SELECTION OF BIOMETRIC MODELS FOR ASSESSMENT OF FERTILITY TRAITS OF RED-MOILED COWS

As a result of studies conducted on 32 168 retired red-motley cows from 11 regions and 43 breeding farms, linear operational models were determined for assessing the fertility traits of dairy cows - the interval between calvings in days, the service period in days, the frequency of insemination and the pregnancy index. The operating model includes fixed effects: region, farm, milk yield for 305 days of lactation and a random sire effect. Information for the calculation included 153 796 records of insemination dates in dairy farms for cows born in 2000 2009 for the first five lactations. Fertility analysis was carried out within the breed of cows with different bloodlines according to the Holstein breed. The effectiveness of biometric models was assessed using the coefficient of determination (R2).