Do livestock need shade?

There is often debate as to whether livestock should have access to shade. To address this question, researchers in Australia looked at the effect of shade on body temperature and performance of feedlot cattle.

Angus steer

164 Angus steers were allocated to twenty pens.  Ten pens were shaded with an 80 percent solar block shade cloth.  Ten pens were unshaded. Water usage and dry matter intake was measured. Average daily gain and gain-to-feed ratio was calculated on a pen basis.  Body temperature was determined every 30 minutes via an implanted transmitter. After 120 days, the cattle were harvested and carcass data was collected.

Average body temperature was not affected by shade, except during a 21-day heat wave (8 hr/d of >86 degrees F) when the shaded cattle had a lower body temperature.  Dry matter intake, average daily gain, and gain-to-feed ratio were higher for cattle that had shade. The shaded cattle also had heavier hot carcass weights. Shade had no effect on loin muscle area, fat depth, or marbling score.

Shade improved the performance of feedlot cattle, but did not completely eliminate the impact of a high heat load, as during the heat wave, the shaded cattle consumed 39 percent less feed (the unshaded cattle consumed 51 percent less feed).

Source:  Journal of Animal Science.  December 2010.  Read abstract.