Overview of the use of genomic data in animal breeding / Panorama do uso de dados genômicos no melhoramento genético animal

The use of molecular information in breeding programs contributed to important advances in the improvement of traits of economic interest in livestock production. The advent of single nucleotide polymorphism (SNP) panels applied to genome-wide selection (GWS) and genome-wide association studies (GWAS), along with computational advances (e.g., use of powerful software and robust analyses) allowed a better understanding of the genetic architecture of farm animals and increased the selection efficiency. In this context, the statistic method single-step GBLUP has been frequently used to perform GWS, and more recently GWAS analyses, providing accurate predictions and QTL detection, respectively. Nevertheless, in developing countries, species such as sheep and goats, whose genomic data are more difficult to be obtained, the use of data simulation has been efficient in the study of the major factors involved in the selection process, such as size of training population, density of SNP chips, and genotyping strategies. The effects of these factors are directly associated with the prediction accuracy of genomic breeding values. In this review we showed important aspects of the use of genomics in the genetic improvement of production traits of animals, the main methods currently used for prediction and estimation of molecular marker effects, the importance of data simulation for validation of those methods, as well as the advantages, challenges and limitations of the use of GWS and GWAS in the current scenario of livestock production.

Em programas de melhoramento genético, o uso de informações moleculares garantiu importantes avanços para a melhoria de características de interesse econômico, no âmbito da produção animal. O advento da tecnologia de painéis de SNPs aplicados à seleção genômica ampla (GWS) e associação genômica ampla (GWAS), aliado ao avanço computacional, com o uso de softwares e análises robustas, permitiram melhor compreensão sobre a arquitetura genética dos animais de produção e, consequentemente, maior eficiência na seleção. Nesse contexto, o método estatístico single-step GBLUP tem sido utilizado, frequentemente, na execução da GWS e, mais recentemente, em GWAS, possibilitando predições acuradas e detecção de QTLs, respectivamente. No entanto, em países em desenvolvimento e, em espécies como os ovinos e caprinos, que existe maior dificuldade para a aquisição de dados genômicos, o uso da simulação de dados tem se mostrado eficiente para estudar os principais fatores envolvidos no processo de seleção, como o tamanho da população de treinamento, densidade de chipde SNPs e estratégias de genotipagem, cujos efeitos estão diretamente associados à acurácia da predição de valores genéticos genômicos. Nesta revisão, serão abordados pontos importantes sobre o uso da genômica no melhoramento genético de características produtivas em animais, principais métodos de predição e estimação de efeitos de marcadores moleculares na atualidade, a importância da simulação de dados para a validação desses métodos, bem como as vantagens, os desafios e as limitações no cenário atual da produção animal com o uso da seleção e associação genômica ampla.

Overview of the use of genomic data in animal breeding / Panorama do uso de dados genômicos no melhoramento genético animal

ABSTRACT: The use of molecular information in breeding programs contributed to important advances in the improvement of traits of economic interest in livestock production. The advent of single nucleotide polymorphism (SNP) panels applied to genome-wide selection (GWS) and genome-wide association studies (GWAS), along with computational advances (e.g., use of powerful software and robust analyses) allowed a better understanding of the genetic architecture of farm animals and increased the selection efficiency. In this context, the statistic method single-step GBLUP has been frequently used to perform GWS, and more recently GWAS analyses, providing accurate predictions and QTL detection, respectively. Nevertheless, in developing countries, species such as sheep and goats, whose genomic data are more difficult to be obtained, the use of data simulation has been efficient in the study of the major factors involved in the selection process, such as size of training population, density of SNP chips, and genotyping strategies. The effects of these factors are directly associated with the prediction accuracy of genomic breeding values. In this review we showed important aspects of the use of genomics in the genetic improvement of production traits of animals, the main methods currently used for prediction and estimation of molecular marker effects, the importance of data simulation for validation of those methods, as well as the advantages, challenges and limitations of the use of GWS and GWAS in the current scenario of livestock production.

RESUMO: Em programas de melhoramento genético, o uso de informações moleculares garantiu importantes avanços para a melhoria de características de interesse econômico, no âmbito da produção animal. O advento da tecnologia de painéis de SNPs aplicados à seleção genômica ampla (GWS) e associação genômica ampla (GWAS), aliado ao avanço computacional, com o uso de softwares e análises robustas, permitiram melhor compreensão sobre a arquitetura genética dos animais de produção e, consequentemente, maior eficiência na seleção. Nesse contexto, o método estatístico single-step GBLUP tem sido utilizado, frequentemente, na execução da GWS e, mais recentemente, em GWAS, possibilitando predições acuradas e detecção de QTLs, respectivamente. No entanto, em países em desenvolvimento e, em espécies como os ovinos e caprinos, que existe maior dificuldade para a aquisição de dados genômicos, o uso da simulação de dados tem se mostrado eficiente para estudar os principais fatores envolvidos no processo de seleção, como o tamanho da população de treinamento, densidade de chipde SNPs e estratégias de genotipagem, cujos efeitos estão diretamente associados à acurácia da predição de valores genéticos genômicos. Nesta revisão, serão abordados pontos importantes sobre o uso da genômica no melhoramento genético de características produtivas em animais, principais métodos de predição e estimação de efeitos de marcadores moleculares na atualidade, a importância da simulação de dados para a validação desses métodos, bem como as vantagens, os desafios e as limitações no cenário atual da produção animal com o uso da seleção e associação genômica ampla.

Comparison of genetic parameters and estimated breeding values for worm resistance in meat sheep obtained using traditional and genomic models.

Gastrointestinal nematode infections have caused expressive losses in sheep production worldwide. The improvement of host genetic resistance to worms has been used as a strategy to mitigate this problem. In this sense, the inclusion of genomic information has shown potential to increase the accuracy of prediction of breeding values and speed up selection. In this study, we aimed to compare estimates of genetic parameters and breeding values for traits that indicate the resistance to gastrointestinal nematode infection in Santa Inês sheep using the pedigree-based BLUP or including genomic information. There were 1478 animals in the pedigree, of which 271 were genotyped using the OvineSNP50 BeadChip (Illumina, Inc.). The host resistance was assessed using the following traits: fecal nematode egg counts (FEC); FAMACHA score (FAMACHA); and resistance to gastrointestinal nematode infection (RGNI) as a combination of FEC, FAMACHA, body condition score, and hematocrit. The genetic parameters and breeding values were estimated using single- and multi-trait analyses. For RGNI, the heritability estimates ranged from 0.25 using the single-trait genomic model (S-H) to 0.54 using the traditional multi-trait model (M-A). The heritability estimates for FEC ranged from 0.06 to 0.36, using the single-trait pedigree-based model (S-A) and the multi-trait genomic model (M-H), respectively. For FAMACHA, the heritability estimates ranged from 0.46 (M-H) to 0.54 (M-A). Estimates of genetic correlation ranged from 0.22 to 0.69. The inclusion of genomic information provided gain in accuracy for all traits. All estimates of predictive ability obtained using genomic data in a multi-trait setting were higher than those obtained using single-trait models. The estimates of predictive ability ranged from 0.03 (S-A) to 0.46 (M-H). The heritability estimates obtained using genomic information showed that all traits evaluated are suitable for genomic selection. Despite the low accuracies obtained, the use of the genomic model provided more accurate estimates of breeding values in comparison to the pedigree-based model.

Genetic evaluation of sheep for resistance to gastrointestinal nematodes and body size including genomic information.

OBJECTIVE: The genetic evaluation of Santa Inês sheep was performed for resistance to gastrointestinal nematode infection (RGNI) and body size using different relationship matrices to assess the efficiency of including genomic information in the analyses. METHODS: There were 1,637 animals in the pedigree and 500, 980, and 980 records of RGNI, thoracic depth (TD), and rump height (RH), respectively. The genomic data consisted of 42,748 SNPs and 388 samples genotyped with the OvineSNP50 BeadChip. The (co)variance components were estimated in single- and multi-trait analyses using the numerator relationship matrix (A) and the hybrid matrix H, which blends A with the genomic relationship matrix (G). The BLUP and single-step genomic BLUP methods were used. The accuracies of estimated breeding values and Spearman rank correlation were also used to assess the feasibility of incorporating genomic information in the analyses. RESULTS: The heritability estimates ranged from 0.11±0.07, for TD (in single-trait analysis using the A matrix), to 0.38±0.08, for RH (using the H matrix in multi-trait analysis). The estimates of genetic correlation ranged from -0.65±0.31 to 0.59±0.19, using A, and from -0.42±0.30 to 0.57±0.16 using H. The gains in accuracy of estimated breeding values ranged from 2.22% to 75.00% with the inclusion of genomic information in the analyses. CONCLUSION: The inclusion of genomic information will benefit the direct selection for the traits in this study, especially RGNI and TD. More information is necessary to improve the understanding on the genetic relationship between resistance to nematode infection and body size in Santa Inês sheep. The genetic evaluation for the evaluated traits was more efficient when genomic information was included in the analyses.

Influence of non-genetic factors on the maternal ability of Santa Inês ewes / Influência de fatores não-genéticos na habilidade materna de ovelhas Santa Inês

ABSTRACT: The aim of this study was to evaluate the influence of different non-genetic effects on indicator traits for maternal ability in Santa Inês ewes. Data included performance records of 100 lambs (males and females) born from 59 dams, from 2009 to 2012. The analyzed traits were birth weight (BW), weaning weight (WW), average daily gain from birth until weaning (ADGBW), total litter weight at birth (TLWB), and total litter weight at weaning (TLWW). The effects analyzed were the year of birth of the lamb, birth season, dam age at lambing, dam weight at lambing, sex of the lamb, lamb birth type, interaction between sex and birth type, and interaction between sex and birth season. SAS® software (SAS University Edition, USA) was used for calculation of the analysis of variance, means, and Pearson correlation coefficients. With the exception of the birth season, all the other environmental effects evaluated had a significant influence on at least one of the studied traits. The correlation estimates ranged from low to high and were either positive or negative. Birth weight was negatively correlated with the birth type and influenced positively all the other performance traits evaluated. The maternal ability of Santa Inês ewes was more clearly influenced by the age and weight of the dam at lambing, and the lamb birth type.

RESUMO: O objetivo deste estudo foi avaliar a influência de diferentes efeitos não-genéticos sobre características indicadoras de habilidade materna em ovelhas da raça Santa Inês. Os dados utilizados incluíram registros de desempenho de 100 cordeiros (machos e fêmeas) filhos de 59 ovelhas, nascidos de 2009 a 2012. As características analisadas foram peso ao nascimento (PN), peso ao desmame (PD), ganho médio diário do nascimento ao desmame (GMND), peso total das crias ao nascer (PTCN) e peso total das crias ao desmame (PTCD). Os efeitos analisados foram ano de nascimento da cria, estação de nascimento, idade da mãe ao parto, peso da mãe ao parto, sexo da cria, tipo de nascimento da cria, interação entre sexo e tipo de nascimento, e interação entre sexo e estação de nascimento. O programa SAS (SAS University Edition, EUA) foi utilizado para o cálculo de análise de variância, médias e coeficientes de correlação de Pearson. Com exceção da estação de nascimento, os demais efeitos avaliados exerceram influência significativa sobre pelo menos uma das características estudadas. As estimativas de correlação variaram de baixa a alta magnitude e foram tanto positivas quanto negativas. O peso da cria ao nascimento foi negativamente correlacionado com o tipo de nascimento e influenciou positivamente todas as outras características de desempenho avaliadas. A habilidade materna de ovelhas Santa Inês foi mais claramente influenciada pela idade e peso da mãe ao parto e pelo tipo de nascimento da cria.

Influence of non-genetic factors on the maternal ability of Santa Inês ewes / Influência de fatores não-genéticos na habilidade materna de ovelhas Santa Inês

The aim of this study was to evaluate the influence of different non-genetic effects on indicator traits for maternal ability in Santa Inês ewes. Data included performance records of 100 lambs (males and females) born from 59 dams, from 2009 to 2012. The analyzed traits were birth weight (BW), weaning weight (WW), average daily gain from birth until weaning (ADGBW), total litter weight at birth (TLWB), and total litter weight at weaning (TLWW). The effects analyzed were the year of birth of the lamb, birth season, dam age at lambing, dam weight at lambing, sex of the lamb, lamb birth type, interaction between sex and birth type, and interaction between sex and birth season. SAS® software (SAS University Edition, USA) was used for calculation of the analysis of variance, means, and Pearson correlation coefficients. With the exception of the birth season, all the other environmental effects evaluated had a significant influence on at least one of the studied traits. The correlation estimates ranged from low to high and were either positive or negative. Birth weight was negatively correlated with the birth type and influenced positively all the other performance traits evaluated. The maternal ability of Santa Inês ewes was more clearly influenced by the age and weight of the dam at lambing, and the lamb birth type.(AU)

O objetivo deste estudo foi avaliar a influência de diferentes efeitos não-genéticos sobre características indicadoras de habilidade materna em ovelhas da raça Santa Inês. Os dados utilizados incluíram registros de desempenho de 100 cordeiros (machos e fêmeas) filhos de 59 ovelhas, nascidos de 2009 a 2012. As características analisadas foram peso ao nascimento (PN), peso ao desmame (PD), ganho médio diário do nascimento ao desmame (GMND), peso total das crias ao nascer (PTCN) e peso total das crias ao desmame (PTCD). Os efeitos analisados foram ano de nascimento da cria, estação de nascimento, idade da mãe ao parto, peso da mãe ao parto, sexo da cria, tipo de nascimento da cria, interação entre sexo e tipo de nascimento, e interação entre sexo e estação de nascimento. O programa SAS (SAS University Edition, EUA) foi utilizado para o cálculo de análise de variância, médias e coeficientes de correlação de Pearson. Com exceção da estação de nascimento, os demais efeitos avaliados exerceram influência significativa sobre pelo menos uma das características estudadas. As estimativas de correlação variaram de baixa a alta magnitude e foram tanto positivas quanto negativas. O peso da cria ao nascimento foi negativamente correlacionado com o tipo de nascimento e influenciou positivamente todas as outras características de desempenho avaliadas. A habilidade materna de ovelhas Santa Inês foi mais claramente influenciada pela idade e peso da mãe ao parto e pelo tipo de nascimento da cria.(AU)

Genetic parameters for marbling and body score in Anglonubian goats using Bayesian inference via threshold and linear models.

OBJECTIVE: The aim of this study was to estimate (co) variance components and genetic parameters for categorical carcass traits using Bayesian inference via mixed linear and threshold animal models in Anglonubian goats. METHODS: Data were obtained from Anglonubian goats reared in the Brazilian Mid-North region. The traits in study were body condition score, marbling in the rib eye, ribeye area, fat thickness of the sternum, hip height, leg perimeter, and body weight. The numerator relationship matrix contained information from 793 animals. The single- and two-trait analyses were performed to estimate (co) variance components and genetic parameters via linear and threshold animal models. For estimation of genetic parameters, chains with 2 and 4 million cycles were tested. An 1,000,000-cycle initial burn-in was considered with values taken every 250 cycles, in a total of 4,000 samples. Convergence was monitored by Geweke criteria and Monte Carlo error chain. RESULTS: Threshold model best fits categorical data since it is more efficient to detect genetic variability. In two-trait analysis the contribution of the increase in information and the correlations between traits contributed to increase the estimated values for (co) variance components and heritability, in comparison to single-trait analysis. Heritability estimates for the study traits were from low to moderate magnitude. CONCLUSION: Direct selection of the continuous distribution of traits such as thickness sternal fat and hip height allows obtaining the indirect selection for marbling of ribeye.

Behavioral and thermoregulatory characteristics of Dorper sheep

The objective of this study was to evaluate the behavioral and thermoregulatory characteristics of Dorper sheep. The experiment involved 12 adult females in which the respiratory frequency (RF), heart rate (HR), and rectal temperature (RT) were measured and the following behavioral activities were evaluated: Idling while standing, Idling while lying, Drinking, Ruminating while standing, Ruminating while lying, Defecating, Urinating, Walking, Vocalizing, Biting, Coughing, Playing, Fighting, Rubbing, Self-cleaning, and Sleeping. The physical analysis of the thermal environment in the facility was obtained at the meteorological station of the Technical School of Teresina, where the air temperature (AT) and air relative humidity (ARH) were recorded. The black globe humidity index was obtained using a thermometer inserted in a black globe. A significant difference was detected for AT and ARH, especially the former, which had a higher value in the afternoon period (36.5 ºC). A significant effect was observed for the physiological variables, for which the highest values were found in the afternoon period, as follows: 85.30 mov./min, 93.11 beats/min, and 39.51 ºC (RF, HR, and RT, respectively). Air temperature had positive correlations of 0.572, 0.516, and 0.165 with all thermoregulatory characteristics (RF, HR, and RT, respectively). There was a significant difference for the ‘Idling while standing, ‘Idling while lying, ‘Ruminating while lying, ‘Vocalizing, ‘Eating, ‘Playing, and ‘Sleeping behaviors in relation to the evaluated periods of the day. The animals showed a certain level of thermal discomfort, especially in the afternoon period.(AU)

Behavioral and thermoregulatory characteristics of Dorper sheep

The objective of this study was to evaluate the behavioral and thermoregulatory characteristics of Dorper sheep. The experiment involved 12 adult females in which the respiratory frequency (RF), heart rate (HR), and rectal temperature (RT) were measured and the following behavioral activities were evaluated: Idling while standing, Idling while lying, Drinking, Ruminating while standing, Ruminating while lying, Defecating, Urinating, Walking, Vocalizing, Biting, Coughing, Playing, Fighting, Rubbing, Self-cleaning, and Sleeping. The physical analysis of the thermal environment in the facility was obtained at the meteorological station of the Technical School of Teresina, where the air temperature (AT) and air relative humidity (ARH) were recorded. The black globe humidity index was obtained using a thermometer inserted in a black globe. A significant difference was detected for AT and ARH, especially the former, which had a higher value in the afternoon period (36.5 ºC). A significant effect was observed for the physiological variables, for which the highest values were found in the afternoon period, as follows: 85.30 mov./min, 93.11 beats/min, and 39.51 ºC (RF, HR, and RT, respectively). Air temperature had positive correlations of 0.572, 0.516, and 0.165 with all thermoregulatory characteristics (RF, HR, and RT, respectively). There was a significant difference for the ‘Idling while standing’, ‘Idling while lying’, ‘Ruminating while lying’, ‘Vocalizing’, ‘Eating’, ‘Playing’, and ‘Sleeping’ behaviors in relation to the evaluated periods of the day. The animals showed a certain level of thermal discomfort, especially in the afternoon period.

Genetic parameters for carcass traits and body size of meat sheep / Parâmetros genéticos para características de carcaça e tamanho corporal em ovinos de corte

The present study aimed to estimate variance components and heritability coefficients (h2) in Santa Inês sheep by single- and two-trait analyses for the traits loin eye area (LEA), length (LEL) and maximum depth (LED), in the longissimus dorsi muscle, subcutaneous fat thickness (SFT), fat thickness over the biceps femoris muscle (FTBF), croup height (CH), thoracic circumference (TC), thoracic depth (TD), body length (BL), and adult live weight (ALW). The restricted maximum likelihood (REML) was used to estimate variance components in an animal model. In both types of analyses, we estimated moderate heritability for all traits, with the exception of SFT, CH, TC, BL, and ALW (all of which yielded low h2 estimates). In two-trait analysis for body size, only TD yielded a lower h2 estimate, when compared to single-trait analysis. On the other hand, CH, TC, and BL yielded higher h2 estimates. Most estimates for variance components and h2 in two-trait analysis were higher than those in single-trait analysis. This finding suggests the possibility of a moderate response to selection for improvement in the carcass of meat sheep using the specific carcass traits evaluated (except SFT), highlighting LEA. The fat thickness over the biceps femoris muscle showed higher potential for response to direct selection for fat deposition than SFT. Thoracic depth showed higher potential for response...(AU)

Objetivou-se com esta pesquisa estimar componentes de variância e coeficientes de herdabilidade (h2) por análises uni e bicaracterística para as características área (AOL), comprimento (COL) e profundidade máxima (POL) de olho de lombo, no músculo longissimus dorsi, espessura de gordura subcutânea (EGS), espessura de gordura do músculo biceps femoris (EGBF), altura da garupa (AG), circunferência torácica (CT), profundidade torácica (PT), comprimento corporal (CC) e peso vivo à idade adulta (PA), em ovinos Santa Inês. Foi utilizado modelo animal pela metodologia da máxima verossimilhança restrita (REML). Estimou-se herdabilidade moderada para as características, nos dois tipos de análise, exceto para EGS, AG, CT, CC e PA, para as quais as estimativas foram de baixa magnitude. Nas análises bicaracterísticas para tamanho corporal, apenas PT apresentou menor estimativa de h2, quando comparado com a análise unicaracterística, enquanto que AG, CT e CC apresentaram valores maiores. Nas análises bicaracterísticas, a maioria das estimativas de componentes de variância e h2 foram superiores àquelas obtidas nas análises unicaracterística, o que evidencia a possibilidade de resposta moderada à seleção para melhoria da carcaça em ovinos de corte usando as características de carcaça avaliadas, com exceção de EGS e com destaque para área de olho de lombo. A espessura de gordura do músculo...(AU)

Genetic parameters for carcass traits and body size of meat sheep / Parâmetros genéticos para características de carcaça e tamanho corporal em ovinos de corte

The present study aimed to estimate variance components and heritability coefficients (h2) in Santa Inês sheep by single- and two-trait analyses for the traits loin eye area (LEA), length (LEL) and maximum depth (LED), in the longissimus dorsi muscle, subcutaneous fat thickness (SFT), fat thickness over the biceps femoris muscle (FTBF), croup height (CH), thoracic circumference (TC), thoracic depth (TD), body length (BL), and adult live weight (ALW). The restricted maximum likelihood (REML) was used to estimate variance components in an animal model. In both types of analyses, we estimated moderate heritability for all traits, with the exception of SFT, CH, TC, BL, and ALW (all of which yielded low h2 estimates). In two-trait analysis for body size, only TD yielded a lower h2 estimate, when compared to single-trait analysis. On the other hand, CH, TC, and BL yielded higher h2 estimates. Most estimates for variance components and h2 in two-trait analysis were higher than those in single-trait analysis. This finding suggests the possibility of a moderate response to selection for improvement in the carcass of meat sheep using the specific carcass traits evaluated (except SFT), highlighting LEA. The fat thickness over the biceps femoris muscle showed higher potential for response to direct selection for fat deposition than SFT. Thoracic depth showed higher potential for response...

Objetivou-se com esta pesquisa estimar componentes de variância e coeficientes de herdabilidade (h2) por análises uni e bicaracterística para as características área (AOL), comprimento (COL) e profundidade máxima (POL) de olho de lombo, no músculo longissimus dorsi, espessura de gordura subcutânea (EGS), espessura de gordura do músculo biceps femoris (EGBF), altura da garupa (AG), circunferência torácica (CT), profundidade torácica (PT), comprimento corporal (CC) e peso vivo à idade adulta (PA), em ovinos Santa Inês. Foi utilizado modelo animal pela metodologia da máxima verossimilhança restrita (REML). Estimou-se herdabilidade moderada para as características, nos dois tipos de análise, exceto para EGS, AG, CT, CC e PA, para as quais as estimativas foram de baixa magnitude. Nas análises bicaracterísticas para tamanho corporal, apenas PT apresentou menor estimativa de h2, quando comparado com a análise unicaracterística, enquanto que AG, CT e CC apresentaram valores maiores. Nas análises bicaracterísticas, a maioria das estimativas de componentes de variância e h2 foram superiores àquelas obtidas nas análises unicaracterística, o que evidencia a possibilidade de resposta moderada à seleção para melhoria da carcaça em ovinos de corte usando as características de carcaça avaliadas, com exceção de EGS e com destaque para área de olho de lombo. A espessura de gordura do músculo...

Caracterização fenotípica de ovinos da raça Santa Inês no Estado do Piauí / Phenotypic characterization of Santa Inês sheep in the State of Piauí

The objective of this work was to study the morphometric characterization of Santa Inês sheep to aid the conservation genetics of this breed in different micro-regions of the State of Piauí. For this, morphometric measurements have been collected in sheep from different micro-regions of the state of Piauí. The body measurements, collected were withers height, hip height, chest circumference, body length and ear length. The averages of the measures obtained in each micro-region were evaluated and by the use of the principal component analysis, helped by the SAS PROC PRINCOMP, it was possible to group populations based on similarity measures. The groups were formed relying on a cluster analysis by Ward method. Considering the analyzes, phenotypic diversity was found in Santa Ines sheep reared in the state of Piaui; being formed by a group of larger animals, located in the region of Floriano, Médio Parnaíba Piauiense, Teresina and Campo Maior; another group of animals of intermediate size, but with greater body length and girth circumference and small ears, located in the microregion of São Raimundo Nonato, another group with intermediate size and big ears and the last group of smaller animals located in the region of the Litoral Piauiense and Valença. The measures that contributed mostly for the principal component analysis were measures of hip height, withers height and body length.(AU)

Objetivou-se, com esse trabalho, estudar a caracterização morfométrica de ovinos da raça Santa Inês para auxílio à conservação genética desta raça em diferentes microrregiões do Estado do Piauí, de modo a contribuir com a conservação da raça. Para isso, foram coletadas medidas morfométricas em ovinos oriundos de diferentes microrregiões do Estado do Piauí. As características de medidas corporais coletadas foram a altura de cernelha, a altura de garupa, a circunferência torácica, o comprimento corporal e o comprimento de orelha. Foram avaliadas as médias das medidas por microrregião e através da análise de componentes principais, com auxílio do PROC PRINCOMP do SAS, foi possível agrupar as populações com base em medidas de similaridade. Os grupos foram formados através da análise de agrupamento pelo método Ward. A partir das análises foi encontrada diversidade fenotípica nos ovinos Santa Inês criados no Estado do Piauí, sendo formada por um grupo de animais maiores, localizados nas microrregiões de Floriano, Médio Parnaíba Piauiense, Campo Maior e Teresina; um grupo de animais de tamanho intermediário, porém com comprimento corpora e circunferência torácica maiores e orelhas pequenas, localizado na microrregião de São Raimundo Nonato, outro grupo com tamanho intermediário e orelhas grandes e o último grupo composto por animais menores, localizados nas microrregiões do Litoral Piauiense e Valença. As medidas que mais contribuíram para a análise de componente principal foram as medidas de altura de garupa, altura de cernelha e comprimento corporal.(AU)

Caracterização fenotípica de ovinos da raça Santa Inês no Estado do Piauí / Phenotypic characterization of Santa Inês sheep in the State of Piauí

The objective of this work was to study the morphometric characterization of Santa Inês sheep to aid the conservation genetics of this breed in different micro-regions of the State of Piauí. For this, morphometric measurements have been collected in sheep from different micro-regions of the state of Piauí. The body measurements, collected were withers height, hip height, chest circumference, body length and ear length. The averages of the measures obtained in each micro-region were evaluated and by the use of the principal component analysis, helped by the SAS PROC PRINCOMP, it was possible to group populations based on similarity measures. The groups were formed relying on a cluster analysis by Ward method. Considering the analyzes, phenotypic diversity was found in Santa Ines sheep reared in the state of Piaui; being formed by a group of larger animals, located in the region of Floriano, Médio Parnaíba Piauiense, Teresina and Campo Maior; another group of animals of intermediate size, but with greater body length and girth circumference and small ears, located in the microregion of São Raimundo Nonato, another group with intermediate size and big ears and the last group of smaller animals located in the region of the Litoral Piauiense and Valença. The measures that contributed mostly for the principal component analysis were measures of hip height, withers height and body length.

Objetivou-se, com esse trabalho, estudar a caracterização morfométrica de ovinos da raça Santa Inês para auxílio à conservação genética desta raça em diferentes microrregiões do Estado do Piauí, de modo a contribuir com a conservação da raça. Para isso, foram coletadas medidas morfométricas em ovinos oriundos de diferentes microrregiões do Estado do Piauí. As características de medidas corporais coletadas foram a altura de cernelha, a altura de garupa, a circunferência torácica, o comprimento corporal e o comprimento de orelha. Foram avaliadas as médias das medidas por microrregião e através da análise de componentes principais, com auxílio do PROC PRINCOMP do SAS, foi possível agrupar as populações com base em medidas de similaridade. Os grupos foram formados através da análise de agrupamento pelo método Ward. A partir das análises foi encontrada diversidade fenotípica nos ovinos Santa Inês criados no Estado do Piauí, sendo formada por um grupo de animais maiores, localizados nas microrregiões de Floriano, Médio Parnaíba Piauiense, Campo Maior e Teresina; um grupo de animais de tamanho intermediário, porém com comprimento corpora e circunferência torácica maiores e orelhas pequenas, localizado na microrregião de São Raimundo Nonato, outro grupo com tamanho intermediário e orelhas grandes e o último grupo composto por animais menores, localizados nas microrregiões do Litoral Piauiense e Valença. As medidas que mais contribuíram para a análise de componente principal foram as medidas de altura de garupa, altura de cernelha e comprimento corporal.