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The objective of the project is to develop concepts for breeding for longevity and its indicator traits such as type traits, stayability, milking speed, udder health and reproduction traits (calving interval, calving to first insemination interval and number of inseminations etc) by defining breeding goals, to evaluate economic values for named above traits and enhance response to selection of breeding program.It is not quite clear which approach is the most beneficial for decreasing reasons for involuntary culling and thus improving longevity - using the actual determinants of longevity as selection criteria, i.e. traits like mastitis, conception rate et cetera, or using indicator traits such as type traits, stayability, or longevity analysis using failure time analysis. Project research activities will be focused at the longevity data analysis of Estonian cattle breeds, estimation of the effects of genetic and environmental factors on longevity measures, breeding goal definition including named above traits by setting up the aggregate genotype and deriving economic values of aggregate genotype traits, phenotypic and genetic correlation of longevity traits with conformation, reproduction and udder functional traits, derivation of genetic and phenotypic parameters of aggregate genotype and index traits, information index derivation, breeding programme optimisation, the organisation of routinely information on potential breeding animals and mate strategies to accomplish optimal lifetime profit. Selection response per unit time for all traits, selection response due to selection among sires and due to selection among dams, contribution of each sex and each trait to the total selection response, selection response after each stage, separate for sires, dams and total, accuracy of selection and index variance for sires and dams in each age class, the number of selected sires and dams from each age class and the rate of inbreeding will be estimated. Economic value of trait expresses to what extent the economic efficiency of production is improved at the moment of expression of one unit of genetic superiority for every single trait. Relative levels of economic values of traits give optimum levels of genetic improvement according to the future production circumstances; absolute levels are important for an accurate calculation of economic revenues of breeding programme.¿¿¿¿¿ |