Duration and effectiveness of lifelong use of cows according to their milk yield for first and better lactation

Abstract

The aim of research was to study the duration the effectiveness and lifelong use of Ukrainian Black-Spotted dairy breed cows and the impact on these indicators of milk yield for the first and best of lactation. Research was carried out in Ltd. «Milk River» Sokal district, Lviv region. It is established, that the highly indices of life expectancy, productive use, lactation, number of lactations for life and the coefficient of economic use there were cows, milk yield for the first lactation of which was 3501–4000, for the best – 5001–5500 kg, but for the lifelong yields and the amount of milk fat – with the milk yield for the first lactation 4001–4500,  for better – more than 6000 kg. Better by yields and the number of butterfat on one day of life, productive use and lactation were cows with milk yield for the first lactation of over 5500 kg, and for better – more than 6000 kg. Thanks to the correlation analysis is set different levels and the direction of indicators duration communication and the efficiency and lifetime use of experimental cows with their milk yield for the first lactation. The highest positive and significant correlation coefficients have been established between the animals yields for the first lactation and their yields (0.426–0.812) and the amount of milk  fat  (0.445–0.811) for a day of life, productive use and lactation. Negative, but probable links were between milk yield of cows for the first lactation and the duration of their life, productive use, lactation, number of lactations in life, the coefficient economic use. The greatest influence of cows yield for the first lactation had their yield and the amount of milk fat for a day of productive use (61.89 and 62.47% respectively) and lactation (54.97 and 56.44%) and the lowest – in a lifelong yield (2.01%) and the lifelong number of milk fat (1.97%). The largest predicted value had the links between the yields for the best lactation of cows and their lifelong milk yield, lifelong number of milk fat, yields and the amount of milk fat for a day of life and productive use and lactation. These links in all cases were close, highly reliable and were in the range 0.598–0.911. The lowest correlation coefficient, in addition improbable and negative, was observed between milk yield of cows for the best lactation and average fat content in milk for all lactation (-0.008). Significant influence of better lactation on the above mentioned indicators are confirmed by our calculation the indicators of influence power, which ranged from 39.53 to 77.68%. The lowest power of influence of this factor was observed in the average fat content in milk for all investigated lactation (1.02%).