Factors influencing passive transfer in dairy calves.

Records from 2105 calves born over 2 yr on a large dairy in a subtropical climate were examined to delineate factors that influence passive transfer of colostral immunoglobulins and the effect of passive transfer of immunoglobulin on calf mortality. Seasonal effects on immunoglobulin absorption were detected with highest serum total protein occurring in February and March. Lower total protein concentrations were associated with elevated environmental temperatures in the summer months. Maternal antibody was highest in calves from second parity cows; and dystocia appeared to decrease the amount of immunoglobulin absorbed by the neonatal calf. Calves that died of infectious disease during the first 14 wk of life had significantly lower serum total protein concentrations than those that lived. Heritability of serum protein concentration in calves was .02 +/- .03.