Escape Protein for Growing Cattle Grazing Stockpiled Tall Fescue1

Forty steers and 40 heifers were allocated by gender and previous treatment to eight 12-acre Kentucky-31 tall fescue pastures. Each pasture was assigned to one of four supplement treatments to test the ability of either supplemental energy or two levels of supplemental escape protein to correct a possible ruminal imbalance of protein and energy found in high quality forages. Supplementation treatments consisted of 1) no supplemental feed offered (CONTROL), 2) supplemental corn (CORN), 3) a 22% CP supplement designed to supply 100 g/ day escape protein, a low level of escape protein supplementation (LEP), or 4) a 42% CP supplement designed to supply 200 g/day of escape protein, a higher level of escape protein (HEP). Supplements were designed to supply 200 mg/day of lasalocid, and free-choice mineral was offered to all calves in weather vane type feeders. Statistical analysis was conducted using steers only, heifers only and with both genders in the data set. Combined gender analysis indicated that performance of calves grazing fescue is increased by supplementation, but gains were not improved with the addition of escape protein to energy supplements. Performance of steers was increased by supplementation, while supplementation did not statistically increase gains in heifers. The different responses due to gender indicate energy supplementation is required in steers grazing stockpiled fescue in the winter and spring, but is unnecessary in heifers.