Calf paratyphoid III. The transmission of anti-bodies to newly-born calves

Abstract

1. In a study of the transmission of anti-bodies from immunized pregnant cows to the colostrum and to their progeny it was noticed that the agglutinin titre of the colostral whey and of the calf's serum might be several times that of the dam. At the time of birth hardly any agglutinins, or no agglutinins at all, could be detected in the calf's serum, but the titre suddenly rose to this high level within 24 hours after the first suckle. The calf's titre remained high for two weeks or more, and then gradually declined; but it remained at a significant level for about three months. 2. When newly-born calves from immunized or unimmunized mothers were fed on hyperimmune serum before the first suckle large amounts of agglutinins could be detected in their sera twelve hours later. These agglutinins persisted, though in progressively decreasing titre, for at least three months. 3. When the calves from immunized cows were inoculated with S. dublin vaccine one, two or three weeks after a colostral feed, no rise could be effected in the agglutinin titre and no difference could be detected in the titre whether the calves had been inoculated or not. The immunity was apparently completely blocked by the anti-bodies absorbed from the colostrum. 4. When the colostral immunity was challenged with virulent milk cultures given by the mouth the calves exhibited a fair degree of resistance, and it was extremely difficult to produce typical symptoms of paratyphoid in them. It is believed that this immunity is sufficient to protect young calves against natural exposure to paratyphoid. The immunization of pregnant cows as a means of protecting new-born calves against paratyphoid is, therefore, recommended as an additional method of combating the disease. But as hyperimmune sera, when given before the first suckle, can also transmit anti-bodies to new-born calves the use of immune sera is advised in cases where immune colostrum is not available.