В работе представлены результаты исследований по внутрипородной типизации казахской белоголовой породы крупного рогатого скота с целью выявления различий в продуктивных и экстерьерных характеристиках между анкатинским и шагатайским типами. Сравнительный анализ проводился по показателям живой массы, среднесуточного прироста, морфометрическим измерениям тела и племенным признакам. Результаты показали, что бычки анкатинского типа демонстрируют более высокие показатели живой массы к 15 месяцам (превышение на 2,6 %, p <0,05) и среднесуточного прироста (на 4,5 %, p <0,01) по сравнению с шагатайским типом. Экстерьерная оценка выявила достоверные различия по ключевым морфометрическим признакам, включая высоту в холке, ширину груди и косую длину туловища, что подтверждает преобладание мясного формата у анкатинских бычков. Корреляционный анализ показал значимую положительную связь между живой массой и экстерьерными показателями (r = 0,71-0,92), а расчѐт коэффициентов наследуемости (h² = 0,25-0,46) подтвердил возможность эффективного селекционного отбора по данным признакам. Полученные результаты подчеркивают высокую племенную ценность анкатинского и шагатайского внутрипородных типов и их практическое значение для улучшения мясной продуктивности и формирования качественного поголовья казахской белоголовой породы, что имеет важное значение для развития мясного скотоводства в регионе.

The article presents the results of a comparative evaluation of the milk and meat productivity of cows belonging to different intra-breed types of the Kazakh Whiteheaded cattle — Ankaty (big Ankaty), Shagatay (polled), and Zavolzhsky. The relevance of the research is stemmed from the need to increase the efficiency of beef farming through the rational use of genetic diversity and the identification of the most efficient genotypes. The research objective was to determine differences among intra-breed types in terms of milk yield, age-related live weight dynamics, and slaughter traits of young stock. The research materials included data on milk productivity depending on calf age and gender, as well as results of control slaughter of bulls. Milk productivity was assessed indirectly using calf weight during the suckling period. Beef performance indicators included pre-slaughter live weight, hot carcass weight, slaughter yield, visceral weight, and its proportion in the carcass. Results showed that the Ankaty type demonstrated the highest milk productivity, more intensive live-weight gain, and superior slaughter performance. The Shagatay type showed lower milk yield and reduced fat deposition, while the Zavolzhsky type occupied an intermediate position. The findings confirm that intra-breed differentiation is an important tool in breeding programs, enabling the formation of highly productive herds tailored to production goals. The results can be used in selection strategies and to improve the efficiency of beef cattle breeding.

This article presents the results of dairy productivity, live weight, exterior assessment, measurements of body articles and body indexes of pedigree cows-the first heifers of the Hereford breed of the Zhabai line in comparison with their peers. Due to their excellent adaptive qualities and high meat productivity, Hereford breed animals have become widespread throughout the world in various climatic and feeding zones. To further improve the economically useful characteristics of the breed, it is necessary to apply modern methods of assessing breeding value. Currently, in countries with developed beef cattle breeding, modern methods of assessing the Hereford breed are used, which combine traditional phenotypic assessment (appearance, constitution, productivity) using the genetic method of the Best Linear Unbiased Prediction and genomic selection assessment. The first-born cows of the Zhabai line had a fairly large live weight at the age of 3 years, met the requirements of the elite-record class and exceeded their peers from other breeding bulls by 18.5 - 54.6 kg. All first-time cows were characterized by high milk content and on average exceeded the breed standard in terms of live weight of calves at 6 months by 52.4 kg, heifers – by 51.6 kg. The first-heifer cows were distinguished by their strong constitution, broad-bodied and massive.

Introduction: Under conditions of intensive beef cattle industry development in Kazakhstan, evaluating the genetic diversity and population structure of Aberdeen Angus cattle, as well as the distribution of alleles and genotypes of functional TG5 and LEP SNPs associated with meat quality, is an urgent task. The study aimed to perform an integrated population and functional genetic analysis of Aberdeen Angus cattle using neutral STR markers and TG5 and LEP SNPs to simultaneously assess genetic diversity, population structure, and the distribution of alleles potentially associated with meat productivity traits and beef quality. Methods: A total of 122 bulls from three farms were analyzed; genotyping at 15 microsatellite loci was performed using capillary electrophoresis, while the SNP loci of the TG5 and LEP genes were investigated via PCR-RFLP with validation by Sanger sequencing; statistical processing included the calculation of genetic diversity indices and F-statistics, and PCoA and STRUCTURE analyses. Results: A moderate level of genetic diversity was established, with close heterozygosity values and no signs of inbreeding; interpopulation differentiation was low (mean Fst≈0.016) with a high gene flow, while cluster analysis revealed the absence of a distinct population structure and a high degree of admixture. For TG5 , a predominance of the C allele and the CC genotype was noted, whereas for the LEP gene, a more uniform distribution of genotypes with a high proportion of heterozygotes was observed. Discussion: The obtained results indicate that the studied populations are characterized by moderate genetic diversity and low interpopulation differentiation, which can be applied to genetic monitoring and the enhancement of breeding programs.