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Zilpaterol hydrochloride (ZH) supplementation was evaluated on performance of growing goats for the last 42 days before slaughter. Forty-eight Anglo-Nubian × Criollo animals (12 per treatment) were randomly assigned to one of four treatments (ZH at daily doses of 0.0, 0.1, 0.2 or 0.3 mg/kg of BW in diet) in a complete block design. Basal diet contained 16.3% CP and 2.5 Mcal/kg ME. The ZH supplementation at doses of 0.1, 0.2 and 0.3 mg/kg of BW increased ADG by 22.1, 54.0 and 56.6%, and gain/feed ratio by 20.0, 40.0 and 60.0%, respectively. The DMI (g/kg of BW0.75) increased quadratically (P = 0.037). Carcass weight and dressing percentage (DP) augmented linearly (P ≤ 0.031) as level of ZH increased in diet. The ZH supplementation increased (P ≤ 0.023) longissimus muscle area (LM) and leg perimeter (LP) with a linear improvement (P 0.05) or trends (P > 0.10) were detected on purge loss (PL) or cooking loss (CKL). Growth differences between wether goats fed ZH doses of 0.2 or 0.3 mg/kg of BW were small, and therefore lower dose of 0.2 mg/kg of BW seems enough to enhance growth. Moreover, the carcass characteristics showed minor differences between levels of ZH supplementation, and therefore could be considered that the lower dose of 0.1 mg/kg of BW of ZH was sufficient to improve these traits. It is concluded that addition of ZH to diets of wether goats increased growth performance and carcass characteristics in a similar manner to that reported for cattle and sheep. |
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