Soybean Hull Supplementation for Growing Beef Cattle in Winter Rye Pasture Production Programs

A grazing study was conducted over 2 yr at the Samuel Roberts Noble Foundation Red River Demonstration and Research Farm (Burneyville, OK) to determine the effect of stocking rate and ad libitum soybean hull (SBH) supplementation on cattle growth performance while grazing cereal rye (Secale cereal). Steers were randomly allotted to 1 of 5 treatments as follows: (1) conventional-steers grazed rye pasture beginning December 6, 2004 (yr 1), and December 13, 2005 (yr 2), at an initial stocking rate of 2.5 steers/ha or 560 kg BW/ha; (2, 3, and 4; designated as treatments SR1120, SR1400, and SR 1680)-steers grazed rye pasture at increasing initial stocking rates that resulted in 1,120, 1,400, or 1,680 kg BW/ ha and had ad libitum access to soybean hulls; (5) optimum-steers grazed rye pasture at variable stocking rates in an attempt to maintain a forage mass of not less than 840 kg/ha throughout the study. Daily SBH consumption in yr 1 ranged from 5.2 to 6.2 kg /steer for treatments SR1120, SR1400, and SR1680 and increased linearly (P < 0.01) as stocking rate increased. A quadratic response (P < 0.05) was observed for daily SBH consumption during yr 2. There was no significant linear (P > 0.36) or quadratic (P > 0.16) trend for ADG or gain per steer in both years. In contrast, gain per hectare increased linearly (P < 0.01) as stocking rate increased. Averaged across the SR1120, SR1400, and SR1680 treatments, providing soybean hulls ad libitum allowed stocking rate to be increased about 2.0 to 2.25-fold over the conventional treatment and increased gain per hectare by about 465 kg without decreasing individual animal performance.