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Predominately Angus steers (n = 24; initial BW = 435 ± 28.3 kg) were used to evaluate non-coated (NC) and coated implants (CI) containing equal amounts of trenbolone acetate (TBA; 200 mg) and estradiol benzoate (EB; 28 mg) in finishing steers on sera metabolite responses, gene expression, and immunohistochemical analyses of the Longissimus muscle (LM). Performance data were analyzed as a randomized complete block design, and all other data were analyzed as repeated measures for a completely randomized design. Treatments were no implant (NI), NC (Synovex-PLUS; Zoetis, Parsippany, NJ), and CI (Synovex-One Feedlot) implant. There were 2 pen replicates per treatment (n = 4 steers/pen). LM biopsies, blood, and BW were collected before feeding on days 0, 14, 28, 56, 84, 112, and 133, with final BW being captured on day 140. Genes of interest were determined by RT-qPCR using two housekeeping genes. Sera was analyzed for estradiol-17β (E2),17β-trenbolone (TbOH), insulin-like growth factor 1 (IGF-I), NEFA, and urea-N (SUN). An α of 0.10 determined significance for performance and sera data; α of 0.05 was used for gene and histology data. No performance differences (P ≥ 0.10) were detected. An implant × day interaction (P ≤ 0.10) for E2, IGF-I, and SUN was detected; implants elevated (P ≤ 0.10) E2, 17β-TbOH, and IGF-I; and decreased SUN across day of the study, meaning sera metabolites are not altered with time on feed. An implant × day interaction was detected for myogenic factor 5 (MYF-5) positive cells and proportions of MHCIIX. In LM, CI had greater (P < 0.10) IGF-I in LM over NI. CI increased (P < 0.05) G protein-coupled estrogen receptor 1 (GPER1) expression, as well as, GPER1 semi-quantitative scores over NI and NC. An implant × day interaction (P ≤ 0.05) for estrogen and androgen receptor-positive nuclei was detected; implants had increased (P ≤ 0.05) estrogen and androgen receptor-positive nuclei compared to NI. CIs increase genes associated with muscle tissue growth., (© The Author(s) 2019. Published by Oxford University Press on behalf of the American Society of Animal Science. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

A 34-year old male was found breathless and panting at home by his girlfriend three hours after a gym workout. Minutes later, he collapsed and died. Autopsy, histological and chemical analyses were conducted. The examination of the heart showed left ventricular hypertrophy, while the right coronary artery showed only a small vascular lumen (3 mm in diameter), due to its anatomical structure. In femoral blood concentrations of approx. 1 μg/L clenbuterol, approx. 56 μg/L stanozolol and approx. 8 μg/L metandienone, with trenbolone (

Exogenous growth promoters have been used in US beef cattle production for over 50 yr. The environmental fate and transport of steroid growth promoters suggest potential for endocrine-disrupting effects among ecological receptors; however, the initial excretion of steroid metabolites from cattle administered growth promoters has not been well characterized. To better characterize excretion of trenbolone acetate and estrogen metabolites, steers were assigned to 1 of the following treatment groups: control, given no implant, or treatment, administered a combination implant (200 mg trenbolone acetate, 40 mg estradiol). Blood, urine, and fecal samples were collected over the course of 112 d following implantation. Samples were extracted and analyzed by liquid chromatography tandem mass spectrometry for trenbolone acetate and estrogen metabolites. In both urine and feces, 17α-trenbolone and 17α-estradiol were the predominant metabolites following implantation. Mean concentrations of 17α-trenbolone and 17α-estradiol in feces of implanted steers were 5.9 ± 0.37 ng/g and 2.7 ± 0.22 ng/g, respectively. A best-fit model is presented to predict 17α-trenbolone and 17α-estradiol excretion from steers receiving implants. The present study provides the first characterization of both trenbolone and estrogen metabolites in excreta from implanted cattle and will help provide estimates of steroid production from feedyards in the United States., (© 2014 SETAC.)

The effects of the growth-promoting steroids estradiol-17 beta (E2), trenbolone acetate (TBA), and melengestrol acetate (MGA) in heifers on serum concentrations of E2 and trenbolone-17 beta (TBOH) were examined. Feed intake and growth performance were also measured. Serum concentrations of E2 and TBOH were measured on d 0, 1, 3, 5, 7, 13, 21, 28, 42, 56, 84, 112, and 140 in finishing heifers administered the following treatments: 1) control; 2) MGA, .5 mg per heifer daily; 3) Revalor-H (140 mg TBA + 14 mg E2); 4) Revalor-H + MGA; 5) Finaplix-H (200 mg TBA); and 6) Finaplix-H + MGA. Revalor-H implantation (Treatments 3 and 4) increased (P < .05) serum E2 concentrations; peak concentrations (67.5 pg/mL) occurred between d 21 and 56. Feeding MGA (Treatment 4) had no effect (P > .05) on this increase in serum E2 concentrations (63.3 pg/mL). From d 84 until d 140, serum E2 was greater (P < .05) for the Revalor-H treatment (average of 19 pg/mL) than for the control (7 pg/mL) or Finaplix-H treatments (6.5 pg/mL). Serum E2 concentrations increased numerically two- to threefold from d 56 to 140 in controls fed MGA, compared with controls not fed MGA. There was the expected increase in serum TBOH concentrations after TBA implantation in the Revalor-H and Finaplix-H treatments; concentrations were similar (P > .05) for Revalor-H (221 pg/mL) and Finaplix-H (280 pg/mL). After d 56, serum TBOH concentrations decreased in both treatments to 10 and 20% of these concentrations, respectively. Feeding MGA increased serum TBOH (P < .05). Dry matter intake by heifers did not differ among treatments. Feeding of MGA improved gains (P = .12) and efficiencies (P < .01) in nonimplanted heifers and had no effect (P > .4) on gains or efficiencies in Finaplix-implanted heifers.

Fifty crossbred cows (38 multiparous and 12 nulliparous) were used to evaluate in utero androgenization of heifer calves with trenbolone acetate. Three 200-mg trenbolone acetate (Finaplix-H) implants were implanted in the ear of treated cows (n = 24) on d 214 +/- 11 of gestation; the remaining animals (n = 26) were used as controls. Cows' rate of gain, serum levels of trenbolone acetate, gestation length, degree of dystocia, percentage bred back, days until conception, and 24-h milk production were evaluated. Fourteen-day weigh periods until parturition indicated that trenbolone acetate-treated dams had an increased (P < .05) average daily gain (1.05 +/- .1 kg) compared with control cows (.55 +/- .1 kg). Serum concentrations of trenbolone acetate were higher (P < .01) in treated cows with a peak at 9 d after implantation and returned to basal concentrations by d 77. Treatment did not affect degree of dystocia among all cows (P > .05) but seemed to increase (P < .01) the incidence of dystocia in nulliparous cows compared with nulliparous control cows. Gestation length and subsequent fertility were not affected by treatment (P > .05). Similarly, there was no difference in 24-h milk production (P > .05) between treated and control cows. Calf birth weight, phenotypic measurements at birth, vigor, average daily gain, carcass characteristics, and heifer reproductive tract and ovarian weights did not differ with treatment (P > .05). These data showed that late-gestation treatment with 600 mg of trenbolone acetate significantly increased weight gain of dams without demonstrating any androgenizing effects on the growth or physical characteristics of heifer calves.

Objectives of this study were to determine the influence of trenbolone acetate (TBA) and estradiol (E2) in a combined implant on feedlot performance, carcass characteristics, and carcass composition in finishing steers. Sixty-four large-framed (394.1 kg) crossbred steers were randomly assigned to one of four pens. Subsequently, pens were randomly assigned to one of two treatments, implanted (120 mg of TBA and 24 mg of E2) and nonimplanted. Eight steers/treatment were slaughtered for initial carcass composition. Remaining steers were assigned to one of three serial slaughter dates (d 40, 115, or 143). Implantation increased circulating trenbolone (TBOH) and E2 concentrations throughout the trial. Implantation increased ADG 18% (P < .001) during d 0 to 40, 21% (P < .001) from d 0 to 115, and 16% for the entire 143 d. Implant status had no effect (P > .05) on dry matter intake. Feed efficiency was improved 13% during d 0 to 40 (P < .01) and from d 41 to 115 (P = .07). Longissimus muscle area was larger (P < .05) in implanted steers than in nonimplanted steers on d 115. Carcasses from implanted steers had a smaller (P < .05) percentage of kidney, pelvic, and heart (KPH) fat on d 143 than those from nonimplanted steers. Carcasses from implanted steers possessed more carcass protein (P < .05) on d 40. Implanted steers had an 82% increase (P < .05) in daily carcass protein accretion during the first 40 d. Implantation increased (P < .01) carcass water but did not affect carcass fat accumulation throughout the feeding period. The combined TBA+E2 implant improved feedlot performance and stimulated carcass protein accretion in feedlot steers.

The effects of anabolic implant on growth, carcass characteristics, and serum hormones were examined in 30 young bulls and steers fed a growing diet then a finishing diet. In a 2 X 3 factorial arrangement, steers and bulls received an implant of trenbolone acetate (TBA), TBA and estradiol-17 beta (E2), or no implant. Blood samples were taken serially (every 20 min for 6 h) at intervals during the growing and finishing phases. Percentage of DM, fat, protein, and ash and Warner-Bratzler shear test were measured and taste panel evaluations of the 9-10-11 rib section were obtained. Treatment with TBA and E2 increased weight gain in steers but not in bulls. There were no differences in feed efficiency, serum growth hormone (GH), and cortisol concentrations between bulls and steers or between treated groups and controls in bulls or steers, although during the finishing phase mean GH concentrations in treated steers were twofold higher than in controls and were similar to those in the bull groups. Serum insulin-like growth factor-I (IGF-I) increased twofold during the growing phase, then remained at that level. Steers implanted with TBA and E2, which had the highest gains among the steer groups, had the highest serum GH and IGF-I. Longissimus steaks from bulls treated with TBA alone or TBA and E2 were comparable to steaks from steers in the shear test. Taste panelists found steaks from TBA- and E2-treated bulls to be similar in tenderness and connective tissue to steaks from steers.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of castration and anabolic implants on weight gain, rib soft tissue composition and serum hormones were studied in cattle using a completely random design with a 2 x 2 factorial arrangement. Half of 16 bulls and 16 steers (Angus or Angus x Brahman) aged 9 mo and weighing 290 kg were treated with an implant (200 mg trenbolone acetate and 24 mg estradiol). Half of each group were not treated with an implant. A growing diet was fed for 95 d and half the animals in each group were slaughtered. Animals in the treated groups were reimplanted with trenbolone acetate and fed a finishing diet for 84 d and slaughtered. Percentage dry matter, fat and protein were determined on soft tissue from the 9-10-11th rib. Two blood samples were collected from each animal every 2 wk. Serum was assayed for five hormones. During the growing phase, untreated and treated bulls and treated steers gained more weight and had leaner rib sections that untreated steers (P less than .05); after the finishing phase, there were no differences among groups. Untreated steers had lower insulin-like growth factor (IGF-I) and higher cortisol concentrations during both phases of growth than untreated bulls did (P less than .05). Treatment with implants increased IGF-I concentrations in steers during both phases and reduced cortisol during the finishing phase.(ABSTRACT TRUNCATED AT 250 WORDS)