Аннотация
Live-animal evaluation of replacement young animals including bull-calves on their own productivity in the breeding of Kazakh White-Headed cattle has of scientific and practical importance. The purpose of the work was a live-animal evaluation of the quality of Kazakh White-Headed bull-calves by their own productivity. Bull-calves of the 3rd group (line of Veteran) in all periods of evaluation on growth can be assigned to the elite-record class. Replacement bull-calves of the 1st group (line of Circled) at all ages for live weight belonged to the elite class. Replacement bull-calves of the 2nd group since 9-month age have been evaluated as a class elite-record. According to the adjusted live weight of replacement bull-calves at the age of 210 and 365 days, the animals of the 3rd group were the best. According to this indicator the bull-calves of the 3rd group at the age of 210 days can be attributed to the 1st class, and at the age of 365 days the elite-record. When evaluating the reproductive capacity of the replacement bull-calves of Kazakh White-Headed breed of different lines the superiority of animals of the 3rd group (line of Veteran) has been found. They have significantly higher scrotum girth than the bull-calves of the 1st group by 7,1 cm or 27,0 % (P ≤ 0,01) and 1,9 cm or 6,0 % (P ≤ 0,05) than the young bulls of the 2nd group. The meat qualities also revealed the superiority of bull-calves of the 3rd group. They had higher indicators for the area of the muscle eye, marbling of meat and a comprehensive assessment of meat qualities. Live-animal evaluation of replacement young animals of beef breeds on their own productivity allows us to quickly increase the number of breeding stock.