Raimundo Nonato Braga Lôbo

University of São Paulo, San Paulo, São Paulo, Brazil

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Publications (126)73.71 Total impact

  • Raimundo N. B. Lobo
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    ABSTRACT: Abstract Text: The major part of technicians with knowledge in the productions systems for goats and sheep are concentrated in Northeastern and South regions of Brazil. However, in recent years, the goats and sheep industries expanded to other areas of Brazil that suffer with the absence of professionals trained with these animals. GENECOC is a breeding program coordinated by Brazilian Agricultural Research Corporation, Embrapa Goats and Sheep, and has among the objectives to assist in training of human resources with specific skills on the animal breeding and production systems of meats goats and sheep. The program had supported the training of 36 students, being 14 graduate students and the development of 16 master projects and 6 PhD theses and it also has abroad actions. A breeding program with its dynamic process can help the education of the young preparing them to their professional life. Keywords: animal breeding GENECOC goats sheep
    10th World Congress on Genetics Applied to Livestock Production; 08/2014
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    ABSTRACT: Selection in heterogeneous environments has had increasing importance since production system definition is linked to economic instability and climatic changes. The aim of this work was to compare environmental sensitivity between sexes and along development. Data were collected in 366 Brazilian herds for the Brazilian Nelore Cattle Breeding Program with 1,110,662 body weights from 408,416 animals. Eight different analyses were applied using a principal component analysis of the cubic polynomial random regression coefficients' estimates, with a sex-separated developmental reaction norm approach. Results showed different estimated eigenvalues for coefficients of different orders in different sexes. Eigenvalues of level and slope coefficients explained a great majority of the variation of Nelore beef cattle weight in Brazilian production systems, with a distinguished increase of slope coefficient eigenvalue in female analyses along the age axis when compared to male analyses.
    10th World Congress of Genetics Applied to Livestock Production; 08/2014
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    Ana Maria B. O. Lobo, Samuel R Paiva, Raimundo N. B. Lobo
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    ABSTRACT: Abstract Text: A total of 84 animals were genotyped on the Illumina OvineSNP50K BeadChip for identifying the genome-wide footprints of positive selection for the age at first lambing (AFL) of Santa Inês ewes. 90 SNP markers were significant by Fisher’s exact test. From these SNPs, eight satisfied the imposed constraint of 100kb distance between two consecutive markers. It was identified at least two genes on chromosome 25 as probable targets of selection. The NRG3 comprised between the markers OAR25_38884374.1 and s19656.1, and the PTPN20B comprised between s69834.1 and s26762.1. The results suggest that NRG3 plays an important role in AFL of Santa Inês. This gene can have potential for genomic selection and this is particularly useful for sheep industry. The genotyping more animals of the population and the estimative of additive effect of NRG3 gene for the trait AFL may validate this data. Keywords: Ovis aries Locally adapted sheep OvineSNP50K Beadchip
    10th World Congress on Genetics Applied to Livestock Production; 08/2014
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    ABSTRACT: The objective of the present study was to estimate genetic parameters for growth and reproductive traits of Morada Nova sheep reared by smallholder farmers in the semi-arid northeastern region of Brazil. Data from 11 participating flocks, between 2007 and 2011, were used for the estimation of (co)variance components and genetic parameters for birth weight (BW), weight at weaning adjusted for 112 days of age (WW), average daily weight gain from birth to weaning (ADG), days to lambing (DL), lambing interval (LI), total litter weight at birth (LWB), total litter weight at weaning (LWW) and the ratio between total litter weight at birth and weaning and metabolic weight of the dam (LWB/MW and LWW/MW, respectively). The direct heritabilities obtained by one-trait analysis were 0.19, 0.14, 0.11, 0.13, 0.0, 0.44, 0.19, 0.41, 0.15, respectively for BW, WW, ADG, DL, LI, LWB, LWW, LWB/MW and LWW/MW. The direct heritabilities for BW and WW obtained by two-trait analysis were similar to those estimated by one-trait analysis. However, the direct heritabilities for LWB, LWW and LWW/MW obtained by two-trait analysis were higher than those estimated by one-trait analysis. The genetic correlation between BW and WW were 0.75 and between LWB, LWW and LWW/MW were 0.8, 0.9 and 1.0, respectively. In conclusion, except for LI, there is genetic variability that can be explored by direct and indirect selection to obtain genetic gains in the flocks participating in the Nucleus of Participatory Breeding of Morada Nova Sheep.
    Small Ruminant Research 08/2014; · 1.12 Impact Factor
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    ABSTRACT: Genetic parameters for ultrasound carcass and growth traits were estimated by factor analyses used as a special case of structural equation models in a Bayesian framework. Data were analyzed using the standard multi-trait mixed models with sire model (Model 1; SMTMs). The factor analyses (FA) were done by four alternative FA models. The results indicate that FA models could estimate breeding values of the bulls practically equal relative to the SMTMs. The FA models may reduce the ranking model and give a parsimonious estimation of genetic covariance matrices. Although the FA models may reduce covariance matrices ranks and give a parsimonious estimation of dispersion parameters, these models have to be tested in order to implement the benefits, as an alternative of SMTMs. INTRODUCTION The continuous increasing of records and traits in genetic evaluation schemes for beef cattle generally involve multi-trait mixed models analyses, which requires genetic links among these traits. It leads to statistical and computational difficulties in estimating the genetic (co)variance matrix needed to have accurate breeding values. Structural equation models (SEM, e.g., Wright 1921) are multivariate models adapted to obtain more parsimonious quantitative genetic mixed-effects models (Gianola and Sorensen (2004)). SEM can be understood like a term that does not denote a particular statistical technique, but a number of techniques and procedures used together aiming to model some covariance structure. In animal breeding, specifically in this paper, SEM was used to model the estimated genetic and residual (co)variance matrix. These models can be viewed as an extension of the standard multi-trait mixed models (SMTM, e.g., Henderson and Quaas (1976)) that are capable of expressing functional networks among traits. Gianola and Sorensen (2004) discussed the use of recursive and simultaneous equation models (special case of SEM) acting on phenotypes. Alternatively, the Factor Analysis (FA) may be used as another special case of SEM to represent the genetic covariance matrix (Jӧreskog (1970)). FA can be used to model genetic effects in the context of a multivariate linear mixed model for reducing the dimension of the estimated genetic (co)variance matrix, obtaining a more parsimonious model without reducing dimension of the original records (e.g., de los Campos and Gianola (2007)). The objective of this study was to consider FA (a special case of SEM) acting on genetic and residual effects separately to estimate genetic and residual (co)variance parameters modeling traits and estimating genetic parameters in genetic improvement of Brazilian Nelore beef cattle.
    World Congress of Genetics Applied to Livestock Production, Vancouver; 08/2014
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    ABSTRACT: The objective of this study was to estimate genetic parameters for female mature weight (FMW), age at first calving (AFC), weight gain from birth to 120 days (WG_B_120), from 210 to 365 days (WG_210_365), rib eye area (REA), back fat thickness (BF), rump fat (RF) and body weight at scanning date (BWS) using single and multiple-trait animal models by the REML method from Nellore cattle data. The estimates of heritability ranged from 0.163±0.011 for WG_210_365 to 0.309±0.028 for RF using the single-trait model and from 0.163±0.010 for WG_210_365 to 0.382±0.025 for BWS using the multiple-trait model. The estimates of genetic correlations ranged from −0.35±0.08 between AFC with BF to 0.69±0.04 between WG_B_120 with BWS. Selection for weights gains, REA, and BWS can improve FMW.
    Livestock Science 07/2013; 155(1):1–7. · 1.25 Impact Factor
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    Ana Fabrícia Braga Magalhães, Raimundo Nonato Braga Lobo, Olivardo Facó
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    ABSTRACT: The aim of this study was to estimate genetic parameters for growth traits in Somalis Brasileira hair sheep breed. The data used in this study were from the flock of Embrapa Caprinos and Ovinos, located in the city of Sobral - CE, Brazil. Data contained records of 1,120 animals in the pedigree file. The analyzed traits were birth weight (PN), weaning weight (PD), weight gain from birth to weaning (GND) and adult weight (PA). Estimates of (co)variances and genetic parameters were obtained by Derivative Free Restricted Maximum Likelihood Method (DFREML) using the MTDFREML software. The heritabilities were low to moderate in univariate analysis. The maternal heritabilities were higher than direct heritabilities. The heritabilities in multivariate analysis exceeded those in univariate analysis. The values of genetic correlations varied widely.
    Ciência Rural 05/2013; 43(5):884-889. · 0.38 Impact Factor
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    ABSTRACT: A total of 61,528 weight records from 22,246 Nellore animals born between 1984 and 2002 were used to compare different multiple-trait analysis methods for birth to mature weights. The following models were used: standard multivarite model (MV), five reduced-rank models fitting the first 1, 2, 3, 4 and 5 genetic principal components, and five models using factor analysis with 1, 2, 3, 4 and 5 factors. Direct additive genetic random effects and residual effects were included in all models. In addition, maternal genetic and maternal permanent environmental effects were included as random effects for birth and weaning weight. The models included contemporary group as fixed effect and age of animal at recording (except for birth weight) and age of dam at calving as linear and quadratic effects (for birth weight and weaning weight). The maternal genetic, maternal permanent environmental and residual (co)variance matrices were assumed to be full rank. According to model selection criteria, the model fitting the three first principal components (PC3) provided the best fit, without the need for factor analysis models. Similar estimates of phenotypic, direct additive and maternal genetic, maternal permanent environmental and residual (co)variances were obtained with models MV and PC3. Direct heritability ranged from 0.21 (birth weight) to 0.45 (weight at 6 years of age). The genetic and phenotypic correlations obtained with model PC3 were slightly higher than those estimated with model MV. In general, the reduced-rank model substantially decreased the number of parameters in the analyses without reducing the goodness-of-fit.
    Livestock Science 04/2013; 152(s 2–3):135–142. · 1.25 Impact Factor
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    ABSTRACT: a b s t r a c t The objective of this study was to compare gene transcription profiles in Longissimus dorsi muscle of the following four hair sheep genetic groups, Morada Nova (MO), Brazilian Somali (SO), Santa Inês (SI) and ½Dorper  ½Morada Nova (F1). These groups all display different postnatal muscle growth. The transcriptomes of the skeletal muscle of the lambs (at 200 days of age) were profiled by using oligonucleotide microarrays and reverse transcription-quantitative real-time PCR (RT-qPCR). The microarray experiment identified 262 transcripts that were differentially expressed when transcription levels were compared between the different breeds. A total of 23 transcripts among which those involved in skeletal muscle development (MyoD1 and IGFBP4), lipogenesis and adipogenesis (C/EBPd, PPARg and PGDS) were differentially expressed in at least in one comparison. Clustering analysis showed that there is greater similarity in gene expression between the MO and SI breeds and between F1 and SO genetic groups. The SO breed has the most distinct expression pattern. The RT-qPCR results confirmed the findings from the microarray study. A positive correlation was observed between the expression of MyoD1 and the cold carcass yield. The negative correlations between the weight and yield of cold carcass with the expression of C/EBPd mean that the selection for adipogenesis could lead to a lower carcass weight. The GLUT3 and PYGL gene transcripts were negatively correlated with fat thickness, but ATP5G1 was positively correlated with this trait. Interestingly, many genes negatively correlated with PUFA were positively correlated with cold carcass yield. In conclusion, the present work demonstrated that there are breed-specific expression patterns in Brazilian hair sheep genetic groups. The differences in gene expression among genetic groups were consistent with their phenotypic differences. The positive correlation of the MyoD1 expression with the cold carcass yield suggests that this gene is important for tissue growth in sheep. The positive correlation of the C/EBPd expression with PUFA provides an opportunity to select for lipid deposition in meat animals. & 2012 Elsevier B.V. All rights reserved.
    Livestock Science 12/2012; 150(1-3):31-41. · 1.25 Impact Factor
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    ABSTRACT: Para fins de estabelecer critérios de seleção para a raça Brahman, no Brasil, este estudo objetivou estimar parâmetros genéticos e ambiental para peso ao nascer (PN), período de gestação (PG) e perímetro escrotal aos 365 (PE365), 455 (PE455) e 550 (PE550) dias de idade e eficiências relativas de seleção indireta versus a direta para essas características. Os dados referem-se a 15 851 animais de 16 rebanhos de seis estados, participantes de um programa de melhoramento genético. Componentes de (co)variância e coeficientes de herdabilidade e de correlações genéticas e ambientais entre características foram estimados pelo método da máxima verossimilhança restrita, sob modelo animal multi-característica. No modelo, foram incluídos como efeitos fixos, grupo de contemporâneos e idade da vaca ao parto como covariável (efeitos linear e quadrático) e, como efeitos aleatórios, genético aditivo direto, ambiente permanente da vaca e resíduo. Para PN e PG considerou-se ainda o efeito aleatório genético materno. As herdabilidades estimadas para PN, PG, PE365, PE455 e PE550 foram, respectivamente, 0,36; 0,29; 0,55; 0,43 e 0,40. As correlações genéticas entre PN e PG, PG e PE365, PG e PE455, PG e PE550, PE365 e PE455, PE365 e PE550 e PE455 e PE550 foram, respectivamente, 0,06; 0,13; 0,20; 0,13; 0,96; 0,98 e 0,99. Todas as características apresentaram variabilidade genética aditiva suficiente para responder favoravelmente à seleção. No que tange a precocidade sexual, a melhor opção seria PE365, devido à alta herdabilidade estimada, além de que a seleção indireta a esta idade seria mais eficiente que a direta para PE455.
    Archivos de Zootecnia 12/2012; 61(236):559-567.
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    ABSTRACT: Objetivou-se avaliar a estrutura populacional e a relação desta com o progresso genético ocorrido em características de crescimento em rebanhos da raça Guzerá do Nordeste do Brasil. Foram utilizadas informações de pedigree e dados do peso corporal ajustado para 205, 365 e 550 dias de idade de animais nascidos no período de 1976 a 2007. O intervalo médio de geração por passagem gamética foi de 7,9 ± 4,4 anos, assim estratificado: Pai-Filho (7,5±4,5 anos); Pai-Filha (7,9±4,8); Mãe-Filho (7,8±4,2) e Mãe-Filha (7,9±3,9 anos). O coeficiente de endogamia apresentou tendência a crescer da segunda até a sétima geração, a passar de 0,17% para 2,06%, mas, ao se considerar apenas os animais endogâmicos, observou-se que o coeficiente médio de endogamia diminuiu, de 15,66% para 6,75% no período. O intervalo de geração foi alto. Para reduzi-lo é recomendável a utilização de touros jovens. O tamanho efetivo de população da raça na região foi entre 197 e 674 animais. Se analisado juntamente com a tendência de redução da endogamia nas últimas três décadas, evidencia existir potencial para ganho genético por seleção na raça, visto que o coeficiente de herdabilidade do peso corporal aos 365 e 550 dias de idade foi de tamanho moderado. Pela análise da tendência do ganho genético nas características do período avaliado, constatou-se que foi pequena diante de ganho fenotípico alto, o que indica que o progresso fenotípico observado foi decorrente, em sua maior parte, das melhorias realizadas no manejo.
    Revista Brasileira de Saúde e Produção Animal. 12/2012; 13(4):1032-1043.
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    ABSTRACT: In most studies on beef cattle longevity, only the cows reaching a given number of calvings by a specific age are considered in the analyses. With the aim of evaluating all cows with productive life in herds, taking into consideration the different forms of management on each farm, it was proposed to measure cow longevity from age at last calving (ALC), that is, the most recent calving registered in the files. The objective was to characterize this trait in order to study the longevity of Nellore cattle, using the Kaplan-Meier estimators and the Cox model. The covariables and class effects considered in the models were age at first calving (AFC), year and season of birth of the cow and farm. The variable studied (ALC) was classified as presenting complete information (uncensored = 1) or incomplete information (censored = 0), using the criterion of the difference between the date of each cow's last calving and the date of the latest calving at each farm. If this difference was >36 months, the cow was considered to have failed. If not, this cow was censored, thus indicating that future calving remained possible for this cow. The records of 11 791 animals from 22 farms within the Nellore Breed Genetic Improvement Program ('Nellore Brazil') were used. In the estimation process using the Kaplan-Meier model, the variable of AFC was classified into three age groups. In individual analyses, the log-rank test and the Wilcoxon test in the Kaplan-Meier model showed that all covariables and class effects had significant effects (P < 0.05) on ALC. In the analysis considering all covariables and class effects, using the Wald test in the Cox model, only the season of birth of the cow was not significant for ALC (P > 0.05). This analysis indicated that each month added to AFC diminished the risk of the cow's failure in the herd by 2%. Nonetheless, this does not imply that animals with younger AFC had less profitability. Cows with greater numbers of calvings were more precocious than those with fewer calvings.
    animal 10/2012; · 1.65 Impact Factor
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    ABSTRACT: In this study, the objective was to estimate genetic parameters of body weight at 210 (BW210) and 365 (BW365) days of age in relation to rib eye area (REA), subcutaneous back fat thickness (BF) and rump fat (RF), and their respective genetic trends, in Nelore beef cattle. Estimates of genetic parameters and breeding values for the studied traits were obtained using the REML method. The direct and maternal heritability estimates were respectively: 0.25±0.02 and 0.21±0.01, for BW210, and 0.29±0.02 and 0.09±0.01, for BW365. The heritability estimates for transformed REA, BF and RF were 0.29±0.03, 0.21±0.02 and 0.23±0.03, respectively. There were genetic associations between BW210 and REA, BW365 and REA, and BF and RF, while the other correlations were low. The selection process that was conducted at the farms participating in the breeding program, taking the proposed selection index into consideration, caused genetic changes to these traits.
    Meat Science 02/2012; 91(3):352-7. · 2.75 Impact Factor
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    ABSTRACT: The objective of this study was to estimate (co)variance components using random regression on B-spline functions to weight records obtained from birth to adulthood. A total of 82 064 weight records of 8145 females obtained from the data bank of the Nellore Breeding Program (PMGRN/Nellore Brazil) which started in 1987, were used. The models included direct additive and maternal genetic effects and animal and maternal permanent environmental effects as random. Contemporary group and dam age at calving (linear and quadratic effect) were included as fixed effects, and orthogonal Legendre polynomials of age (cubic regression) were considered as random covariate. The random effects were modeled using B-spline functions considering linear, quadratic and cubic polynomials for each individual segment. Residual variances were grouped in five age classes. Direct additive genetic and animal permanent environmental effects were modeled using up to seven knots (six segments). A single segment with two knots at the end points of the curve was used for the estimation of maternal genetic and maternal permanent environmental effects. A total of 15 models were studied, with the number of parameters ranging from 17 to 81. The models that used B-splines were compared with multi-trait analyses with nine weight traits and to a random regression model that used orthogonal Legendre polynomials. A model fitting quadratic B-splines, with four knots or three segments for direct additive genetic effect and animal permanent environmental effect and two knots for maternal additive genetic effect and maternal permanent environmental effect, was the most appropriate and parsimonious model to describe the covariance structure of the data. Selection for higher weight, such as at young ages, should be performed taking into account an increase in mature cow weight. Particularly, this is important in most of Nellore beef cattle production systems, where the cow herd is maintained on range conditions. There is limited modification of the growth curve of Nellore cattle with respect to the aim of selecting them for rapid growth at young ages while maintaining constant adult weight.
    animal 02/2012; 6(2):212-20. · 1.65 Impact Factor
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    ABSTRACT: Validity of comparisons between expected breeding values obtained from best linear unbiased prediction procedures in genetic evaluations is dependent on genetic connectedness among herds. Different cattle breeding programmes have their own particular features that distinguish their database structure and can affect connectedness. Thus, the evolution of these programmes can also alter the connectedness measures. This study analysed the evolution of the genetic connectedness measures among Brazilian Nelore cattle herds from 1999 to 2008, using the French Criterion of Admission to the group of Connected Herds (CACO) method, based on coefficients of determination (CD) of contrasts. Genetic connectedness levels were analysed by using simple and multiple regression analyses on herd descriptors to understand their relationship and their temporal trends from the 1999-2003 to the 2004-2008 period. The results showed a high level of genetic connectedness, with CACO estimates higher than 0.4 for the majority of them. Evaluation of the last 5-year period showed only a small increase in average CACO measures compared with the first 5 years, from 0.77 to 0.80. The percentage of herds with CACO estimates lower than 0.7 decreased from 27.5% in the first period to 16.2% in the last one. The connectedness measures were correlated with percentage of progeny from connecting sires, and the artificial insemination spread among Brazilian herds in recent years. But changes in connectedness levels were shown to be more complex, and their complete explanation cannot consider only herd descriptors. They involve more comprehensive changes in the relationship matrix, which can be only fully expressed by the CD of contrasts.
    Journal of Animal Breeding and Genetics 02/2012; 129(1):20-9. · 1.65 Impact Factor
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    ABSTRACT: Heritability (h2) and genetic correlations (rg) were estimated between reproductive traits such as age at first calving (AFC), first calving interval (FCI) and other economically relevant traits, i.e., weight (W) at year (Y) and at 18 months of age (S), scrotal circumference (SC), and hip height (HH) in Nelore cattle. The genetic parameters were estimated in a multiple-trait analysis, with animal models using the Bayesian inference by Gibbs Sampling algorithm. The genetic parameters estimated in this work suggest the existence of genetic variability for AFC (h2 = 0.26), where the selection for the reduction of Nelore females AFC should respond to mass selection, without causing genetic antagonism in the selection of W (rg = -0,22 (Y) and -0,44 (S)), and SC (rg = 0,02). The selection for the AFC in the long term could lead to an increase in the animal's frame, although this association is relatively low (-0.35). The posteriori heritability estimate for FCI was low, 0.11±0.03. The rg between FCI and the other traits studied indicate that selection for these growth traits will not affect the FCI.
    Arquivo Brasileiro de Medicina Veterinária e Zootecnia 02/2012; 64(1):91-100. · 0.27 Impact Factor
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    ABSTRACT: Objetivou-se com este trabalho estimar os parâmetros genéticos do índice perímetro escrotal/ peso padronizado para 365 dias de idade (IND365), via inferência bayesiana, sob dois modelos de análise distintos, em animais da raça Nelore criados no Estado do Tocantins, Brasil. O arquivo final estava constituído de 693 registros do IND365 distribuídos em 16 grupos de contemporâneos. Os componentes de variância foram analisados via inferência bayesiana, por meio de programas em linguagem Fortran. Amostragem a cada 100 ou 500 rodadas e um burn-in pouco conservador poderão ser implementados. As médias pontuais para os coeficientes de herdabilidade direta e materna para o IND365 foram respectivamente: 0,18 (com ou sem efeito materno) e 0,14. Estes resultados sugerem que o IND365 possa ser utilizado como critério alternativo nos programas de melhoramento e responder de forma satisfatória ao processo de seleção.
    Archivos de Zootecnia 12/2011; 60(232):871-882.
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    ABSTRACT: The testis-specific protein Y-encoded gene (TSPY) is a Y-specific gene present in variable copy number in many mammalian species, including cattle. We tested the applicability of the TSPY gene as a Y-specific marker to predict preimplantation embryo sex in Nelore (Bos indicus) cattle. Two blastomeres were removed from each embryo. A total of 36 single blastomeres and the remaining cells of their 18 matched in vitro conceived embryos were screened for TSPY amplification by nested-PCR. The results obtained from a single blastomere and the remaining cells of the same embryo were concordant in all cases. All blastomeres (16/16) from eight embryos produced with sexed sperm (specific for production of male embryos) were TSPY-positive. We conclude that TSPY is a good male-specific marker, the usefulness of which is probably enhanced by the high copy number. Other methods that are less time-consuming, such as real-time PCR, could be improved with the use of the TSPY gene sequences to generate primers and/or probes. This is the first report to demonstrate the applicability of the TSPY gene for sexing single cells in cattle.
    Genetics and molecular research: GMR 10/2011; 10(4):3937-41. · 0.99 Impact Factor
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    ABSTRACT: Este trabalho foi realizado com o objetivo de avaliar o consumo voluntário, a digestibilidade aparente e o balanço de nitrogênio em ovinos alimentados com dietas contendo torta de dendê. A adição da torta de dendê foi avaliada nos níveis 0; 20; 40; 60 e 80% em substituição à silagem de capim-elefante utilizando-se 20 ovinos machos castrados em um delineamento experimental inteiramente casualizado. Em todas as formas como foram expressos, o consumo e a digestibilidade de nutrientes apresentou em geral resposta quadrática aos níveis de torta de dendê utilizados na dieta. A inclusão de torta de dendê nas dietas teve efeito quadrático também sobre o balanço de nitrogênio, que aumentou até o nível de 45% de adição desse subproduto e decresceu, devido ao baixo consumo de proteína bruta nos maiores níveis. A torta de dendê possui características próprias de um alimento volumoso e tem como principal limitação o baixo consumo alimentar, por isso, seu uso na alimentação de ovinos deve ser restrito ao nível máximo de 37,34% da dieta total.
    Revista Brasileira de Zootecnia 09/2011; 40(9):1975-1983. · 0.56 Impact Factor
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    ABSTRACT: The interest in the effect of genotype × environment interaction is increasing because animal breeding programs have become geographically broader. Climate changes in the next decades are also expected to challenge the present breeding goals, increasing the importance of environmental sensitivity. The aim of this work was to analyze genotype × environment interaction effect on cattle BW using the environmental sensitivity predicted by random regression reaction norm models, including sex and age effects as additional dimensions in the study. Genetic parameters were estimated for adjusted BW of Brazilian Nelore cattle at different ages (120, 210, 365, and 450 d), using linear polynomials for random regression analysis. The analyses with sex as a fixed effect (total analyses) were compared with those with sex-separated progenies (male and female progeny analyses, respectively). (Co)variance components were estimated and breeding values calculated EPD. The results showed important differences in reaction norm model genetic parameter estimates according to different age and sex analyses. The results confirmed the presence of an important genotype × environment × sex × age interaction for Nelore cattle BW. The patterns in these results lead to a revision of the importance of sexual and developmental factors on plasticity and adaptation concepts.
    Journal of Animal Science 07/2011; 89(11):3410-25. · 2.09 Impact Factor

Publication Stats

320 Citations
73.71 Total Impact Points

Institutions

  • 2005–2013
    • University of São Paulo
      • Ribeirão Preto School of Medicine (FMRP)
      San Paulo, São Paulo, Brazil
  • 2008–2012
    • São Paulo State University
      • • Departamento de Zootecnia
      • • Departamento de Ciências Exatas
      • • Faculdade de Ciências Agrárias e Veterinárias
      São Paulo, Estado de Sao Paulo, Brazil
  • 2010–2011
    • Brazilian Agricultural Research Corporation (EMBRAPA)
      Brasília, Federal District, Brazil
    • Universidade Federal de Uberlândia (UFU)
      UDI, Minas Gerais, Brazil
  • 1998–2010
    • Universidade Federal do Ceará
      • • Departamento de Zootecnia
      • • Center of Agricultural Sciences (CAA)
      Ceará, Ceará, Brazil
  • 1999–2009
    • Universidade de Ribeirão Preto
      Entre Rios, São Paulo, Brazil
  • 2006
    • CEP America
      Emeryville, California, United States
  • 1995
    • University of Nebraska at Lincoln
      • Department of Animal Science
      Lincoln, NE, United States