(2.) In successively isolating cows which are about to calve in a small specially detached stable;
(3.) In carefully disinfecting the genital organs of cows which have aborted, firstly with boiled water at a temperature of 100° Fahr., and then with 1 per cent. iodine solution.
Calves which are infected when born cannot be saved, but abortion can be prevented and dysentery so stamped out.
DIARRHŒIC ENTERITIS IN CALVES.
This disease is usually called “simple sporadic diarrhœa.” It may appear at any time before weaning, and can usually be cured if treated early before the patients show bodily wasting.
Causation. Indigestion from failure of the abomasum to deal with the milk usually precedes diarrhœic enteritis; it may terminate without complications, but very often is followed by diarrhœa. Anything which produces milk indigestion, therefore, favours the occurrence of enteritis. Such predisposing influences include over-distension of the abomasum, milk of bad chemical composition, milk tainted by keeping or by storage in dirty and infected pails, etc. The addition to the milk of nutritive substances which the abomasum and intestine are not yet capable of digesting, such as wheat, rye, barley, or maize meals, very often produces diarrhœa even when the meal is well cooked.
Chills, privations, irregular feeding, and badly-managed weaning may facilitate its development, but none of these causes, however important they may be, seem to play any other part than that of favouring the multiplication of the numerous varieties of microbes to be found in the intestinal tract. Vascular disturbance occurs, either as a result of direct irritation of the intestinal mucous membrane or of the action of toxic products contained in milk which has served as a culture medium for these microbes; this is followed by secretory disturbance, and the intestinal contents being modified in character, the microbes normally present undergo changes in number and quality. Inoffensive organisms assume pathogenic qualities and secrete toxic principles, normal digestion is disturbed, the intestinal defence becomes less perfect, toxic principles which the liver is incapable of destroying are absorbed, and diarrhœic enteritis is set up.
Symptoms. Diarrhœic enteritis appears during the second week of life, towards the end of the first month, or even later. It is characterised by the passage of fæces consisting of mucus and containing little clots of milk.
This is the first stage of alimentary diarrhœa, also termed “white diarrhœa” or “white scour.” It may prove unimportant; it may last a day or two and then cease. Most commonly diarrhœa increases and assumes a mucous and then a serous character, whilst the dejecta exhale a very characteristic repulsive smell. The excrement becomes greenish brown, and after several days or a week or more may appear blood-stained. The number of evacuations varies enormously, depending on the gravity of the condition. The ejected material is irritant, and the parts soiled by it, like the perineum, hocks, and back of the cannon bones, become slightly inflamed as though blistered; later, the hair falls away.
The general health then begins to suffer. Fever remains moderate, but the mouth is pasty, the tongue coated, and the breath fœtid.