Dairy productivity of Simmental breed cows depending on their live weight during growing period
One of the main factors for effective breeding is the level of growth of repair young animals, which at all ages has a significant impact on animal health and their future productivity, duration of economic use and largely determines the efficiency of the dairy farming industry. It is important to know the potential capabilities of each animal's body since its birth, since the genetically programmed productivity of cows can only be realized if they are favorably grown at different ages at a young age. Therefore, the purpose of the research was to study the dependence of the milk productivity of the Simmental breed cows on their live weight during the period of growing. The research was carried out at LCC «Litinske», Drohobych district of Lviv region. The live weight of cows was studied at the age of 6, 12, 18 months, at the first insemination and after the first calving, and the assessment of milk productivity was carried out on the basis of diet, the fat content of milk and the amount of milk fat for the first, second, third and best lactation on the materials of the primary zootechnical accounting. It was established that the milk yield of cows, depending on lactation, were within the range of 3026.4–3685.8 kg, the fat content of milk – within 3.76–3.80% and the amount of milk fat – within the range of 113.6–139.8 kg. The live weight of the experimental animals at birth was 32.5, at 6 months – 185.9, in 12 months – 302.3, in 18 months – 405.2, at the first insemination – 396.9 and in the first calving – 514.7 kg It should be noted that the first fertile insemination of Simmental heifers occurred at the age of 19.7 months, and their first calving – at the age of 29.0 months. The highest diet and the amount of milk fat in cows were observed for their live weight at birth 33–34 kg, at 6 months of age – 171–190, in 12 months – 291–300, in 18 months – 401–415, at the first insemination – 416–430 and in the first calving – 501–530 kg. The correlation coefficients of the live weight of animals at young age and their subsequent milk productivity, depending on the age and lactation of the animals, were within the range of 0.18–0.24, and the influence of live weight of heifers on their subsequent milk productivity – within 12.3–20.1%.