Relationship between passive immunity and morbidity and weight gain in dairy cattle

Abstract

Serum samples from 87 calves from a dairy herd in Southern Brazil were collected to determine the levels of passive transfer and its relationship to morbidity and mean daily weight gain (MDG). Serum immunoglobulin (Ig) levels were measured by the zinc sulfate turbidity test at 24 hours of age in the calves. The average serum Ig level was 11.40g/l. Fourteen out of 87 calves (16.1%) showed serum Ig levels one standard deviation below the mean (4.59g/l) and were considered as having failure of passive immunity transfer (FPT). The occurrence of diarrhea from birth to weaning was higher in the FPT group (100%) than the normal group (90.7%) but the difference was not significant. The occurrence of signs of respiratory disease was similar in both groups (35.7% for FPT and 36.9% for the normal group). The mean daily gain from birth to 13-16 months of age in the FPT group was significantly (P>0.05) lower than in the group with normal serum Ig levels. The difference in MDG from birth to weaning between the groups was not significant. These results demonstrate the importance of passive immunity in cattle, and also provide regional parameters for the evaluation of FPT in cattle.