USEFUL FEATURES OF DAIRY COWS AND THEIR CONNECTION WITH PRODUCTIVE LONGEVITY

A fundamental genetic improvement of domestic dairy breeds is carried out by using the gene pool of the best foreign breeds, in particular Holstein. This approach has greatly improved the milk productivity of cows, but has led to a significant deterioration in reproduction, longevity, product quality, general animal health etc. Taking into account that the increase of the milk productivity of cows leads to a shortening of their use, this problem will only become aggravated over time. Therefore, it is now necessary to direct scientific research into a comprehensive assessment of animals taking into account the signs of lifelong productivity. In view of the above, the purpose of our research was to study the economic utility signs of dairy cows and their relationship with productive longevity. The research was conducted on cows of Holstein (n = 2902), Ukrainian Black- (n = 14876) and Red-and-White (n = 2176) dairy breeds. To characterize the economic useful signs of animals of the studied breeds based on the materials of the primary zootechnical and breeding records, weighed growth of animals, reproductive capacity, milk productivity and duration and efficiency of lifetime use were studied. It was established that heifers of investigated dairy breeds were characterized by a moderate intensity of growth of live weight, as evidenced by average daily increments from birth to 18 months of age: in animals of Holstein breed – 644, Ukrainian Black-and-White milk breed – 641 and Ukrainian Red-and-White dairy breed 692 g. The first fruitful insemination of heifers of the Holstein breed occurred on average at the age of 19.1, Ukrainian Black and Red-and-White dairy breeds - 20.4 and 20.8 months, while their live weight at that was 405.3; 414.3 and 438.5 kg respectively. The milk yield of the Holstein breed cows, depending on the lactation, was 4846–7920 kg, the fat content in milk was 3.63–3.74% and the amount of milk fat was 181.2–279.7 kg, the Ukrainian Black-and-White milk breed was 4008–6317 kg, 3.63–3.70% and 148.6–228.8 kg respectively, while Ukrainian Red-and-White milk is 4578–6592 kg, 3.74–3.87% and 177.2–245.9 kg. The cows of the given breeds were used in herds only 2.32–2.50 lactation. The highest life milk yield was noted in animals of the Holstein breed (18,669 kg), and the lowest (14,940 kg) in the cows of the Ukrainian Red-and-White breed. Correlation analysis of economic characteristics of dairy cows with indicators of their productive longevity confirms the possibility of conducting an indirect predictive selection of animals in order to form high-yielding herds with long-term economic use. Among the studied features, the greatest predictive value (P < 0.001) for the indicators of life expectancy, productive use, lactation, the number of lactation per life, life yield and lifetime of milk fat have yield of cows for the first (r = -0.217 – +0.205) and the best lactation (r = +0.061 – +0.609). An intermediary predictive selection of animals can also be carried out according to the duration of their first service period (r = -0.462 – +0.106) and live weight during growing season (r = -0.286 – +0.126). It was established that live weight at the first insemination and the first calving significantly influenced the indicators of life yields, economic use and lactation of animals, as evidenced mainly by higher and reliable values of correlation coefficients between these indices. It should also be noted that the correlation coefficients between the live weight of cows in the first calving and the duration of life, productive use, lactation and the number of lactations in life were somewhat higher but negative values (r = -0,130 – -0,070), compared with the between live weight at the time of first insemination and the above indicators of longevity of animals (r = -0,037 – +0,094). This suggests that the effect of live weight on the first calving of animals on their longevity was somewhat higher than the effect of live weight at the first insemination. Our data show that the selection of cows by the age of the first calving and the duration of the first lactation is not significant, since there is practically no link between these features and the indicators of productive longevity.