The effect of shade on steer performance after terminal sort

Abstract

Heat stress negatively impacts performance and welfare and occurs when total environmental and metabolic thermal load exceeds an animal’s ability to dissipate heat. Access to shade has been associated with reductions in body temperature and respiratory rate in cattle, but previous findings on cattle performance has been inconsistent. This pen-level randomized controlled trial evaluated the effects of shade (1.3 m2/head, 100% solar block; n = 12 pens) versus no shade (n = 12 pens) on steer performance following terminal sort at a commercial feedyard in the Pacific Northwest, where animals were housed on roller-compacted concrete floors. Data collected included water consumption, feed delivery, disease events, open mouth breathing (OMB) behavior, and carcass traits. Shade reduced water consumption by 15% (P < 0.05), and pens without shade showed a 6% decrease in feed delivery when the previous day’s temperature-humidity index (THI) was ≥ 80 (P < 0.05). Additionally, shade reduced OMB behavior (P = 0.09), the number of culled steers (P < 0.05), and the incidence of dark cutters (P < 0.05). A greater proportion of steers in shaded pens graded choice and prime (93%), compared to those in unshaded pens (91%) (P < 0.05). Inclusion of shade improved animal health, welfare, carcass quality, and environmental stewardship during the summer months in a commercial feedyard setting. Shade should be considered a valuable management tool for mitigating heat stress in finishing cattle.