중동부유럽

Assessment of the heritability coefficients of longevity traits in the population of Black and White cows was performed on a data set that included production results of 16,539 of black and white culled cows, which reached a total of 50,382 lactations in the period from 1985 to 2012. The cows were grown on 7 farms of the Agricultural Corporation Belgrade and are progeny of 277 bulls. The analysis covered the following traits: length of productive life (LPL), lifetime milk yield (LMY) and number of lactations (NL). Variance components of longevity traits were estimated using a BLUP linear mixed model with animal as a random effect. Cows included in the analysis calved for the first time in the average age of 26.86 months, while the average length of productive life amounted to 1,299.9 days and during that time the animals achieved an average of 3.04 lactations and life time production of 21,016 kg of milk. The values of the heritability coefficients of longevity traits ranged from 0.066; 0.061 and 0.074 regarding the length of productive life, lifetime milk yield and number of lactations respectively.