The objectives of this study were to estimate phenotypic and genetic parameters for growth traits of meat quails. A total of 1022 birds were housed, identified and individually weighted at 7 days (PES7); 14 days (PES14); 28 days (PES28) and at 42 days (PES42). Covariance components and genetic parameters were estimated by Bayesian procedures using Gibbs sampling with MTGSAM software. Genetic correlations between PES7 and PES14, PES28, and PES42 were respectively 0.73, 0.52 and 0.55 and between PES14 and PES28 […]

Records of growth traits of 1,698 animals born from 1979 to 2002 in a Caracu herd selected for yearling weight were used to estimate genetic parameters for birth weight (PN), weight at 4 months adjusted at 120 days (P120), weaning weight adjusted at 210 days (P210), daily weight gain from birth to weaning (GND), weight adjusted at 378 days of males (P378), weight adjusted at 550 days of heifers (P550), daily weight gain during the performance test (G112), post-weaning daily […]

Data from 326 animals of a F2 swine population were used to select traits related to meat quality by principal components analysis. The following traits were considered: pH at 45 minutes post mortem (pH45), pH at 24 hours post mortem (pHu), drip loss (DL), cooking loss (CL), total loss (TL), intramuscular fat (IMF), objective tenderness (OT), lightness (L), redness (a) and yellowness (b). Variation lower than 0.7 (eigenvalue lower than 0.7) indicated four traits, which were significantly correlated to the […]

Data consisting of 47.668 records of a Nellore-Angus crossbred population, raised in several regions of Brazil, from 1991 to 2001, were used to estimate heritability for post-weaning daily gain (ADG) and for scrotal circumference at yearling age (SCY) using REML. Genetic and phenotypic trends for ADG were also estimated. The model used to estimate heritability and breeding values (BVs) for ADG included the fixed effects of breed composition (defined by the percentage of contribution of the Nellore breed of the […]

Data consisting of 3,531 test day records of 620 first parity Jersey cows were used to estimate genetic parameters for milk yield. Covariance components were estimated by repeatability and random regression animal models. The Wilmink function was used in the random regression model to fit the fixed effect of season of calving and the additive genetic, permanent environment and residual random effects. The repeatability model included the fixed effects of herd-year-month of test, season of calving and age at calving […]

Data from Hereford and Nelore breeds and their crosses were used to estimate the effect of genotype and environment interaction on weaning and yearling weights. The statistical analyses were performed by the least-squares method using models that included region, contemporary group within region, month of birth and sex of the calf, linear and quadratic effects of age of the calf and age of the cow, both nested within sex, and the genetic group and genetic group × region interaction effects. […]

Four simulation studies were conducted to verify the distribution of the inverse of variables with normal distribution, relatively to variances, averages, truncation points and sample sizes. The variables simulated were GMD, with normal distribution and representing average daily gain, and DIAS defined as a multiple of the inverse of GMD and representing days to reach a fixed body weight. The SAS® (1990) system was used, for simulation of the data, and for subsequent analysis of the results in all studies. […]

The objective of this study was to estimate genetic and phenotypic parameters for reproductive traits of Nelore cows raised in the North and Northeast regions of Brazil. The traits studied were age at first calving (AFC), calving interval (CI), post-partum interval (PPI), number of services per conception (NSC) and gestation length (GL). The statistical analyses were done using the SAS program (Statistical Analysis System) and variance components were estimated by Restricted Maximum Likelihood method using the MTDFREML software. Means and […]

Selection for yearling weight has been applied in a herd of Gir breed (80 cows, 6 sires) since 1976 and a Nelore Control herd (60 cows, 4 sires) has been used to evaluate the environmental change. Selection criteria were bull weight at 378 days (P378) in a performance test and heifer weight at 550 days (P550), under grazing conditions. The effective midparent selection differentials for P378 and P550 were 19.5 and 1.8 kg respectively for Gir and NeC, corresponding to […]

Random regression models were used to estimate genetic parameters for test-day milk yield (PLDC) of Alpine dairy goats, implemented by Bayesian methods with Gibbs Sampling. The estimates were compared with those obtained by random regression analysis, using REML. Heritability estimates obtained by Bayesian analysis ranged from 0.18 to 0.37, while those obtained by REML ranged from 0.09 to 0.32. Genetic correlations between yields of close test days approached the unit, but decreased gradually as the interval between test days increased. […]