RESUMEN
Background The Zebu cattle are represented by a diverse group of breeds in México. Traditionally these breeds have been associated with the tough beef characteristic. Validated genetic markers have the potential to be included in marker-assisted selection and management programs in order to improve traits such as beef tenderness. The incidence and distribution of Calpain and Calpastatin polymorphisms strongly associated with beef tenderness were estimated in registered cattle of five Zebu breeds in Mexico. Results A low and in some cases null frequency of favorable C allele of CAPN316 was determined in all breeds. Conversely, a more equilibrated frequency in CAPN4751 and CAST loci was observed. Conclusions Although the relatively low occurrence of favorable alleles in assessed loci may limit their use in selection programs, genotyping availability might be a practical and comprehensive tool for introgression programs by marker assisted selection and management as to improve meat tenderness of Zebu breeds.
Asunto(s)
Animales , Bovinos , Polimorfismo Genético , Bovinos/genética , Carne , Calpaína/genética , Marcadores Genéticos , Alelos , Frecuencia de los Genes , Genotipo , Productos de la Carne , MéxicoRESUMEN
Objective. To determine how some non-genetic factors influence weights at birth (BW), weaning (WW) and yearling (YW) of Brahman calves. Materials and methods. Data corresponding to 58257, 57045 and 40364 for BW, WW and YW, respectively, were analyzed. The models included the effects of year and season of birth and sex, and were considered simple interactions. Results. All effects were significant (p<0.05) for BW, WW and YW. Only the season of birth didn’t have a significant effect (p>0.05) on WW. The average general BW, WW and YW were 32±3.2, 188±37.7 and 291±56.8 kg, respectively. Variables evaluated that take into account the year of birth show a trend to increase weight each year. In relation to the birth season on BW and YW, it was observed that calves born during the rainy season were heavier than those born during the dry season. Similarly, male calves were heavier than females at birth, weaning and one year of age. The effects of the analyzed interactions were significant (p<0.05) for the three variables, except for the season of birth per sex interaction, which did not have a significant effect (p>0.05) for BW and WW. Conclusions. The studied non-genetic factors were important and should be taken into account in management strategies when striving to increase the efficiency of the productive system.
Objetivo. Determinar cómo influyen algunos factores no genéticos sobre los pesos al nacer (PN), al destete (PD) y al año (PA) de terneros Brahman. Materiales y métodos. Se analizaron 58257; 57045 y 40364 datos para PN, PD y PA, respectivamente. Los registros fueron de animales nacidos durante los años 1994 a 2012. El modelo incluyó los efectos de año y época de nacimiento y sexo, también se consideraron las interacciones simples. Resultados. Todos los efectos resultaron significativos (p<0.05) para PN, PD y PA. Sólo el efecto de época de nacimiento no tuvo efecto significativo (p>0.05) para el PD. Las medias generales de PN, PD y PA fueron de 32±3.2, 188±37.7 y 291±56.8 kg, respectivamente. Para las variables evaluadas sobre el año de nacimiento se observó una tendencia de aumento del peso conforme transcurrieron los años de estudio. Con relación a la época de nacimiento sobre el PN y PA se observó que los terneros nacidos durante la época de lluviosa fueron más pesados, que los nacidos durante la época seca. De igual modo, los terneros machos fueron más pesados que las hembras al nacimiento, destete y al año de edad. Los efectos de las interacciones analizadas fueron significativas (p<0.05) para las tres variables, a excepción, de la interacción época de nacimiento por sexo que no tuvo efecto significativo (p>0.05) para el PN y PD. Conclusiones. Los factores no genéticos estudiados fueron importantes y deben ser tenidos en cuenta en las estrategias de manejo cuando se quiere incrementar la eficiencia del sistema productivo.