Genetic parameters for growth traits in Mexican Nellore cattle

Abstract

The aim of this study was to estimate genetic parameters for growth traits in Mexican Nellore cattle. A univariate animal model was used to estimate (co)variance components and genetic parameters. The traits evaluated were birth weight (BW), weaning weight (WW), and yearling weight (YW). Models used included the fixed effects of contemporary groups (herd, sex, year, and season of birth) and age of dam (linear and quadratic) as a covariate. They also included the animal, dam, and residual as random effects. Phenotypic means (SD) for BW, WW, and YW were 31.4 (1.6), 175 (32), and 333 (70) kg, respectively. Direct heritability, maternal heritability, and the genetic correlation between additive direct and maternal effects were 0.59, 0.17, and -0.90 for BW; 0.29, 0.17, and -0.90 for WW; and 0.24, 0.15, and -0.86 for YW, respectively. The results showed moderate direct and maternal heritabilities for the studied traits. The genetic correlations between direct and maternal effects were negative and high for all the traits indicating important tradeoffs between direct and maternal effects. There are significant possibilities for genetic progress for the growth traits studied if they are included in a breeding program considering these associations.

Genetic Parameters of Birth Weight and Weaning Weight and Their Relationship with Gestation Length and Age at First Calving in Hanwoo (Bos taurus coreanae)

“…The observed direct and maternal heritability estimates for BW of 0.22 ± 0.02 ( Table 3 ) and 0.12 ± 0.01, respectively, were comparable to 0.20 and 0.09 obtained by Choi et al [ 15 ] in Hanwoo calves using a model similar to this study, except only for a non-zero covariance assumption between the additive genetic and maternal effects. Contrastingly, numerous researchers including Kars et al [ 16 ] (0.41, Nguni cattle stud), Mujibi et al [ 17 ] (0.46, Charolais), Martínez-González et al [ 18 ] (0.59, Nellore), and Tawah et al [ 19 ] (0.39, Gudali; 0.65, Wakwa Cattle) reported higher direct heritability estimates compared with our findings. Meanwhile, the obtained maternal heritability for birth weight in this study was lower compared with those observed by Kars et al [ 16 ] and Martínez-González et al [ 18 ] of 0.16 and 0.17, respectively.…”

“…Contrastingly, numerous researchers including Kars et al [ 16 ] (0.41, Nguni cattle stud), Mujibi et al [ 17 ] (0.46, Charolais), Martínez-González et al [ 18 ] (0.59, Nellore), and Tawah et al [ 19 ] (0.39, Gudali; 0.65, Wakwa Cattle) reported higher direct heritability estimates compared with our findings. Meanwhile, the obtained maternal heritability for birth weight in this study was lower compared with those observed by Kars et al [ 16 ] and Martínez-González et al [ 18 ] of 0.16 and 0.17, respectively. In addition, Tawah et al [ 19 ] reported a lower maternal heritability of 0.06 in Gudali cattle and a higher heritability of 0.22 in Wakwa cattle.…”

Genotype×Environment Interactions in Growth Performance of Brahman Crossbred Cattle in Bangladesh

“…In a similar study, Rahman (2013) observed that the differences in weight at birth and 9 month in Red Chittagong cattle were 2.29 and 7.53 kg, respectively between nucleus and farmer's herd, although differences were not significant. Evaluating growth traits of Maxican Nellore cattle, Martinez-Gonzalez et al (2010) revealed that the phenotypic means were 31.4, 175.0 and 333.0 kg, respectively for birth weight, weaning weight and yearling weight, which are higher compared to present results. In dairy cattle, Boettcher et al (2003) found that per cow production was greater in the conventionally managed herds than in the grazing herds.…”

“…In dairy cattle, Boettcher et al (2003) found greater heritability for milk yield in conventional herds (0.37) compared to pasture herds (0.31). Martinez-Gonzalez et al (2010) showed that the direct heritability increased with the increase of age for Nellore cattle, which are 0.59, 0.29 and 0.24, respectively for birth weight, weaning weight and yearling weight. However, different heritability values (0.23, 0.45 and 0.25) were detected by Van Niekerk et al (2004) in the Nguni cattle for weaning weight in three different ecological regions, which indicated a higher effect of the environment.…”

Épocas de nacimiento basadas en un índice climático para el ajuste de modelos estadísticos para peso vivo de ganado bovino en México

“…La época de nacimiento involucra diversos factores climáticos reconocidos por impactar la variabilidad de estos indicadores de producción (5) ; generalmente los efectos ambientales que determinan la variación en las características de crecimiento son diferentes según la zona agroecológica, el sistema de producción y la población que se estudia (13,14) . Cuando se han tratado de definir estos períodos climáticos para el ajuste de modelos estadísticos en características productivas, el criterio principal para la clasificación es la definición específica asociada a la presencia o ausencia de la precipitación pluvial, clasificando los climas simplemente en secos o lluviosos (15,16) , aunque algunos autores han considerado también la temperatura (17) , estaciones del año (17,18) o criterios definidos por clústeres entre meses durante el año (19,20) .…”