Effects of Diet Fed in Drylot on Subsequent Grazing Performance of Growing Cattle1

Two experiments were conducted to determine the effects of diet and rate of BW gain in drylot before grazing on subsequent grazing performance. In Experiment 1, 154 calves (initial BW ± SE = 181 ± 1.98 kg) were fed bermudagrass (Cynodon dactylon (L.) Pers.) hay or were program-fed for an ADG of 0.23, 0.57, or 0.91 kg/d. In Experiment 2, 96 calves (initial BW ± SE = 211 ± 1.63 kg) were fed bermudagrass hay with either a dry (DS) or a molasses-based supplement (MBS) or were program-fed a diet containing either a dry (PFD) or molasses- based (PFM) supplement (2 × 2 factorial). Regression analysis of grazing performance during Experiment 1 suggested that pasture ADG was reduced by 0.10 kg for every kilogram increase in gain during the feeding period (P<0.01; r2 = 0.13). During the first 41 d of grazing small grains or tall fescue, calves program fed in drylot gained 0.31 kg/d (P<0.01) or tended (P=0.07) to gain 0.26 kg/d, respectively, more than calves fed hay in drylot. In Experiment 2, during the first 14 d of the grazing period, program-fed calves (PFD and PFM) gained 0.74 kg/d more (P<0.01) than calves fed hay-based diets (DS or MBS), and calves on the MBS and PMBS treatments gained 0.23 kg/d more (P=0.01) than calves on the DS and PFD treatments. Program feeding is an economical alternative to feeding calves hay and supplement, and diet fed in drylot can influence performance of calves adapting to high quality pasture.