Effect of passive transfer status on preweaning growth performance in dairy lambs

Objective-To evaluate the effect of passive transfer status, determined by measuring serum IgG concentration 24 hours after parturition, on preweaning growth performance in dairy lambs. Design-Prospective observational study. Animals-20 healthy Sardinian dairy lambs. Procedures-Serum IgG concentration was measured 24 hours after birth. Body weight was measured at birth and at the time of weaning 28 days (ie, 27 to 29 days) after birth. Mean daily gain from birth to day 28 and day 28 weight were used as measures of preweaning growth performance. Regression analysis was used to evaluate associations between serum IgG concentration 24 hours after birth and measures of preweaning growth performance. Results-Mean +/- SD serum IgG concentration 24 hours after birth was 24.6 +/- 175 mg/mL. Mean body weights at birth and weaning were 2,696 +/- 937 g and 9,253 2,116 g, respectively, and mean daily gain was 234 +/- 63 g/d. No significant association was detected between serum IgG concentration 24 hours after birth and birth weight. However, serum IgG concentration 24 hours after birth was significantly associated with mean daily gain (R-2 = 0.26) and day 28 weight (R-2 = 0.25). Each 1 mg/mL increase in serum IgG concentration 24 hours after birth was associated with a 1.8 g/d increase in mean daily gain and a 60.8-g increase in day 28 weight. Conclusions and Clinical Relevance-Results indicated that passive transfer status, determined as serum IgG concentration 24 hours after birth, was a significant source of variation in preweaning growth performance in dairy lambs.