Performance and carcass and cut yield of finishing pigs of three sexual categories fed diets with different levels of ractopamine were studied. Forty-eight hybrid animals (initial weight of 92.1±2.4 kg) were distributed in a completely randomised design in 3 × 2 factorial arrangement (three sexual categories: surgically castrated males, two females and immunologically castrated males – with or without 10 ppm of ractopamine), totalling six treatments and eight repetitions with one animal per experimental plot during 28 days. Ractopamine improved […]

The objective of the present study was to analyze models with genetic and/or residual heteroskedasticity for genetic evaluation of the weaning weight of Charolais-Zebu crossbred calves. Weaning weight data from 56,965 crossbred calves were analyzed using animal models with different combinations of genetic and residual heteroskedasticity and/or homoskedasticity. The inference on a posteriori distributions of genetic parameters were by the Monte Carlo method via Markov chains. The model with genetic and residual heteroskedasticity was the best fit on the data. […]

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 […]

The objective of this study was to characterize the population genetic structure of the Gir breed in the Northeast of Brazil. The data used in this study were taken from pedigree information of 8,897 Gir animals between 1957 and 2007, obtained from the Brazilian Zebu Breeders Association (ABCZ). The program ENDOG was used to estimate the parameters based on the probability gene origin. From the amount of the studied animals, 67.22%, 18.41% and 3.15% had complete pedigree only on the […]

The objective of this study was to evaluate selective mating using distribution of extremes, among other mating strategies, on its ability to decrease the endogamy and the loss of genetic variability. The genetic simulation system (Genesys) was used to simulate two genomes (each one with a single characteristic whose distinction was the value of heritability) and the base and original populations. Each initial population was submitted to assisted selection by markers for ten consecutive generations. For evaluation of strategies, the […]

Os objetivos neste trabalho foram investigar, em uma população de bovinos de corte mestiços a obtenção dos efeitos genéticos não-aditivos para as características peso aos 205 e 390 dias e perímetro escrotal e avaliar a consideração desses efeitos na predição dos valores genéticos dos reprodutores utilizando diferentes metodologias de estimação. No método 1, os dados foram pré-ajustados para os efeitos não-aditivos obtidos pelo método de mínimos quadrados em modelo que considerou os efeitos fixos genéticos aditivos diretos e maternos e […]

The objective of this study was to evaluate the mass of the forage and of the morphological components, and the sward structure in Piata palisadegrass (Brachiaria brizantha cv. Piata) deferred in function of different initial heights and nitrogen levels. Two levels of nitrogen (75 and 150 kg/ha) and one control without fertilization associated to three initial deferring heights (20, 30, and 40 cm) were evaluated. The design was of completely randomized blocks with three replications in a subdivided plot scheme. […]

The objective of this study was to evaluate the divergence of bromatological and fermentative characteristics of silages of 25 sorghum (Sorghum bicolor L. Moench) hybrids. The experimental design was completely randomized with 25 treatments and four replications. The mean values of pH differed with variation from 3.45 to 3.87 for hybrids 866005 and 870051, respectively, and the mean pH value was 3.66. The average percentage of lactic acid ranged from 2.90 to 7.43 dag/kg of dry matter (DM) in hybrids […]

The objective of this study was to evaluate the effect of different levels of nitrogen supply and plants densities in the productivity of mombasa guineagrass (Panicum maximum) in the period of establishment. The design was of completely randomized blocks, with 12 treatments and three repetitions, with four nitrogen supplies (absence of application, 80, 160 and 320 kg/ha.year) and three plant densities (9, 25 and 49 plants/m²). The plot was cut at 30 cm from the ground when the sward high […]

The objective of this experiment was to characterize the dry matter production of vegetative components (stalk, leaf, husk, and cob) and reproductive components (grain) of the corn plant according to planting time and the grain maturity stage. Eight corn hybrids with different agronomic characteristics were used to carry out the experiments. Two experiments were performed with planting undertaken on 11/11/2007 and 12/12/2007 under a conventional tillage system. The eight corn cultivars were harvested at three grain maturity stages, half milk […]