The objective of this study was to obtain estimates of genetic and phenotypic parameters for egg mass of meat quails and also to propose an optimal age for selection of birds through the egg mass. The data used in this study came from 3,503 female meat quails (UFV1: 1.811 quails; UFV2: 1.692 quails) of the Poultry Breeding Program from Universidade Federal de Viçosa. The traits examined were egg mass in partial periods until 77, 112, 147 and 182 days, and […]

In order to compare the residual heterogeneity variance influence on the genetic parameters estimated for the growth curve of meat quail, data from 26835 and 27447 observations, from 3909 and 4040 meat quails of the UFV-1 and UFV-2 strains, respectively, were used. Body weight was evaluated, for the two strains, at 1, 7, 14, 21, 28, 35 and 42 days of age, through an animal model at random regression, considering residual variances in the age classes. Loge L showed increase, […]

Polynomial functions of age of different orders were evaluated in the modeling of the average growth trajectory in Santa Ines sheep in random regression models. Initially, the analyses were performed not considering the animal effect. Subsequently, the random regression analyses were performed including the random effects of the animal and its mother (genetic and permanent environment). The linear fit was lower, and the other orders were similar until near 100 days of age. The cubic function provided the closest fit […]

It was used 17,767 weight records of 4,210 Santa Inês breed lambs aiming to compare random regression models with different structures to model the residual variance in genetic studies of the growth curve. The fixed effects included in the analysis were contemporary group and age of the ewe at lambing. Fixed and random regressions were fitted through Legendry polynomials of orders 4 and 3, respectively. The residual variance was fitted by heterogeneous classes and by functions of variances employing ordinary […]

It was evaluated in this work the components of (co)variance and heritability of the parameters of egg production curve in quails in a model of double stages: the first stage is composed of the adjustment of a nonlinear curve, and the second is composed of the assessing of the genetic parameters obtained by the animal model. It was used daily individual records from laying to 90 days, starting with the first egg in the batch, of 308, 374 and 378 […]

The objective of this study was to evaluate impacts of ignoring the dominance effects on the estimation of genetic parameters and prediction of genetic values by the restricted maximum likelihood method, under the additive animal model, using MTDFREML. Two gene action models were simulated for the same genomic architecture: one model that included only additive effects of the genes and the other with additive effects and positive and complete dominance into 100% of the loci. Under each genetic model, three […]

Random regression and Legendre polynomial (LP) of different orders were used for modeling the genetic, permanent environmental and residual variances of test day milk yield in dairy goats. The models included the fixed effects of contemporary group, age of dam at kidding as a covariate and the fixed regression of LP for the average lactation curve and the additive genetic, permanent environmental and residual as random effects. According to the values of the logarithm of the likelihood function, AIC and […]

Variance components and genetic parameters for growth traits of Gyr breed were estimated using univariate analyses by restricted maximum likelihood. Five models differing in the random effects were evaluated. The models included the fixed effects of month of birth, contemporary group and age of cow. According to the likelihood ratio test (LRT) the best fit for all traits measured in the pre-weaning period was obtained by the model including the direct and maternal effects (genetic and environment). Heritability estimates for […]

The aim of this work was to study the adjustment of Richards, Brody, Gompertz, Von Bertalanffy and Logistic functions on the growth curve of Santa Inês hair sheep and to estimate genetic parameters for the traits obtained from the best fitting function. Information from females of the Embrapa Tabuleiros Costeiros herd recorded between 1993 and 2004 and from the Embrapa Caprinos herd recorded between 1981 and 2004 was used. Functions were fitted for each herd, using NLIN procedure of Statistical […]

Data consisting of 26,389 individual test day milk yield from 825 lactations of 356 Parda Alpina goats, recorded from 1997 to 2004, were used to estimate genetic parameters and to predict breeding values for test day (PLDC) and accumulated (PAC) milk yields. The model for PLDC included the fixed effects of contemporary group (year-month of test), age of dam at kidding as covariate, and additive genetic, permanent environment and residual random effects. The model for PAC included the same random […]