Short communication: Performance evaluation of beef calves fed different levels of colostrum replacer in tropical conditions.

This study aimed to evaluate the effect of colostrum replacer supplementation on the health and performance of beef calves. Two studies were conducted to evaluate whether crossbred and purebred calves differ in their responses after receiving a colostrum replacer. In study 1, 162 ¾ Angus × Nellore calves born to ½ primiparous cows were assigned to three treatments: cow colostrum (no colostrum replacer: NCR; n = 54), cow colostrum + 50 g of immunoglobulin G supplementation (50IGG; n = 54), and cow colostrum + 100 g of IgG supplementation (100IGG, n = 54). In study 2, 244 Nellore calves were assigned to the same treatments: NCR (n = 82), 50IGG (n = 81), and 100IGG (n = 81). For both studies all calves had free access to cow colostrum. Serum protein concentrations were measured using a digital Brix refractometer. Calves were weighed using a tape at birth and weaning (80 days of age) to estimate average daily gain. In study 1, no significant differences (P > 0.0855) were observed among treatments for passive transfer. In study 2, significantly higher Brix concentrations were observed for calves supplemented with colostrum replacer (P = 0.01). No improvements on performance were observed for supplemented calves. These findings suggest that although all calves achieved successful transfer of passive immunity, colostrum replacer supplementation can further enhance passive immunity, as observed in Nellore calves. However, in production systems with adequate nutritional management, such as that used in the present study, colostrum replacer supplementation may not be necessary.