ESTIMATES OF BREED DIRECT, MATERNAL AND HETEROSIS EFFECTS FOR WEANING AND YEARLING WEIGHTS OF BEEF CATTLE IN THE HUMID TROPICS OF MEXICO
The objective of this study was to determine the breed-direct, breed-maternal and heterosis effects for weaning and yearling weights of Brahman cattle and its crosses with Charolais, Simmental and Brown Swiss breeds in a beef cattle system in Tabasco, Mexico. The climate of the region is tropical hu...
| Autores: | , |
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| Formato: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2010 |
| País: | México |
| Recursos: | Universidad Autónoma de Yucatán |
| Repositorio: | Redalyc-UADY |
| OAI Identifier: | oai:redalyc.org:93915170007 |
| Acesso em linha: | https://www.redalyc.org/articulo.oa?id=93915170007 |
| Access Level: | acceso abierto |
| Palavra-chave: | Agrociencias tropics heterosis breed maternal Breed direct effect |
| Resumo: | The objective of this study was to determine the breed-direct, breed-maternal and heterosis effects for weaning and yearling weights of Brahman cattle and its crosses with Charolais, Simmental and Brown Swiss breeds in a beef cattle system in Tabasco, Mexico. The climate of the region is tropical humid. Data were obtained on 1217 calves born from 1995 to 2007; among the 16 breed-group combinations one was purebred mating (Brahman), 3 two-breed static crosses, 7 three-breed static crosses and 5 backcrosses. Cows were fed in paddocks of Jaragua grass (Hyparrenia rufa) of poor condition and invaded with native grass of Paspalum and Axonopous genera. Calves remained with their dams until weaning. They were weighed at weaning and about one year of age. Calve weights from the record cards kept at the ranch were used to calculate adjusted weaning (W240) and yearling weights (W365). During the 13 year period of data collection, 711 cows and heifers were inseminated with semen of 23 Charolais (Ch), 50 Simmental (Si), 19 Brown Swiss (BS) and 15 Brahman (Br) unrelated sires. Also 32 Br bulls were used for natural mating. A multiple regression procedure was used to obtain estimates of the breed-direct, breed-maternal and direct heterosis effects for W240 and W365. The overall means and standard errors for W240 and W365 were 178.5+0.89 and 219.9+1.78 kg, respectively. The analysis of variance showed effects (P<0.01) of year of birth, season of birth, sex of the calf, calving number of the cow and year x season interaction on W240, and of year, sex and year x season interaction on W365. Breed-direct and breed-maternal specific effects were significant on W240, but only of breed-direct on W365. Heterosis effects were nonsignificant (P>0.05) for both traits. |
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