Characteristics of economically important traits of cows depending on their body built

Abstract

A comparative evaluation of Ukrainian Black-and-White Dairy cows of friable and dense, delicate and rough body built have been carried out. The dynamics of their live weight during the growing period, exterior, milk productivity and reproductive ability were investigated. Heifers with dense body built compared to the animals with friable body built were characterized by higher live weight at the age of 3; 6; 9; 12; 15 and 18 months and at the first insemination by 5,4-47,9 kg. Heifers with delicate body bult compared to the cows of the same age with rough body built were dominated by a live weight during growing period by 2,0-24,4 kg. The average daily gain of heifers with dense body built was 665 g (+93 g compared to friable body bullt, P <0,01), average daily gain of heifers with delicate body bult was 624 g (+24 g compared to rough body built). The primiparous cows with friable body built had larger sizes than cows of the same age with dense body built. At the withers they were higher by 1,2 cm, they had an advantage in chest girth – 8,9 cm (P < 0,001), chest width and chest depth behind the shoulder – 3,2 cm (P < 0,001) and 2,0 cm (P < 0,05), respectively, chest width and chest depth behind the last rib – 3,1 cm (P < 0,01) and 2,6 cm (P < 0,001), chest length – 2,1 cm (P < 0,05 ). The primiparous cows with delicate and rough body built were characterized by less marked differences in body measurements. Cows with delicate body bult compared to the cows with rough body built were taller by 4,9 cm (P < 0,001), with deeper chest behind the shoulder –1,7 cm (P < 0,05) and with longer body (oblique body length was more on 1,3 cm). Cows with rough body built had significantly larger chest width behind the last rib – by 2,1 cm (P < 0,05) and metacarpus girth – by 0,7 cm (P < 0,01). Higher milk productivity has been observed in cows with dense and delicate body built. The primiparous cows with dense body built had higher 305-d milk yield on 117 kg, milk fat yield –on 6,2 kg, milk protein yield – on 4,2 kg, fat content and protein content in milk – on 0,02% and 0,01%, respectively. Between cows with delicate and rough body built difference in milk yield was 340 kg, milk fat yield and milk protein – 12,1 kg and 10,5 kg, respectively,fat content and protein content in milk had no differences. Better reproductive ability has been observed in cows with friable body built (open days – 157, calf crop percent – 85,5%) and rough body built (145 days and 85,9%, respectively), it meant in cows with body built, that had lower milk productivity. Taking into account the characteristics of cows with different body built makes it possible to optimize the selection process in a particular herd and directing the selection in the desired direction. Key words: cows, Ukrainian Black-and-White Dairy breed, body built, live weight, body measurements, milk productivity, reproduction ability.