The freezing ability of semen from Alpine and Saanen goats submitted to an artificial photoperiod exposure were evaluated by the thermo-resistance (TTR) and hypoosmotic (HOST) tests and integrity of the acrosome using eight male goats, four of each breed and two age groups (young and adults). The quality of semen during the freezing process was superior for the young animals of both breeds. Spermatic motility immediately after thawing showed a positive effect on TTR; animals with higher motility after collection […]

This study aimed to evaluate reproductive characteristics (sexual behavior, scrotal perimeter and quali-quantitative aspects of semen) of young and adults Alpine and Saanen male goats exposed to an artificial photoperiod (16 hours of light and 8 hours of darkness for 2 months). The young animals showed greater libido than the adults, based on the smallest time of reaction. Frequency of manifestation of the behavior traits varied between breeds and ages and higher intensity was observed on adult animals. Scrotal perimeter […]

Data comprising 39,578 test-day records of 3,766 first lactation Holstein cows calving from 1994 to 2002 was used to estimate genetic parameters for test-day yields (TDY) and 305-day milk yield (MY305) and to compare two selection criteria. Variance components were estimated by restricted maximum likelihood using univariate and bivariate animal models. The TDY models included the additive genetic random effect and the fixed effects of contemporary groups and the regressions of calving age (linear and quadratic effects) and days in […]

Four structures of data with different degree of genetic connectness and heterogeneity of parameters among herds: 1) heterogeneity of all parameters; 2) genetic means homogeneous and other parameters heterogeneous; 3) heterogeneity of phenotypic parameters and 4) no heterogeneity for herds, were simulated. After prediction of breeding values, the percentage of top animals common to group 1 (animals ranked by the true breeding values) and group 2 (animals ranked by the predicted breeding values) was calculated. For data with heterogeneity of […]

The aim of this work was to evaluate arrays of fixed effects and residual covariance structures that best fit the herd and the animal variability to weights at birth, weaning, twelve and eighteen months of 3,690 Canchim animals. Different arrays of fixed effects (contemporary groups and, or the main effects of year, month or season of birth and sex) and different residual covariance structures (considering or not change of variance and of correlation between weights at different ages) were studied. […]

This study aimed to evaluate 27 microsatellites for genetic characterization of Brazilian native goats using samples of hair collected from 332 animals of the Moxotó, Canindé, Serrana Azul, Marota, Repartida and Graúna breeds. Twenty-seven microsatellites were selected, amplified by polymerase chain reaction (PCR). The amplified products were submitted to electrophoreses in poliacrylamide gel using an ABI 377XL automatic sequencer. The number of alleles ranged between three (MAF209) and twenty-three (CSSM66). Averages of expected and observed heterozigosity were respectively 0,672 and […]

The relationships among soluble proteins of the seminal plasma, the hypoosmotic test, the physical and morphologic analyses of semen and the reproductive performance of male goats of the Alpine breed under controlled mating were studied using forty samples of semen from four adult male goats collected twice a week between February and April of 2001. Differences among male goats were observed for soluble protein concentration of the seminal plasma, but not for the hypoosmotic test and the pregnancy rate. These […]

This study aimed to evaluate changes in hormone secretion and in seminiferous epithelium of Angus bulls between 10 and 38 weeks of age. Samples of testicular parenchyma and blood were collected from 25 animals castrated in 4 week intervals. Traits associated to testicular development and quantitative aspects of spermatogenesis and hormonal concentrations were transformed by logarithm before analyses of variance. Changes in testis and seminiferous tubule diameter and testis weight were more pronounced after 26 weeks of age. The percentage […]

A total of the 550 F2 animals produced by divergent cross using two sires of the native Brazilian breed named Piau and 18 commercial dams were genotyped for 13 microsatellite markers in swine chromosome 6. The traits evaluated were: carcass length by the Brazilian carcass classification method, carcass length by the American carcass classification method, carcass weight, carcass yield, higher backfat thickness at last 2nd-3rd thoracic vertebrae, backfat thickness after last rib, backfat thickness between last 1st-2nd lumbar vertebrae, lower […]

Data from a Nelore population was used to evaluate environmental effects and to estimate genetic parameters for days to calving (DPP). The influence of contemporary group, age at breeding season, month of last calving and weaning weight of the calf at the end of the breeding season were evaluated with fixed models. The weaning weight of the calf at the end of the breeding season was the only effect that did not influence DPP. Two different contemporary group (CG) definitions […]