The characteristic of economically important traits of dairy cows depending on type of body constitution

Abstract

This study focuses on research of economically important traits of Ukrainian black-and-white dairy cows with different types of body constitution. The aim of the study was to differentiate dairy cows into constitution types and to identify the best types in terms of growth, exterior, milk productivity and reproductive capacity. The cows were differentiated into low-, mid- and high-capacity types of body constitution. Depending on their type the features of growth, exterior, milk productivity and reproduction capacity of primiparous have been studied. It has been established, that the intensity of growth of heifers from birth to 18 months depended on the type of their body constitution. Higher live weight, absolute and average daily gains were characteristic of heifers with low-capacity body constitution. Their live weight at the age of 18 months on average was 388.5 kg, it was on 30.9 kg and 60.3 kg (Р < 0.01) more than live weight of mid- and high-capacity heifers. The advantages of low-capacity heifers in average daily gain during the growing period were 60 g and 117 g, respectively. The results of the exterior evaluation have shown that primiparous with the high-capacity type of body constitution had greater size and larger measurements primarily of the chest and barrel (Р < 0.05–0.001).The higher values of linear evaluation were also observed in cows with the high-capacity type, which were characterized by well-developed chest, wide rump, desired rear view of rear legs, firm udder attachment and strong central ligament. The power of influence of the type of body constitution on linear type traits ranged from 0.5 % (rear teat placement) to 46.2 % (chest width). Higher milk productivity was a characteristic of mid-capacity cows (an advantage of 305-d milk yield – 340–662 kg, milk fat yield – 9.0–21.0 kg, milk protein yield – 9.8–19.8 kg).The best results of reproduction capacity have been observed in cows with the high-capacity type of body constitution (calving percentage – 87.5 %)