Immunocompetence against viruses associated with the supply of maternal colostrum, colostrum replacement and lactotherapy in calves

Abstract

Forty calves were systematically assigned to one of two groups, as follows: (1) supply of ≈ 171 g of IgG in 1.8 L of MC (A1 group A1, n=20) and (2) supply of ≈ 150 g of IgG in 1.5 L of CR (group A2, n=20). Then, the application of intramuscular MC at 55 days of age was included to form two blocks, as follows: (1) without intramuscular MC (group N0, n=17), (2) with intramuscular MC (group N1, n=18) and four combinations between levels of A × N (A1N0, n=10; A1N1, n=11; A2N0, n=7 and A2N1, n=7). Blood, serum, stool or respiratory secretion samples were periodically analyzed by serological tests or polymerase chain reaction from birth to 102 days of age. Antibody titers measured by percent inhibition (PI) against BLV, BVDV, and BHV-1 were higher and more persistent in the group A1 compared to the group A2, but the difference between means was not significant. PI-seronegative BVDV was significantly associated with the intake of CR from 60 to 81 days of age. Vaccination increased the number of BVDV seropositive calves up to 102 days of age in the CR A2. Lactotherapy did not change the trend of antibody levels against BVDV and other viruses. Overall, lactotherapy with intramuscular MC did not affect immunocompetence against viruses, but in calves that ingest MC it was better than the one provided with CR.