IMPACT OF INTENSIVE HEIFERS GROWING ON THEIR DAIRY PRODUCTIVITY AND DURATION OF AGRICULTURAL USE

Abstract

The research explores the cattle of dairy Sibiryachka breed with high genetic dairy capacity. The paper estimated the periods of economic use of Sibiryachka cows considering the season they were born, their different growth, age of first insemination and calving, season of the first calving and milk and exterior assessment after first lactation. The authors define the most important factors for productive animal longevity, relations between qualitative parameters and parameters of  lifetime productivity and forecasting this parameter in explored cattle. All the data collected was processed biometrically by means of computer program Microsoft office Excel. As genetic factors determine the features of productive longevity on 10-20 %, and environmental factors affect 80-90%, than revealing paratypic factors that determine productive longevity of cows becomes significant and relevant. The researchers didn’t observe the impact caused by cows’ birth season and body weight at first insemination on cows longevity. The highest parameters of productive longevity (life expectancy equal to 3193.7 days, lifetime milk yield -  30283.9 kg, yield of milk fat equal to 1189.26 kg and protein - 928.07 kg) were observed in cows that first calved aged 30-32 months. When the age of first calving increases, cows longevity is 437.9 days lower and lifetime milk yield is reduced on 5951.9 kg. The authors used the method of dispersion analysis (P < 0.001) and found out the impact caused by first calving age on cows’ longevity.