You are in the accessibility menu

Please use this identifier to cite or link to this item: http://acervodigital.unesp.br/handle/11449/1415
Title: 
Genetic associations between age at first calving and heifer body weight and scrotal circumference in Nelore cattle
Author(s): 
Institution: 
  • Universidade Estadual Paulista (UNESP)
  • SAA
  • Universidade de São Paulo (USP)
  • ANCP
ISSN: 
0931-2668
Sponsorship: 
  • Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
  • Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
  • Genetics and Animal Improvement at FCAV/UNESP
Abstract: 
P>Age at first calving (AFC) measures the entry of heifers into the beef cattle production system. This trait can be used as a selection criterion for earlier reproductive performance. Using data from Nelore cattle participating in the 'Program for Genetic Improvement of the Nelore Breed' (PMGRN-Nelore Brazil), bi-trait analyses were performed using the restricted maximum likelihood method, based on an AFC animal model and the following traits: female body weight adjusted to 365 (BW365) and 450 (BW450) days of age, and male scrotal circumference adjusted to 365 (SC365), 450 (SC450), 550 (SC550) and 730 (SC730) days of age. The heritability estimates for AFC ranged from 0.02 +/- 0.02 to 0.04 +/- 0.02. The estimates of additive direct heritabilities (with standard error) for BW365, BW450, SC365, SC450, SC550 and SC730 were 0.36 +/- 0.07, 0.38 +/- 0.07, 0.48 +/- 0.07, 0.65 +/- 0.07, 0.64 +/- 0.07 and 0.42 +/- 0.07, respectively, and the genetic correlations with AFC were -0.38, -0.33, 0.10, -0.13, -0.13 and 0.06, respectively. In the herds studied, selection for SC365, SC450, SC550 or SC730 should not cause genetic changes in AFC. Selection based on BW365 or BW450 would favor smaller AFC breeding values. However, the low magnitude of direct heritability estimates for AFC in these farms indicates that changes in phenotypical expression depend mostly on non-genetic factors.
Issue Date: 
1-Oct-2009
Citation: 
Journal of Animal Breeding and Genetics. Malden: Wiley-blackwell Publishing, Inc, v. 126, n. 5, p. 387-393, 2009.
Time Duration: 
387-393
Publisher: 
Wiley-Blackwell Publishing, Inc
Keywords: 
  • Beef cattle
  • Genetic correlation
  • Nonlinear models
  • reproductive traits
Source: 
http://dx.doi.org/10.1111/j.1439-0388.2008.00791.x
URI: 
Access Rights: 
Acesso restrito
Type: 
outro
Source:
http://repositorio.unesp.br/handle/11449/1415
Appears in Collections:Artigos, TCCs, Teses e Dissertações da Unesp

There are no files associated with this item.
 

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.