Estimativas de parâmetros genéticos e fenotípicos para características associadas ao comportamento ingestivo e eficiência alimentar em bovinos Nelore
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Data
2021-10-25
Autores
Schuchmann, Rafaela Kava
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Universidade Estadual Paulista (Unesp)
Resumo
Objetivou-se com o presente estudo estimar parâmetros genéticos e fenotípicos em bovinos da raça Nelore (Bos taurus indicus) entre características de eficiência alimentar (CAR: consumo alimentar residual e IMS: ingestão de matéria seca) e de comportamento ingestivo (FR: frequência de refeição; MDR: média da duração da refeição; MCR: média de consumo por refeição; DR: duração da refeição; CR: critério de refeição; e TXC: taxa de consumo). Além disso, objetivou-se entender se o comportamento ingestivo do animal influencia na eficiência alimentar e verificar se as medidas de comportamento podem ser preditivas para CAR e IMS. Foram utilizados registros fenotípicos de 4.840 animais, com uma idade média de 13,5±4,15 meses. Os animais foram testados para eficiência alimentar entre os anos de 2011 e 2018 em 39 fazendas localizadas em quatro regiões brasileiras. O banco de dados contendo as informações de pedigree de 58.374 animais foi disponibilizado pela Associação Nacional de Criadores e Pesquisadores (ANCP, Ribeirão Preto, Brasil). A estimação dos componentes de (co)variância foi realizada em análises multi- características através da metodologia da máxima verossimilhança restrita. Foram estimadas as herdabilidades e correlações genéticas e fenotípicas entre todas as características de eficiência alimentar e comportamento ingestivo. As estimativas de herdabilidade foram de 0,24±0,01 (CAR), 0,30±0,01 (IMS), 0,63±0,01 (FR), 0,47±0,01 (MDR), 0,24±0,02 (MCR), 0,75±0,01 (DR), 0,49±0,01 (CR) e 0,87±0,00 (TXC). A DR apresentou as maiores correlações genéticas e fenotípicas estimadas com CAR (0,60±0,02 e 0,67±0,01, respectivamente) e fenotípica com IMS (0,78±0,01). Entre as características de comportamento ingestivo, a maior correlação genética foi observada entre MDR e DR (0,87±0,01) e fenotípica entre MCR e MDR (0,88±0,01). As características que tiveram melhor eficiência relativa de seleção com CAR foram CR, FR, MCR e DR, sendo DR a característica de eleição devido a sua estimativa de herdabilidade alta e maior correlação genética com CAR. Para IMS, os resultados indicaram que a resposta à seleção direta para essa característica foi superior a seleção indireta através das características de comportamento ingestivo. Concluiu-se que o comportamento ingestivo tem alta influência na eficiência alimentar dos animais e, portanto, pode ser incluído em programas de melhoramento genético. Além disso, as características de comportamento ingestivo também podem ser utilizadas para predizer o CAR e IMS, diminuindo os custos com mensuração e facilitando a identificação de bovinos da raça Nelore superiores para eficiência alimentar.
The aim of this study was to estimate genetic parameters in Nelore beef cattle (Bos taurus indicus) as well as the genetic and phenotypic correlations between feed efficiency-related traits (RFI: residual feed intake and DMI: dry matter intake) and feeding behavior-related traits (MF: meal frequency; AMD: average meal duration; ACM: average consumption per meal; MD: meal duration; MC: meal criteria; and CR: consumption rate). It also aimed to understand if feeding behavior influences feed efficiency and to verify if the behavior measures can be predictive for RFI and DMI. Phenotypic records from 4,840 animals, with an average of 13.5±4.15 months of age were used. Animals were tested for feed efficiency between 2011 and 2018 in 39 farms located in four Brazilian geographical regions. The database containing the pedigree information from 58,374 animals was provided by the National Association of Breeders and Researchers (ANCP, Ribeirão Preto, Brazil). The (co)variance components were estimated using the maximum-likelihood estimation in a multi-trait analysis. Heritability and genetic and phenotypic correlations between all traits were estimated. Heritability estimates were 0.24±0.01 (RFI), 0.30±0.01 (DMI), 0.63±0.01 (MF), 0.47±0.01 (AMD), 0.24±0.01 (ACM), 0.75±0.01 (MD), 0.49±0.01 (MC), and 0.87±0.00 (CR). The MD showed the highest genetic and phenotypic correlations estimated with RFI (0.60±0.02 and 0.67±0.01, respectively) and phenotypic with DMI (0.78±0.01), respectively. Among the feeding behavior traits, the highest genetic correlation was described between AMD and MD (0.87±0.01) and phenotypic between ACM and AMD (0.88±0.01). The traits that had the best relative efficiency of selection with RFI were MC, MF, ACM e MD, with MD being of choice due to its high heritability estimate and greater genetic correlation with RFI. However, for DMI, the results indicated that the response to direct selection for this trait was higher than the indirect selection through feeding behavior-related traits. With the results described herein, it should be noted that feeding behavior traits have a high influence on feeding efficiency-related traits and, therefore, they can be included in breeding programs. Further, feeding behavior v traits can also be used to predict RFI and DMI, decreasing its cost and facilitating the identification of feed efficient animals.
The aim of this study was to estimate genetic parameters in Nelore beef cattle (Bos taurus indicus) as well as the genetic and phenotypic correlations between feed efficiency-related traits (RFI: residual feed intake and DMI: dry matter intake) and feeding behavior-related traits (MF: meal frequency; AMD: average meal duration; ACM: average consumption per meal; MD: meal duration; MC: meal criteria; and CR: consumption rate). It also aimed to understand if feeding behavior influences feed efficiency and to verify if the behavior measures can be predictive for RFI and DMI. Phenotypic records from 4,840 animals, with an average of 13.5±4.15 months of age were used. Animals were tested for feed efficiency between 2011 and 2018 in 39 farms located in four Brazilian geographical regions. The database containing the pedigree information from 58,374 animals was provided by the National Association of Breeders and Researchers (ANCP, Ribeirão Preto, Brazil). The (co)variance components were estimated using the maximum-likelihood estimation in a multi-trait analysis. Heritability and genetic and phenotypic correlations between all traits were estimated. Heritability estimates were 0.24±0.01 (RFI), 0.30±0.01 (DMI), 0.63±0.01 (MF), 0.47±0.01 (AMD), 0.24±0.01 (ACM), 0.75±0.01 (MD), 0.49±0.01 (MC), and 0.87±0.00 (CR). The MD showed the highest genetic and phenotypic correlations estimated with RFI (0.60±0.02 and 0.67±0.01, respectively) and phenotypic with DMI (0.78±0.01), respectively. Among the feeding behavior traits, the highest genetic correlation was described between AMD and MD (0.87±0.01) and phenotypic between ACM and AMD (0.88±0.01). The traits that had the best relative efficiency of selection with RFI were MC, MF, ACM e MD, with MD being of choice due to its high heritability estimate and greater genetic correlation with RFI. However, for DMI, the results indicated that the response to direct selection for this trait was higher than the indirect selection through feeding behavior-related traits. With the results described herein, it should be noted that feeding behavior traits have a high influence on feeding efficiency-related traits and, therefore, they can be included in breeding programs. Further, feeding behavior v traits can also be used to predict RFI and DMI, decreasing its cost and facilitating the identification of feed efficient animals.
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Palavras-chave
Consumo alimentar residual, Correlação fenotípica, Correlação genética, Herdabilidade, Zebuínos