Effect of Cottonseed Cake Supplementation Rate and Stocking Rate on the Growth Performance of Summer Stockers

Seventy-two steers (291 kg; SD = 31.4) were allocated to one of eighteen 0.81-ha bermudagrass (Cynodon dactylon L.) pastures to study the effects of stocking rate and cottonseed cake supplementation. Pastures were assigned to 1 of 3 stocking rates (SR: 3.7, 4.9, or 6.2 calves/ha) and 1 of 3 cottonseed cake supplementation rates (CCR: 0, 0.3, or 0.6% BW, as fed). Poor summer growth resulted in early termination of 9 pastures; however, the number of grazing days did not differ among SR (P = 0.34), CCR (P = 0.47), or their combination (P = 0.81). There were no interactions (P > 0.10) between SR and CCR for any BW response. Average daily gain followed CCR linearly (P < 0.001); however, the incremental gain between 0 and 0.3% CCR was 0.2 kg/d greater than the incremental gain between 0.3 and 0.6% CCR. In addition, BW gain per hectare responded quadratically (P = 0.04) to CCR. The 0.3% CCR pastures produced 140 kg/ha more BW than 0% CCR, whereas 0.6% CCR pastures produced 19 kg/ha more BW compared with 0.3% CCR. Supplemental feed efficiency tended (P = 0.09) to be greater for 0.3% CCR. Increasing SR resulted in a linear reduction in forage allowance (P < 0.001). Although ADG did not differ among SR (P = 0.41), BW gain per hectare increased linearly (P = 0.003) and was greatest at 6.2 calves/ha. In conclusion, supplementation resulted in similar performance gains across all SR. Supplementing at 0.3% BW was most efficient, and 6.2 calves/ha maximized BW gain per hectare.