To provide information that can contribute to the genetic evaluation and selection in Tabapuã cattle, genetic parameters were estimated for growth traits using a multi-trait animal model. (Co)variance components were estimated by a Bayesian approach using the Gibbs Sampler. Moderate and similar responses to selection are expected when selecting for weights at the four ages evaluated, since the direct heritability estimates were similar and of average magnitude (0.18 to 0.19). The direct and maternal additive genetic correlations between all pairs […]

Data from Nellore beef cattle breed were used to study the influence of variance heterogeneity on genetic evaluation. Adjusted weights at 365, 450 and 550 days of age were classified as high and low classes of standard deviation, based on phenotypic standard deviation of herds in each weight. At multiple trait analyses, where the same weight was considered a distinct characteristic regarding each class of standard deviation, genetic and residual variances increased as the standard deviation of the class increased. […]

The objectives of this study were to evaluate a multibreed heteroskedastic animal model (MAMR) to estimate residual variance heterogeneity due to breed, heterozigosity, sex and contemporary groups (CG) and robustness to outliers. Differences on variance components, heritability and genetic values estimates were evaluated. It was used 4,016 records of post weaning weight gain (PWG) from Brangus foundation herd of Embrapa Pecuária Sul. Data were analyzed by MAMR with four different residual distribution specifications, which were defined by the nature of […]

It was evaluated statistical models with different assumptions to define the one that best describes the presence of genotype × environment interaction on adjusted post-weaning weight gain (PWG345) of Hereford cattle, through the study of reactions norms to the environment, obtained by random regression using a Bayesian approach. Four reaction norms hierarchical models (RNHM) were used through the INTERGEN program. The RNHMK uses the solutions of contemporary groups previously estimated by the standard animal model (AM) and considers them as […]

Genetic parameters and genetic and phenotypic trends were estimated for weight at weaning (WW) and visual scores (VS) of conformation (C), precocity (P), musculature (M) and navel (N) for Angus × Nellore crossbred calves. It was used 39,676 records from pre-weaning phase of animals born from 1992 to 2002 in mid-western, southeastern and southern Brazil. The components of covariance were estimated using REML, in animal model, considering as random the maternal and direct additive genetic effects, and as fixed, the […]

The objectives of this study were to use a multibreed animal model to verify the presence of heterogeneity of genetic variance between Angus and Nelore breeds, to verify the importance of the variance due to the segregation between these two breeds and to estimate breed additive genetic effects on the dominance and additive × additive epistatic effects. It was used in this study 4,016 records of post weaning weight gain from Brangus breed foundation herd from Embrapa Pecuária Sul, analyzed […]

The objective of this study was to evaluate alternatives for modeling the age of dam at calving (AOD) effect on the weaning weight of Charolais-Zebu crossbred calves. Data from 56,965 calves were analyzed, using statistical models considering the fixed effects of the contemporary groups, sire and dam genetic groups, and AOD. The AOD effect was fitted to models using annual age classes, and ordinary quadratic to quintic-ordered polynomials (OP) or segmented polynomials (SP) with two, three, four, six and twelve […]

Increased movement toward alliances and grid pricing in the U.S. has led to an increase interest in genetic values for carcass traits. The literature suggests that carcass genetic values are an effective tool to enhance selection for carcass traits, and that it is possible to select sires within a breed that can increase marbling score without adversely affecting external fat thickness or percent retail product relative to the breed mean. Ultrasound has been investigated as a cheaper means of collecting […]

To estimate genetic parameters and to evaluate the genetic and phenotypic progress for the traits birth weight (PN), average daily gain from birth to weaning (GMDND), weaning weight adjusted to 205 days of age (P205) and the visual scores for conformation, precocity, musculature and size, at the pre weaning phase, there were used information from 23,176 Aberdeen Angus breed animals born between 1994 and 2004. The covariance components were obtained by REML, using an animal model. The direct and maternal […]

It was analyzed 117,082 complete lactation records adjusted for 305 days in milk yield (MY305) of 49,676 Holsteins cows from 308 herds distributed among seven dairy production units in the state of Paraná, Brazil. The objective was to verify the genotype × environment interaction to MY305 of Holsteins cows between dairy production units in the state of Paraná using the Bayesian inference. All animals were officially controlled by the Serviço de Controle Leiteiro Mensal of Associação Paranaense de Criadores de […]