The pathogenesis of tuberculosis in the calf

The pathogenesis of tuberculosis in young calves was studied in a series of twenty-four animals from a tuberculosis-free herd, given, when seven days old, an infective dose in the form of either naturally contaminated milk (ordinary raw bulk milk or undiluted milk from cows with tuberculous mastitis) or a virulent culture of bovine tubercle bacilli.

The infective dose was given by various routes: ordinary and teat bucket, stomach tube, directly into the duodenum, and intra-tracheally. The pathogenesis was studied at autopsy, supplemented by histological examination and guinea-pig inoculation.

The results are discussed with especial reference to the pathogenesis of tuberculosis in young calves naturally infected by contaminated milk either by suckling or by bucket feeding.