Impact of shade in beef feedyards on performance, ear temperature, and heat stress measures

Abstract

A 2-yr study (year 1: March to September 2017; year 2: February to August 2018) was conducted using crossbred steers (year 1: n=1677; initial body weight [BW]=372 kg, SD=47; year 2: n=1713; initial BW=379 kg, SD=10) in a commercial feedyard study in Eastern NE to determine the effects of shade on cattle performance, ear temperature, and cattle activity. Two treatments were evaluated using a randomized complete block design (n=5 blocks based on arrival). Treatments were assigned randomly to pens and consisted of five pens without shade (NO SHADE) and five pens with shade (SHADE). Ear temperatures were collected throughout the trials using biometric sensing ear tags on a subset of cattle. Panting scores were collected using a 5 point scale determined visually based on the level of panting occurring on the same subset of steers a minimum of twice weekly from June 8 to August 21 in year 1 and May 29 to July 24 in year 2 by one trained individual each year. In year 1, no differences (P≥0.24) were observed for growth performance or carcass characteristics. Dry matter intake (DMI) and average daily gain (ADG) were greater (P≤0.04) for SHADE cattle in year 2. Over the entire feeding period in year 1, greater (P<0.01) ear temperature was observed for NO SHADE cattle, but cattle movement was not different (P=0.38) between treatments. When evaluating the entire feeding period in year 2, cattle movement and ear temperature were not different (P≥0.80) between treatments. Cattle in the SHADE treatment had lower (P≤0.04) panting scores in years 1 and 2. These data suggest that providing shade can lessen the negative influence of heat events on DMI and was an effective way to reduce heat stress in feedlot operations, but only impacted ADG if heat events were close to the cattle slaughter date.