Genetic correlations between heifer subsequent rebreeding and age at first calving and growth traits in Nellore cattle by Bayesian inference

Abstract

ABSTRACT. We estimated heritability for subsequent rebreeding (SR) of heifers and genetic correlations between this trait and weaning weight (WW), weight gain from weaning to yearling (WG), age at first calving (AFC), and mature cow weight (MW), in order to evaluate whether SR could be included as selection criterion in Nellore cattle. The SR of heifers was defined by attributing a value of 1 (success) or 0 (failure) to heifers that calved or not, respectively, given that they had calved once before. Records from 127,430 Nellore animals were analyzed. Genetic parameters were estimated by Bayesian inference using a nonlinear (threshold) animal model for SR and a linear animal model for the other traits in three-trait analyses, including SR and WW in all analyses. The posterior means of heritability for SR, WW, WG, AFC, and MW were 0.18 ± 0.02, 0.21 ± 0.01, 0.30 ± 0.01, 0.21 ± 0.01, and 0.45 ± 0.04, respectively. The posterior mean estimates of genetic correlations between SR and WW, WG, AFC, and MW were -0.20 ± 0.06, 0.31 ± 0.07, -0.77 ± 0.05, and -0.15 ± 0.09, respectively. Based ©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 11 (4): 4516-4524 (2012) Heifer subsequent rebreeding and other trait correlations 4517 on these genetic correlations, selection for higher gains for WG and younger AFC should result in an increase in heifer SR rates, while long-term selection for increasing WW should promote unfavorable responses in heifer SR. The use of breeding values for heifer SR as a selection criterion of Nellore bulls could increase heifer SR rate without significant changes in MW.

Genetic study of skin thickness and its association with postweaning growth in Nellore cattle: estimation of the genetic parameters

“…Laureano et al (2011) estimated a lower heritability (0.23) by the restricted maximum likelihood method. Using Bayesian analysis, Van Melis et al (2010) and Boligon et al (2012) reported heritabilities of 0.25 and 0.30, respectively, for postweaning weight gain in the Nellore cattle. The posterior estimate of heritability obtained in the present study agrees with those reported by other authors for Nellore populations, suggesting that direct selection for this trait should result in genetic progress in the population.…”

Estimates of genetic parameters and genetic trends for reproductive traits and weaning weight in Tabapuã cattle1,2

“…effect and without maternal permanent environment effect) and with model 3 (without maternal genetic effect and with maternal permanent environment effect), using df = 1. For AFC, the maternal random genetic effects and the permanent environmental effects were not tested, as seen in other studies (Buzanskas et al, 2010;Laureano et al, 2011;Boligon et al, 2012), because the influence of these components is observed mainly until weaning (Boligon et al, 2010). The inclusion of the maternal random genetic effect and the permanent environmental effect in the model was also not evaluated for the remaining traits, because the structure of the data set and the pedigree records was not sufficient to estimate them.…”

Heredabilidad de características reproductivas de vacas Indubrasil.

“…Otros investigadores (Lôbo 1998, Yilmaz et al 2004, Roughsedge et al 2005, Azevêdo et al 2006b, Boligon et al 2012 han reportado menores estimadores con valores que van (2005) reportaron estimadores de heredabilidad cercanos a cero, sugiriendo que la varianza genética aditiva para edad a primer parto es escasa. Bajos estimadores de heredabilidad para edad a primer parto pueden deberse a la corta duración de los empadres de las vaquillas, ya que con empadres más largos se pueden concebir más hembras, lo que puede contribuir a la identificación de diferencias genéticas entre animales (Forni y Albuquerque 2005).…”

“…En consecuencia, el estimador de repetibilidad fue similar al estimador de heredabilidad. Este último sugiere que la selección sería efectiva; además, es similar a los estimadores reportados para vacas Angus (0,45; Northcutt y Wilson 1993) y Nelore (0,45; Boligon et al 2012). Con vacas Angus, Hereford y F1 Angus x Hereford, Arango et al (2002) obtuvieron una heredabilidad para peso maduro de 0,49, valor que es igual al estimado en el presente estudio.…”