Genetic and non-genetic effects on calf vigor at birth and preweaning mortality in nellore calves
Carregando...
Data
2013-06-01
Autores
Schmidek, Anita
Rodrigues Paranhosda Costa, Mateus José [UNESP]
Zerlotti Mercadante, Maria Eugênia
Macedode Toledo, Luciandra
Gonçalves Cyrillo, Joslaine Noelydos Santos
Branco, Renata Helena
Título da Revista
ISSN da Revista
Título de Volume
Editor
Resumo
The objective of the present study was to evaluate the genetic and non-genetic effects that influencevigor at birth and preweaning mortality in Nellore calves. A total of 11,727 records of births that occurred between 1978 and 2006, offspring of 363 sires, were analyzed. Poor calf vigor at birth (VB) and preweaning mortality divided into stillbirth (SB), early mortality (EM) and total mortality (TM) were analyzed as binary variables. Generalized linear models were used for the evaluation of non-genetic effects and generalized linear mixed models for genetic effects (sire and animal models). The incidences were 4.75% for VB, 2.66% for SB, 5.28% for EM, and 7.99% for TM. Birth weight was the effect that most influenced the traits studied. Calves weighing less than 22kg(females) and less than 24kg (males) were at a higher risk of low vigor and preweaning mortality. Preweaning mortality was higher among calves born from cows aged .3 and .11 years at calving compared with cows aged 7 to 10 years. Male calves presented less vigor and higher preweaning mortality than female calves. Selection for postweaning weight did not influence preweaning mortality. The heritability estimates ranged between 0.01 and 0.09 for VB, 0.00 and 0.27 for SB, 0.03 and 0.17 for EM and 0.02 and 0.10 for TM. Stillbirth should be included as a selection criterion in breeding programs of Nellore cattle, alone or as part of a selection index, aiming to reduce preweaning mortality. © 2013 Sociedade Brasileira de Zootecnia.
Descrição
Palavras-chave
Animal welfare, Beef cattle, Calf mortality, Genetic improvement, Risk factor
Como citar
Revista Brasileira de Zootecnia, v. 42, n. 6, p. 421-427, 2013.