Research Article

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Bayesian approach; Beef cattle; Bos indicus; Genetic correlation; Growth traits; Reproduction

Survival or longevity is an economically important trait in beef cattle. The main inconvenience for its inclusion in selection criteria is delayed recording of phenotypic data and the high computational demand for including survival in proportional hazard models. Thus, identification of a longevity-correlated trait that could be recorded early in life would be very useful for selection ... more

M.H. Van Melis; H.N. Oliveira; J.P. Eler; J.B.S. Ferraz; J. Casellas; L. Varona
Beef cattle; Carcass and meat quality traits; Myf6; MyoD1; PCR-RFLP; Polymorphism

Myogenic determination factor 1 (MyoD1) and myogenic factor 6 (Myf6) genes belong to the myogenic differentiation (MyoD) gene family, which play key roles in growth and muscle development. The study aimed to investigate the effects of variants in cattle MyoD1 and Myf6 on carcass and meat traits. We screened single nucleotide polymorphisms (SNPs ... more

X.H. Du; Q.F. Gan; Z.R. Yuan; X. Gao; L.P. Zhang; H.J. Gao; J.Y. Li; S.Z. Xu
Bayesian inference; Beef cattle; Fertility; Genetic parameters

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 ( ... more

A.A. Boligon; F. Baldi; L.G. Albuquerque
Beef cattle; Bos indicus; Leptin; Molecular markers; Ultrasound traits

Given the important role of leptin in metabolism, we looked for a possible association of leptin and leptin receptor polymorphisms with carcass and growth traits in Nellore cattle. We examined associations of leptin and leptin receptor SNPs with ultrasound carcass (longissimus dorsi muscle area (ribeye area), backfat thickness and rump fat thickness and growth traits (weaning weight ... more

R.C.G. da Silva; J.B.S. Ferraz; F.V. Meirelles; J.P. Eler; J.C.C. Balieiro; D.C. Cucco; E.C. Mattos; F.M. Rezende; S.L. Silva
Beef cattle; Performance tests; Random regression

The aim of this study was to estimate genetic parameters for body weights of individually fed beef bulls measured at centralized testing stations in South Africa using random regression models. Weekly body weights of Bonsmara bulls (N = 2919) tested between 1999 and 2003 were available for the analyses. The model included a fixed regression of the body weights on fourth-order orthogonal ... more

N.W. Selapa; K.A. Nephawe; A. Maiwashe; D. Norris
Beef cattle; Gibbs sampling; Monte Carlo method; Threshold models

Finishing precocity visual score selection was adopted to estimate the time from birth to reach slaughter age. This study estimated (co)variance components and genetic correlations for the finishing precocity score at weaning (WP) and yearling (YP) stages by using daily weight gain (BWG = from birth to weaning; WYG = from weaning to yearling) and speed of weight gain (BWR = from birth to ... more

D.M. Everling; T. Bresolin; P.R.N. Rorato; R.O. Araujo; A.A. Boligon; T. Weber; M.A. Dornelles; L.T. Campos
Beef cattle; Contemporary group; Genetic correlation; Heritability

Data from 69,525 animals were used to compare two types of analyses, one of them having the weaning management group (WEMANG) included as an effect in the contemporary group (F_WEMANG) and the other considering the weaning management group as a random effect, not related to the mathematical model (R_WEMANG) for post-weaning traits. The components of (co)variance were estimated for pre- ... more

V.B. Pedrosa; J.P. Eler; J.B.S. Ferraz; E. Groeneveld
Beef cattle; Categorical trait; Conformation; Production traits

Records of 17,141 Nellore cattle participating in cattle championships, born from 1994-2009, were used to estimate genetic parameters between animal rank in cattle championships, evaluated from weaning to 36 months of age as repeated traits, and growth, fertility, and carcass traits, evaluated at 365 days of age as single traits. Two traits were defined for animal rank in cattle ... more

E.A.Simielli Filho; M.E.Z. Mercadante; J.A.I.I.Vasconc Silva; L.A. Josahkian
Beef cattle; Breeding value; Genetic evaluation; Selection index; Sire ranking

For genetic evaluation of beef cattle, univariate or bivariate analyses are often performed as an alternative to decrease the complexity of matrices and mathematical models compared to multivariate analysis, which considers a larger number of joint traits. The use of bivariate methods to calculate genetic predictors may cause bias in the estimation of breeding values and, as a ... more

V.B. Pedrosa; E. Groeneveld; J.P. Eler; J.B.S. Ferraz
Beef cattle; Censored records; Fertility; Heritability; Reproduction

The continuous trait age at subsequent rebreeding (ASR) was evaluated using survival analysis in Nellore breed cows that conceived for the first time at approximately 14 months of age. This methodology was chosen because the restricted breeding season produces censored data. The dataset contained 2885 records of ASR (in days). Records of females that did not produce calves in the ... more

M.H. Van Melis; L.G.G. Figueiredo; H.N. Oliveira; J.P. Eler; G.J.M. Rosa; M.L. Santana; F.M. Rezende; J.B.S. Ferraz