Estimation of genetic parameters for body weights, scrotal circumference, and testicular volume measured at different ages in Nellore cattle.
J Anim Sci
; 88(4): 1215-9, 2010 Apr.
Article
em En
| MEDLINE
| ID: mdl-19966155
Data from 129,575 Nellore cattle born between 1993 and 2006, belonging to the Jacarezinho cattle-raising farm, were used to estimate genetic parameters for scrotal circumference measured at 9 (SC9), 12 (SC12), and 18 (SC18) mo of age and testicular volume measured at the same ages (TV9, TV12, and TV18) and to determine their correlation with weaning weight (WW) and yearling weight (YW), to provide information for the definition of selection criteria in beef cattle. Estimates of (co)variance components were calculated by the REML method applying an animal model in single- and multiple-trait analysis. The following heritability estimates and their respective SE were obtained for WW, YW, SC9, SC12, SC18, TV9, TV12, and TV18: 0.33 +/- 0.02, 0.37 +/- 0.03, 0.29 +/- 0.03, 0.39 +/- 0.04, 0.42 +/- 0.03, 0.19 +/- 0.04, 0.26 +/- 0.05, and 0.39 +/- 0.04, respectively. The genetic correlation between WW and YW was positive and high (0.80 +/- 0.04), indicating that these traits are mainly determined by the same genes. Genetic correlations between the growth traits and scrotal circumference measures were positive and of low to moderate magnitude, ranging from 0.23 +/- 0.04 to 0.38 +/- 0.04. On the other hand, increased genetic associations were estimated between scrotal circumference and testicular volume at different ages (0.61 +/- 0.04 to 0.86 +/- 0.04). Selection for greater scrotal circumference in males should result in greater WW, YW, and testicular volume. In conclusion, in view of the difficulty in measuring testicular volume, there is no need to change the selection criterion from scrotal circumference to testicular volume in genetic breeding programs of Zebu breeds.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Escroto
/
Testículo
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Peso Corporal
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Bovinos
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Característica Quantitativa Herdável
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Revista:
J Anim Sci
Ano de publicação:
2010
Tipo de documento:
Article
País de afiliação:
Brasil
País de publicação:
Estados Unidos