Using the selection indexes in breeding work with Simmental cattle
Relevance . The selection index reflects the value of an animal for selection, which will increase genetic progress in the herd, increase productivity, longevity and improve the quality of offspring. Methods . The research was conducted in 2024-2025, database includes 55,078 Simmental cows. The estimate breeding values were calculated using the BLUP methodology and the Program to construct the selection indexes: «Calculating the selection index of breeding value of farm animals». Results . It has been established that the use of the I2 index (35% milk productivity, 15% fertility and 50% longevity) is optimal for increasing both milk productivity and longevity. By selecting cows for the selection group of mothers bull (intensity 10%), the superiority will be in milk yield 1135 kg (24.5%), 6930 kg (48.4%) milk of lifelong productivity, longevity increase by 195 days (21.6%) or by 0.52 lactations (19.2%), with a decrease in the service period by 2.1 days (1.7%). When selecting cows for the breeding core group (30% intensity), the superiority will be 633 kg (13.7%) of milk yield, 4878 kg (34.1%) milk of lifelong productivity, and longevity will increase by 105 days (11.6%) or by 0.30 lactations (11.1%).