Formation of a breeding group of cows based on a complex breeding index

The breeding value of the animal is the main criterion for selecting cows for the breeding group. Determination of the breeding value of animals using index selection is relevant for most livestock enterprises in the Omsk region. The purpose of the research is to determine the criteria for selecting cows in a breeding group based on their comprehensive assessment according to the selection indexes. The research included Jersey cows with completed lactation in the amount of 115 heads. The breeding value of cows was determined by the value of the complex index, which reflects the origin of the animals (genotype index), conformation, productivity and rate of milk flow. The genotype index of the entire livestock was above 100, which indicates the high breeding value of the parent stock. In 2.3% of cows of the first lactation, the productivity index was less than 80 units. The bulk of cows (48.8%) received 100-119 units according to the productivity index. The maximum index values were obtained in 22.8% of the animals. When assessing the breeding value at the level of 120 units or more according to the complex selection index, the cows had the maximum milk production during the first lactation. The milk yield of the first-calf heifers of this group exceeds the milk yield of their peers with an estimate of less than 80 units by 3847 kg or by 104%. Most cows have complex index values in the range of 80-99 units, their milk yield is 5432 kg, which corresponds to the average milk yield of cows of the first-calf heifers in the herd. The values of the selection differential show the superiority of cows of the selection group in terms of milk yield relative to the average for the herd by 1805 kg, which indicates the effectiveness of selection according to the complex selection index. It is necessary to form a breeding group of cows from livestock with pronounced dairy forms, correct conformation and breeding value of 100 or more units according to the complex selection index. This selection will make it possible to obtain a selection differential for abundant milk production of + 1805 kg, or 33.2%.