Genetic association between clinical mastitis occurrence and milk yield in Holstein cows/Associacao genetica entre ocorrencia de mastite clinica e producao de leite em vacas Holandesas

• Published in: Ciência rural 2015-12, Vol.45 (12), p.2187
• Main Authors: Oliveira, Elisa Junqueira, Bignardi, Annaiza Braga, Santana, Mario Luiz, Jr, de Paz, Claudia Cristina Paro, Zadra, Lenira El Faro
• Format: Article
• Language: Portuguese
• ISSN: 0103-8478
• DOI: 10.1590/0103-8478cr20131639

The objective of this study was to estimate genetic and phenotypic parameters for the occurrence of clinical mastitis (MC) and milk production during lactation (PR305) and study the genetic associations between them, using information from 11,738 lactations of 5,084 Holstein herd cows, that calved from 1995 to 2010. The covariance components were estimated by Bayesian inference using the animal model. Heritability estimates for the PR305 and the MC were 0.16 (0.02) and 0.11 (0.02), respectively and repeatability were 0.34 (0.012) for PR305 and 0.21 (0.02) for MC. The genetic correlation between the PR305 and the MC was negative and of low magnitude (-0.21 [+ or -] 0.13). Heritability estimates for PR305 and MC indicate that these characteristics are influenced by environmental factors, however there is enough genetic variability to obtain gains through selection. Key words: bayesian inference, genetic correlation, heritability. O objetivo deste trabalho foi estimar os parametros geneticos e fenotipicos para ocorrencia da mastite clinica (MC) e para a producao de leite acumulada ate 305 dias (PR305) e estudar as associacoes geneticas entre elas, usando informacoes de H.738 lactacoes de 5.084 vacas de um rebanho da raca Holandesa, paridas entre 1995 a 2010. Os componentes de covariancia foram obtidos por abordagem Bayesiana, sob modelo animal. As estimativas de herdabilidade para a PR305 e para a MC foram de 0,16 (0,02) e 0,11 (0,02), respectivamente, e as repetibilidadesforam 0,34 (0,012) e 0,21 (0,02), para PR305 e MC, respectivamente. A correlacao genetica entre a PR305 e a MC foi negativa e de baixa magnitude (-0,21 [+ or -] 0,13). As estimativas de herdabilidade para PR305 e MC indicam que estas caracteristicas sao influenciadas por fatores ambientais, entretanto ha suficiente variabilidade genetica para obtencao de ganhos atraves da selecao. Palavras-chave: correlacao genetica, herdabilidade, inferencia bayesiana.