Effect of ionophore supplementation and trenbolone implant on growth and carcass characteristics of lambs

Abstract

To study the effect of ionophore (monensin) and trenbolone implant on feedlot lamb growth performance (60 d) and carcass characteristics, 18 intact males (Pelibuey x Dorper 19.9 +/- 2.25 kg) were housed in individual pens and assigned to 3 treatments viz. T1: no additive nor implant (control), T2: basal diet (14\% CP and 2.6 Mcal/kg ME) with ionophore (25 ppm sodium monensin) supplementation and T3: T2 plus implant (35 mg of trenbolone acetate + 5 mg of 17-beta estradiol). No differences (P > 0.05) were found among treatments for daily dry matter intake, daily weight gain, feed efficiency and subcutaneous fat. Longissimus dorsi area was similar in T2 and T3 (P > 0.05) but higher than that in T1 (P < 0.05). Ionophore alone or with implant did not improve feedlot lamb performance (P < 0.05) or subcutaneous fat, but had beneficial effect on Longissimus dorsi area. Implant in addition to ionophore did not cause any further improvement.