INFLUENCE OF TECHNOLOGICAL CRITERIA ONTO LIFESPAN AND LIFE-LONG YIELDING CAPACITY OF WHITE-ANDBLACK CATTLE
The article provides research results of paratypic factors influence on cows' longevity and lifespan milk yielding of Blackand- White cattle in conditions of Trans-Baikalye. For increasing efficiency of dairy cattle breeding management it is necessary to inseminate heifers of 16-18 month age and pick up cows for future reproduction with first lactation yield not less than 4500 kg and with body weight of 500 kg. It would allow increasing productive cattle longevity up to 6 calving.