Measurement of transfer of colostral passive immunity in dairy calves

The administration of high quality colostrum reduces preweaning morbidity, mortality and, therefore, economic losses related to replacement animals. It also stimulates and improves calf growth, increasing milk production and longevity of the future dairy cows. The aim of the present study was to evaluate the influence of breed and parity of the dam on colostrum quality, and of breed and gender of the calf, and time from calf birth to the administration of the first colostrum meal on the transfer of passive immunity to the calf by the field test of the Failure of Passive Transfer (FPT) on calf serum. A further objective was to improve the diagnostic accuracy of the field FPT test through a second laboratory phase improving the turbidity evaluation. The amount of IgG fed to calves (IgG concentration multiplied by the volume of colostrum administered) was influenced by dam parity as significant differences (P < 0.05) were detected between first- and fourth-parity cows, and between second- and fourth-parity cows. The administration of good quality colostrum (IgG > 50 mg/ml) between 5 and 9 h of life was able to reduce the risk of FPT more effectively than the administration performed within the first 4 h of life. However, further studies on larger sample size is needed to confirm the present findings. The spectrophotometric measurements confirmed the results obtained by the field turbidity test at 14% sodium sulphite dilution. It would be interesting in future to expand the dataset and validate the spectrophometric method