Productive differences of red steppe cows of different constitution types

In order to establish the specific weight of cows of exterior-constitutional types and to evaluate economically useful traits in a Red Steppe cattle herd, we conducted research on the morphofunctional properties of udder and milk productivity of animals. The distribution of the first-calf heifers of the herd according to the specific weight coefficient exterior-constitutional types revealed the highest specific weight of dense (40.0%) and intermediate (37.3%) types. The specific weight coefficient of first-calf heifers of loose exterior-constitutional type was 1.34 units, intermediate - 1.48 units, dense - 1.59 units. The results of the commission udder evaluation of the first-calf heifers show the highest proportion of individuals with cup- and tub-shaped udder forms among the animals of loose exterior-constitutional type - 88.2%, who outperformed their coevals of other types by 4.9-9.6 abs.%. The highest milk flow rate was shown by loose-type animals, whose superiority over their coevals of other types ranged from 0.16-0.22 kg/min (P>0.95-0.999), which can be explained by high values of the average daily milk yield of this group and absence of reliable inter-group differences in the milking time. The superiority in milk yield of loose type heifers over their dense type counterparts was established, which reached 420 kg during lactation (P > 0.95), intermediate type - 162 kg. The highest yield of milk products was demonstrated by representatives of the loose type, whose superiority over the dense type peers was 17.5 kg (P > 0.95) in milk fat and 17.3 kg in milk protein (P > 0.999). Animals referred to the loose type of constitution produced a higher milk yield for every 100 kg of live weight than their dense and intermediate counterparts - by 83 (P > 0.95) and 39 kg, respectively. Dense and intermediate types of constitution prevail among the first-calf heifers of Red Steppe cattle dairy herds. In spite of the fact that the animals of loose constitution type are characterized by a higher proportion of individuals with tub-shaped and cup-shaped udders and a higher level of milk yield per lactation, it is premature to unambiguously recommend increasing their representation by appropriate selection methods in the herd, since further research up to attrition is necessary for comprehensive monitoring of the lifetime production use.