Zilpaterol Hydrochloride on Performance and Sperm Quality of Lambs Fed Wet Brewers Grains

Forty Rambouillet x Pelibuey male lambs were grouped as light-weight (LW; n = 20; 28±1.2 kg BW) and heavy-weight (HW; n = 20; 40.5±1.6 kg BW) to be fed a finishing diet containing 60% wet brewers grain with or without 6 mg kg⁻¹ DM of β-adrenergic agonist zilpaterol hydrochloride (ZH). On d 60 of the feeding trial, ZH was removed and semen collection was measured by electroejaculation. Further, on d 63 animals were slaughtered for carcass and meat quality evaluation. On d 15 of the feeding trial, lambs fed ZH gained significantly (about 25%) more weight. However, at the end of feeding trial (60 d period), ADG, DMI and feed efficiency were unaffected by ZH consumption. Sperm motility was significantly reduced by ZH only in HW lambs; but, sperm concentration was not affected. Conversely, storage loss at 96 h, cooking loss and drip loss were significantly higher and water holding capacity was significantly lower in animals fed ZH. It appears that ZH addition to diet of lambs had not caused positive performance effects during long period of feeding, however, it affected the reproductive performance of rams.