ZOOTECHNICAL ASSESSMENT OF THE TECHNOLOGY OF REARING REPLACEMENT HEIFERS OF THE KAZAKH WHITE-HEADED BREED

Abstract

The article presents a zootechnical assessment of the technology for rearing replacement heifers of the Kazakh white-headed breed under the conditions of Northern Kazakhstan. The research aimed at comparing growth performance, physiological status, and reproductive traits of heifers from different sire lines (Veteran 7880, Mir 2497, and Baikal) in order to determine the most efficient breeding technology.  The research was conducted at Olzha Borovskoye LLP, where three experimental groups of 10 heifers each were formed and monitored from birth to 18 months of age. Live weight dynamics, average daily gain, hematological and biochemical blood parameters, as well as reproductive indicators were evaluated.  The results showed that heifers of the Veteran 7880 line demonstrated the highest growth intensity: at 18 months of age, their live weight reached 465.9 kg, exceeding that of the Mir 2497 and Baikal lines by 26.0 and 45.6 kg, respectively. The average daily gain over the entire rearing period was 820 g, which was 4.9–9.0% higher than in the other groups. Blood analysis revealed higher erythrocyte counts (6.96×10¹²/L) and hemoglobin levels (175.2 g/L) in this group. Reproductive performance was also superior, with effective insemination occurring at 471 days of age and a calving rate of 100%.  The findings indicate that the Veteran 7880 sire line is biologically and economically preferable for stock breeding.