117 resultados para Livestock breeding

em Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho"


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P>In livestock genetic resource conservation, decision making about conservation priorities is based on the simultaneous analysis of several different criteria that may contribute to long-term sustainable breeding conditions, such as genetic and demographic characteristics, environmental conditions, and role of the breed in the local or regional economy. Here we address methods to integrate different data sets and highlight problems related to interdisciplinary comparisons. Data integration is based on the use of geographic coordinates and Geographic Information Systems (GIS). In addition to technical problems related to projection systems, GIS have to face the challenging issue of the non homogeneous scale of their data sets. We give examples of the successful use of GIS for data integration and examine the risk of obtaining biased results when integrating datasets that have been captured at different scales.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Pós-graduação em Zootecnia - FCAV

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Genomics has been propagated as a paradigm shifting innovation in livestock during the last decade. The possibility of predicting breeding values using genomic information has revolutionized the dairy cattle industry and is now being implemented in beef cattle. In this paper we discuss how genomics is changing cattle breeding through genomic selection, and how this change is creating new ways to articulate assisted reproduction technologies with animal breeding. We also debate that the scientific community is still starting the long journey to reveal the functional aspects of the cattle genome, and that knowledge in this field is the frontier to a whole new venue for the development of novel applications in the livestock sector.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Given the importance of Guzera breeding programs for milk production in the tropics, the objective of this study was to compare alternative random regression models for estimation of genetic parameters and prediction of breeding values. Test-day milk yields records (TDR) were collected monthly, in a maximum of 10 measurements. The database included 20,524 records of first lactation from 2816 Guzera cows. TDR data were analyzed by random regression models (RRM) considering additive genetic, permanent environmental and residual effects as random and the effects of contemporary group (CG), calving age as a covariate (linear and quadratic effects) and mean lactation curve as fixed. The genetic additive and permanent environmental effects were modeled by RRM using Wilmink, All and Schaeffer and cubic B-spline functions as well as Legendre polynomials. Residual variances were considered as heterogeneous classes, grouped differently according to the model used. Multi-trait analysis using finite-dimensional models (FDM) for testday milk records (TDR) and a single-trait model for 305-days milk yields (default) using the restricted maximum likelihood method were also carried out as further comparisons. Through the statistical criteria adopted, the best RRM was the one that used the cubic B-spline function with five random regression coefficients for the genetic additive and permanent environmental effects. However, the models using the Ali and Schaeffer function or Legendre polynomials with second and fifth order for, respectively, the additive genetic and permanent environmental effects can be adopted, as little variation was observed in the genetic parameter estimates compared to those estimated by models using the B-spline function. Therefore, due to the lower complexity in the (co)variance estimations, the model using Legendre polynomials represented the best option for the genetic evaluation of the Guzera lactation records. An increase of 3.6% in the accuracy of the estimated breeding values was verified when using RRM. The ranks of animals were very close whatever the RRM for the data set used to predict breeding values. Considering P305, results indicated only small to medium difference in the animals' ranking based on breeding values predicted by the conventional model or by RRM. Therefore, the sum of all the RRM-predicted breeding values along the lactation period (RRM305) can be used as a selection criterion for 305-day milk production. (c) 2014 Elsevier B.V. All rights reserved.

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A lógica fuzzy admite infinitos valores lógicos intermediários entre o falso e o verdadeiro. Com esse princípio, foi elaborado neste trabalho um sistema baseado em regras fuzzy, que indicam o índice de massa corporal de animais ruminantes com objetivo de obter o melhor momento para o abate. O sistema fuzzy desenvolvido teve como entradas as variáveis massa e altura, e a saída um novo índice de massa corporal, denominado Índice de Massa Corporal Fuzzy (IMC Fuzzy), que poderá servir como um sistema de detecção do momento de abate de bovinos, comparando-os entre si através das variáveis linguísticas )Muito BaixaM, ,BaixaB, ,MédiaM, ,AltaA e Muito AltaM. Para a demonstração e aplicação da utilização deste sistema fuzzy, foi feita uma análise de 147 vacas da raça Nelore, determinando os valores do IMC Fuzzy para cada animal e indicando a situação de massa corpórea de todo o rebanho. A validação realizada do sistema foi baseado em uma análise estatística, utilizando o coeficiente de correlação de Pearson 0,923, representando alta correlação positiva e indicando que o método proposto está adequado. Desta forma, o presente método possibilita a avaliação do rebanho, comparando cada animal do rebanho com seus pares do grupo, fornecendo desta forma um método quantitativo de tomada de decisão para o pecuarista. Também é possível concluir que o presente trabalho estabeleceu um método computacional baseado na lógica fuzzy capaz de imitar parte do raciocínio humano e interpretar o índice de massa corporal de qualquer tipo de espécie bovina e em qualquer região do País.

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The purpose of this study was to verify the breeding potential of the maize composite Isanao VF1 in the second growing season. One hundred and fifty half-sib progenies were evaluated of spacing of 0.45 m, densities of 57,778 and 80,000 plants ha(-1), in a randomized block design with three replications. Gains of 16.0 and 19.2% were estimated for grain Yield, H. I and 10.5% for prolificacy and 12.3 and 12.9% for ear height, respectively, at 57,778 and 80,000 plants ha(-1). The heritabilities for plant height, ear height and grain yield were 65.2 and 61.3%, 64.3 and 66.9% and 53.5 and 63.3%, respectively, confirming the potential for breeding at both densities. The absence of progeny by density interaction indicates that no further selection programs are necessary. The occurrence of segregation for modifier genes for height suggests stabilizing selection based on ear height.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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There is little information on the nutrition of red-winged tinamous (Rhynchotus rufescens) reared in captivity, and their nutritional requirements still need to be determined. This study aimed at determining dietary crude protein requirements and testing four organic selenium supplementation levels in the diet of red-winged tinamous during the breeding season. Birds were housed in a conventional broiler house divided in 16 boxes with one male and three females each. Iso-energy (2800kcal ME/kg) pelleted feeds, based on corn and soybean meal, were supplied in tube feeders. In the first experiment, treatments consisted of four different diets containing different crude protein (CP) contents (15, 18, 21, or 24%) and in the second experiment, the four diets contained equal protein level (22.5%) and four different organic selenium levels (0, 0.2, 0.4, or 0.8ppm). Data were analyzed by the least square method. The best egg weight and eggshell thickness were obtained with 22.5% dietary CP. Organic selenium did not influence the studied reproductive traits of red-winged tinamous (Rhynchotus rufescens) males or females.

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O mercado demanda, desde final da década de 20, uma tecnologia para a sexagem de espermatozóides que possa ser inserida na indústria de produção de sêmen congelado e que tenha as seguintes características: a) não altere a viabilidade espermática; b) seja compatível com a congelação do espermatozóide sexado; c) permita a sexagem de espermatozóides previamente congelados e descongelados; d) permita a produção de várias doses de sêmen sexado congelado por dia, com custo compatível ao mercado. A importância dessa tecnologia para maximizar a produção animal a um custo baixo tem sido um desafio da pesquisa a vários anos. A possibilidade de produzir, em escala comercial, doses de sêmen enriquecidas com espermatozóides X ou Y aumentará os benefícios do uso da inseminação artificial no seu papel de maximizar o progresso genético entre gerações de acordo com os requerimentos de cada programa de melhoramento animal. Diferentes rotas tecnológicas são percorridas na tentativa de selecionar-se o sexo em mamíferos, tanto nas espécies de interesse zootécnico quanto em espécies ameaçadas de extinção, animais de companhia. Neste sentido, existem duas alternativas: a separação de espermatozóides portadores do cromossomo X, daqueles portadores do cromossomo Y; ou a sexagem de embriões pré-implantados. A viabilidade da sexagem de espermatozóides em bovinos é esperada por muitos anos e os desenvolvimentos recentes tornaram essa tecnologia de aplicação commercial. Entretanto, muitas limitações ainda existem, principalmente, referente à taxa de gestação em condições de campo. Isso restringe a utilização dessa tecnologia no melhoramento genético e produção animal. Nessa palestra abordaremos os potenciais sistemas de criação e produção que poderão beneficiar-se com a sexagem de espermatozóides, quando essas limitações forem solucionadas.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Genetic parameters were estimated for pre-weaning average daily gain (ADG) and number of days to gain 160 kg from birth to weaning (D 160) of Nelore cattle. Ranks of animals were compared for these traits. Heritability estimates were 0.17 and 0.10 for ADG (direct and maternal), and 0.14 and 0.09, for D 160 (direct and maternal). Rank correlations between expected breeding values (EBV) were 0.97 and 0.95, for direct and maternal effects, respectively. Despite similar heritability estimates and high rank correlations, results showed that changes in rank could happen when choosing the best animals according to EBV for D 160 or ADG. There were evidences that sires selected using D 160 would produce progeny that achieve a specified market weight at an earlier age and would be more uniform, since this criterion is calculated as a harmonic mean function. (C) 2003 Elsevier B.V. All rights reserved.