title: Effects of creep feeding, zeranol implants and breed type on beef production: I. Calf and cow performance.
abstract: A 2-yr study was conducted to evaluate the effects of a high-energy creep feed, preweaning zeranol implants and breed type on calf and cow performance. Two hundred calves sired by Brahman and Romana Red bulls out of Angus and Angus x Brown Swiss reciprocal crossbred (F1) dams were stratified by breed type and sex to three creep treatments: no creep feed (NC); long-term creep (LC), creep-fed from 56 to 210 d of age (weaning); and short-term creep (SC), creep-fed from 146 to 210 d of age. Alternate calves within sex, breed type and creep treatment were implanted with 36 mg of zeranol at an average of 56 d and reimplanted 90 d later. The LC and SC calves had heavier (P less than .001) 210-d weights than NC calves (264 and 257 vs 231 kg, respectively), and the LC calves were heavier (P less than .001) at 146 d than NC calves. The LC calves had higher (P less than .001) ADG from 118 to 210 d of age and higher 146 and 210-d condition scores than did NC calves. Pregnancy rate was not affected (P greater than .46) by creep treatment of calf. Zeranol implants increased (P less than .01) 146- and 210-d weights (184 vs 175 kg and 259 vs 243 kg) and ADG during all periods to weaning. Brahman-sired calves had higher (P less than .005) 146- and 210-d weaning weights and frame scores than Romana Red-sired calves.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: University of Florida, Gainesville 32611.
authors.forename: D L
authors.initials: DL
authors.lastname: Prichard
authors.forename: D D
authors.initials: DD
authors.lastname: Hargrove
authors.forename: T A
authors.initials: TA
authors.lastname: Olson
authors.forename: T T
authors.initials: TT
authors.lastname: Marshall
mesh_terms: D000821:Animal Feed; D000818:Animals; D001947:Breeding; D002417:Cattle / Q000254:growth & development* / Q000502:physiology; D004343:Drug Implants; D005260:Female; D005298:Fertility; D008297:Male; D012118:Resorcinols / Q000494:pharmacology*; D012737:Sex Factors; D015430:Weight Gain / Q000187:drug effects; D015029:Zeranol / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D004343:Drug Implants; D012118:Resorcinols; D015029:Zeranol