Productive Traits and Reproductive Capacity of First-Calf Cows at Different Selection Options

The research work is aimed at determining and establishing the degree of influence various selection options on productive reproductive qualities first-calf cows black-and-white breed. results showed that according to Parental Index Cows (PIC), animals 5th experimental group surpass their mates in 2 3 groups milk yield by 746 kg, with p≤0.05 1746 p≤0.001 difference fat content 0.07 0.01%, respectively. same advantage over possessed 1st control 4th 1827 1885 p≤0.001. In terms protein, are inferior heifers 1, 2, 5 0.03, 0.08, 0.09%, a significant p≥0.99. Groups have superiority -0.03%, p≤0.05, as well 0.05 0.06%, p≤0.01. Realization Genetic Potential (RGP) for 305 days lactation was higher amounted 88.3%, which 7.1% more than control, p≤0.05. For fat, 1 high potential 99.5 99.9%. mass fraction from 2.1 1.8%, has most optimal indicator calving period (406.5), while tested ones exceed it 40 days. service all been increased almost times. highest calf crop (92.3%) reproduction rate (0.92%) observed group.