Congestion may merge into active inflammation, or it may arise direct, in connection with exposure to cold or wet, with standing in a cold draft, with blows on the udder with clubs, stones, horns, or feet, with injury from a sharp or cold stone, or the projecting edge of a board or end of a nail in the floor, with sudden and extreme changes of weather, with overfeeding on rich albuminous feed like cotton seed, beans, or peas, with indigestions, with sores on the teats, or with insufficient stripping of the udder in milking. In the period of full milk the organ is so susceptible that any serious disturbance of the general health is liable to fall upon the udder.
Symptoms.—The symptoms and mode of onset vary in different cases. When following exposure there is usually a violent shivering fit, with cold horns, ears, tail, and limbs, and general erection of the hair. This is succeeded by a flush of heat (reaction) in which the horns, ears, and limbs become unnaturally warm and the gland swells up and becomes firm and solid in one, two, three, or all four quarters. There is hot dry muzzle, elevated temperature, full, accelerated pulse, and excited breathing, impaired or suspended appetite and rumination, with more or less costiveness, suppression of urine, and a lessened yield of milk, which may be entirely suppressed in the affected quarter.
In other cases the shivering escapes notice, the general disorder of the system is little marked or comes on late, and the first observed sign of illness is the firm swelling, heat, and tenderness of the bag. As the inflammation increases and extends, the hot, tender udder causes the animal to straddle with its hind limbs, and, when walking, to halt on the limb on that side. If the cow lies down it is on the unaffected side. With the increase in intensity and the extension of the inflammation the general fever manifests itself more prominently. In some instances the connective tissue beneath the skin and between the lobules of the gland is affected, then the swelling is uniformly rounded and of nearly the same consistency, pitting everywhere on pressure. In other cases it primarily attacks the secreting tissue of the gland, then the swelling is more localized and appears as hard, nodular masses in the interior of the gland. This last is the usual form of inflammation occurring from infection entering by the teats.
In all cases, but especially in the last-named form, the milk is suppressed and replaced by a watery fluid colored with blood (sometimes deeply) and mingled with masses of clotted casein. Later it becomes white and purulent, and in many cases of an offensive odor.
The course of the disease is sometimes so rapid and at others so slow that no definite rule can be laid down. In two or three days, or from that to the end of the week, the bag may soften, lose its heat and tenderness, and subside into the healthy condition, even resuming the secretion of milk. The longer the inflammatory hardness continues the greater the probability that its complete restoration will not be effected. When a portion of the gland fails to be restored in this way, and has its secretion arrested, it usually shrinks to a smaller size. More commonly a greater quantity of the inflammatory product remains in the gland and develops into a solid, fibrous mass, causing permanent hardening (induration). In other cases, in place of the product of inflammation developing into a fibrous mass, it softens and breaks down into white, creamy, liquid pus (abscess). This abscess may make its way to the surface and escape externally, or it may burst into a milk duct and discharge through the teat. It may break into both and establish a channel for the escape of milk (fistula). In the worst types of the disease gangrene may ensue, a quarter or half or even the whole udder, losing its vitality, and sloughing off if the cow can bear up against the depressing influence. These gangrenous cases are probably always the result of infection and sometimes run a very rapidly fatal course. I remember one to which I was called as soon as the owner noticed it, yet I found one-quarter dark blue, cold, and showing a tendency to the formation of blebs containing a bloody secretion. The cow, which had waded through a depth of semiliquid manure to reach her stall, died within 24 hours.
Treatment.—Treatment varies with the type and the stage of the disease. If the case is seen in the shivering fit, every effort should be made to cut it short, as the inflammation may be thereby greatly moderated, if not checked. Copious drinks of warm water thrown in from horn or bottle; equally copious warm injections; the application of heat in some form to the surface of the body (by a rug wrung out of hot water; by hanging over the back and loins bags loosely filled with bran, sand, salt, chaff, or other agent previously heated in a stove; by the use of a flatiron or the warming of the surface by a hot-air bath), or by active friction with straw wisps by two or more persons; the administration of 1 ounce of ground ginger may serve to shorten the attack. After half an hour's sweat the animal should be rubbed and covered with a dry blanket.
If, on the other hand, there is little or no fever, and only a slight inflammation, rub well with camphorated ointment or a weak iodin ointment, and milk three, four, or six times a day, rubbing the bag thoroughly each time. Milking must be done with great gentleness, squeezing the teat in place of pulling and stripping it, and if this causes too much pain, the teat tube ([Pl. XXIV], fig. 4) or the spring teat dilator ([Pl. XXIV], fig. 3) may be employed. Antiseptic injections of the teats and udder are often useful, and iodoform in water has been especially recommended. It may be replaced by one of the injections advised for parturition fever, used with the same careful precautions.
In cases in which the fever has set in and the inflammation is more advanced, a dose of laxative medicine is desirable (Epsom salt, 1 to 2 pounds; ginger, 1 ounce), which may be followed, after the purging has ceased, by daily doses of saltpeter, 1 ounce. Many rely on cooling and astringent applications to the inflamed quarter (vinegar, sugar-of-lead lotion, cold water, ice, etc.), but a safer and better resort is continued fomentation with warm water. A bucket of warm water, replenished as it cools, may be set beneath the udder, and two persons can raise a rug cut of this and hold it against the udder, dipping it anew whenever the temperature is somewhat lowered. A sheet may be passed around the body, with holes cut for the teats, soft rags packed between it and the udder, and kept warm by pouring water on every 10 or 15 minutes, as warm as the hand can bear. When this has been kept up for an hour or two, the bag may be dried, well rubbed with soap, and left thus with a soapy coating. If the pain is great, extract of belladonna may be applied along with the soap, and a dry suspensory bandage with holes for the teats may be applied. Strong, mercurial ointment is very useful in relieving pain and softening the bag. This is especially valuable when the disease is protracted and induration threatens. It may be mixed with an equal quantity of soap and half as much extract of belladonna. In cases of threatened induration excellent results are sometimes obtained from a weak-induction current of electricity sent through the gland daily for 10 minutes.
If abscess threatens, it may be favored by fomentation and opened as soon as fluctuation from finger to finger shows the formation of matter at a point formerly hard. The wound may bleed freely, and there is a risk of opening a milk duct, yet relief will be obtained; also a dressing twice daily with a lotion of carbolic acid 1 part, water 20 parts, and glycerin 1 part will suffice to keep the wound clean and healthy.
Gangrene of the affected part is often fatal. It demands antiseptics (chlorid of zinc, 1 dram to 1 quart water) applied frequently to the part, or, if the case can not be attended, smear the affected quarter with Venice turpentine, melted, or even wood tar. Antiseptic tonics (tincture of chlorid of iron, 4 drams) may also be given four times daily in a quart of water.