Comparison among three approaches for evaluation of sexual precocity in Nellore cattle
Contribuinte(s) |
Universidade Estadual Paulista (UNESP) |
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Data(s) |
20/05/2014
20/05/2014
01/04/2007
|
Resumo |
Restricted breeding seasons used in beef cattle produce censored data for reproduction traits measured in regard to these seasons. To analyze these data, adequate methods must be used. The objective of this paper was to compare three approaches aiming to evaluate sexual precocity in Nellore cattle. The final data set contained 6699 records of age at first conception (AFC14) (in days) and of heifer pregnancy (HP14) (binary) obtained from females exposed to the bulls for the first time at about 14 months of age. Records of females that did not calve in the following year after being exposed to a sire were considered censored (77.5% of total). The models used to obtain genetic parameters and expected progeny differences (EPDs) were a Weibull mixed and a censored linear model for AFC14 and threshold model for HP14. The mean heritabilities obtained were 0.76 and 0.44, respectively, for survival and censored linear models (for AFC14), and 0.58 for HP14. Ranking and Pearson correlations varied (in absolute values) from 0.54 to 0.99 (considering different percentages of sires selected), indicating moderate changes in the classification. Considering survival analysis as the best selection criterion (that would result in the best response to selection), it was observed that selection for HP14 would lead to a more significant decrease in selection response if compared with selection for AFC14 analysed by censored linear model, from which results were very similar to the survival analysis. |
Formato |
411-418 |
Identificador |
http://dx.doi.org/10.1017/S1751731107392732 Animal. Cambridge: Cambridge Univ Press, v. 1, n. 3, p. 411-418, 2007. 1751-7311 http://hdl.handle.net/11449/13973 10.1017/S1751731107392732 WOS:000245875000011 WOS000245875000011.pdf |
Idioma(s) |
eng |
Publicador |
Cambridge University Press |
Relação |
Animal |
Direitos |
closedAccess |
Palavras-Chave | #beef cattle #linear models #precocity #pregnancy #mesurvival analysis |
Tipo |
info:eu-repo/semantics/article |