[Use of nonspecific agents and vaccination in bronchopneumonia prevention in cattle]

A group of 463 calves, kept under one and the same conditions of tending and feeding, were followed up from the fifteenth day after birth up to one year of age, after treatment by subgroups with a hyperimmune antibovine rabbit serum, biomass of chlorella, a tissue preparation of swine embryos, and vaccines against mucosal diseases and infectious bovine rhinotracheitis. The experiment revealed that those of the calves that were treated with a combination of chlorella biomass and a hyperimmune antibovine rabbit serum were most in number (80 per cent) that did not contract and develop diseases. Calves that were individually treated with each single one of these two agents also showed a high percent of intacts --72-73%. Third ranked the subgroup of animals in remaining unaffected with diseases (56 to 60 per cent) that were treated with the MD and IBR vaccines and the swine embryo tissue preparation.