Data/hora: 11/06/2024 09:40:39

Provedor de dados: | 65
País: | Brazil
Título: | Genetic trends for mature body weight, visual scores, and growth traits in Nellore cattle
Autores: | Koetz Júnior,Celso; Roso,Vanerlei Mozaquatro; Claus,Luís Afonso Marques; Oliveira,Rui Paulo Lopes de; Fávaro,Patrícia da Cruz; Borges,Marcelo Henrique Favaro; Barcellos,Júlio Otavio Jardim; Ribeiro,Edson Luís de Azambuja.
Data: | 2017-01-01
Ano: | 2017
Palavras-chave: | Beef cattle; Productive traits; Selection.
Resumo: | ABSTRACT: Mature weight (MW) of cows is related to the costs of their production. Usually, cows with moderate MW are more efficient in challenging environments, such as those available in the production systems in Brazil. In the present study, the selection index comprises the following traits: conformation, finishing precocity, musculature at weaning (WC, WP, WM) yearling (YC, YP and YM), scrotal circumference at yearling (SC), days to gain 160kg from birth to weaning (D160) and 240kg after weaning (D240). This are related to birth weight gain at weaning (WG) and from weaning to yearling (YG). The mature (MW) and birth weight (BW) traits were not considered in the selection index. The aim of this study was to estimate the values for the genetic trends (GT) of some important selection (MW) and economic traits (BW). A bi-character analysis of MW and other characteristics was performed to estimate the (co)variance components and genetic parameters. The GT results obtained for MW were null (0.0065% or 0.02718kg per year) in the period 1990-2007. The GT values were determined for BW (-0.0650% or -0.02017kg), WG (0.0758% or 0.0865kg), YG (0.1051% or 0.11377kg), and MW (0.0393% or 0.11276kg) per year. The visual score values (in score units) were also determined for GTat weaning [WC (0.2310%; 0.00707), WP (0.3624%; 0.3623%),aWM (0.01149; 0.01087)] yearling [YC (0.3256%; 0.00990), YP (0.4795%; 0.01496),YM (0.5041%; 0.01457)] per year. Index-based selection was effective to promote genetic progress in WG, WC, WP, WM, YG, YC, YP, and YM characteristics keeping BW and MW constant.
Tipo: | Info:eu-repo/semantics/article
Idioma: | Inglês
Identificador: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782017000300652
Editor: | Universidade Federal de Santa Maria
Relação: | 10.1590/0103-8478cr20151506
Formato: | text/html
Fonte: | Ciência Rural  v.47 n.3 2017
Fonte: | info:eu-repo/semantics/openAccess