PRODUCTIVE LONGEVITY OF DIFFERENT LINES COWS OF PRYCARPATSKYY INTRA-BREED TYPE OF UKRAINIAN RED-AND-WHITE BREED

Duration of economic use of dairy cattle is one of the most important reserves for the further growth of the number of livestock, improvement of breeding and productive qualities of animals. Since the improvement of domestic dairy breeds is mainly due to the crossbreeding with the bulls of the Holstein breed, a continuous analysis of the breeding process in the breed and in its individual genealogical formations, in particular in the types and lines, in order to establish the best ways to conduct selective work with the breeds, is relevant. Detection and evaluation of lines, the descendants of which are capable of prolonged productive use, will allow for an optimizing selection for lengthening the life-time use of cows. In this regard, the purpose of our research was to study the duration and effectiveness of life-time use of cows of different lines of the Prycarpathian intra-breed type of Ukrainian Red-and-White breed and the reasons for their release from the herd. Research conducted on cows of inter-breed type of Prycarpathian Ukrainian Red-and-White dairy breed in the PAE "Mamayivske" Kytsman district based on the base of zootechnical register. The sample included 1075 animals, the first of which was at least eight years before the start of the study. Retrospective analysis of the duration and effectiveness of life-time use of cows was carried out according to Yu. P. Polupan's method. It was established that the duration of economic use of cows in the PAE Mamayevske, depending on the line, was within the range of 3.1–6.5 lactation. Life yield (3294 days), productive use (2454 days), lactation (1954 days), lifetime milk yield (37444 kg), lifetime number of fat (1394 kg), the number of lactations for life (6,5 lactation) and the rate of economic use (0.74) were the best animals that belonged to the P. Astronavt line 1458744. Approximate figures of productive longevity of cows were marked in Rigel line 352882. The descendants Valiant 1,650,414 were of the smallest used in herds and had the lowest performance line. The effect of the linear dependence of cows on the duration and effectiveness of their productive use, depending on the indicator, was within the range of 4.26–31.17%. It should be noted that the most significant impact of the line was on yield for one day of productive use (31.17%) and one day of lactation (30.43%). The least effect on the linear dependence of cows was on yield for one day of life (4.26%) and the average lifespan of fat in milk (4.79%). Strength of the line's influence on life yield, productive use and lactation of animals, the number of lactation per life and the rate of economic use, depending on the indicator, was within 12.11–16.45%. The coefficients of inheritance of life yields, productive use and lactation and the number of lactations calculated by the mother-daughter method were 15.8; 22.0; 21.4 and 19.1%. Life yields, the lifetime of milk fat and the average lifespan of fat in milk were the lowest level of inheritance – respectively 6.3; 7.5 and 10.1%. The highest coefficients of inheritance were noted for one day of productive use (39.4%) and lactation (46.8%). As a rule, daughters whose mothers have maintained high productivity for a long time and have long been exploited also have potential for prolonged productive use. We did not reveal any special differences between animals of different lines by the coefficients of inheritance of the above-mentioned indices. Disposal of animals from the herd was mainly due to reproductive function disorders (25.2–34.6%) and low productivity (13.4–27.1%). Among the studied lines due to the reproductive function impairment, the most abandoned animal lines of the P. Astronavt and Rigel were 34.6 and 31.7% respectively, while the least of those of the Valiant line was 25.2%. Due to its low productivity and disease, the largest number of cows (13.4–27.1%) fell out of the Valiant line. At the same time, the animals of the Valiant line were marked by the lowest percentage of rejection due to physiological aging (15.0%), and the highest was in animals P. Astronavt line (21.3%). Due to diseases of the limbs, from the herd dropped, depending on the line, 8.0–12.1% of cows, due to injuries and accidents - 3.2–5.7%, and for other reasons - 4.7–9.3%.