Genetic and phenotypic parameters of lifetime and stayability traits in Danish dairy breeds

Data on 216,428 Danish Red, 798,152 Danish Friesian and 232,953 Danish Jersey cows were used to estimate phenotypic and genetic parameters for actual and production-corrected survival traits and for milk production. Genetic effects of imported breeds were also estimated. Phenotypic trends in days in mill; were similar for Danish Red and Danish Friesian, and showed influences of the milk quota system, whereas Danish Jersey showed a continuous downwards trend. Significant additive and non-additive effects due to imported breeds were found. Heritabilities differed between breeds, ranging from 0.072 to 0.122 for actual continuous lifetime traits, and from 0.048 to 0.076 for production-corrected continuous lifetime traits. Binary stayability traits showed lower heritability. Genetic correlations between milk production and actual or production-corrected days in milk were 0.63 and 0.31 respectively. Genetic correlations between binary stayabilities and continuous lifetime traits were high (>0.78), which indicates that stayabilities can be used as early predictors of the lifetime traits.