LAUSR

Abstract The objective of this study was to evaluate the passive transfer (PT), health and performance of calves fed differing volumes of a colostrum replacer and/or maternal colostrum. Newborn calves were colostrum fed within 2 h of birth as follows:1) 2 L (192.78 ± 11.55 g of IgG) of maternal colostrum (2MC); 2) 4 L of maternal (387.69 ± 12.10 g of IgG ) colostrum (4MC); 3) 2 L (196.16 ± 11.48 g of IgG) of maternal colostrum + one package (100 g IgG in 1.4 L) of colostrum replacer (2MC1CR); 4) 2 packages of colostrum replacer (2CR) and 5) 2 packages of colostrum replacer given within 2 h following birth + one package of colostrum replacer given between 6 and 8 h after birth (3CR). Calves were individually housed and following colostrum feeding(s), were fed 6 L/d of milk replacer with ad libitum access to water and calf starter. Passive transfer as assessed by serum immunoglobulin (Ig) levels were high (mean values of 21.8–25.9 g IgG/L) and did not differ signficantly among groups (P > 0.05). Calves fed larger volumes of colostrum and thus greater Ig mass had lower apparent efficiency absorption (P 0.05). However, the number of treatments for cattle tick fever differed among groups (P = 0.0042). The mean weight and ADG, as well as the blood parameters including total protein, albumin, glucose, BHBA, NEFA and insulin levels, evaluated during the pre-weaning period, did not differ among the groups (P > 0.05). While group numbers were modest (10 calves/treatment), this study shows that all protocols used can deliver high levels of passive transfer suggesting that either good quality maternal colostrum and/or the colostrum replacer evaluated may be recommended for newborn calf colostrum management.