The effect of technological factors on stress resistance and manifestation of the productive qualities of cattle
Creation of comfortable conditions for first calf heifers by creating and keeping them separate from adult cows during lactation allows to minimize the impact of technological stresses that allows fuller realization of animal productivity. The results of monitoring cows for stress responses revealed that the largest proportion of stress-resistant individuals was registered among first calf heifers kept separately from adult cows - 26 animal units or 86.7 % of all first calf heifers’ group. At the same time, there were only 7 individuals or 23.3 % of such first calf heifers kept together with the elders. It was found that milk yield from the cows of the control group of a stress-resistant type was 873 kg more than those from the stress-sensitive herdmates (P>0.99), for first calf heifers kept separate from the adult contingent these differences amounted to 1107 kg of milk in favor of individuals of stress-resistant type (P>0.99). Despite a greater feed intake (by 3-6 ECU), more productive first calf heifers of stress-resistant type spent on production of 1 kg of milk less than the ECU (by 0.11 units) which is probably associated with the production of more milk. First calf heifers of the Holstein of American breeding kept separately from the adult contingent differed from the herdmates of joint content by higher productive qualities, greater feed intake and intensive metabolism. At the same time, irrespective of the method of completing the groups, the studied parameters are better expressed for first calf heifers of stress-resistant type.