Effect of Duration of Zilpaterol Hydrochloride Treatment on Carcass Characteristics and Weight Gain in Grazing Pelibuey Lambs

摘要

Salinas-Chavira, J., Dom???-nguez-Mu???±oz, M., D???-az-Mart???-nez, R., Cruz-Bautista, P., Monta???±o-G???3mez, M.F. and Arzola-Alvarez, C. 2006. Effect of duration of zilpaterol hydrochloride treatment on carcass characteristics and weight gain in grazing Pelibuey lambs. J. Appl. Anim. Res., 29: 25?￠????28. The effect of zilpaterol hydrochloride (ZH) supplementation on carcass characteristics and weight gain were studied in grazing Pelibuey lambs. Thirty-six intact male Pelibuey sheep, (21.42???±3.32 kg) were kept in three paddocks with Angleton grass ( Dichantium aristatum ) and were fed a supplement (sorghum, soybean meal, urea, molasses, tallow and minerals) containing 21.76% crude protein and 2.77 Meal I kg ME during 60 days feeding trial. Three paddocks formed the corresponding experimental groups: T1 (control), with no ZH in the supplement; T2 received 10 ppm ZH in supplement during the last 20 days of the trial and T3 received ZH during the last 30 days. The backfat was thinner (P<0.05) in both ZH groups than in the control group, measuring 0.28, 0.24 and 0.24 cm in T1, T2 and T3, respectively. The Longissimus dorsi measured 6.53, 6.24 and 5.84 cm 2 , respectively, and did not differ among dietary treatments. The average daily gain was also similar (P>0.05) among all experimental groups. It may be concluded that supplementation of zilpaterol hydrochloride during different intervals reduced the backfat cover in grazing Pelibuey sheep fed on supplemental concentrate.