc. Moreover, such outbreaks as did occur would in all likelihood attain a wider spread through lack of appreciation on the part of attendants of the evil effects of unclean habits and the need for adopting proper sanitary measures of control. Since the begin ning of the twentieth century veterinarians and stock-owners alike have become increasingly alive to the nature and causes of the disease, as well as the means by which it is spread, but it must be admitted that this advance in know ledge of prophylactic measures has been accom panied by little if any improvement in curative treatment. And, though the contagious char acter of the disease finds general acceptance in outbreaks marked by acute inflammation and rapid spread, it is unfortunate that when the type of disease is subacute and cases succeed each other at comparatively long intervals the role of infection is liable to be contemned, and the resultant neglect of sanitary precautions enables the responsible organisms to find a lodgment in the teats of many members of the herd. Their presence can readily be demon strated in the first-drawn milk of the quarter. So long as the cow so infected maintains her general health and is not subjected to ulterior influences that impair the tenacity of her tissues, the organisms fail to set up mammitis, and any material increase in their number is checked when the quarter is milked morning and evening. Their opportunity only occurs when conditions arise that favour their growth and vitiate the re sistance of their host. In infected herds it is a common experience to find cows defective of a quarter at the beginning of a lactation period that were considered sound when put dry a few months before. The most probable ex planation of the change is that the organisms were present in the defective quarters when the animals were milked for the last time and put to grass, and that they grew unhampered in the milk secreted thereafter and altered its character. Then, through contact with the unhealthy secretion, the acini and lining of the milk-ducts would be prejudiced in the first place, and then directly attacked by the bacteria, causing a state of catarrh more or less destruc tive to the milk-secreting cells. The havoc produced depends on the virulence of the causal organisms; moreover, in some outbreaks of acute mammitis their pathogenicity is such that few cows, naturally exposed, escape infec tion, though their conditions of life are other wise ideal, and every affected quarter is lost completely so far as future secretion of milk is concerned. Without exception the responsible organisms find in milk, at body temperature, a suitable medium for their growth and develop ment, and they readily change the character of the milk. It is notorious that the produce of a herd in which cases of mammitis are occurring does not keep well, and if manufactured into butter or cheese these are of poor quality. This is not always the direct result of actual contamination of the produce with morbid secretion from an affected gland, which no dairyman would allow knowingly. The defect is more often dependent on the presence of bacteria in the unaltered milk, drawn from apparently healthy quarters, which have been lying in wait to set up catarrh when they found a suitable opportunity of lowered tissue-resist ance. Considering the increasing demand for wholesome and pure milk this knowledge brings into relief the great importance of infections of the udder from an economical and sanitary point of view, but many problems are still unsolved which can only be successfully tackled by specialists, who should be subsidized by rating authorities. Udder diseases are peculi arly the product of uncleanness and unclean habits in the cow-shed, and where the conditions of dairying are ideal the disease is almost non existent and the produce is usually unimpeach able. When we consider to what extent the udder is exposed, through its anatomical position, etc., to injuries and filth of various kinds replete with microbes, its comparative freedom from infection constitutes a high tribute to its de fensive powers. The potential sources of infec tion are numerous. Immediately after calving uterine discharges soil the thighs, tail, and udder, and, if the animal is not kept clean, infection may occur by the teat canal. (The recorded occurrence of abortion bacilli in the udder may in some cases be explained in this manner.) The members of a herd are constantly liable to infection when a case of mammitis exists in the byre, and the liability is increased in the absence of sanitary precautions and particularly if the morbid secretion of the diseased gland is drawn on to the floor. Soiling of the floor, whether it be from excreta, alvine discharges, morbid udder secretion, spilt milk that has become soured, or discharges from sore feet, always begets soiling of the udder with its attendant dangers. Cases have been directly traced to bedding which had been used for horses suffering from strangles, and an examination of the contents of the diseased glands revealed streptococci, no doubt conveyed by the straw. Other cases due to streptococci have occurred in cows housed under the same roof as horses suffering from strangles. People engaged in milking cows should refrain from dressing sup purating wounds of any kind, for it is not an easy matter to disinfect hands thoroughly that have been soiled with discharges containing virulent microbes.
Predisposing Causes.Functional activity of the udder is essentially a dominating factor, and acute cases are most commonly seen in cows recently calved, whose udders are highly con gested, swollen, and tense. At this stage also they are more liable to injuries from horn-gores, blows, kicks, and the careless use of implements in the cow-sheds than later on, when they are flexible and soft. Dry stock are only occasion ally the subjects of mammitis, and cases in virgin animals are extremely rare. We have already shown that eruptive diseases are most prevalent soon after parturition, and that they markedly predispose to mammitis. Other con tributing factors include extremes of tempera ture, sudden change of climate, inordinate exertion, exposure to cold and draughts, over stocking or hefting of the gland with secretion, improper milking, leaving teats wet with milk, dirty bedding, and insanitary conditions of the cow-shed.
Infective or Specific Causes.Various kinds of micro-organisms have proved effective in causing mammitis. They may be found acting together as a mixed infection, but it is usual to find some special type predominating in all acute cases. They reach the internal structure of the gland by one of three routes, viz.: (1) By the Teat Canal. This is by far the most common and important route. Reference has already been made to continental experi ments in which pure cultures of microbes recovered from diseased glands were injected into healthy udders and caused mammitis, and by merely painting the point of the teat with such a culture mammitis has been induced, thus proving the penetrating power of pathogenic bacteria. In everyday practice it is a common experience to find cows weeded of their udders through the agency of unclean teat instruments (special or improvised) that have been intro duced into the teat canal to overcome some defect that interfered with hand-milking. Kitt's experiment exemplifies the manner in which infection is commonly carried from diseased to healthy animals by the hands of milkers. The soiled hand leaves bacteria on the newly-milked healthy teat, which multiply on the milk-wet surface and find their way through the teat orifice. That bacteria are able to enter the udder by the teat canal finds further proof in the fact that the first-drawn milk from a large percentage of cows—taken with aseptic precau tions—has been shown to contain a variety of ordinary atmospheric organisms whose power to produce disease has not been established. A relaxed state of the teat sphincter favours bacterial invasion in a double sense, since it allows escape of milk in which the bacteria multiply and offers a lessened resistance to their entrance into the lumen of the teat.
(2) By the Skin. Infection of the udder often occurs through traumatic or eruptive lesions of the skin of the udder. The bacterial invasion is denoted by inflammation, radiating from the infected lesion, which gradually spreads along the lymphatics and subcutaneous tissue, and if unchecked the deeper structures of the gland become involved.
(3) Vascular Infection. Infection by the blood or lymph-stream is very rare in the case of organisms other than the bacillus of tuber culosis. The chief venue of tubercular infec tion of the udder is by the lymphatics, and we have met with non-tubercular cases associated with septic conditions of the uterus and joints which we suspected to be metastatic in origin.
Causal Organisms.Though the number of organisms proved to be culpable in setting up mammitis is small, it is likely to be added to considerably when further research and inves tigation are carried out. On the other hand, it is probable that identity may yet be found in several of the causal organisms that are, at present, thought to be, or are tabulated as, distinct. Those already known belong to different groups and include micrococci of various kinds, some bacilli, and the Strcpto thrix bovis. The following have been indicted, viz.: (a) The streptococcus of Nocard and Moller eau, which is deemed to be identical to the Streptococcus agalactice of Kitt, the Strepto coccus mastiditis contagiosce of Guillebeau, and that of Hess and Borgeaud.
(b) The Streptococcus conglomeratus of P. Dubois.
(c) The small micrococcus of Rivolta—the cause of gangrenous mammitis of ewes and goats.
(d) A diplococcus— thc cause of purulent mammitis in the same animals.
(e) The Staphylococcus mastiditis of Guille beau and Lucet.
(f) The Galactococcus versicolor.
(g) The Galactococcus albus.
(h) The Bacillus tuberculosis.
(i) The Bacillus Was (j) The Staphylococcus pyogenes (k) The Bacillus mastitidis contagiosce of Carre. (1) The Bacillus enteritidis sporogenes (Klein).
(m) The Bacillus coli.
(n) Guillebeau's bacillus, which is regarded as belonging to the coli group.
(o) The Bacillus pyogenes (Poels, Holth, Eggink).
Dr. Savage's investigation of 36 cases of different types of mammitis occurring in various places found streptococci responsible for 68 per cent, and a further 10 per cent were probably streptococcal, 10 per cent were due to staphy lococci, and 3 per cent each to the Bacillus coli and the Bacillus tuberculosis. The records, in the bacteriological laboratory of the County of Lanark, of the results of the microscopical examination of milk samples taken, under"The Dairies, Cow-sheds, and Milk-shops Order,"from indurated udders suspected to be tubercular but which proved negative, show that strepto cocci were present in 75 per cent and staphylo cocci in 25 per cent of the samples that contained organisms other than the Bacillus tuberculosis. None of these samples were taken from quarters acutely inflamed.
The ray fungus or actinomyccs, which belongs to the class Streptothricae, is occasionally the cause of udder disease (actinomycotic mammitis).
It is said to have been proved that contagious agalactia of sheep and goats is due to an invisible virus, although various visible organisms have been found in the lesions. Further research is necessary to prove to what extent, if any, bovine mammitis may depend on ultra-visible microbes. It is not unlikely that they play an important role, and it may yet be shown that some of the visible microbes that are considered independent causes to-day are but secondary infections that can only operate successfully in the environment of an invisible factor. Acci dental parasitism of the udder — apart from actinomycotic invasion —is not unknown. A remarkable case, recorded by Moussu, is trans lated in vol. xxiii. p. 212 of the Veterinary Record. A six-year-old Dutch cow, four months calved, had been grazing for a time on humid, marshy pastures. Though showing no marked signs of mammitis her milk was yellowish, thick, and curdled, and contained blood-coloured streaks and clots, much the same as in a case of catarrhal mammitis. When examined, actively motile parasites were found in the clots. These were reddish in colour, vermicular, cylindrical, and non-tapering, and from -A of an inch to of an inch in length. They were proved to be the larvm of insects (Chironomus). The cow's teat sphincters were unduly relaxed, and it is thought the exuding milk attracted the larvm when the cow was recumbent on the marshy land, and that they found an easy entrance through the wide teat orifices, carrying with them microbial germs.
Classification of Mammitis.The disease has been subjected to various classifications, all more or less useful but mostly open to criticism. An etiological classification, embracing the terms streptococcal, staphylococcal, diplococcal, bacil lary, tubercular and actinomycotic mastitis, will not be satisfactory until the bacteriology of mammitis is better understood. In the light of further research it is not unlikely that we may be able to distinguish with some accuracy the specific effects of the different organisms that most commonly cause mammitis in all animals. When that time arrives, and it has become practicable to apply specific sera and vaccines for the prevention and cure of the disease, an etiological classification will doubt less prevail. We have already much knowledge in this connection as to some subacute and chronic infections, but there is much room for investigation in regard to acute forms of the disease. Some observers differentiate cases according to their pathological anatomy, adopt ing the following terms: (a) Catarrhal mammitis, in which the lining of the milk-sinus and ducts is chiefly the seat of disease.
(b) Parenchymatous mammitis, when the essential milk-secreting tissue or parenchyma of the gland is affected, and (c) Interstitial, phlegmonous, or lymphogen ous mammitis, wherein the infective process begins at a lesion of the skin and involves the subcutaneous lymphatics, the perimammary subcutaneous tissue, and later the interstitial tissue that forms the septa or partitions between the lobes of the gland.
Tn certain mild infections by the teat canal the disease does not advance beyond the catarrhal stage before recovery takes place, and similar remarks apply to benign forms of infec tion beginning at the integument. To such the terms catarrhal mammitis and interstitial mam mitis truly apply, but classification based on pathological anatomy is only possible at the earliest stage of the disease, for in all acute cases infection proceeds within a short time into all the tissues of the gland, when the whole of the terms are applicable. The chief fault of this classification, therefore, lies in its early failure. Other designations which explain their own application are occasionally used, e.g. metastatic, suppurative, and gangrenous or sloughing mammitis. But the disease in the cow can be studied most comprehensively and easily when cases are differentiated according to the virulence of the pathogenic process and the clinical symptoms, when they readily fall under the following heads, viz.: subacute, acute, and chronic mammitis.
Subacute Mammitis.Cases of mammitis may be considered subacute when the inflammatory process is mild and shows tendency to early resolution. It is seen at all stages of lactation, and is due to causal organisms whose power of attack is not greatly pronounced, being to a great extent dependent for success on the operation of a marked contributory cause. The infection may begin at the skin, but usually it occurs by the teat canal, where it may have been held in abeyance for many weeks until tissue resistance has been reduced by some pre judicial factor. The bacteria then gain the mastery, alter the character of the milk, and set up a catarrhal condition of the milk-ducts and, it may be, some degree of inflammation of the secreting cells.
Morbid Structural Changes. When infection begins at the skin there is exudation into the subcutaneous cell-tissue and lymphatics, and this may penetrate some distance into the interlobular connective tissue of the gland. With infection by the teat the lesions are at first confined to the sinus and milk channels. Their lining membrane is first congested and then thickened by exudation into the sub mucous coat, the result of the irritant action of the bacteria and their products. Epithelial cells are abundantly shed into the lumen of the ducts and are held up in the clots of abnormal secretion, and occasionally there is extrusion of granulation tissue which gives immediate and future trouble in the process of milking. In better-developed cases the parenchyma of the gland is more or less involved.
Symptoms. Constitutional disturbance is not well marked. Appetite and rumination are little altered, the temperature is only slightly raised, and the activity of the udder is not much impaired. Locally, in cases beginning at the surface of the organ, there is redness of the integument and a radiating oedema, but the milk is unaltered and early treatment is followed by complete recovery in a short time. In sub acute catarrhal mammitis the local manifesta tions are, at first, slight tumefaction of the teat and the glandular tissue at its base, with more or less marked tenderness in manipulation. The secretion may be unchanged in colour, but small clots are observable when it is examined in thin film. Later on these changes are better developed, the secretion loses its whiteness and consists of yellowish serum and clots of casein containing cells shed from the mucous coat of the ducts. Pain and swelling are increased, but under suitable treatment the attack soon recedes and the milk gradually becomes normal in appearance. It should not, however, be put into use for some time thereafter, as it would influence the keeping quality of the produce of the dairy. The future milk-secreting capacity of the affected quarter is lessened according as the secreting cells have been destroyed by the attack. In some cases when the cow calves again the evident loss of function shows some improvement if the defective quarter be milked first for a time, but the rule is to find the atrophy and lessened activity as persistent and per manent features that become more and more pronounced as the lactation period advances.
Acute Mammitis.Acute forms of udder disease are more frequently met with during the first month after parturition in all animals, especially in primiparm, than at any other time. Indeed, as already explained, the process is in immediate relation to the function of lactation, the virulence of the bacterial attack being at all times enhanced by the susceptibility of the animal, during the parturient period, to suffer shock from influences to which she is more resistant later on. According to the venue of origin of the infection, the attack in its initial stage involves only the milk-ducts (catarrhal mammitis) or the subcutaneous lymphatics and septa of the quarter (interstitial mam mitis), but the implication of the whole quarter is soon accomplished when the point of attack cannot be clearly determined. In infection via the teat—the more common entrance—the in cubation period is short, from twenty-four to forty-eight hours. The milk of the previous evening may have shown no change, yet the following morning the product of the painful quarter is radically altered in character, the result of bacterial activity. Through contact with diseased secretion the mucous membrane of the ducts is vitiated, and the bacteria are able to force their way through to the deeper structures, which become involved, to the con fines of the affected quarter or even beyond this to a neighbouring quarter if the envelope of the gland be not intact. Conversely, when acute infection begins at the skin the quarter may be much swollen and painful for a brief period, during which the milk is scarcely altered, but by active penetration of the bacteria the acini and ducts are soon included in the inflamed area and the product of the quarter becomes as diseased as if infection had come by the teat canal.
Morbid Structural Changes. As the disease is practically never fatal in its first stages, pathologists have had little opportunity to examine and describe the early morbid anatomy of mammitis, naturally acquired. The naked eye appearance of the cut surface necessarily varies according to the point of origin of the infection. Following teat infection it is evident that there is a gradually extending sclerosis or thickening of the lining of the teat, the sinus, and milk ducts, and congestion of the surrounding tissues. Later, there is infiltration of the deep structures with inflammatory exudate and tumefaction of the teat, and the appearance of the cut surface of the gland indicates that the interstitial tissue is the chief seat of inflammation. It is yellowish in colour and punctuated by small areas of extravasated blood. Owing to the pressure of the exuded material the acini and blood-vessels are more or less compressed, causing grave vascular disturbance which often amounts to blood stasis causing patches of gangrene that gradually increase in size. When this has occurred the structure is dark - coloured and evil-smelling, and when cut into, a noisome, dark, septic fluid escapes which is tinged with secre tion. Gangrene may be diffuse or circum scribed, and in the later stages the line of demarcation between the living and dead portions of the gland is very evident. When vascular changes occur more slowly the inter lobular connective tissue becomes greatly thickened and fibrous, giving the surface a marbled appearance, purulent foci appear here and there, and these gradually enlarge and coalesce to form considerable abscesses, which may point externally or into the milk-sinus. We have occasionally seen the whole interior of the quarter transformed into a huge pus cavity. The microscopical appearances of the diseased tissues in all stages admit of lengthy description, but are only of interest to the pathologist.
Symptoms. The constitutional symptoms of acute mammitis appear with startling sudden ness and severity. It often happens that a violent shivering fit first draws the owner's attention to the fact that a deep-milking cow has been seized with mammitis. The animal , stands with hair on end, straddling and restless, with a full, frequent pulse and temperature as high as 106° or 107° F. Respiration is short and quick, the countenance is dull and anxious looking, appetite and rumination are suspended, and it is only occasionally that she will take a little fluid. Not uncommonly there is slight tympanites and irregularity of the bowels. The body surface is alternately hot and cold, and though she becomes leg-weary she finds no rest when recumbent owing to the painful state of her udder.
The local signs in cases beginning with catarrh are early tumefaction of the base of the teat and congestion and enlargement of the quarter. The whole surface of the quarter is red and soon becomes reddish-purple in colour, turgid and tense, and so painful that the animal frets at the slightest interference. In many cases only a little yellowish serosity can be drawn from the teat, and this contains many bacteria. At subsequent strippings small flocculi of casein appear in the secretion, which gradually becomes altered in colour and consistence from the presence of blood elements, epithelial and pus cells, and the material has a repulsive appearance and odour. Though, under treatment, the con stitutional symptoms abate to some extent in a day or two, the diseased process in the quarter advances through different stages. If the teat is not unduly tumefied, an increasing quantity of morbid secretion is available, and its appear ance becomes more and more pus-like. But if the teat be defective from extreme tumefaction or other cause, so that little or nothing can be drawn from the quarter, the suffering of the animal is intense and gangrene may supervene. This is first evidenced by coldness, stiffening and change of colour in the teat and integument of the quarter around the base of the teat, which gradually assume a purple or greenish black hue and the skin peels off when handled. If not quite obstructed, the teat yields a few streams of blackish fluid of putrefactive odour. If the gangrene be clearly circumscribed, septic intoxication may not occur, and the part be comes demarcated and eventually is cast off by the healthy tissue, leaving an irregular, angry - looking cavity which soon heals up. Occasionally it happens that the larger nutrient vessels of the mortified zone are not completely involved and protrude as bleeding stumps from the raw surface, and if not ligatured and removed they are rapidly ensheathed in a thick coating of sensitive and vascular granulation tissue, impeding the closure of the wound. But when mortification is diffuse and penetrating the con dition of the animal is exceedingly grave and death becomes imminent. The septic state of the blood is accompanied by marked pros tration, the internal and surface temperatures become subnormal, the pulse almost imper ceptible, respiration short and frequent, and the enfeebled animal soon goes off her feet and a quiet death ensues. Abscess formation is, how ever, a much more common sequel to acute mammitis, and, though it is responsible for disas trous local results, the dissipation of systemic disturbance is accompanied by an increasing restoration of function in the healthy quarters of the udder. After some time or at a subse quent lactation it is not unusual to have com pensatory hypertrophy and increased functional activity in the quarters that remain. But, in certain cases, the disease invades a second or third quarter either by extension or teat infection, the period of illness is much prolonged, and the cow becomes a wreck. When a cow survives an acute attack the affected quarter continues for a time to yield a quantity of purulent material, but later on it dries up and becomes atrophied. In rare cases, occurring towards the end of lactation in pregnant animals, the diseased process recedes in activity and becomes latent when the cow goes"dry,"but when function is restored again at calving time the unexhausted infection is reactivated, the animal sickens anew, and her utility is seriously discounted. Such cases are fruitful of disputes between buyers and sellers of dairy-stock. In acute mastitis originating through infection at the skin, though the constitutional symptoms are as alarming as those described above, the local changes are different in the early stages. The perimammary tissue of one or two quarters becomes markedly infiltrated with exudate, causing a painful oedematous swelling that pits on pressure, and the skin is reddish and tense.
The swelling may extend anteriorly and pos teriorly beyond the limits of the udder. At first, and for a shorter period than in subacute forms of the disease, the secretion is little changed, but the infection soon penetrates to the lobular tissue and the product of the quarter is radically altered. Superficial abscesses may form, and patches of the integument occasion ally lose vascularity, die, and are cast off. Deep-seated abscesses, which are at first diffi cult to detect, may also form and cause much destruction of the mammary tissue. Under proper treatment it is sometimes possible to abort an acute superficial infection.
Complications. Digestive disturbances are usually apparent at first, tympany may be evident, and the bowels constipated. Of local complications gangrene is the most serious and abscess formation the most common. The induration of tissue that is always present during and after the attack gives place to a more or less complete wasting of the gland, but knots of hardened tissue usually persist. Secondary arthritis (inflammation of joints) is not unusual, and in our experience this occurs at a time when the acuteness of an attack due to streptococci or Bacillus pyogenes has passed off and an almost chronic state of suppuration exists in the gland. The joints most often affected are the hocks and the fore and hind fetlocks, in the order named. Usually the first sign is a slightly painful swelling on the flat of one or both hocks, often a little more pronounced in one than the other, which makes the cow less willing and less able to rise. The swelling increases and the capsule of the joint becomes distended, the hollow of the joint being bogged with a tense, globular, and painful swelling. This makes the animal ill at ease when on her feet and relief is sought in the recumbent position. The difficulty in rising occasioned by prolonged flexion of the painful joints is such that animals so affected have often been treated blindly for paralysis, and ineffectual attempts to get up often beget bruising of the brisket against the feeding-trough, and the resulting swelling has been mistaken for that seen in advanced cases of traumatic pericarditis. When the fore and hind fetlocks are also in volved the animal is so sorely crippled that she can only stand in a fidgeting manner for a few minutes at a time, and, owing to her pymmic state and constant lying, bed-sores result which are sometimes the seat of extensive suppuration. Fortunately the pain in the joints is not diffi cult to relieve if treated early.
Chronic Mammitis.Under this head we include those forms of the disease characterized by the minimum of constitutional disturbance and some degree of slow persistent induration, or by the gradual formation of abscesses in different parts of the quarter. In many cases it is the relict of an acute attack.
Structural Changes. The indurated quarter is fibrous and hard to cut and the exposed surface is yellowish in colour and coarsely nodular in appearance. The interlobular tissue is greatly thickened, the acini are crushed and wasted, and here and there small foci of suppura tion are seen hemmed in by hardened walls of fibrous tissue. It would seem that the respon sible streptococci were not sufficiently aggressive to set up extensive suppuration and that tissue resistance prevailed, as evidenced by the forma tion of a dense sclerotic wall around each centre.
Symptoms. Little or no constitutional dis turbance accompanies chronic mammitis. When it is not the result of an attack of acute mam mitis, in which case there is a fairly uniform and hardened state of the whole or a large part of the quarter, the first sign of infection is the appearance of one or several nodules in the udder tissue near to the base of the teat. They gradually increase in size and number, with no great tendency to become confluent, and the quarter at this stage feels like a bag of small tumours. The secretion is reduced in quantity, though at first apparently normal in quality. It does not keep well and it soon changes in colour, contains small clots, and is unfit for use. Under certain conditions, favourable to the reproduction of the causal organisms and the activity of their life-products, the inflammation becomes more acute, induration proceeds more quickly, accompanied by increase of pain and a variable degree of constitutional disturbance. Abscesses form slowly and burst externally or into the milk-sinus and ducts, when almost pure pus is got by stripping the teat. In other cases the indurated parts remain hard until the cow goes"dry,"when resolution and atrophy occur, and the future milk-yield of the affected quarter depends on the extent of destruction of the acini which has taken place.
Treatment of Mammitis. (a) Prophylactic. During the last decade practitioners and owners have become increasingly alive to the great and primary value of preventive measures against a disease so insidious in its spread and unresponsive to remedial treatment. Scrupulous cleanliness is the sum of these measures, and when this is given effect to, the beneficial result is not limited to the pre vention of udder disease but ensures the accom plishment of a pure and first - quality milk supply. Whatever the causative agent may be, the prophylactic, and to a great extent the curative, measures remain the same. General measures include proper housing, thorough dis infection of the cow-shed two or three times a year, and removal of defects in the floors, etc., of stalls. Attendants should wear clean over alls when milking, their hands should be washed clean before, and at repeated intervals during, milking, and the finger-nails kept short. The teats and under surface of the udders should be swabbed with a cloth wet with antiseptic solution, and then dried with a clean cloth before milking. If the udder, tail, and hind parts of the cow he soiled, actual washing and disinfection are essential. The little trouble that this entails ensures the minimum of contamina tion of the milk from falling debris, and the teats are rendered more pliable. After milking, the teats and udder should be dried with a cloth. Milkers should not be allowed to dress suppurating sores of any kind if direct carriage of dangerous organisms to the teats is to be avoided. If milk be unavoidably spilt on the floor it should be cleaned up at once. Cows newly bought should be housed separately until the absence of udder disease is proved. The purchase of newly-calved or due-to-calve cows defective of a quarter is to be avoided unless the quarter is completely atrophied and dry or its secretion is guaranteed fit for use. When the disease has appeared special measures are called for. Affected cows should be isolated and have a special attendant who understands the value of antiseptic precautions. He should milk the affected quarter last, using a special pail containing some antiseptic, and the material should be burned or buried. The produce of the apparently healthy quarters of each cow should be kept separate and tested as to quality and, if necessary, it should be sterilized or actually boiled and fed to pigs. If facilities for isolation are awanting and the infection is extremely virulent, as revealed by the nature of the first case or two, and especially if attendants are unreliable, slaughter of the affected cows is worthy of consideration as a measure calculated to abort the outbreak. All ordinary sanitary measures should be redoubled when disease exists or has existed, there should be complete local and general disinfection, and repair of broken parts of the floor should be carried out. We have already indicated the dangers that attach to the use of soiled milk - tubes and other teat instruments, and referred to the precautions necessary. In this connection negligence in the care and use of instruments employed in inflating the udders of cows suffering from milk-fever has not uncommonly been the cause of mammitis. This is quite avoidable if the instruments are properly sterilized before and after use. A careful examination of the quarters is also needed to detect any evidence of existing catarrh. If this be neglected and the product of one quarter is soured, infection is sure to be carried to the quarters inflated sub sequent to the affected one. When cases of mammitis have occurred in a herd we may presume that the udders of some other members of it contain latent infection, and the need for efficient and complete milking is imperative. Overstocking is a potent factor in setting up disease in udders that are harbouring bacteria.
(b) Curative. Acute mammitis is singularly intractable to curative treatment, though much may be done to lessen constitutional disturbance and modify the course of the disease in its different stages. Subacute cases are more amenable to remedial measures. The force of the attack indicates the extent to which internal remedies are called for. The first essential is to isolate the patient and have her housed and clothed comfortably. Bleeding is only per missible in plethoric animals when fever runs high, and, if practised, the blood should be taken from the jugular and not the mammary vein because of the risk of infection to a wound that would have contact with the floor. The shivering fit is to be controlled by the adminis tration of half a pint of whisky in water, and purgation should be induced by giving a pound of Epsom salt, which has a salutary effect on the activity of the disease and lowers the function of the udder. For less robust animals it is sufficient to give repeated smaller doses in gruel or drinking-water. Potassium nitrate in 2-drachm doses may be given in the same way twice daily, and if an internal antiseptic is called for, there is none better than formalin in 1-drachm doses well diluted with water. If the temperature remains high, recourse may be had to antifebrin or acetyl-salicylic acid in 2 to 3-drachm doses placed on the back of the tongue with a dry metal spoon and washed over with a little water. The latter drug is called for when arthritis complications appear. The diet should be sparing and easily digested: bran mash, light gruel, roots, and hay. Richer feeding-stuffs, though preferred by the patient, increase lactation and put an unnecessary strain on the quarter affected.
Locally. Pain is relieved by continued hot antiseptic fomentations and gentle massage, to be followed by rubbing in some mildly stimulat ing, antiseptic, or anodyne liniment or ointment and stripping of the teat. Poultices of linseed, bran, marsh-mallows, or hops are held in high repute in some districts, but they may be super seded with advantage by cataplasms of kaolin and glycerine, whose antiphlogistic effect is un doubted. The tin containing the material is put into a hot-water bath, and when it reaches blood-heat it is thickly spread on the inflamed quarter and covered with a layer of cotton-wool, gamgee tissue, or a piece of flannel. It may be renewed every twelve hours, and should be held in position by means of a many-tailed suspensory bandage fastened over the animal's back, and provided with an aperture that leaves the teat bare, so that it can be stripped every two hours without interfering with the dressing. The support of the bandage gives additional comfort to the animal. Local applications that find favour in the early stages comprise mustard and water, and liniments or ointments contain ing belladonna, opium, camphor, spirit, etc., the basis of which may be vaseline, lard, lanolin, glycerine, white of eggs, soap liniment, soft soap, or embrocation, etc. Their use not only pre vents loss of heat but facilitates massage, which should be gentle or firm according to the tender ness of the quarter. Care is essential to avoid injury to the teat and skin of the udder by the use of fomentations or poultices that are too hot or dressings that are too irritating. The use of teat-syphons is to be condemned.
When pain subsides, resolution is assisted by the application of iodine ointment, painting the part repeatedly with tincture of iodine or rub bing in a little red iodide of mercury ointment, the teat being first smeared with pure vaseline, lanolin, or lard. Every effort must be made to maintain a healthy effective teat that can with stand the necessary forcible stripping. If its utility be lost and suppurative discharge accumulates in the quarter the teat may be amputated at the root, a local anaesthetic being used. This 'gives immediate and perfect drainage, which may be assisted by exercising the cow, massaging the udder, and forcibly injecting the cavity with tepid antiseptic solutions. Where abscess formation is evident, fomentations or poultices may be used with advantage, and when fluctuation can be detected the abscess should be opened with much caution, because of the tendency to excessive bleeding when too free incisions are made into an organ so vascular and pendulous. To lessen the danger of haemorrhage, many practitioners prefer to open mammary abscesses with a hot-pointed firing-iron. When gangrene occurs and is limited or well circumscribed, with no marked evidence of intoxication, we may wait the spontaneous elimination of the part, assisting the process by means of fomentations containing permanganate of potash. But if it shows a tendency to become diffuse the patient should be cast and the dead tissue removed by opera tion before septic intoxication has set in. Joint complications should be dealt with heroically, and the early application of blistering ointment, well rubbed in, affords speedy relief from the pain that keeps the cow abed. Milder applica tions are too slowly effective, and in heavy, lymphatic, and recently-calved cows disaster quickly follows continued lying and ineffectual attempts to get up. When hocks are dealt with they must be clothed to prevent blistering of the teats, while blistered fetlocks should be covered and smeared with aloes solution or manure to prevent licking of the parts. The risk of strangulation when the cow makes awkward attempts to rise is minimized by having a string link put in iron binding-chains and filling the dung-channel to the floor-level by placing in it an inverted wooden rone fashioned to the capacity of the gutter.
Treatment by Intramammary Injection of Antiseptic Solutions. —Bigoteau in 1905 pub lished the results of systematic treatment of mastitis with injections of boric acid solution, and this plan has been extensively adopted since then in France and elsewhere, a 4 per cent solution being used. He declared that the treatment can only be successful when the diseased quarter has been completely emptied of secretion before the injection is made, and he believed that all forms of the disease in the cow are equally amenable to treatment if his directions are carefully carried out. The solu tion is injected at body temperature, the quarter being comfortably filled and gently massaged during the process, and the operation may be repeated at intervals of two to four days. In our experience the greatest difficulty to be encountered is the perfect emptying of the diseased quarter before injecting, especially in virulent forms of the disease occurring at the height of lactation and characterized by tume faction of the teat and great pain, so that the dislodgement of clotted material is impossible and only a little liquid secretion can be obtained. Under such conditions no good results follow the use of boric injections, but we have often been satisfied with their efficacy when the state of the parts permitted proper emptying of the gland. For virulent mastitis, Schmidt, of Kold ing, Denmark, the famous originator of the udder treatment of milk-fever, recommends the infusion into the quarter of 4 ounces each of alcohol and glycerine, and if the affection is not too severe he adds to this 3 ounces of normal salt solution. The affected quarter is not milked out during three days after the infusion. If two or three quarters are affected, only one is to be dealt with at a time, and it is said that substantial improvement is apparent in four days and the animal's life is preserved, though milk-production is not always restored.
Treatment by Serum and Vaccines. The rational consideration of the problem of dealing with mammitis by means of serum or vaccine, or both, suggests the initial use of a hyper immune animal's serum in all cases characterized by marked illness and high fever. These symptoms betoken a high degree of reaction in the animal's economy to the toxic products absorbed from the seat of disease, and the use of a vaccine at this stage would render the reaction more profound and perhaps insupport able. In the more chronic forms of the disease the use of vaccine is indicated. But the results of such attempts as have been made with vaccine have not been very encouraging. The ana tomical conditions are, to some extent, opposed to the success of vaccine therapy. The infecting organisms, especially in the early stages of cases set up by way of the teat canal, are chiefly located outside of the mammary tissue though within the lumen of the ducts and acini, where they multiply and produce their toxic products. In that position they are but little amenable to the influence of body fluids fortified by vaccine treatment. Good results cannot be expected from the use of ordinary stock vaccines of dead organisms whose identity with the causal microbes of the particular cases to be treated has not been proved. The time is ripe for the preparation of an antimammitis serum for use in acute cases, a serum obtained by hyper immunizing with several strains of the organisms found in actual cases of the disease, so that the antiserum may be polyvalent; also for the preparation of mixed vaccines derived, for preference, from a variety of strains, for use in the more chronic forms of the disease. Their application should be accompanied by the use of a solution of citrate of soda or of common salt injected at body temperature into the affected gland, and the administration of citric acid in 1-ounce doses, a sufficiency of common salt being allowed in the food or drinking-water. These means are calculated to increase the flow of serum from the diseased gland. It has been suggested to us, and it would seem feasible, to attempt early treatment of cases unaccompanied by much fever by making use of the culture procurable from the diseased gland. Such an experiment might be made by straining the secretion drawn from the teat, sterilizing the filtrate by heat at 60° C. for twenty or thirty minutes, or by the addition of an antiseptic such as 0.5 per cent solution of tri-cresol or microbene, and vaccinating the animal with a suitable dose of the prepared material. Ex periments are also indicated, in cases showing the minimum of systemic disturbance, to try the effect of the oral administration of the product of the diseased gland as soon as it is drawn off, the dose being regulated by the effect produced.
Mammitis in Mares.The mare is rarely affected with mammitis, and this is not surpris ing when we consider that her udder is not subject to many of the influences that beget the disease in the cow. The equine udder is also more favourably situated to escape contamina tion from the ground, and it is comparatively little exposed to infection from human hands, though it cannot be considered more resistant to the attack of disease-producing germs. The disease may be seen prior to parturition, but it usually occurs during lactation, and cases have been met with in animals whose foals were weaned early while the udder was still active.
It has also been observed in virgin mares. Almost without exception investigated cases have been due to streptococci, and acute forms of the disease usually end in abscess formation. Diseased conditions existing in the foal are usually responsible, e.g. strangles, suppurating sores on the head, etc., and abnormal states of the interior of the mouth. Bermbach saw two cases in the mothers of foals affected with strangles, and Lucet, Schutz, and Parent found streptococci in the secretion taken from cases of equine mammitis. J. F. Healy, of Middleton, in the Veterinary Record, January 24, 1903, reports having met with twenty-three cases in mares during the months of June, July, and August 1902 within a radius of ten miles.
Symptoms. The general symptoms include uneasiness, marked stiffness in the hind limb of the side affected during progression and when turning, and intolerance of the attention of the foal. The pulse is frequent, full, and strong, and the temperature may rise to 105° F., accom panied by rigors.
Locally. One or both sides of the organ are the seat of much swelling and pain, the integu ment being hot, tense, and shining, and the teat or teats tumefied and stiff. Accompanying edema often extends fore and aft to the abdomen and the perineal region. The secretion is changed in character and at first is often reddish black in colour and disagreeable in odour. Later, it becomes more pus-like. The pathological process usually ends in abscess formation and induration, but gangrene occasionally occurs. Though the formation of abscesses is the natural result of all acute streptococcal infections, there is, in some subacute cases of a catarrhal char acter, a slowly-developing induration and en largement of the affected gland, which is changed into a hardened, fibrous mass. This condition often becomes chronic, though by and by the dimensions of the gland decrease. This is also true of the bulky induration that invariably succeeds abscess formation. Occasionally we have seen the formation of abscesses so prolonged that the process assumed a botryomycotic char acter. If early treatment is adopted the pro gress of the disease can be much modified, but the function of the affected gland is always destroyed. When gangrene occurs death often follows, but in some cases the dead part is cast off and the mare recovers.
Prognosis is always unfavourable for the reasons mentioned above; the foal has to be fostered, and the mare is unlikely to succeed in rearing future offspring.
Prophylaxis. Heavy-milking mares are diffi cult to put dry at weaning-time. They should be physicked to lessen functional activity, or should be put into suitable constant work, and, if necessary, the udder should occasionally be unloaded by hand to prevent overstocking. The udder may be rubbed with vinegar or painted over with a solution of extract of belladonna.
Treatment. The patient must be comfortably housed and clothed, and should receive from 10 to 12 ounces of sulphate of soda or magnesia in solution, followed by febrifuges and diuretics such as antifebrin, salicylate of soda, or acetyl salicylic acid in 2-drachm doses, and small doses of potassium nitrate in the drinking - water. The local treatment required is essentially the same as for bovine mammitis. (See p. 1043.) Mammitis in the Bitch.Acute and chronic forms of the disease occur in bitches, and the former often give place to the latter. The mamum of the bitch are much subject to soiling through contact with the ground, and they often suffer from overstocking through wanton and early removal of undesired puppies when functional activity is at its height.
Symptoms. The usual signs of systemic dis turbance prevail. The animal lies on her side stretched out, is very sick and feverish, and refuses food. The affected glands are hot, painful, swollen, and oedematous, the secretion is altered and soon becomes purulent, multiple abscesses form and burst leaving ulcerating wounds or fistulae, and not infrequently pymic conditions supervene and the animal dies. A condition of chronic induration often succeeds acute mammitis in dogs, and a productive form of chronic mammitis causing enlargement and hardening of two or more glands occasionally results from neglect of conditions of functional activity that frequently recur in some non pregnant bitches.
The tumour-like condition of the indurated glands is in most cases innocent, but carcino matous transformation has been known to occur.
Prophylaxis. The floor of breeding-kennels should be kept in a clean, sanitary condition, and before and after parturition the mammw should be sponged over with an antiseptic solution and dried. If the puppies are not to be reared, they should be removed gradually so that the loss of function may be gradual. Scratches and sores on the mammae should receive proper antiseptic treatment.
Treatment. This comprises proper housing, the administration of a purge, warm antiseptic fomentations carried out by making the patient stand in a tub of warm water to which an anti septic has been added, and applying it by means of a sponge. Or cataplasms of kaolin and glycer ine may be used, kept in position by bandages. Stripping of the teats of affected glands must be practised, and the offspring should be removed and the healthy glands milked by hand. Massage with an anodyne ointment or liniment is useful when pain is less marked, the stripping of the teats being continued. When abscesses form they should be opened and treated antiseptically, and when indurated glands are unduly large and pendulous they may be extirpated by operation without fear of regrowth in most cases.
Mammitis in the Sow.Though occasionally seen, mammitis is rare in the sow, and is almost unknown in brood animals that are well housed and cared for. Sows are mostly affected shortly before or after farrowing. Cases occur when they are allowed to roam about on broken ground in cold weather. The mammae reach close to the ground, and are liable to suffer injury through contact with large stones, rough logs of wood, loose barbed-wire, and other obstacles. When brood sows are allowed out in frosty weather, with snow on the ground, the mamnace find contact with the frozen snow and become frost-bitten here and there, when sores result that often involve the teat. Infection of one or more glands readily follows. The pro gress of the disease and the measures necessary for treatment are in all respects the same as in the bitch.
Gangrenous Mammitis of Ewes.This disease has been recognized in many countries. It has been known in France for the greater part of a century, it occurs in Italy and Germany, in England it is known as"Black Udder,"and Gilruth has published his investigations regard ing the disease as it occurs in New Zealand in the Veterinary Journal, 1910, p. 648. All authors agree as to the infectious nature of the disease. The Cause of the disease was dis covered by Rivolta in 1875 to be a specific and minute micrococcus, which in 1887 was studied to greater extent by Nocard. The organism gains access to the glands through the teat or lesions of the skin.
Structural Changes. — The inflammatory exudate infiltrates the skin and subcutaneous tissue, causing extensive oedema. Soon there is evidence of gas formation in the tissues and gangrene. Only a little 'red fluid can be got from the teat, and the cut surface of the diseased gland resembles that of half-cooked meat.
Prognosis is always grave. If the affected gland is not extirpated before sepsis occurs the disease is almost sure to prove fatal.
Symptoms. The onset of the disease is sudden and its progress speedy, indicating the operation of highly aggressive bacteria or low resistance of the ovine manimm, or both. The local and general symptoms are therefore simultaneously evident. The affected ewes become segregated and move about painfully, refusing the atten tion of their lambs, and the temperature is much increased. Meanwhile, the affected gland— usually one only—is swollen and oedematous, hot and painful, and the secretion is reddish. Emphysema (gas formation in the tissues) and gangrene of the part soon follow, as indicated by the appearance of violet-coloured cold and insensitive patches on the skin, and the product of the gland is reddish-black and offensive. Septicaemia of an acute type is now evident, temperature is subnormal, the animal remains recumbent, suffers from rigors, grinds the teeth, and dies in two or three days. In rare cases the area of gangrene is limited and the part is cast off, leaving an indolent suppurating sore. In non-fatal cases the recovery is extremely protracted.
Prophylaxis. Affected ewes should be isolated and their surroundings disinfected. The whole flock should be dipped and put in new and sheltered pasture in charge of a new shepherd.
Treatment. Complete ablation of the affected gland is the only safe procedure, but in some cases free incisions may be made into the gland, the cuts being packed with crystals of per manganate of potash and cotton - wool, or swabbed with strong antiseptic solutions. Esser and Moussu have repeatedly amputated the dead part with success. Bridre has success fully practised immunization with an attenu ated culture of the micrococcus in bouillon. He also found that the blood serum of hyper immunized ewes possessed protective pro perties.
Mammitis in Goats.Two types of the disease are met with in goats: gangrenous and purulent.
(a) Gangrenous Mammitis.This disease is almost identical to that occurring in ewes, as proved by Nocard, Leclainche, Mathis, Leblanc, and Moussu.
(b) Purulent Mammitis is usually seen soon after parturition. It is said to be due to a diplococcus that has a tendency to form chains. The disease develops more slowly than the gangrenous type, though characterized by acute inflammation. The usual general and local symptoms that accompany the process of abscess formation are present. After the abscesses burst the resulting sores discharge for a time, and when this ceases a considerable degree of in duration remains.
Prophylaxis consists in isolation of the in fected and disinfection of the premises, and the dressing of the mamnam of all in-contact goats with antiseptic solutions.
Treatment. Pointing abscesses should be opened carefully and the purulent cavities suit ably treated with antiseptics.
Actinomyeosis of the Mammm.Mammitis due to the ray fungus (actinomyces) has been observed in the cow, the sow, and the mare. It is also said to have been seen in the human subject —the result of the extension of pulmonary actinomycosis through the chest - wall; and poultices have been blamed for some superficial cases of the disease. That the disease is com mon in the sow is evidenced by the fact that Rasmussen and Bang saw fifty-two cases in Copenhagen abattoirs in three months. The same authors and other continental observers have found the disease in the cow. Cases are also recorded by Williamson 1 and Henderson and Dr. J. H. Patterson, County Bacteriologist, Lanarkshire, examined about fifty udders of cows for suspected tubercle and found forms of actinomyces in five specimens, in one of which there existed a double infection, tubercle bacilli being also present. To the naked eye the tubercular nodules were indis tinguishable from those of actinomycotic origin. We believe that further investigation will show that the disease in the cow is more common than might be concluded from published records, and the author has suspected its existence in the udders of many live cows that he had no opportunity of examining after slaughter. In the milk samples taken from one or two such cases Patterson detected the elements of acti nomyces. The animal's bedding is probably the source of infection, the fungus gaining access to the udder by the teat.
Structural Appearances. The affected udder of the live animal has a shotty or nodular feeling when palpated that is not dissimilar to that of some rare cases of tubercular mammitis. The cut surface of the gland is yellowish-brown in appearance and shows numbers of cream-coloured foci from the size of a pea or smaller to that of a marble. The nodules protrude from the surface, and where softening has occurred the characteristic yellow particles are observable. Actinomycosis of the udder is important from the public health point of view, since the product of the affected gland may, and often does, contain the fungus.
Treatment. In the pig, extirpation of the affected glands is called for. The specific effect of iodine in actinomycosis indicates the internal administration of the drug, but cows suspected or known to be affected with udder actinomy cosis should be fattened for slaughter.
Tubercular Mammitis.Tuberculosis of the mammary gland in the human subject was first described by Sir A. Cooper in 1836, and Fiinf stuck in 1870 was the first observer to refer to bovine mammary tuberculosis. Since then the disease has been much investigated by many continental observers. No one has given the condition closer study than Sir John M`Fadyean, and we are indebted to him for his latest and most erudite dissertation on the subject in vol. xxx. of the Journal of Comparative Pathology and Therapeutics, which will be accepted as standard."Tuberculosis of the udder"was one of the forms of the disease included within the scope of the Tuberculosis Orders of 1913 and 1914 (presently under sus pension). Before then, some local authorities, acting under the provisions contained in Article 15 of the Dairies, Cow-sheds and Milk-shops Order, 1885 and 1899, carried out systematic veterinary inspection of dairy herds within their areas for the detection of cows suffering from this form of tuberculosis.
Routes of Infection. (a) By the Blood Stream. M`Fadyean has concluded, contrary to the expressed views of most authors, that infection by the blood stream cannot be the method of infection in ordinary cases for the following reasons, viz.: (1) The disease usually begins in one quarter and not in all four quarters.
(2) In the majority of cases a hind quarter is first attacked.
(3) The disease generally appears to have begun at the upper part of the quarter.
(4) The lesions, as a rule, do not seem to develop from separate discrete centres in the quarter first attacked.
(5) In certain cases the supramainmary lymphatic glands are found to be visibly tuber cular, while the udder-tissue appears to be normal. He does not deny that infection by the blood stream does occur in animals affected with generalized tuberculosis in which consider able numbers of bacilli escape into the blood stream and become arrested in the capillaries of the udder. He concludes, however, that in such cases death must occur before the bacilli have time to cause the formation of tubercles visible to the naked eye. His deductions in regard to ordinary cases of mammary tuber culosis are well founded, and no fault can be found with the general application of his remarks on the incidence and course of cases of miliary tuberculosis of the udder. In 1913, however, we encountered two cases that we thought, perhaps without sufficient reason, to be the result of infection by the blood stream, and the animals were still in moderate condi tion of body when condemned under the Tuber culosis Order. Both animals were heifers, one a virgin the other in calf and two months from her calving date. In both cases the whole udder was uniformly hardened and tuberculous. The in-calf heifer was detected during herd inspection. Though rather spare of flesh, her health was not suspected by the owner, as sbe fed well and had a good coat. The udder was found to be uniformly hard as a board through out, and so even of its surface and beautifully shaped, with teats properly set, that it was considered almost perfect from an exhibitor's point of view. Indeed the heifer had been sold the day before our visit, and was expected by the buyer to be first in her class at a forth coming show. The size of her udder was like that of an animal due to calve, but there was no cedema or pain on palpation. The post mortem in this case and that of the virgin heifer revealed old lesions of tuberculosis in the lungs and on the pleurae and. peritoneum. The supra mammary glands were enlarged, and, though slightly tubercular, we thought their infection was secondary to that of the udder.
(b) By the Lymph Stream. This is doubtless the chief route of infection, although it is against the flow of the lymph stream, but M`Fadyean says it has been experimentally proved that infection extends in both directions when sub cutaneous inoculations are made. His irrefut able arguments against the theory of infection by the blood stream in all but the most excep tional of cases serve to establish centrifugal infection through the lymphatics as the chief route.
(c) By the Teat Canal. Primary infection of the udder by the teat canal is undoubtedly rare. MTadyean considers it probable, since it is the common venue of other infections of the gland, but states that he has only seen one case in which he was satisfied the disease began at the lower part of the udder. In Hoare's System of Veterinary Medicine, vol. i. p. 393, we state that we frequently encountered the tuberculous lesion just behind the teat, causing the quarter to sag, or immediately in front of it, extending backwards over its base. If some of these well-defined low-lying tumours are primary infections, and if it be possible that human tubercle bacilli of virulent type can find a lodg ment in bovine tissues (consumptive milkers are not unknown), a new significance is attached to the use of the milk secreted by the quarter, since bacilli of human type are more potent than bovine to induce progressive and fatal tuber culosis in the human consumer. Tuberculosis of the udder in bovines is essentially a disease of aged animals, but we have met with it three times in virgin heifers and occasionally in three and four-year-olds. Our records in Lanarkshire for several years, and including the fifteen months' operation of the Tuberculosis Order, show that mammary tuberculosis was detect able in 3 per 1000 animals without the use of the tuberculin test, a positive reaction to which, in our view, is no proof that an indurated udder is the seat of tuberculosis.
Symptoms. In 90 per cent of cases only one quarter is affected, and that a hind one in 9 out of every 10 cases, and the usual seat of the lesion is the upper third of the quarter. Occa sionally, as already explained, it is lower down in front of or behind the teat, and in extremely rare cases there is a simultaneous hardening of all four quarters. There is no history of mam mitis or injury, and the growth of the tumour is very insidious. The lesion is usually single, hard, fibrous, and painless, with well-defined irregular borders, and there is no adherence to the udder integument. It varies much in size and sometimes grows very quickly. In most cases it feels like a crudely - shaped piece of vulcanized rubber lying in the softer tissue of the gland. The appearance of the secretion is at first unaltered, and its amount only gradu ally decreases. It soon becomes poorer in fat and sugar and is very like whey. It never contains pus or clotted material, though, when centrifuged, it shows a plentiful greyish deposit. Later on, and especially in animals that are dry, the product of the quarter is of a characteristic canary-yellow colour. The tuberculous quarter of a dry cow always contains some fluid. It has been found possible to detect tubercle bacilli microscopically in 95 per cent of samples taken from affected quarters, and when acid. fast bacilli are got in a properly taken sample of milk, direct from the udder, the existence of udder tuberculosis may be asserted with con fidence. It is generally held that the last milk or strippings taken from an affected quarter contains the greatest number of bacilli, but careful tests made in the county of Lanark laboratory showed that they were most plenti ful in middle milk.' Milk containing tubercle bacilli is eminently dangerous. It readily begets disease in young animals, in children, and in older people suffering from disease of the digestive organs who are largely fed on milk. Many observers have shown that the great majority of cases of cervical tuberculosis in children are dependent on bacilli of bovine type, and we have met with three cases of tuberculosis of the vertebrae in stallions which were fed on cow's milk, when they were colts, to increase their growth and condition.
Structural Changes. The nature of the lesion in its early stages is not well known. When a, quarter containing a recently-developed lesion is incised the diseased part has a fibrous, firm feeling, and this is seen to be due to increase in the interlobular tissue. Of a greyish colour, the cut surface varies in appearance with the age of the lesion, and the diseased tissue appears to merge more gradually into the healthy than is betrayed by the feel of the lesion in the live animal. Older lesions, on section, show evidence of caseation and necrosis, and the cut surface, instead of being smooth, is studded over with innumerable nodules of a yellowish-grey colour, resembling grains of sago. For a description of the microscopical appearances of the diseased tissue and its morbid histology the reader is referred to M`Fadyean's article mentioned above.
Increase in Bulk (Progressive Metamorphoses) of the Mammary Gland. Increase in the size of the mamma may be due to hypertrophy or the existence of tumours.
(a) Hypertrophy. The increased growth of the mamma associated with lactation is a natural condition. But we have already shown that excessive growth of a physiological char acter is occasionally seen in non-pregnant animals, and can be induced to some extent by stimulating the mammaor applying a young animal to the teat, when even the secretion of milk may occur. We have repeatedly observed uniform hypertrophy of the whole of the bovine Hoare's System of Veterinary Medicine, vol. i.
udder, causing the organ to sag to such a degree that the teats reached near to the ground and the milk had to be drawn off into a shallow vessel placed on the ground. In these cases the enlarged and heavy organ seems to have broken away from its attachments, for the udder-tissue is no longer in intimate contact with the trunk, and a distinct compressible neck is formed. CEdematous swelling is usually excessive at the time of parturition, and, owing to defective circulation in the pendulous organ, it is slow to undergo absorption and materially adds to the hugeness of the udder. The animal seeks relief in the recumbent position. The cause of this condition is obscure, but it may be associated with some disorder of the genital functions. In most cases the udder has a hardish fibrous feel due to increase in its connective tissue elements, and, though the milk secreted may be normal in quantity and quality, its removal does not materially lessen the bulk of the organ. The application of a many-tailed suspensory bandage tied over the back of the cow affords marked relief, and the udder should be unloaded at least four times a day, and the animal should occupy a double stall and have a good bed.
Compensatory hypertrophy is not uncommon in the remaining healthy quarters of an udder that has lost one or two of its sections as a result of past mammitis, and Ribbert has experi mentally shown in animals that removal of one-half of the mammary gland is followed by hypertrophy of the remainder.
(b) Tumours of the Mammce. If we except the vegetative warts or papillomata that are so commonly met with on the teats and udder integument of young bovine stock, it must be conceded that mammary tumours are exceed ingly rare in the larger domesticated animals.
Their rarity in the cow is surprising when we consider the constant unrest, anatomical and physiological, to which her udder is subject, but it is to be recollected that stock-owners habitually prepare the cow for slaughter that shows a defect in her udder. Our knowledge of mammary tumours in the lower animals is almost entirely based on our experience of them as met with in bitches. In them it would appear that the natural balance of things was more easily upset under the stress of the irritation that accompanies different grades of inflamma tory action. And it is very often a difficult matter to differentiate between the neoplastic overgrowth that so often follows inflammatory irritation and true tumour formation. The causes of tumour growth in the mamma are obscure, but the structure of the new tissue, whether benign or malignant, bears a distinct relation to one or other of the elemental types of tissue of which the mamma are composed, viz.: skin, fibrous stroma, and glandular tissue. Mixed growths are not uncommon, for the fibrous and glandular tissues of the organ often undergo simultaneous proliferation, re sulting in much variety of tumour formation, but epithelial tumours are invariably true to type.
on the Udder (Papillomata). These outgrowths are almost entirely confined to young animals, are caused by irritation, and have a tendency to disappear with age. They do not return when surgically removed. By some authors they are ascribed to a definite infective origin, and in the human subject clear evidence has been brought forward of the transmissibility of papillomata by implantation or There is also some proof of their transmission from the cow to man. Whether the irritation that gives rise to warts is of bacterial origin has yet to be determined. Three distinct types occur on the udders of cattle, viz.: globular, flat, and cylindrical.
(a) Globular warts are peculiar to cattle. They appear as whitish or yellowish tumours, flatly globular or oval in shape, and attached to the teat, or the skin of the udder near the teat, by a narrow neck, or are loosely embedded in the skin.
They vary in size and occasionally measure from 1 to 2 inches, though most of them are smaller. They are easily enucleated from their epithelial or horny covering, and this often happens during removal by hand, and when cut into the exposed surface shows a bulging mass of greyish-white fibrous tissue.
(b) Flat warts, also peculiar to cattle, are yellowish-white in appearance, and are usually attached to the teat by a thin pedicle, though sometimes they appear as a scale-like thickening of the epidermis.
(c) Cylindrical Warts.These are the ordinary variety of warts—an outgrowth of a collection of papilla of the corium—pointed and covered by a common, thickened, and somewhat hyper trophied horny epiderm, the free ends being darker in colour. Single ones appear as tapering, thorn-like growths, but they are often con glomerate and appear as brush-like outgrowths. They are markedly vascular and intimately attached to the skin. In some instances they are so numerous that the teat is almost entirely hidden by them.
Treatment. Affected animals should be iso lated. Removal of the warts should be prac tised early so that the teats may be healed before calving time. If this be neglected in the case of cylindrical warts they give rise to much trouble during the process of milking. Globular pedunculated forms are easily pulled off by 1 Jadassohn, V erhandl. d. deutsch. dermatolog. Kongr., 1898.
hand, and the resulting bleeding is insignificant. For the proper removal of flat and cylindrical warts it is often necessary to cast the animal, and with a pair of scissors the warts arc snipped off at their base. The bleeding surface is then dressed with an astringent and antiseptic solu tion, and later with an emollient ointment or liniment. Deeply-rooted warts should not be forcibly pulled off or a fistula of the teat may result. None of the papillomata recur after removal.
Other kinds of tumour of the bovine mammae are almost unknown. Reference has already been made to intra-canalicular warts that cause stasis of the teat.
Mare. Equine mammary tumours are as rare as bovine, and the teats of the mare, unlike those of the cow, are not subject to verrucose papillo mata. We believe that most of the so-called tumours of the mare's udder are due to botryo mycotic infection, and those resembling adeno fibromata are perhaps the result of simple inflammatory induration.
Bitch. Neoplasms, innocent and malignant, are commonly met with in the mamma of the bitch. Benign or innocent growths consist of fibromata, adenomata, lipomata, myxomata, and chondromata, or a mixture of these varieties. They are painless and of slow limited growth. Malignant tumours include sarcomata, carcino mata, and epitheliomata. They are painful, cause emaciation, grow rapidly, and often involve the neighbouring lymphatics or ulcerate, and they readily become generalized.
Fibromata.This common form of mammary tumour is composed of fibrous tissue. They are usually discrete and encapsuled, smooth and firmly elastic, and greyish-white on section. Softer forms of fibromata are due to transforma tion into myxo-fibromata.
Adenomata consist of retrograde gland struc ture and are not common. Fibro-adenomata a mixture of connective tissue and gland elements—are more common. In these, cysts which contain a yellowish fluid occasionally OMIT.
Lipomata.Fatty tumours are usually seen in plethoric animals in the subcutaneous tissue, outside the gland, and are caused by oft-repeated bruising of the mammze. They are smooth, round, soft, and discrete, and the cut surface is white and oily or lardaceous.
Myxomata are rarely met with as pure tumours of the mammze—without admixture of glandular elements. Mutinous transformation of fibromata and sarcomata is not uncommon. Chondromata.Cartilaginous tumours and osteomata or bony tumours are common in the bitch. They occur as pure growths or may .be associated with fibrous tissue or with sarcomata or carcinomata. Care is necessary to avoid mistaking cysts with calcified walls for these tumours.
Cartilaginous and bony tumours are easily diagnosed on account of their hard consistence. They are of slow growth; discrete, unattached to the skin, lobulated, and easy to enucleate.
Sarcomata are malignant connective-tissue tumours, and though they sometimes occur in pure form they are usually associated with cartilaginous and osseous structure, and occasion ally with cyst formation. Their consistence, therefore, is variable. They are often very large, have a round contour, and the mass shows many rounded outgrowths that invade the neighbouring tissues. They develop quickly, are metastatic, and the neighbouring lymphatics are usually infiltrated. In some cases they are unattached to the skin—in others the skin is broken and the tumour is ulcerated. Sarcomata may have a history of traumatism.
Carcinomata may originate as true primary growths, but this is rare. They are more often produced by the transformation of fibrous and adenomatous tumours into cancer growths. A certain percentage of cases are traumatic in origin. The carcinomas are hard and knotty; they vary much in size and usually coalesce with the skin, giving the latter a reddish-blue appearance, and granulating ulceration eventu ally occurs. More than one gland may be involved, and the tumours are never encapsuled. The knotty surface of the tumour shows rounded outgrowths from the margin, and its hard substance gives an impression of weight, and, when cut into, a colostral-looking fluid exudes, the exposed surface being grey-white in colour. Some cases of the scirrhous type run a chronic course, but metastasis to vital centres is the rule.
Epitheliomata are derived from the epithelium of the ducts and acini which proliferate to form new growths. Opinions vary regarding the frequency of their occurrence in the mammze of the bitch. The surface of epitheliomas is lobulated, and in many respects they resemble carcinomas and adenomas. The interior of the tumour is yellowish-white and some fluid escapes when it is cut into.
Treatment. All tumours of the manamm should be removed by early operation, and as the parts are very vascular precautions must be taken to avoid undue bleeding. The results are usually good when the tumour is discrete or encapsulated, but if there be marked evidence of malignancy, as shown by infiltration of the tissue around the tumour and local metastasis, the prognosis is bad, and recurrence of the growth is to be expected. If cachexia be present, the patient should be destroyed. We know of no internal treatment that can influence the growth of the tumours referred to.
The g of cows by mechanical means has engrossed much attention for many years, and the makers of these machines that have proved their utility should find their opportunity for the more extensive use of their apparatus in the growing difficulty of dairymen to find good hand-milkers. Almost without exception the machines of to-day work by intermittent suction, in imitation of the sucking calf. The earliest attempt at mechanical milking was by means of teat-tubes or syphons, but this was doomed to failure by reason of the attendant risk of udder infection when instruments of any kind are introduced into the teats. Machines that operated by"mechanical pressure"were next tried and were more or less successful, but they have now been almost entirely superseded by suction machines. The first-used suction machines did their work by"continuous"suction and were not satisfactory. Their defect was got over by adapting pulsators to the apparatus which, by interrupting the vacuum, make the suction intermittent. The number of pulsators and the nature of the pulsating arrangement vary in the different types of machines in use to-day. With the exception of the"Amo,"which is a single - cow machine suspended below the udder by straps of web bing, the whole apparatus, including the milk receiving pail, rests on the ground and may be single or double. In the latter case two cows in the same stall are milked simultaneously, and they should be of about the same milking capacity. The necessary power is provided by means of water, oil or petrol engine, steam or steam ejector, electricity or gas, and is in most cases transmitted to the cow-shed by means of metal pipes running the length of the building above the heads of the cows. In each stall a single or double stopcock is attached to the pipe, to which the free end of a rubber tube from the milking-machine is attached. The teat-cups, of aluminium, brass, or gun-metal, are usually lined with rubber, and when the power is turned on at the overhead stopcock and the cups are held to the teats they virtually jump into position. In this country there are at least seven types of suction machines that have found favour, viz.: The Wallace, the Lawrence Kennedy, the Lister, the Amo, the Amanco, the Vaccar, and the Gane.
each are hung on the apparatus, one below each teat, to lessen the upward pressure of the cups on the udder. The Amo is a suitable machine for a small herd. Hand-stripping of 12 cows milked by it produced 6 lbs. of milk.
The Amanco, or Hynman - Amanco. — This single-cow machine differs from those already de scribed in its pulsating mechanism. The engine power is conveyed to a pulley with a crank-shaft, and from this a to-and-fro motion is given to a wooden shaft that runs the length of the byre and is suspended to a beam by eyelets, which are kept well greased. The movement of this shaft operates the plunger of a small brass pump fixed to a beam above each cow, and the alternate suction and compression produced is transmitted by a flexible tube to the valve chamber on the top of the milk receptacle. The cups used are the same as those of the Lawrence-Kennedy, and the udder unit is pro vided with a hook by means of which, in the case of a three-teated cow, one of the cups can be hung up and suction to it cut off. Mr. Retson, Kirkfieldbank, Lanark, has found the Hynman Amanco a cheap, effective, and economical machine for the milking of 20 cows, and says it operates best at 51 strokes per minute.
The Vaccar is in many respects like the Lister, being a double-tube machine.
The Gane.The special feature of this machine, which is made in New Zealand, is that it is not provided with a pulsator for each machine but has a single one fixed overhead that does duty for a byre of average size. It is a double-tube machine, and the greater part of the tube between the stopcock and the machine is of nickelled metal, the ends only being of rubber.
— This is customary in the majority of herds milked by machine, and an average quantity of 2 lbs. of milk is got from each cow. The amount varies in different animals, and is least in those that have been long used to machine-milking, and in cows at the height of lactation. In herds where strip ping is not practised as a precaution, the owners state that the ultimate weekly or monthly yield of milk is not appreciably affected thereby. They hold that habitual stripping encourages the cow to master the machine when the udder is nearly empty, and the need for stripping is thereby accentuated. Stripping should always be done if there is reason to believe the machines have been operating defectively.
General Remarks.Milking by machines has passed beyond the experimental stage, and, while it is a difficult matter to choose the best among so many reliable types, it is easy to find among users advocates for every make. In deed it is exceptional to find a dairyman who will go back on his own choice or admit that for his own special herd it is inferior to any other. Success or failure depends much more on the individual than the machine. The proper cleansing of the apparatus will not suffer neglect, and there should always be one intelligent and interested individual at hand to supervise and to attend to any break-down that may take place. The different makes vary within narrow limits in initial cost, up keep, speed in milking, suitability for different sized herds and premises, in the amount of labour necessary for cleansing, and in the need for hand-stripping after the machine, but with out exception all of them attain practical success when properly operated and kept in order. The great majority of cows take kindly to the milking-machine in spite of the noise caused by the pulsators, and many tender teated animals which are restless to hand milking stand quietly to the machine. With cows that are extremely nervous and given to kicking and spilling the milk it is judicious to make the best of them by hand-milking. The machine excels in milking heifers with swollen udders and short, tender teats—animals that try the patience of the hand-milker. We are sceptical of reports to the effect that cows are milked by machines in four to five minutes. Even with skilled operators many take almost double that time, but as a rule the machine should be removed after ten minutes even though it is thought the udder is not quite empty, for by that time the cow has mastered the machine and yields no more to it. Newly calved cows should be milked by hand for three or four days until the milk is normal in appearance; if the machine is used from the beginning, a special set of cups and receptacle should be set apart for this purpose. If a cup falls from a teat at any time all the cups should be removed, the teats hand-stripped a few times, and the cups reapplied. The cleansing of milking-machines is all-important, not only to prevent tainting of the produce, but to reduce the tendency of the rubber parts to perish. Experts are agreed that it is essential to disconnect, examine, and thoroughly cleanse every part of the machine once in seven days. After each milking on the other days it is sufficient to wash the milk-soiled parts with lukewarm and then hot water, after which the rubber tubes and the cups are left to steep until required again in a solution of inodorous antiseptic, such as formalin 1 in 100-150 of water. The washing process is usually accom plished by suction. All udders should be swabbed with a clean wet cloth before milking is begun.
The chief advantages that attend the use of a reliable milking-machine are as follows: (1) Diseases of the udder and teats are quite exceptional. This is due to the fact that a supervisor can easily make sure that all teat cups are clean, though he cannot so readily control the condition of the hands of careless milkers.
(2) The milk is clean and wholesome and therefore keeps well, and if manufactured into butter and cheese these should be of first quality. Unlike hand-milking, the use of the machine exposes the warm milk to a minimum of atmo spheric contamination, and there should be an entire absence of the filth and skin debris that so readily reach the open pail during hand milking.
(3) The owner of a milking-machine is more or less relieved from the vagaries of the labour market, and in many cases it enables him to conduct his business with a lessened staff.
Abnormal Milk.Pure milk is acknowledged to be the most perfect of all food-stuffs, since it contains all the elements necessary for the support of life. But its purity is unstable, for though it may be sterile when drawn from the udder, changes at once begin in it which are due to micro-organisms that gain entrance to it from many sources. These bacteria find in milk a suitable medium for their growth, especially when the milk is warm or is kept in a warm atmosphere. The refrigeration of newly-drawn milk—so commonly practised in warm weather—inhibits bacterial development and lengthens the period during which the milk remains sweet and fit for use in a raw state. Bacterial growth practically ceases if the milk be cooled to near 40° F., though the bacteria are not actually killed. But if milk has been exposed to contamination for some time its period of sweetness can only be materially lengthened by artificially raising its tempera ture to 140' –165° F., which kills the great majority of the bacteria. A longer exposure is necessary at the lower than at the higher temperature, and the milk so treated should be at once refrigerated. It will be seen that the most important changes that take place in milk are due to microbes. The bacterial flora of exposed milk comprises many species, the most important being the lactic bacteria, which are so common that they may be considered as normal constituents. They usually preponderate over the putrefactive organisms present, and by changing the milk lactose into lactic and car bonic acids they produce a medium that is inimical to the growth of putrefactive organisms. Occasionally, however, the contamination by microbes of putrefaction is so gross that they gain supremacy to a greater or lesser degree, with the result that the milk acquires an odour and flavour that are objectionable, and these"milk faults"are maintained through the process of manufacture into butter and cheese, rendering them inferior in quality.
Clotting or Curdling Milk.This is one of the commonest of milk faults. It usually appears very soon after the milk is withdrawn from the udder, and in a few hours the milk is curdled into a cheesy condition. It is usually due to a preponderance of some of the lactic ferments, which may have been derived from the udder itself or the atmosphere, or may have been present in the milk-receiving vessels. There is also reason to believe that disorders of the digestive organs caused by soured food, as well as electrical conditions of the atmosphere and bad ventila tion in the cow-shed, result in the production of milk that is peculiarly suitable to the growth of lactic ferments. Milk that is about to curdle in this way always gives a poor return in butter and is difficult to churn.
Treatment. Faults that are suspected in the food, ventilation, or the dairy utensils should be removed at once. Disorders of the digestive organs or the udder demand special treatment, and with a view to producing an alkaline state of the milk 1-ounce doses of bicarbonate of soda may be given to each cow twice daily, two hours before the milking periods, or a tea spoonful of the bicarbonate dissolved in 2 ounces of warm water may be added to every 8 gallons of newly-drawn milk.
Milk producing little Butter.It is character istic of milk with this fault that the cream does not rise well. The causes of the defect are ill understood, but are considered to be bacterial. Though often associated with putrescence or rancidity, the non-buttering defect sometimes exists in milk deficient in fat that possesses no unpleasant odour. Instead of rising in a solid uniform layer the fat appears as greasy-looking globules on the top of the milk.
Treatment. All dairy utensils should be cleansed and disinfected, and the affected milk should be centrifugalized. Galactogogues are to be recommended: aniseed, caraway seed, antimony, fennel, vinegar and water, and hydro chloric acid and water.
Putrid Milk.Milk of this quality is usually produced in insanitary byres, where the milk is subject to gross contamination. But on occasion this milk fault appears in up-to-date premises, and is baffling to get rid of because of the difficulty in determining the source of the putrefactive organisms to which it is due. In such an outbreak we found that out of thirty two cows only fourteen yielded milk that turned bad, and on certain days the produce of some of these remained sweet for a normal period of time, and on further analysis it was found that the milk from one or two quarters in some of the indicted cows kept good while that from the remaining quarters became putrid. The fault prevailed more or less for fourteen days in spite of every precaution, and gradually disappeared, to reappear again in a lesser degree three months later when the cows were on grass. The milk usually remained sweet for six or more hours after it was drawn from the cows, and on occasion kept sweet for twelve hours, when it would very quickly be come dirty-coloured and evil-smelling. There was no evidence of ill-health in the cows, and the milk taken from the three healthy quarters of the only cow suffering from mammitis was never affected. No use could be made of milk after it had turned, but, with the exception of what was kept for testing purposes, the produce was salved, until the fault disappeared, by heating and cooling it. The diseased milk contained many different species of putrefactive organisms, and, while in all cases it was of a dirty colour and had a repulsive odour, it some times assumed a bluish tinge. Bubbles of gas were so plentiful in some samples that they seemed to be effervescent. The origin of this outbreak remained obscure.
Treatment. This must comprise complete disinfection of the whole premises, dairy utensils, cows' udders, and the hands of milkers, who should be supplied with clean overalls. The water-supply should be seen to, and every drop of water used for the utensils should be boiled if there is any reason to suspect the purity of the supply.
Bitter Milk. When this fault appears in a dairy it is very difficult to get rid of, and if the produce of the dairy be consumed within a few hours after it has been drawn from the cow the anomaly escapes detection for a time. The appearance of the fault is more quickly detected when the milk or the cream taken from it is made into butter. Defective rations and irregularity of diet have been blamed, but in the bitter cream the existence of organisms has been proved that have the power of render ing milk bitter experimentally. This subject has been much studied on the Continent, and the following organisms have been indicted, viz.: Weismann's bacillus of bitter milk, the bacillus of Bleisch, Conn's micrococcus, the tyrothrix of Duclaux, the Torula amara of Harrison, etc. These and other organisms, have been also isolated from bitter cheese, and it is thought the bitterness in the different products is due to the peptonizing faculty of the causal agents. The question demands further research and ex perimentation, as the fault is a very tenacious one and often defies, for some months, the efforts that are made to get rid of it.
Soapy Milk.This name is given to milk that has a soapy taste, which is caused by the Bacillus saponacei of Weismann and Zirn. This organ ism is said to be present in the fodder, and the milk becomes contaminated when the hay or straw is disturbed during the milking period.
The milk never coagulates but becomes soapy in taste, has a slimy deposit, and yields a, frothy cream from which butter is made with difficulty.
Ropy or Viscous Milk. — These terms are applied to milk that becomes thick, sticky, and thready, and the fault is seldom seen until after twenty-four hours. Little cream is pro duced, and the butter made from it is of bad flavour. Although the milk curdles badly in a true sense, it pours from the jug containing it reluctantly, the cream on the top has a tough appearance and normal colour, and the mucila ginous mass below it is of a beautiful shiny white colour and is almost tasteless. It is a common fault in insanitary cow-sheds, and vari ous micro-organisms have been proved capable of producing this mucilaginous change in milk. These include the Bacillus viscosus of Adametz, the bacillus of Loeffler, the micrococcus of Hiippe, the bacillus of Guillebeau, etc. The fault is often proved in herds where mammitis prevails, and is traceable to contamination of the milk with the diseased products of infected udders. Recent investigations have differenti ated between the slimy and the stringy faults in milk, but it cannot be doubted that they are often coexistent.
Treatment comprises thorough sanitary meas ures in the byre and dairy. The milk can be salved by sterilization.
Red Milk.We do not here refer to the red coloration of newly-drawn milk so commonly met with in some cows for a few days after calving, and which is due to the presence of blood in the milk. When such milk is allowed to stand the red blood corpuscles are deposited to the bottom of the vessel, and a thin red film is seen when the milk is poured out. The red milk fault referred to only appears after a period when the organisms that give rise to it have had time to multiply sufficiently. The organisms that are known to produce the red tint in milk include the Bacillus prodigiosus, which colours chiefly the top layer of the milk, the Bacillus lactis erythrogenes, which tints the milk throughout but is not effective if the dairy is well lighted, and two species of sarcina.
Treatment. The fault readily yields to thorough methods of cleanliness in the cow shed and dairy.
Blue Milk.This milk fault is seldom seen before the second or third day. It is caused by the Bacillus cyanogenus. The earliest signs of the fault consists of small patches of a bluish colour on the surface of the milk, which gradu ally enlarge to produce a uniform blue tint that by and by permeates the whole mass. It has been shown that the Bacillus cyanogenus produces a grey instead of a blue colour in sterile milk, and that to cause the blue colora tion the bacillus requires the association to some extent of the ordinary lactic ferments of milk. A temperature of 140°-150° F. is sufficient to destroy the bacillus.
Yellow Milk.A natural yellow tint in ordi nary milk is characteristic of certain breeds of cows, e.g. Jerseys, and is valued alike in the milk and the butter made from it. But the diseased condition known as yellow milk is due to the Bacterium syxanthum of Ehrenberg and Schrtiter, which produces a lemon - yellow coloration of the milk, curdles it, and after some days liquefies it. It is held that boiled milk only is liable to this infection, so that the fault is of little practical importance.