Abstract
The purpose of the study was to quantify the breeding qualities of Kazakh White-Headed bulls by assessing their productivity metrics. The primary objectives were to analyze live weight dynamics, daily growth rates, feed conversion efficiency, and morphological meat quality and to employ "A" complex indices for evaluating the breeding potential. The study observed bulls aged 8-15 months at the Khafiza farm, located in the West Kazakhstan region. Parameters measured included monthly live weight, average daily growth, and feed cost per kilogram of gain. These data points were statistically analyzed to calculate "A" complex indices, which integrate multiple performance traits to evaluate overall breeding quality. It was found that 60% of bulls were represented by the upper classes, namely, the elite and the record-setting elite. The average daily growth and meat forms were the indicators with the best results in the comprehensive assessment of bulls. Very low point indicators were observed in the bulls in terms of live weight and feed costs per 1 kg of live weight gain. The largest number of bulls with high indicators of complex and breeding indices above 100% was observed in live weight (60%) and meat forms (60%) and the smallest number in feed costs (30%). The study results showed that 10% of the best bulls were selected according to the "A" complex index, their average live weight at the age of 15 months was in the range of 400-430 kg, the average daily gain was 804.76-852.38 g, meat forms equaled 55 points and the average "A" complex index for 10% of the best bulls was in the range from 100.17-104.44%. The application of "A" complex indices proved effective for categorizing bulls based on productivity and potential breeding value. The methodology facilitated a robust evaluation of phenotypic traits associated with meat production, providing a scalable approach for enhancing genetic selection practices in Kazakh White-Headed cattle.