title: Trenbolone acetate/estradiol combinations in feedlot steers: dose-response and implant carrier effects.
abstract: Two experiments were conducted at three locations to determine the correct dosage and carrier for trenbolone acetate (TBA) and estradiol (E2) implants in feedlot steers. In the dose-response experiment, 1,296 steers were allotted to six implant treatments (48 pens per location): control, 140 mg of TBA (140/0), 30 mg of E2 (0/30), 20 mg of TBA + 4 mg of E2(20/4), 80 mg of TBA + 16 mg of E2(80/16), and 140 mg of TBA + 28 mg of E2 (140/28). In the carrier experiment, 575 steers were allotted to five implant treatments (25 pens per location): control, 140 mg of TBA + 28 mg of E2 in lactose (140/28-LA), 140 mg of TBA + 28 mg of E2 in cholesterol (140/28-CH), 140 mg of TBA + 20 mg of E2 in LA (140/20-LA), and 200 mg of progesterone + 20 mg of E2 benzoate (SS, reimplanted). In both experiments steers were fed a finishing diet for 140 to 168 d. In the dose-response experiment, response to TBA alone (140/0) did not differ from control (P greater than .2). Estradiol alone (0/30) improved ADG by 7% (P less than .01) and tended to improve feed efficiency over control (3%, P = .17). The highest dosage (140/28) improved ADG by 18% (P less than .001) and feed efficiency by 10% (P less than .001) over control and 10% (P less than .001) and 7% (P less than .01) over E2 alone, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Animal Science, Texas Tech University, Lubbock 79409.
authors.forename: S J
authors.initials: SJ
authors.lastname: Bartle
authors.forename: R L
authors.initials: RL
authors.lastname: Preston
authors.forename: R E
authors.initials: RE
authors.lastname: Brown
authors.forename: R J
authors.initials: RJ
authors.lastname: Grant
mesh_terms: D000273:Adipose Tissue / Q000033:anatomy & histology / Q000187:drug effects; D045930:Anabolic Agents / Q000494:pharmacology*; D000704:Analysis of Variance; D000818:Animals; D002417:Cattle / Q000254:growth & development*; D002784:Cholesterol; D004305:Dose-Response Relationship, Drug; D004343:Drug Implants; D004435:Eating / Q000235:genetics; D004958:Estradiol / Q000008:administration & dosage / Q000494:pharmacology*; D007785:Lactose; D008297:Male; D008460:Meat / Q000592:standards; D024510:Muscle Development; D009132:Muscles / Q000033:anatomy & histology / Q000187:drug effects; D011336:Probability; D011897:Random Allocation; D014204:Trenbolone Acetate / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology; D015430:Weight Gain / Q000187:drug effects
chemical_list: D045930:Anabolic Agents; D004343:Drug Implants; D004958:Estradiol; D002784:Cholesterol; D007785:Lactose; D014204:Trenbolone Acetate