Dependence of productive longevity of cows on their index of origin

Abstract

The data on the duration and effectiveness of lifetime use of Ukrainian Black-Spotted breeds of dairy cows and their influence on these indices of the index of origin are given. The research was conducted at the Ltd «Milk Rivers» in the Sokalj district, Lviv region. Retrospective analysis of productive longevity of cows was carried out on materials of zootechnical records. The index of the origin of cows was defined as the average value for the best lactation of their female ancestors (mothers, mothers of mothers and parents' mothers). It was established that cows with different index of origin differed in duration and efficiency of life-long use. The longest life expectancy, productive use and lactation, the highest life expectancy, the lifetime of milk fat, the greater number of lactation per life and the coefficient of economic use were animals with an index of origin of up to 4500 kg of milk, and the average lifetime fat in milk- individuals who have these indices were in the range 5500–6000 kg of milk. Better for milk yield for one day of life, productive use and lactation and the amount of milk fat for one day of life and productive use were cows with an index of origin of over 7000 kg of milk, and in the amount of milk fat for one day of lactation – individuals with a magnitude of this index of 6500–7000 kg of milk. Of particular interest for breeding of dairy cattle is the clarification of the links between the indicators of the duration and effectiveness of life-time use of cows with the milk productivity of their female ancestors, in particular with an index of origin. The correlation coefficients between the investigated indicators ranged from low negative (-0.003) to moderate positive values (+0.279). By the level of connection, the greatest predicted value was yields and the amount of milk fat for one day of life, productive use and lactation. One-factor dispersion analysis has established a different degree of influence of the index of origin of cows on the indicators of their productive longevity. The lowest influence of this indicator was observed on life expectancy, productive use and lactation, life expectancy, average lifetime fat content in milk and the lifetime of milk fat, yields and the amount of milk fat per day of life, the number of lactation per life and the coefficient of economic use of cows. At the same time, it should be noted that this influence on the average lifetime content of fat in milk, yields and the amount of milk fat per day of life was reliable (P < 0.05–0.01). The highest and most probable effect of the index of origin was on yields and the amount of milk fat per day of productive use and lactation (ηx2=23.41–30.17%).