Prolonged retention in dirty stables, where the bedding is mixed with manure and continually moistened with urine, is the principal cause of the disease. Individual predisposition and the action of some specific organism may also have some influence.
Canker in oxen, like the same disease in horses, is recognised by softening and separation of the horn of the sole, and by progressive extension of the process towards neighbouring parts. The usual course consists in invasion of the podophyllous tissue, separation of the wall and of the heels, and pathological hypertrophy of the horn-forming tissues, producing condylomata.
The new growths do not attain the same dimensions as in the horse, but, on the other hand, the disease very frequently takes a progressive course, involving the whole of the claw. A trifling accidental injury may be followed by infection of the subungual tissues, and thus become the point of origin for canker.
Canker may attack only one claw; on the other hand, it may extend to both claws of one foot, or to the claws of more than one foot in the same animal.
Diagnosis. Diagnosis is easy. The separation of the horn, the presence of a caseous, greyish-yellow and offensive discharge between the separated parts and the horn-secreting tissues, the appearance of the exposed living tissues, etc., leave no room for doubt.
Prognosis. The prognosis is grave; for, as in the horse, the disease is obstinate.
Treatment consists in scrupulously removing all separated horn, so as fully to expose the tissues attacked by the disease. The parts should then be thoroughly disinfected with a liquid antiseptic, and a protective pressure dressing applied.
As a rule, cauterisation with nitric acid, followed by applications of tar or of mixtures of tannin and iodoform, iodoform and powdered burnt alum, etc., effect healing, without such free use of the knife as has been recommended in the horse during the last few years.
GREASE.
Grease in the ox seems only to have been described by Morot and Cadéac, and even in these cases the descriptions appear rather to apply to elephantiasis or fibrous thickening of the skin than to grease proper. The descriptions are not sufficiently clear, and the symptoms described differ too much from the classical type seen in the horse to convince us without further confirmation of the occurrence of the disease.