Análise multivariada de características de eficiência alimentar, crescimento e carcaça em touros nelore em teste de desempenho
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Data
2021-11-22
Autores
Lopes, Matheus Rodrigues
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Universidade Estadual Paulista (Unesp)
Resumo
O objetivo do trabalho foi aplicar análises multivariadas em características de eficiência alimentar, crescimento e carcaça de touros Nelore em teste de desempenho, com intuito de compreender a associação das características e como incluí-las em programas de melhoramento animal. Foram utilizadas informações de 1294 touros Nelore oriundos de fazendas participantes do Programa de Melhoramento Nelore Qualitas e submetidos ao teste de eficiência alimentar entre os anos de 2010 a 2020, selecionados em cada safra com base no índice de seleção. As características avaliadas foram separadas em três grupos: características morfométricas, que consistia em altura de garupa (AG), altura de cernelha (AC), comprimento corporal (COMP), perímetro torácico (PT) e circunferência escrotal (CE); características de carcaça, que considerou área de olho de lombo (AOL), espessura de gordura subcutânea no lombo (EGS), espessura de gordura subcutânea na garupa (EGS8) e marmoreio (MARM); características de crescimento, com o peso vivo final (PESOF), peso vivo metabólico (PMET), consumo (CONS), conversão (CONV), consumo alimentar residual (CAR) e ganho médio diário residual (GMDR). A estrutura de associação das características foi verificada utilizando o método Análise de Componentes Principais (ACP) para extrair novas variáveis por meio do software estatístico SAS®. Na correlação entre as características morfométricas AG e AC se mostraram fortemente associadas. O Componente Principal 1 (CP1) das características de carcaça reteve 50,28% da variância total e mostrou associação entre AOL, EGS e EGS8, o CP2 mostrou contraste da característica MARM em relação a EGS, EGS8 e AOL. No CP1 das características de crescimento PESOF, PMET e CONS mostraram altos valores de ponderação o que indicou relação entre estas características e o CP1. Através da matriz de correlação das características de crescimento três CPs explicaram 89,34% da variância total. Valores próximo a zero entre CAR e GMDR com PESOF, PMET, AOL, EGS, EGS8 e PT foram estimados. As características de eficiência alimentar devem ser priorizadas pois não apresentaram correlação com as demais e são importantes na produção animal. Os resultados obtidos com análise de componentes principais, a viabilidade da aplicação e diminuição das variáveis em análise, mostraram a possibilidade de incorporação das características para critério de seleção.
The aim of the study was multivariate analyses for feed efficiency, growth and carcass traits in nellore cattle in performance test, to understand the association of characteristics and how include them in animal breeding programs. Records of 1294 Nellore cattle sires from the Nelore Qualitas® animal breeding Program and submitted to the food efficiency test between the years 2010 to 2020, selected in each harvest based on the selection index. The evaluated characteristics were separated into three groups: morphometric trait, which consisted of rump height (RH), withers height (WH), body length (BL), girth circumference (GC) and scrotal circumference (SC); carcass traits with loin eye area (LEA), backfat (BFT) and rump fat thickness (RFT) and marbling (MARB); growth traits, with final weight (FW), metabolic body weight (BW), feed intake (FI), feed conversion (FC), residual feed intake (RFI), residual average daily gain (RG). The association structure of the traits was verified using the Principal Component Analysis (PCA) method to extract new variables by using the SAS® statistical software. In correlation between the morphometric traits RH and WH are associated. The Principal Component 1 (PC1) of the carcass trait retained 50.28% of the total variance and showed an association between LEA, BFT and RFT, the PC2 evidenced contrast of the MARB in relation to LEA, BFT and RFT. PC1 of growth traits FW, BW and FI showed high weighting values. Through the correlation matrix of growth characteristics, three PCs explained 89.34% of the total variance. Values close to zero between RFI and RG with FW, BW, LEA, BFT, RFT and GC were estimated. Feed efficiency characteristics should be prioritized as they did not present correlation with the others and are important in animal production. The results obtained with analysis of principal components, the feasibility of the application and reduction of the variables under analysis, show the possibility of incorporating the characteristics for selection.
The aim of the study was multivariate analyses for feed efficiency, growth and carcass traits in nellore cattle in performance test, to understand the association of characteristics and how include them in animal breeding programs. Records of 1294 Nellore cattle sires from the Nelore Qualitas® animal breeding Program and submitted to the food efficiency test between the years 2010 to 2020, selected in each harvest based on the selection index. The evaluated characteristics were separated into three groups: morphometric trait, which consisted of rump height (RH), withers height (WH), body length (BL), girth circumference (GC) and scrotal circumference (SC); carcass traits with loin eye area (LEA), backfat (BFT) and rump fat thickness (RFT) and marbling (MARB); growth traits, with final weight (FW), metabolic body weight (BW), feed intake (FI), feed conversion (FC), residual feed intake (RFI), residual average daily gain (RG). The association structure of the traits was verified using the Principal Component Analysis (PCA) method to extract new variables by using the SAS® statistical software. In correlation between the morphometric traits RH and WH are associated. The Principal Component 1 (PC1) of the carcass trait retained 50.28% of the total variance and showed an association between LEA, BFT and RFT, the PC2 evidenced contrast of the MARB in relation to LEA, BFT and RFT. PC1 of growth traits FW, BW and FI showed high weighting values. Through the correlation matrix of growth characteristics, three PCs explained 89.34% of the total variance. Values close to zero between RFI and RG with FW, BW, LEA, BFT, RFT and GC were estimated. Feed efficiency characteristics should be prioritized as they did not present correlation with the others and are important in animal production. The results obtained with analysis of principal components, the feasibility of the application and reduction of the variables under analysis, show the possibility of incorporating the characteristics for selection.
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Palavras-chave
Eficiência alimentar, Correlação, Análise multivariada, Feed efficiency, Correlation, Multivariate analyses