Serum concentrations of trenbolone-17beta and estradiol-17beta and performance of heifers treated with trenbolone acetate, melengestrol acetate, or estradiol-17beta

• Published in: Journal of animal science 1997-10, Vol.75 (10)
• Main Authors: Henricks, D.M, Brandt, R.T. Jr, Titgemeyer, E.C, Milton, C.T
• Format: Article
• Language: English
• Subjects: ACETATE (ESTER); ACETATES (ESTERS); ACETATOS (ESTERES); ADIPOSE TISSUES; ADMINISTRACION ORAL; ADMINISTRATION ORALE; AREAS; BEEF; BEEF CATTLE; BLOOD SERUM; BOVIN DE BOUCHERIE; CALIDAD; CANAL ANIMAL; CARCASSE; CARCASSES; CARNE DE RES; CONTROLLED RELEASE; COWS; DEPOT FAT; DOSAGE; DOSIFICACION; DRESSING PERCENTAGE; EFFICACITE ALIMENTAIRE; EFICIENCIA DE CONVERSION DEL PIENSO; ESTEROIDES; ESTROGENOS; FAT THICKNESS; FEED CONVERSION EFFICIENCY; FEED INTAKE; GAIN DE POIDS; GANADO DE CARNE; GANANCIA DE PESO; GENISSE; HEIFERS; HORMONAS SINTETICAS; HORMONE SYNTHETIQUE; IMPLANTATION; INGESTION DE PIENSOS; LIBERACION CONTROLADA; LIBERATION CONTROLEE; LIVEWEIGHT GAIN; MARBLING; MUSCLE; MUSCLES; MUSCULOS; NOVILLA; OESTROGENE; OESTROGENS; ORAL ADMINISTRATION; PESO; POIDS; PRISE ALIMENTAIRE (ANIMAUX); QUALITE; QUALITY; RADIOIMMUNOASSAY; RENDEMENT A L'ABATTAGE; RENDIMIENTO EN CANAL SIN DESOLLAR; SERUM SANGUIN; STEROIDE; STEROIDS; SUERO SANGUINEO; SYNTHETIC HORMONES; TECHNIQUE RADIOIMMUNOLOGIQUE; TECNICAS RADIOINMUNOLOGICAS; TEJIDO ADIPOSO; TISSU ADIPEUX; TRANSPLANTATION; TRASPLANTES; TREMBOLONA; TRENBOLONE; VACA; VACHE; VIANDE BOVINE; WEIGHT; WEIGHT GAIN
• ISSN: 0021-8812; 1525-3163

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 .4) on gains or efficiencies in Finaplix-implanted heifers