Interactions of shade and feeding management on feedlot performance of crossbred steers during seasonal periods of high ambient temperature

Three experiments were conducted to evaluate the influence of shade and feeding management on performance of crossbred steers during periods of high ambient temperature. Exp. 1 evaluated the influence of shade (0 vs. 3.3 m2/steer) on growth performance and dietary NE. Air temperature and humidity averaged 29.7 °C and 44%, respectively. Shade improved DMI (6%, P < 0.10) and ADG (9%, P < 0.05). Exp. 2 and 3 evaluated the interaction of shade (0 vs. 2.4 m2/steer) and feeding schedule (providing 70% of DMI at 0630 vs. 1430 h). Air temperature and humidity for both studies averaged 31 °C and 41%. In Exp. 2, providing shade increased (P < 0.05) DM and water intake (5 and 30%, respectively). There were interactions (P < 0.05) between shade and feeding schedule on ADG, gain efficiency, and dietary NE. In the absence of shade, providing 70% of DMI in the afternoon increased ADG (22%), gain efficiency (14%), and dietary NE (6%). However, in the presence of shade, feeding schedule did not affect cattle performance or dietary NE. In Exp. 3, providing shade increased ADG (14%, P < 0.10), gain efficiency (10%, P < 0.05), and dietary NE (6%; P < 0.05). Providing 70% of DMI in the afternoon did not affect (P > 0.20) ADG but increased (4%, P < 0.10) dietary NE. It is concluded that both provision of shade and management of feeding schedule are effective tools for improving growth-performance and efficiency of energy use in feedlot cattle.