Herd-level Management and Biosecurity Factors associated with Measures of Reproductive Success in California Beef Cow-calf Herds

Abstract

A cross-sectional study was performed to evaluate the relationship between herd-level management and biosecurity practices in a sample of California's beef cow-calf operations, and the estimated within-herd prevalence of antibodies to Neospora caninum , Anaplasma marginale, and the persistent carrier state of bovine viral diarrhea virus (BVDV PI). Serum samples were collected from 917 adult beef cows from 29 herds. Multivariable linear and logistic regression models were created to predict calving season length and the probability of a cow weaning a calf using selected herd-level management and biosecurity factors and the seroprevalence data. The overall seroprevalence of A. marginale , N. caninum and BVDV PI was 47.4% (435/917), 8.9% (82/917) and 0.1% (1/917), respectively. The multiple linear regression analysis revealed no significant associations between management variables and calving season length. A logistic regression model found that the probability that a cow weaned a calf was associated with the number of first-calf heifers in the herd, whether the bulls were semen tested, whether the herd had a history of epizootic bovine abortion, and if the cow herd was vaccinated against Clostridium spp. Based on these findings, we conclude that herd-level management and biosecurity factors may be associated with reproductive success in beef cow-calf farms in California through their effect on the probability that a cow weans a calf.