Colostrum feeding and calf welfare assessment: the first steps to a better future

Summary

Dairy calf welfare is influenced by a wide range of factors. Following removal of the European milk quota system in 2015, Irish dairy herds have expanded in an effort to increase production and profitability. This expansion coupled with pre-existing standards of colostrum management, previously described as sub-optimum, could negatively impact on calf welfare, and particularly so given the short calving period applied among seasonal calving systems which operate in Ireland. The aim of this thesis was to evaluate the effect of colostrum quality and management on calf health and immunity, but also to assess calf welfare on commercial farms and identify improvement options. The effect of feeding single dam and pooled colostrum on calf passive immunity was assessed in a controlled experiment. The results showed that calves which received pooled colostrum had reduced absorption efficiency for IgG as well as lower 24 h serum IgG concentrations, compared to calves fed single dam colostrum. Having developed a welfare assessment protocol for dairy calves, which was feasible and reliable, this was then applied on commercial dairy farms. Findings indicate colostrum management on Irish dairy farms is of a high standard, with over 90 % of calves receiving adequate transfer of passive immunity. While mean calf serum IgG concentration was higher among smaller size herds, the mean calf serum IgG concentration across all herd sizes exceeded the threshold (>10 mg/ml IgG) for adequate passive immunity. Colostrum quality in Irish dairy herds was good; however large variation exists, both within and between herds. Based on collected data, associations between pre-weaning calf management and calf welfare and mortality on commercial dairy farms were investigated. Calf mortality was not associated with either herd size, space allowance per calf or post-colostrum feeding practices. Higher calf mortality was identified among herds which reported experiencing an on-set of calf pneumonia during weeks 8-10 of the calving season. Behavioural observations indicate that smaller group sizes could promote expression of positive behaviours, potentially resulting from an overall improvement in welfare. Space allowance per calf was not associated with observed behaviour frequencies. It was also identified that calf mortality was not associated with herd size. Improvements in the area of colostrum management, as described in this thesis, combined with regular assessment of calf welfare, using reliable protocols, can provide the future basis for enhanced calf welfare on commercial dairy farm.