Influence of Creep Feeding and Protein Level on Growth and Maternal Performance of Replacement Beef Heifers

Abstract

Crossbred Simmental cows (n = 102) nursing heifer calves at two farms (36 pairs grazed mixed cool-season grasses; 66 pairs grazed endophyte infected tall fescue pasture) were randomly assigned to three treatments to determine the effects of creep feed and creep feed protein level on growth, reproduction, and first lactation performance of replacement heifers. Treatments were no creep, 14% CP creep, and 18% CP creep. Creep feeds were offered ad libitum for 84 d prior to weaning. Pasture replicate served as the experimental unit for pre-weaning performance, and postweaning growth, reproduction, and maternal performance utilized individual animal as the experimental unit. Creep feeding and additional dietary protein in creep feed improved (P≤0.05) ADG of nursing calves on pasture. Creep feeding resulted in heavier weight, fatter (P≤0.05) heifers at breeding, but creep CP level did not affect (P>0.05) breeding composition. Body weight at pregnancy determination and postcalving were not different (P≥0.05) because of treatments. Pre-weaning treatment did not influence (P≥0.05) pregnancy, weaning, and calving rates. Noncreep-fed heifers produced more (P≤0.01) milk during the first lactation than creep-fed replacements. High protein creep tended (P≤0.10) to improve milk production during the first 2 mo of lactation. Nonetheless, total milk production was not different (P≥0.05) because of creep CP level. Creep feeding improves pre-weaning growth and depresses first lactation milk production; however, providing additional dietary CP in creep feeds may improve lactation performance during the first 2 mo.