Milk productivity of first-calf heifers depending on the line and age of the first insemination

Relevance . One of the key types raw materials that ensure food security Russian citizens is milk. To obtain it, dairy cattle are used, including Holstein, created by absorbing breeding stock domestic black-and-white bulls Holstein breed. The study economically useful qualities a new genetic formation in Middle Urals zone both scientific and practical interest. Methods aim work to evaluate milk productivity depending on age first insemination, taking into account linear origin. Results As result research, certain features were established that, our opinion, associated precisely with origin (depending animals divided 4 subgroups). So, group heifers line Reflection Sovering 198998, same trend change as well average for herd. insemination up 14 months had highest (p ≤ 0.05 between 1st 3rd groups favor 1st). In Vis Back Idial line, contrary, yields inseminated time at more than 18 months. They have compared cows from other lines. superiority ranged 700 (Reflection line) 2275 kg (Montwick Chieftain or 7.6–24.9% (р 0.05–0.01). Among Montvik 95679 yield first-calf outperformed periods 886–891 0.05).