Public x private partnership in the development of animal breeding research

O melhoramento genético animal é, normalmente, pesquisado e desenvolvido nas universidades e instituições públicas de pesquisa do Brasil. No entanto, os rebanhos de exploração zootécnica, verdadeiros objetivos desses estudos, pertencem à iniciativa privada. O melhoramento genético animal e as parcerias público-privadas constituem-se em um caso especial de grande sucesso, que é analisado no presente texto, com ênfase especial ao Grupo de Melhoramento Animal e Biotecnologia da Faculdade de Zootecnia e Engenharia de Alimentos da Universidade de São Paulo, instituição de origem dos autores. O sucesso desse grupo, medido em atividades de pesquisa e suas conseqüentes publicações, de ensino e formação de recursos humanos e de extensão de serviços à comunidade, é apresentado como incentivo aos pesquisadores das mais diversas áreas ligadas à produção animal.Animal breeding is, normally, developed and investigated in public institutions in Brazil. However, herds and populations, true users of that knowledge, are private. The relationship between the public and the private is a very successful case in animal breeding and that case is discussed in this text, with special emphasis on the Animal Breeding and Biotechnology Group of the College of Animal Science and Food Technology of the University of Sao Paulo, Brazil. The exit of that group, measured in research and publications, education and extension is presented as an incentive to other research groups related to animal production in the country

Genome Wide Association Study for Heifer Pregnancy in Nellore Cattle

Considering the economic importance of sexual precocity in Brazilian beef cattle production systems, we were interested in a genome wide association study (GWAS) to find genomic regions that might explain the genetic variability of precocity assessed from heifer pregnancy rates. Given each suggestive region of large effect, we were interested in contrasting the two paternally-inherited haplotype alleles to identify sires that were heterozygous for the effect caused by that region. The database consists of reproductive information on 1,337 Bos indicus Nellore heifers, from three different herds in Brazil. GWAS results identified genomic regions on chromosomes 5, 14 and 18 that explained more than 1% of the total genetic variance. Haplotype analysis for the chromosome 5 region showed heterozygote sires with significant differences in reproduction between their half-sib progenies

Heterose em suínos na fase de aleitamento

Individual weights at birth (PO), 21 days(P21) and weaning (PD) of 746 piglets, being 201Landrace, 136 Wessex-Saddleback and 409 crossbred were analysed by the least squares method. Estimates of heterosis and weight gains were obtained by a fixed model considering the effects of year and season at birth, litter order, sex and litter sizes, besides paternal and maternal breed effects. The effects were significant and the crossbred piglets were heavier than purebreds. Heterosis estimates were 2.6% for PO, 9.7% for P21 and 13.9% for PD, indicating higher no additive gene effects when the age of piglets increase or their dependence on maternal hability becomes less important. Interactions between maternal and paternal breeds were significant. The results indicate that crossbreeding these two breeds is useful for piglets production.Visando avaliar o ganho de produtividade, advindo da heterose, no peso de suínos em fase de aleitamento, analisaram-se os pesos ao nascimento(PO), 21 dias de idade (P21) e desmama (PD) de 746leitões, sendo 201 da raça Landrace, 136 Wessex-Saddleback e 409 mestiços, pelo método dos quadrados mínimos, considerando-se, ainda, os efeitos fixos de época e ano de nascimento, ordem do parto, sexo do leitão e tamanho da leitegada, além de raças paterna e materna e suas interações. Os efeitos não genéticos tiveram influência significativa em quase todas as características. Os mestiços mostraram, em geral, pesos superiores aos puros, com estimativas de heterose de 2,6% para PO, 9,7% para P21 e 13,9% para PD, indicando a importância da herança não aditiva à medida que os leitões ficam menos dependentes de suas mães. Os efeitos de interação entre as raças paterna e materna foram cada vez maiores com o avançar da idade. Os resultados indicam haver ganho de produtividade coma utilização deste tipo de cruzamento

Influência de fatores ambientais no desempenho de suínos em fase de aleitamento

Individual weights of 746 pigletts at birth, at 21 days of age and at weaning were analysed by Least Squares method considering year and season of birth, litter order, sex and litter sire at birth, as independent variables. The year and the season of the birth affected significantly the 21 day and weaning weights, and the weights were higher with the increase of years. Highest weights were observed during the low temperature season and lowest weights during the hight temperature season. Litter order affected all the weights and a tendency of increasing the weights with flue increasing of order was observed. Sex had significant influence only on birth weight, when the males were heavier. Females had better gain on weight from birth to weaning probably due to the stress caused by castration in the males. Litter sire affected all the weights, although that influence was lowest as the age increased. Generally the weights decreased with the increasing of litter size.Os pesos individuais ao nascimento, aos 21 dias de idade e à desmama de 746 leitões das raças Landrace, Wessex-Saddleback e seus mestiços foram analisados pelo método dos quadrados mínimos, considerando-se os efeitos fixos das variáveis ano e época do nascimento, ordem do parto, sexo do leitão e tamanho de leitegada. O efeito de ano de nascimento revelou-se significativo para os pesos aos 21 dias e à desmama, sendo os pesos crescentes com a progressão dos anos, com exceção de 1978. Os mesmos pesos foram influenciados pela época de nascimento, tendo os maiores pesos sido verificados em épocas de temperaturas mais amenas, ao passo que os menores ocorreram em épocas de altas temperaturas. A ordem do parto teve influência estatisticamente significativa sobre todos os pesos estudados, verificando-se a tendência de aumento dos pesos com a progressão das ordens de parto, indicando que as fêmeas, ao menos até o quarto parto, vão se tomando melhores mães. O sexo do leitão influenciou apenas o peso ao nascimento, quando os machos nasceram mais pesados. As fêmeas apresentaram maiores pesos à desmama, sendo tal fato devido, possivelmente, ao "stress" causado pela castração, realizada aos 21 dias nos machos. O tamanho de leitegada influenciou todos os pesos, embora tal influência tenha sido menor à medida que os leitões ficaram menos dependentes de suas mães. Em geral, os pesos individuais diminuíram com o aumento da leitegada

Opportunities and challenges from the use of genomic selection for beef cattle breeding in Latin America

In 2009, Latin American countries had approximately 401 million cattle (29% of the world’s total cattle population) and produced 8.2 million tonnes of beef, equivalent to 29% of the world’s total production (FAO, 2011). Beef in Latin American countries is produced under widely differing climates (ranging from tropical to temperate), resources available (vegetation, food), types of markets, and genetic backgrounds of the animals. The main production systems are classified as beef and dual-purpose cattle. The genetic backgrounds of animals vary from purebred European (Bos taurus taurus) or Zebu (Bos taurus indicus) to crossbreeds (Figures 1 and 2). Beef production systems may also be characterized by their management intensification levels as grazing only, grazing with food supplementation, and feedlot production. The main beef-producing countries are Brazil (51.6% of the total Latin American beef production), Argentina (18.5%), Mexico (9.4%), and Colombia (5.1%). Other countries contributing more than 1% of the total regional production are Uruguay, Venezuela, Paraguay, Bolivia, Ecuador, and Chile (Table 1). Latin America is a region of the world that can significantly increase its production in response to beef demand. Brazil has a mature beef cattle industry based on grass-fed cattle, in which feeding B. taurus indicus cattle, especially the Nellore breed, is a common practice. Over the last 8 years, beef production in Brazil has become one of the most important activities for employment and wealth creation. Foot-and-mouth disease issues are still a factor limiting the increase in Latin American beef exports (Ferraz and de Felício, 2010; Domingues Millen et al., 2011). Only a few Latin American countries, including Chile and Mexico, have the status of being free of this disease without vaccination. In most countries, the disease is controlled using a combination of free areas without vaccination and areas with vaccination. Other countries with a strong B. taurus indicus background in their beef cattle populations are those with large tropical areas dedicated to beef cattle production, such as Colombia, Venezuela, and Paraguay. Beef production in Argentina, Chile, Uruguay, and some portions of Brazil and Mexico is based mainly around the production of B. taurus taurus cattle (Peel et al., 2010; Arelovich et al., 2011; Domingues Millen et al., 2011). The Mexican beef cattle industry consists of 2 nearly separate market components. Beef producers in the northern part of Mexico have largely focused on the production of calves for export to the United States (Galyean et al., 2011). European beef genetics have been widely used in the region, beginning with importations of Hereford cattle and continuing with today’s popularity of Angus and Brangus along with several continental breeds, such as Charolais and Simmental. The central and southern regions of Mexico have historically produced grass-fed beef for the national market as well as dual-purpose dairy-Zebu crossbred cattle to produce milk and beef (Peel et al., 2010). Currently, breeding programs for the genetic evaluation of beef cattle in Latin America are based on statistical analyses in which performance and pedigree information are integrated. These analyses are based on a mixed model methodology, in particular the animal model statistical approach using best linear unbiased prediction methods to obtain estimated breeding values (EBV) for economically important traits. This methodology for obtaining EBV has been set up in Argentina, Brazil, Colombia, Mexico, Uruguay, Venezuela, and other countries. It has been established for specific purebred populations and also for some crossbred populations, such as multibreed populations with a dual purpose (beef and milk) in the Latin American humid tropics, which involve animals crossbred between B. taurus taurus and B. taurus indicus and composite breeds. Most programs focus on evaluating growth and reproductive traits, although a few have included longevity (stayability), heifer pregnancy, conformation, and carcass and meat quality traits

Características de produção e de composição corporal de frangos em relação ao peso de peito avaliada por análise de trilha

O peso do peito possui grande importância econômica na indústria de frangos, podendo estar associado a outras variáveis passíveis de seleção. Estimaram-se correlações fenotípicas entre características de desempenho (peso vivo aos 7, 28 dias e ao abate e profundidade de músculo peitoral por ultra-sonografia), carcaça (peso eviscerado e de pernas) e composição corporal (peso do coração, do fígado e da gordura abdominal), em uma linhagem de frangos, e quantificou-se a influência direta e indireta destas variáveis sobre o peso do peito. Para tanto, utilizou-se a análise de trilha, desdobrando-se a matriz de correlações parciais em coeficientes que forneceram a influência direta de uma variável sobre a outra, independentemente das demais. A manutenção das variáveis peso vivo ao abate e peso eviscerado na matriz de correlações pode ser prejudicial à análise estatística que envolve os sistemas de equações normais, como a análise de trilha, devido à multicolinearidade observada. O peso vivo ao abate e a profundidade do músculo peitoral por ultra-sonografia apresentaram efeitos diretos importantes sobre o peso de peito e foram identificadas como as principais responsáveis pela magnitude dos coeficientes de correlação obtidos. Assim, uma pré-seleção individual para estas características pode favorecer um aumento no peso de peito nesta linhagem, se mantidas as condições ambientais de criação dos frangos, uma vez que o peso vivo ao abate e a profundidade de músculo peitoral por ultra-sonografia afetam fenotipicamente e diretamente o peso de peito.Breast weight has great economic importance in poultry industry, and may be associated with other variables. This work aimed to estimate phenotypic correlations between performance (live body weight at 7 and 28 days, and at slaughter, and depth of the breast muscle measured by ultrasonography), carcass (eviscerated body weight and leg weight) and body composition (heart, liver and abdominal fat weight) traits in a broiler line, and quantify the direct and indirect influence of these traits on breast weight. Path analysis was used by expanding the matrix of partial correlation in coefficients which give the direct influence of one trait on another, regardless the effect of the other traits. The simultaneous maintenance of live body weight at slaughter and eviscerated body weight in the matrix of correlations might be harmful for statistical analysis involving systems of normal equations, like path analysis, due to the observed multicollinearity. The live body weight at slaughter and the depth of the breast muscle as measured by ultrasonography directly affected breast weight and were identified as the most responsible factors for the magnitude of the correlation coefficients obtained between the studied traits and breast weight. Individual pre-selection for these traits could favor an increased breast weight in the future reproducer candidates of this line if the broilers' environmental conditions and housing are maintained, since the live body weight at slaughter and the depth of breast muscle measured by ultrasonography were directly related to breast weight

Medidas de eficiência alimentar para avaliação de bovinos de corte

The converting efficiency of feed into products of animal source is an important issue for the profitability and sustainability of the beef cattle production systems. During the last decades, there has been an increased interest at the study of features that can express the feed efficiency, especially the residual feed intake (RFI).These studies guided this review which discusses the results and implications of the genetic selection based on RFI, and also the new perspectives in the studies of feed efficiency in beef cattle.A eficiência da conversão de alimentos em produtos de origem animal é importante para a lucratividade e sustentabilidade dos sistemas de produção de bovinos de corte. Nas últimas décadas houve um interesse maior pelo estudo de características que expressam a eficiência alimentar, principalmente o consumo alimentar residual (CAR). Esses estudos nortearam essa revisão que aborda os resultados e implicações da seleção baseada no CAR e também as novas perspectivas nos estudos com eficiência alimentar em bovinos de corte

Use of postpartum body condition score to identify the most fertile beef cows raised in extensive operations

The assessment of postpartum body condition score in beef cattle may be a useful tool to recommend technologies to improve reproductive efficiency based on nutrition and reproductive management. The variability and repeatability of body condition scores between 60-90 d postpartum were investigated in order to verify the possibility that such assessments could indicate the inheritance of fertility in beef cows. In three consecutive years a total of 3721 cows predominantly Hereford purebreds and crossbreds, kept on natural pastures in seven farms in the southern region of Rio Grande do Sul, Brazil, were evaluated. More than 60% of these cows had intermediate to superior body condition score (scale of five classes), varying significantly among farms and years studied. A low repeatability of scores in the same animal in two or three consecutive years was found, refuting the possibility of direct selection for higher fertility as a function of body condition score. Although the scoring system does not define fertility phenotypes, it allows the identification of the one in every 200 cows with the characteristic of being pregnant and maintaining high body condition scores during three consecutive years, which may serve as base animals for future genome association studies employing single nucleotide polymorphisms

Sensitivity to halothane and its relationship to the development of PSE (Pale, Soft, Exudative) meat in female lineage broilers

This work aimed to evaluate female lineage broilers for halothane sensitivity and for their susceptibility to the subsequent development of PSE meat. The halothane test was carried out in an anesthetic chamber with 3.0% halothane. The unconscious birds were examined for leg muscle rigidity. If one or both legs became extended and rigid, the birds were classified as halothane sensitive (HAL+), while unresponsive birds were classified as halothane negative (HAL-). The results showed that of 298 birds aged 42 days old, 95.6% were HAL- and 4.4% were HAL+. A sample of pectoralis major muscle was collected from HAL- (n=105) and HAL+ (n=13) birds. The pH and breast fillet color were determined at 4ºC, 24 hours post-mortem. Interestingly, only 2.5% of HAL+ birds displayed PSE meat characteristics compared to 12.7% of HAL- individuals. The halothane test demonstrated that female lineage broilers displayed very little sensitivity towards halothane, indicating that the development of PSE meat is related to other environmental factors.O objetivo deste trabalho foi avaliar a sensibilidade de aves de uma linhagem fêmea ao halotano e sua relação com o desenvolvimento de carnes PSE. O teste do halotano foi conduzido com o auxílio de uma câmara anestésica com 3,0% de halotano volatilizado. As aves inconscientes foram examinadas pelo enrijecimento dos seus membros inferiores. Quando ambos ou um dos membros permaneceram rígidos, os frangos foram classificados como sensíveis ao halotano (HAL+) e os frangos sem enrijecimento dos membros foram classificados como não-sensíveis (HAL-). Os resultados mostraram que de 298 frangos com 42 dias de idade, 95,6% foram HAL-, e apenas 4,4% HAL+. O peito foi coletado das aves HAL- (n=105) e HAL+ (n=13) em que o pH e Cor (L*,a*,b*) foram determinados a 4ºC, 24h postmortem. Interessantemente, apenas 2,5% das aves HAL+ demonstraram carnes PSE, enquanto que as aves HAL- apresentaram 12,7% de carnes PSE, em relação ao total de aves abatidas. O teste do halotano demonstrou que frangos da linhagem fêmea mostraram pouquíssima sensibilidade ao halotano, indicando que a ocorrência de carnes PSE está mais associada a fatores ambientais.Fundação AraucáriaFINEPCNPqProne

Genetic parameters and trends of growth traits in Nelore cattle raised in the Northern region of Brazil

The objective of this study was to estimate (co)variances and genetic parameters and to predict genetic trends for weight at 120 (W120), 210 (W210), 365 (W365), and 450 (W450) days of age in Nelore cattle raised in the northern region of Brazil. The database comprised records of 30,387 animals born between 2000 and 2013 in the Brazilian North. Estimates were calculated by the Restricted  Maximum Likelihood (REML) method, in single- and multi-trait analyses in an animal model. Heritability as obtained using single- and multi-trait models for W120 (0.22 and 0.31), W210 (0.20 and 0.34), W365 (0.51 and 0.51), and W450 (0.49 and 0.51) indicated moderate to high magnitudes, with the possibility of genetic selection and incorporation into the herd. Genetic correlations between growth traits were favorable, ranging from 0.78 to 0.96. Genetic trends for W120 and W210 varied largely, from -0.31 to 4.68 and -0.53 to 7.62 kg/year, respectively. Smaller fluctuations were observed in genetic trends for W365 and W450, which ranged from -1.08 to 10.90 and -1.29 to 12.51 kg/year, respectively. Selection for W365 and W450 proved to be the criterion of choice for Nelore herds raised in the region; however, it may compromise adult performance because of higher costs and time for production. A thorough analysis of mattings is recommended to allow the selection of earlier-developing animals. O presente trabalho foi delineado para estimar as (co) variâncias, parâmetros genéticos e de predizer as tendências genéticas para o peso aos 120 (W120), 210 (W210), 365 (W365) e 450 (W450) dias de idade de gado Nelore criado na região norte do Brasil. A base de dados foi constituituída por registro de 30387 animais, nascidos entre 2000 e 2013 no norte do Brasil. As estimativas foram calculadas pelo método de máxima restrição de probabilidade (REML) em um modelo animal com análises isoladas e multi variadas. A herdabilidade obtida para os modelos utilizados foi: W120 (0,22 e 0,31); W210 (0,20 e 0,34); W365 (0,51 e 0,51) e W450 (0,49 e 0,51), indicando moderada e alta magnitude com a possibilidade de seleção genética e incorporação no rebanho. As correlações genéticas entre grupos de tendências foram favoráveis variando de 0,78 a 0,96. As tendências genéticas para W120 e W210 apresentaram ampla variação de -0,31 a 4,68 e -0,53 a 7,62 kg/ano, respectivamente. Menores flutuações foram observadas nas tendências genéticas para W365 e W450, as quais variaram de -1,08 a 10,90 e -1,29 a12,51 kg/ano, respectivamente. Foi constatado que a seleção para W365 e W450 deve ser um critério de escolha para os rebanhos Nelore criados na região; contudo ela pode comprometer a performance dos adultos devido aos elevados custos e da duração da produção. Uma completa análise de cruzamentos é recomendada para possibilitar a seleção de animais jovens em desenvolvimento.