Specific antibodies of Pasteurella multocida in newborn calves of vaccinated dams.

Twenty-five newborn Holstein Friesian calves, from dams vaccinated against haemorrhagic septicaemia (HS), were tested repeatedly over the first 6 months of life to monitor the transferred antibody levels against HS. Enzyme-linked immunosorbent assays were used to measure the specific HS antibodies with antigens from Pasteurella multocida strains B:2 and E:2. There was a significant curvilinear relationship between the monitored IgG response and the age of the calves. Peak serum IgG levels were obtained during the period from 8 to 16 weeks of age. Beyond this age, the concentration of IgG in the serum fell away.