THE EFFECT OF TRENBOLONE ACETATE ON PERFORMANCE, PLASMA-LIPIDS, AND CARCASS CHARACTERISTICS OF GROWING RAM AND EWE LAMBS

The purpose of the study was to determine the effect of trenbolone ace tate (TBA) on performance, plasma lipid metabolites, and carcass chara cteristics of growing ram and ewe lambs in two separate experiments. T reatments consisted of 1) a control, no implants, and 2) a TBA implant (60 mg of Finaplix(R); Hoechst-Roussel Agri-Vet). Twelve Rambouillet cross ram lambs (average 19.9 kg BW; Exp. 1) and 18 Suffolk-Hampshire ewe lambs (average 37.2 kg BW; Exp. 2) were given ad libitum access to a 77% forage/23% concentrate diet (15.5% CP and 2.14 Mcal of ME/kg). On d 0, six rams and nine ewes received TBA as an ear implant and six rams and nine ewes were designated as controls. Blood samples were col lected via jugular venipuncture on d 0, 28, 56, and 84 and plasma was separated and analyzed for lipid metabolites. Rams (30.5 kg BW) and ew es (50.0 kg BW) were slaughtered after 93 and 91 d, respectively. Aver age daily gain was not affected by TBA in rams (117 g/d) or ewes (159 g/d). Nutrient intake restricted normal BW gains in the rams. Plasma c oncentrations of total cholesterol, high-density lipoprotein cholester ol, triglycerides, and nonesterified fatty acids were not affected by TBA in either rams or ewes. Trenbolone acetate had no effect on subcut aneous fat measurements in either rams or ewes. Lamb chops from rams i mplanted with TBA were less (P < .04) tender (5.58 vs 4.26 kg/1.27-cm core) than lamb chops from control rams. Additional studies examining growth and carcass composition are needed in ruminants implanted with anabolic steroids and fed high-forage diets.