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IMMUNE STATUS OF DAIRY HEIFER CALVES IN THE NORTHERN PLAINS OF COSTA RICA. YEAR III
The objective of this study was to characterize the immune status of dairy calves in the Northern Plains of Costa Rica. The results correspond to total serum protein (TSP) measurements obtained from 657 female calves in 23 dairy farms during the period of August and November of 2012. Dam breeds were classified into Holstein, Jersey, HolsteinxJersey crosses and other. Blood samples were collected between d 1 and 7 of age into serum (red top) Vacutainer tubes, refrigerated overnight, centrifuged, and the serum separated from clot within 24 h of collection. A hand-held refractometer was used to measure STP. For the purpose of this study, failure of passive immunity was considered when TSP concentration was less than 5.5 g/dL. GLM procedure was used to establish differences between parity and breed of the dams. Descriptive statistics were generated to define percentage of failure of passive transfer by breed and parity of the dam. TSP concentration ranged from 2.4 to 10.0, with an overall mean of 5.7 g/dL. Of all the calves evaluated, 44.9% presented failure of passive transfer. Calves born to Jersey and HolsteinxJersey crosses had significantly higher TSP concentrations than calves born to Holstein and other breeds. When considering lactation number of the dam, offsprings born to third lactation cows showed the lowest percentage of calves with inadequate transfer of immunity. The findings of this study suggest that colostrum management practices should be placed in order to minimize the risk of failure of passive transfer in dairy herds in the Northern Plains of Costa Rica.
Keywords:
Total Serum Protein, Immunoglobulins, Passive Immunity