Effect of an implant of trenbolone acetate and estradiol on growth, feed efficiency, and carcass composition of Holstein and beef steers1

Abstract

The effects of an implant of 140 mg of trenbolone acetate and 28 mg of estradiol (TBA + E2) on performance and carcass composition were evaluated with 72 individually fed steers. Holstein (n = 24), Angus (n = 24), and Angus x Simmental (n = 24) steer calves were allocated by breed and implant treatment to either an individual feeding pen (n = 36) or an electronic feeding door in a group pen (three pens with 12 animals per pen). Intake and refusal of the 85% concentrate diet were recorded daily. Animals were slaughtered when ultrasonic attenuation values of the longissimus muscle at the 12th rib reached .55, which is correlated with low Choice marbling. At slaughter, complete carcass measurements were taken and the right side of each carcass was separated into boneless wholesale cuts. Implanting with TBA + E2 improved (P less than .01) daily gain and feed efficiency. Daily gain was increased 17, 26, and 21% in Holstein, Angus, and crossbred steers, respectively. The implant increased overall daily protein and fat accretion 23%. Carcass conformation and dressing percentage were not affected (P greater than .05) by TBA + E2 treatment. Implantation with TBA + E2 had little effect on yield of wholesale boneless cuts when expressed as a percentage of carcass weight but increased absolute weight as a small degree of marbling by 6 to 40 kg.

The Effect of Delaying Initial Feedlot Implant on Body Weight, Average Daily Gain, and Carcass Characteristics of Calf-Fed Steers

“…Previous work has shown that implants increase HCW compared with nonimplanted cattle; however, when different implant treatments are compared, little difference exists between HCW (Samber et al, 1996;Scaglia et al, 2004;Bruns et al, 2005), as was the case in the current study. Several studies have shown little effect of implant on external FT (Perry et al, 1991;Pritchard, 1994;Samber et al, 1996;Scaglia et al, 2004;Bruns et al, 2005), LM area (Samber et al, 1996;Scaglia et al, 2004;Bruns et al, 2005), and KPH fat (Foutz et al, 1990;Samber et al, 1996;Bruns et al, 2005), which is in agreement with the present study. The major focus of this study was to determine the impact of delaying the initial feedlot implant on QG in calf-fed steers.…”

Effects of combining recombinant bovine growth hormone and anabolic implants on growth performance and dietary energetics of Holstein bull calves fed finishing diets

“…Treatment effects on growth performance of Holstein bull calves are presented in the Table. Compared with nonimplanted controls, implanting increased (P < 0.01) the overall day 56 DMI (8.3%), ADG (18.5%), gain efficiency (ADG:DMI, 7.9%), dietary NE m and NE g (5.6% and 6.4%, respectively), and apparent energy retention per unit of DMI (7%). These results are consistent with previous studies involving calffed Holstein steers, wherein implanting improved ADG by 12% to 18% and gain efficiency by 7% to 12% (13,14). Zinn , and SBW is the average SBW.…”

Effect of growth-promoting technologies on Longissimus lumborum muscle fiber morphometrics, collagen solubility, and cooked meat tenderness12

“…In their review of the literature, Duckett and Pratt (2014) stated that anabolic implants do not or minimally influence 12th rib BF thickness. Perry et al (1991), Gerken et al (1995), and Roeber et al (2000) reported that various anabolic implants do not influence BF thickness. In the current study, BF thickness tended to be reduced by 25% in the IMP carcasses.…”