Associations between management practices and colostrum quality on New Zealand dairy farmsAuthors: McDougall S, Hunnam JC, Cuttance EL, Denholm KS
Publication: New Zealand Veterinary Journal, Volume 65, Issue 5, pp 257-263, Sep 2017
Publisher: Taylor and Francis
AIMS: To describe colostrum quality in spring-calving dairy herds in New Zealand, in terms of Brix, pH and total and coliform bacterial counts and to investigate associations between farm management practices and these measures of colostrum quality.
METHODS: In June 2015, commercial dairy farms (n=105), located in North and South Islands of New Zealand, were visited shortly after the first cows had calved, and when approximately 50% and 80% of the herd had calved (early, middle and late visits). One litre of pooled colostrum that was being fed to newborn calves was collected at each visit and used to determine Brix, pH, total bacterial and coliform counts. A survey of calf management practices was conducted with the herd manager or calf rearer after the final visit.
RESULTS: Of 298 pooled colostrum samples tested 29/298 (9.7%) had Brix >22%. Brix was higher on farms where calves were picked up twice daily compared with once daily (18.2 (95% CI=16.5â€“19.9)%
CONCLUSIONS AND CLINICAL RELEVANCE: On a large majority of dairy farms included in this study the pooled colostrum fed to newborn calves had sub-optimal Brix and excessive bacterial counts. Farm-level risk factors such as twice daily pick up of calves from the paddocks, herd vaccination and feeding pooled colostrum that did not combine colostrum obtained at later milkings with first milking colostrum were associated with colostrum quality measures.
KEY WORDS: Dairy calves, colostrum, quality, New Zealand, risk factors