MODELING OF THE SELECTION PROCESS DURING INDEX ASSESSMENT BY THE SIGNS OF PRODUCTIVITY, PRODUCTIVE LONGEVITY AND FERTILEITY OF RED SPOT BREED COWS

Methods for selecting the best animals based on several characteristics can be divided into stage-by-stage selection and selection based on the index of general breeding value. Productive longevity, productivity and fertility of dairy cows include several traits characterized by variability, economic importance and correlation between their phenotypes and genotypes, and heritability (h2), genetic (rg) and phenotypic correlations (rp) between several traits included in the index general breeding value, allow us to calculate regression weights per phenotypic unit of each trait and its relative economic importance for forecasting [1]. As a result of the research, heritability coefficients (h2) were identified for the following traits: age in lactation 0,08 – 0,11; milk yield for 305 days of lactation in kg 0,27 – 0,41; the calving interval in days is 0,04 – 0,06. Phenotypic correlations (rp) were established within the following limits: between age at calving and calving interval 0,32 – 0,33; between the age at calving and milk yield for 305 days of lactation in kg from minus 0,04 to 0,06; between milk yield for 305 days in kg and the calving interval in days 0,11 – 0,15. Genetic correlations (rg): between age at calving and calving interval minus 0,31 – 0,33; between the age at calving and milk yield for 305 days of lactation in kg 0,02 – 0,11; between milk yield for 305 days in kg and the calving interval in days minus 0,15 – 0,18.