Assessment of current colostrum feeding practices and passive transfer of immunity in dairy herds in Great Britain: A cross-sectional study

Abstract

Background: Updated targets for measuring transfer of passive immunity (TPI) at the herd level have been suggested, but the current performance of dairy herds in Great Britain is unknown. Methods: A cross-sectional study was performed. Serum total protein (STP) data collected between October 2022 and October 2023 by 21 veterinary practices were benchmarked. Questionnaires were also distributed to collect information about colostrum feeding, calf husbandry and veterinary engagement, and associations between these factors and herd TPI were analysed using ordinal logistic regression. Results: A total of 4455 STP results from 91 herds were collected. Overall, 26% of calves had an STP concentration of less than 52 g/L (n = 1144). The number of herds with less than 10% of measured calves having an STP concentration of less than 51 g/L was 26% (n = 24). In contrast, 44% of herds (n = 40) recorded more than 40% calves having an STP concentration of 62 g/L or more. Herd TPI score was negatively associated with colostrum replacer feeding (odds ratio 0.09, 95% confidence interval: 0.01–0.54, p = 0.01). Limitations: A limited number of veterinarians and farmers completed the accompanying questionnaire, increasing the likelihood of Type I statistical error. Survey responses may be influenced by response bias. Conclusion: The overall herd TPI measured in the study was inadequate, suggesting that renewed emphasis on the optimisation of TPI within British dairy herds is necessary.