Abstract

To evaluate the effect(s) of the heat stress (HS) on body composition thirty-two growing Afshari lambs were randomly housed outdoor (OUT) without access to shade (mean temperature humidity index = 74.98) or kept indoor (IN) under shade (mean temperature humidity index = 73.08). At the end of study 10 lambs were processed and separable body protein and fat were determined. Neither morning rectal temperature nor morning respiratory rate were influenced by treatments, but both were increased in OUT lambs at evening measurement; the evening rectal temperature was higher in OUT lambs and they had more evening respiration rate (48 ± 1.4 more breath per minute). While there was no difference between treatments in carcass weight, fat-tail weight as a percent of cold carcass weight tended to be lighter (P = 0.13) for OUT lambs (15.17%) than for IN lambs (18.77%). Carcass separable fat with and without fat-tail showed no effect of treatments. Carcass EE was not influenced by environment. Carcass crude protein percentage was greater for OUT (16.64%) than for IN lambs (15.17%; P < 0.05). Carcass bone was not influenced by treatments. Collectively, for the first time, our data show that under the conditions of the current experiment, inaccessibility to shade and HS did not markedly change body composition in growing Afshari lambs.