Effect of zilpaterol hydrochloride on carcass composition, subprimal yield, and meat quality of Nellore heifers
The aim of this research was to evaluate the effects of zilpaterol hydrochloride (ZH) on carcass composition, carcass subprimal yield and meat quality of Nellore heifers. Seventy-two animals were fed with ZH (Zilmax®, MSD) during 30 days, allowing for 3 d of product withdrawn before slaughter. The animals were blocked by BW and previous ADG and allocated into two groups: Control and Zilpaterol (8.3 mg ZH/kg of diet DM). After 24 h postmortem, left carcasses were processed and the 9–10–11th rib sections (HH sample) were removed from the primal rib to determine carcass chemical composition. Four steak samples were collected from the longissimus muscle to determine cooking loss and shear force (WBSF) after 0, 7 14 and 21 of aging. The right carcasses were processed into primal cuts, and weighed. Each primal cut was further processed into boneless subprimal cuts, minor cuts, lean trim, fat, and bone. Statistical analyses were conducted using the MIXED procedure of SAS considering the fixed effects of treatment and the random effect of block. Treatments had no effect on the protein, fat or ash content of the carcass, as estimated by water content. Cooking loss was unaffected by ZH supplementation. There was a ZH*Aging interaction for WBSF, with greater WBSF for ZH at 7 and 14 of aging. ZH supplementation increased (P<0.05) the weights of most of the meat cuts analyzed, especially the cuts from the hindquarter (P<0.01), including top sirloin cap (P=0.01), striploin (P=0.05), tenderloin (P<0.01), eye of rump (P<0.01), knuckle (P<0.001), inside round (P<0.001), outside round (P=0.01), and eye of round (P<0.05). Additionally, ZH increased by 7.66% of the subprimal yield and by 1.94% of the debone yield of the heifers. In conclusion, ZH supplementation had no effect on chemical carcass composition, decreased meat tenderness after 7 and 14 d of aging, and increased meat cuts weights and carcass subprimal yield.
Keywords: Beta-agonist, Shear force, Subprimal yield