Feedlot performance and carcass traits of hairbreed ewe lambs in response to zilpaterol hydrochloride and soybean oil supplementation

Abstract

The aim of the present study was to evaluate the impact of zilpaterol hydrochloride (ZH; 0 or 10 mg/lamb daily) and soybean oil (SBO; 0 or 6%) supplementation on feedlot performance, carcass traits, and wholesale cut yield of 32 Dorper × Pelibuey ewe lambs (30.55 ± 2. 57 kg of initial BW). Lambs were blocked by BW and randomly assigned to treatments under a randomized complete block design with a 2 × 2 factorial arrangement. After a 34-d feeding period, all ewes were slaughtered. No ZH × SBO interactions were detected (P ≥ 0.11) for the variables evaluated. In the overall feeding period and first 17 d of experiment, feedlot performance was not affected (P ≥ 0.26) by ZH supplementation, but from d 18 to 34, ZH increased (P ≤ 0.03) total gain, ADG, and G:F without affecting DMI (P = 0.58). Also, ZH increased (P ≤ 0.02) HCW, cold carcass weight, dressing percentage, LM area, and leg perimeter. Lung weight as percentage of final BW decreased (P = 0.05) whereas other noncarcass components and wholesale cut yields were not affected (P ≥ 0.06) by ZH supplementation. Inclusion of SBO did not affect (P ≥ 0.08) feedlot performance or wholesale cut yields. The LM pH at 24 h postmortem as well as liver and peritoneum percentages were decreased (P ≤ 0.05) by SBO supplementation, but no other carcass characteristics or noncarcass components were affected (P ≥ 0.08) by SBO. In conclusion, feedlot performance and carcass characteristics were not altered by the interaction of ZH × SBO. However, ZH alone increased the growth of ewes during the last 17 d of the feeding period. Likewise, carcass characteristics of economic importance (i.e., HCW, dressing percentage, LM area, and leg perimeter) increased with ZH supplementation. In general, feedlot performance, carcass traits, and wholesale cut yields were not altered by including 6% of SBO in the finishing diet of ewe lambs.

Zilpaterol hydrochloride improves growth performance and carcass traits without affecting wholesale cut yields of hair sheep finished in feedlot

“…Thus, ZH in lambs increases the formation of lean meat and, hence, the carcass weight and yield, as well as LM area at the same time that internal fat deposition decreases. Consistent with the present study, most studies in sheep have reported a lack of ZH effects on energy repartition away from subcutaneous fat (Estrada-Angulo et al 2008;Macias-Cruz et al 2010;Ríos-Rincón et al 2010;Dávila-Ramírez et al 2014, 2015.…”

“…slaughter has shown to consistently improve growth and feed efficiency in beef cattle (Avendaño-Reyes et al 2006;Lean et al 2014); however, it has been inconsistent in finishing lambs. Some studies have reported no effects (Macias-Cruz et al 2010;Dávila-Ramírez et al 2015), improvements of growth rate and feed efficiency without affecting DMI (Estrada-Angulo et al 2008;Mondragón et al 2010;Avendaño-Reyes et al 2011) or increased growth rate, and feed efficiency and decreased DMI (López-Carlos et al 2011, 2012 in sheep after 30-34 d consuming feedlot diets supplemented with ZH. Improvement in growth rate has been the most consistent and DMI the least consistent effect of ZH on sheep.…”

Effect of Zilpaterol Hydrochloride on Performance and Meat Quality in Finishing Lambs

“…Avendaño et al [1] reported that wholesale cuts were not affected by ZH, except for neck yield, which decreased (based on HCW) with feeding ZH. The percentage of loin is greater in ewe lambs fed ZH [33]. The variation in response to ZH supplementation among wholesale cut yields obtained from lamb carcasses could depend on the presence and amount of type II muscle fibers located in each cut, given that β2-adrenergic receptors are mainly located in these fibers [34].…”

Suplementación de clorhidrato de zilpaterol en corderos finalizados con dieta sin fibra de forraje

“…En ovinos de pelo finalizados con diferentes dosis de CZ genérico en dos experimentos (22) , se reportó un aumento cuadrático en el largo de canal, profundidad de tórax y perímetro de pierna como la dosis ofrecida de CZ aumentó de 0 a 0.20 mg/kg de peso vivo. En corderos (24,28) y corderas (19) también han encontrado un aumento en el perímetro de pierna sin efecto alguno en otras medidas morfométricas a consecuencia del CZ de patente.…”

“…En el caso del grupo testigo, a manera de placebo, una cápsula de gel que contenía 208 mg de harina de soya fue ofrecida diariamente a cada cordero. La dosis ofrecida de CZ estuvo acorde a recomendaciones de estudios previos (18,19) . EL CZ se ofreció por 28 días, seguido de un periodo de retiro de 48 h antes de sacrificar los animales.…”