Bayesian inference in the genetic evaluation of the brazilian northeast Tabapuã cattle

The objective was to compare models by Bayes factor (BF) to estimate the (co)variance components, genetic parameters and genetic values for the adjusted weights at 205 (W205), 365 (W365) and 550 (W550) days of age in Tabapuã animals reared on pasture in the Brazilian Northeast. Information about 26,838 cattle born in the period from 1975 to 2007 originally from the weight-development-control system of the Brazilian Association of Zebu Farmers (Associação Brasileira de Criadores de Zebu, ABCZ) was used. The (co)variance components and genetic parameters were estimated by the Bayesian approach, in single- and two-trait analysis, using the GIBBS3F90 software. The full model provided the best fit to estimate the breeding value for W205 and W365 characteristics parameters. For trait W550, the model that provided the best fit was the one that did not include the effect of permanent environment. Genetic trends of direct effect were significant for the W205, W365 and W550 features, corresponding to increments of 2.67 kg, 7.35 kg and 8.32 kg, respectively, during the 32 years evaluated. Phenotypic trends were significant only for W205 and W365 characteristics corresponding to increments of 26.82 kg and 22.42 kg, respectively. The genetic correlations between weight at 205, 365 and 550 days of age were of high magnitude (P205P365 = 0.90, = 0.90 and P205P550 P365P550 = 0.98); you can obtain genetic gains via correlated response to the weights at 365 and 550 days old when selecting for W205.Objetivou-se comparar por meio do Fator de Bayes (FB), modelos para estimar componentes de covariância, parâmetros genéticos e valores genéticos para os pesos ajustados aos 205 (P205), 365 (P365) e 550 (P550) dias de idade em animais da raça Tabapuã, criados a pasto no Nordeste do Brasil. Foram utilizadas informações de 26.838 animais no período entre 1975 a 2007 provenientes do controle de desenvolvimento ponderal da Associação Brasileira de Criadores de Zebu (ABCZ). Os componentes de covariância e parâmetros genéticos foram estimados pela abordagem bayesiana em análises uni e bicaracterísticas utilizando-se o programa GIBBS3F90. O modelo completo proporcionou melhor ajuste para a estimativa dos parâmetros genéticos para as características P205 e P365. Quanto à característica P550, o modelo que proporcionou o melhor ajuste foi o que não incluiu o efeito de ambiente permanente. As tendências genéticas de efeito direto foram significativas para as características P205, P365 e P550, correspondendo a incrementos de 2,67 kg, 7,35 kg e 8,32 kg, respectivamente, durante os 32 anos avaliados. As tendências fenotípicas foram significativas apenas para as características P205 e P365, correspondendo a incrementos de 26,82 kg e 22,42 kg, respectivamente. As correlações genéticas entre o peso aos 205, 365 e 550 dias de idade foram de alta magnitude (P205P365=0,90; P205P550=0,90 e P365P550=0,98), podendo-se obter ganhos genéticos via resposta correlacionada para os pesos aos 365 e 550 dias de idade ao selecionar o P205.Mossoró, R

Methodology for studying the behavior of calves in confinement during the post-weaning phase

Twelve 60-day old, 120 kg mean initial age and weight, post-weaning Holstein calves were randomly distributed between two treatments (concentrates in meal or pellet form). The diet consisted of hay ad libitum and 2 kg daily of concentrates. Each animal was observed at six different time intervals: 5, 10, 15, 20, 25, and 30 minutes. A repeated measure of experimental units design, in a 2 x 6 factorial arrangement was used. The objective was to identify the most adequate time intervals to study ingestive behavior compared to the standard 5-minute observation interval scale. Treatments had no effect on the variables studied. Feeding, ruminating and idle activities duration times did no differ (P>0.05) among time interval scales. However, only in the 5- and 10-minute scales were the number of discrete periods of feeding, ruminating and idleness and their duration, statistically the same (P>0.05). Use of scales of up to 10-minute intervals between observations is recommended for this type of experiment (Pt

INFERÊNCIA BAYESIANA NA AVALIAÇÃO GENÉTICA DE BOVINOS DA RAÇA TABAPUÃ DO NORDESTE BRASILEIRO

The objective was to compare models by Bayes factor (BF) to estimate the (co)variance compo- nents, genetic parameters and genetic values for the adjusted weights at 205 (W205), 365 (W365) and 550 (W550) days of age in Tabapuã animals reared on pasture in the Brazilian Northeast. Information about 26,838 cattle born in the period from 1975 to 2007 originally from the weight - development - control system of the Bra- zilian Association of Zebu Farmers ( Associação Brasileira de Criadores de Zebu , ABCZ) was used. The (co) variance components and genetic parameters were estimated by the Bayesian approach, in single - and two - trait analysis, using the GIBBS3F90 software. The full model provided the best fit to estimate the breeding value for W205 and W365 characteristics parameters. For trait W550, the model that provided the best fit was the one that did not include the effect of permanent environment. Genetic trends of direct effect were significant for the W205, W365 and W550 features, corresponding to increments of 2.67 kg, 7.35 kg and 8.32 kg, respectively, during the 32 years evaluated. Phenotypic trends were significant only for W205 and W365 characteristics cor- responding to increments of 26.82 kg and 22.42 kg, respectively. The genetic correlations between weight at 205, 365 and 550 days of age were of high magnitude (P205P365 = 0.90, = 0.90 and P205P550 P365P550 = 0.98); you can obtain genetic gains via correlated response to the weights at 365 and 550 days old when select- ing for W205

Correlation between performance and feeding behavior of feedlot lambs fed without roughage diet

The objective was to evaluate the correlation between performance and feeding behavior of feedlot castrated Santa Inês lambs fed without roughage diet, weighing 20 ± 1,8 kg and four months of age (± 0,34). A completely randomized design was adopted. Correlations were obtained by Pearson’s linear correlation analysis and the t test, and processed on SAS software (version 9.2). The variables number of rumination chews per cud, number of cuds ruminated per day, speed of each chew, and number of rumination cuds per day were positively correlated with the variation in body weight (p < 0.05). For number of cuds ruminated per day, a positive correlation was found with the variations in body weight. Initial and final body weights were positively correlated with the feed and rumination efficiencies of the lambs feeding behavior and with the time per period spent feeding and performing other activities. Feeding time had a positive correlation with variation in body weight per day and the relative variation in body weight. Rumination was positively correlated with performance variables. The correlations show that there is influence between eating behavior and performance.

Production and economic viability of feedlot beef cattle categories

This study was realized to evaluate the production and economic viability of finished beef cattle in feedlot in the Cerrado biome of Piauí State, Brazil. One hundred and fifty cattle -50 bulls (B) with an body weight of 283.0 ± 20.82 kg, at 30 months of age; and 100 cull cows (CC) with an body weight of 296.1 ± 17.80 kg, at 100 months of age- were used in a completely randomized design. The animal performance indicators for the evaluation of economic viability were initial age (months), slaughter age (months), was initial body weight (kg), final body weight (kg), daily feed intake (kg animal-1; kg kg-1 BW), diet cost (R$kg-1 of diet), cost of kg produced (R$ kg-1 produced), and average price of the kg of meat for finishing (R$). The CC consumed more sorghum silage and concentrate than B (p < 0.05).There was a difference between the categories (p < 0.05) for gross revenue, balance, opportunity cost, and net revenue per animal, with higher values found for the steer category. The animal category did not affect the profitability of the system, although the bulls provided lower revenues than cull cows.