Estimation of genetic parameters for milk production and electric conductivity of milk in Holstein cattle

• Grant number: 12/06815-3
• Support type: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): June 01, 2012
• Effective date (End): September 30, 2013
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Genetics and Improvement of Domestic Animals
• Principal Investigator: Danísio Prado Munari
• Grantee: Nicole Colucci Tramonte
• Home Institution: Faculdade de Ciências Agrárias e Veterinárias (FCAV). Universidade Estadual Paulista (UNESP). Campus de Jaboticabal. Jaboticabal , SP, Brazil
• Associated scholarship(s): 12/19249-6 - Estimation of genetic parameters for milk production and electric conductivity of milk in Holstein cattle, BE.EP.IC

Abstract

The dairy cattle breeding is characterized mainly by selecting animals with high milk production. However, this is negatively correlated with cow resistance against mastitis. The drop in milk production and changes in milk quality are the main consequence of this disease, leading to increased electrical conductivity of milk. This study aims to estimate genetic parameters for daily milk yield and electrical conductivity of milk in Holstein cattle in order to provide information for genetic evaluation of these animals. The components of variance and covariance, as well as estimates of heritability, genetic correlation and predicted breeding values will be obtained using the method of restricted maximum likelihood in an two-trait animal model of repeatability. So, the proposed model must contain, besides the fixed effects, the random additive, permanent environmental and residual effects of the animal.