title: Herd-of-origin effect on the post-weaning performance of centrally tested Nellore beef cattle.
abstract: The objective of a performance test station is to evaluate the performance of potential breeding bulls earlier in order to decrease the generation interval and increase genetic gain as well. This study evaluates the herd-of-origin influence on end-of-test weight (ETW), average daily weight gain during testing (ADG), average daily weight gain during the adjustment period (ADGadj), rib eye area (REA), marbling (MARB), subcutaneous fat thickness (SFT), conformation (C), early finishing (EF), muscling (M), navel (N) and temperament (T) scores, and scrotal circumference (SC) of Nellore cattle that underwent a performance test. We evaluated 664 animals that participated in the performance tests conducted at the Center for Performance CRV Lagoa between 2007 and 2012. Components of variance for each trait were estimated by an animal model (model 1), using the restricted maximum likelihood method. An alternative animal model (model 2) included, in addition to the fixed effects present in S1, the non-correlated random effect of herd-year (HY). A significant HY effect was observed on ETW, REA, SFT, ADGadj, C, and Cw (p < 0.05). The estimated heritability of all traits decreased when the HY effect was included in the model; also, the bull rank, in deciles, changed significantly for traits ETW, REA, SFT, and C. The adjustment period did not completely remove the environmental effect of herd of origin on ETW, REA, SFT, and C. It is recommended that the herd-of-origin effect should be included in the statistical models used to predict the breeding values of the participants of these performance tests.
authors.affiliation: Faculdade de Ciências Agrárias e Veterinárias, Via de Acesso Prof. Paulo Donato Castellane, s/no, Jaboticabal, SP, 14884-900, Brazil, haroldozoo@hotmail.com.
authors.forename: Haroldo Henrique
authors.initials: HH
authors.lastname: de Rezende Neves
authors.forename: Felipe
authors.initials: F
authors.lastname: Polin dos Reis
authors.forename: Flávia
authors.initials: F
authors.lastname: Motta Paterno
authors.forename: Aline
authors.initials: A
authors.lastname: Rocha Guarini
authors.forename: Roberto
authors.initials: R
authors.lastname: Carvalheiro
authors.forename: Lilian Regina
authors.initials: LR
authors.lastname: da Silva
authors.forename: João Ademir
authors.initials: JA
authors.lastname: de Oliveira
authors.forename: Sandra
authors.initials: S
authors.lastname: Aidar de Queiroz
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001835:Body Weight / Q000235:genetics* / Q000502:physiology; D001837:Body Weights and Measures / Q000662:veterinary; D001938:Brazil; D001947:Breeding / Q000379:methods*; D002417:Cattle / Q000235:genetics* / Q000254:growth & development*; D016013:Likelihood Functions; D008297:Male; D008460:Meat / Q000032:analysis* / Q000592:standards; D010641:Phenotype; D015430:Weight Gain / Q000235:genetics* / Q000502:physiology