One of the key factors ensuring the increase in sheep production in future is the development of intensive reproduction of the herd. The article presents the results of an experiment that helped study and give comparative characteristics for the meat productivity and natural resistance of the pedigree Edilbay sheep breed in conditions of a pedigree reproducer in 2018-2019. The young stocks of original and new types were studied to assess their interior traits, establish the direction and degree of correlation between the biochemical blood parameters and meat productivity of young sheep, as well as determine indices reflecting the immune status of organisms of the experimental sheep. When starting the test, the live weight of animals of the pure and pedigree types were almost the same, while when finishing the experiment at the age of 12 months, animals in Group II exceeded animals in Group I by 4.3 kg (5.8%, P<0.01). The best average daily gain of experimental sheep was also in Group II, i.e., 167 g, which was higher than in Group I by 9.1% (P<0.01). Consequently, the rams of new type had the highest growth rate. The data of the control slaughter showed that both experimental groups had high meat productivity. The analysis of natural resistance indicators of small ruminants of various types and their relationship with productive qualities in different climatic zones have also shown the need to use different integral indicators to assess the immune status in further breeding of animals. The analysis of natural resistance indicators of small ruminants of various types and their relation with productive qualities in different climatic zones has suggested that there is a need to use several markers to assess the immune status for further sheep breeding.

В статье приведены результаты анализа взаимосвязи признаков мясной продуктивности с предубойной массой бычков, выращенных по традиционной и интенсивной технологиям. Исследования проводили в условиях сельхозпредприятия в Волгоградской области в 2019—2022 годах на бычках русской комолой породы в возрасте 8 мес, которых разделили на 2 группы по10 голов. В I группе животных откармливали по традиционной технологии, во II — по интенсивной. Средняя живая масса отобранного молодняка составляла 190 кг. По окончании опыта предубойная живая масса бычков во II группе была выше, чем в I, на 11,7%, а коэффициент изменчивости больше на 3,7%. Убойный выход у бычков во II группе был на 2% выше, чем у сверстников из I группы. Коэффициенты корреляции между предубойной массой бычков и массой печени, почек, шкуры, шейного и плечелопаточного отрубов, высшего, I и II сортов мяса характеризуются средними значениями (0,136—0,822). Выявленные на основе корреляционного анализа взаимосвязи в опытных группах позволили определить основные параметры наиболее эффективной технологии выращивания молодняка крупного рогатого скота. The article presents the results of correlation analysis among meat productivity parameters and pre-slaughter weight of bulls breeding in accordance with traditional and intensive technologies. The research was performed in conditions of an agricultural enterprise in the Volgograd region in 2019—2022 on Russian brown breed bulls at the age of 8 months, which were divided into 2 groups of 10 heads. In group I, animals were fattened according to traditional technology, in group II — according to intensive. The average live weight of selected animals was 190 kg. It was determined that the pre-slaughter live weight of bulls in group II was 11.7% higher in comparison with animals in group I, and the relative standard deviation was 3.7% higher. The slaughter yield of bulls in group II was 2% higher than that of their coeval in the group I. The correlation coefficients, which describes relation between the pre-slaughter weight of bulls and the weight of liver, kidneys, skin, neck and shoulder, and also higher, I and II meat grade are characterized by average values (0.136-0.822). The interrelations, revealed as a result of the correlation analysis, made it possible to determine the main parameters of the most effective technology for cattle farming.

The article considers the regularities of the adaptive ability of cows of different genotypes. The study is based on traits of natural resistance and biochemical analyses of blood serum. Crossbred animals in Group III have been found to have higher indices of the natural resistance of the organism. The metabolism intensity in the animal body was indicated a high immunological status, i.e. the bactericidal activity of blood serum (BABS) of crossbred first-calf heifers was 83.1%, which was higher by 7.4% than the analogs’ indices in Group II and by 5.8% than indices in Group I. Similar results were recorded in terms of the lysozyme activity of blood serum. The highest phagocytic activity (PhA) was also found in crossbred heifers. The increased metabolism in the body of crossbred heifers can be explained by the effect of heterosis.

Приведены результаты изучения роста, мясной продуктивности и качества говядины, полученной от молодняка русской комолой (I группа), казахской белоголовой (II группа) и калмыцкой (III группа) пород. Установлено, что при постановке на опытв 8-месячном возрасте животные II подопытной группы превосходили по живой массе сверстников I и III групп, соответственно, на 4,1 кг и 23,9 кг, в 17 мес — на 16,2 кг и 49,8 кг.Бычки I группы превосходили по живой массе сверстников III группы в возрасте 8 мес на 19,8 кг, в 17 мес— на 33,6 кг. По результатам контрольного убоя бычки казахской белоголовой породы превосходили сверстников I и III групп по массе туш на 6,88 кг, или 2,7% (Р<0,05) и 35,81 кг, или 14,0% (Р<0,001). Убойный выход был более высоким у животных русской комолой породы (I группа). Их превосходство по этому показателю над сверстниками II и III групп составило1,07 и 2,29%. На основании результатов обвалки установлено, что выход мякоти в тушах бычков I группы был выше, чем у сверстников II и III групп — на 0,77 и 2,00%. Индекс мясности у бычков I группы в сравнении со сверстниками был выше на 0,24 и 0,70. Выход мякоти в тушах на 100 кг живой массы у бычков I группы был также превышал данный показатель у сверстников на 1,09 кг, или 2,44% и на 2,52 кг, или 5,83%. Наиболее ценных отрубов было получено больше от бычков I группы (русская комолая) по сравнению со сверстниками II и III групп. Установлена положительная корреляционная связь между живой массой бычков в начале и конце откорма с общим белком в сыворотке крови — в I группе 0,54—0,64, во II — 0,50—0,67, в III группе — 0,67—0,69; убойной массой и общим белком в сыворотке крови — в I группе она составила 0,47—0,50, во II — 0,49—0,51, в III группе — 0,51—0,53.The results of the study of growth, meat productivity and quality of beef obtained from young stock by Russian comola (I group), Kazakh white-headed (II group) and Kalmyk (III group) breeds are presented. It was established that when setting up the experiment at 8 months of age animals II experimental groups surpassed live weight of their peers I and III groups, respectively, by 4.1 kg and 23.9 kg, at 17 months - by 16.2 kg and 49.8 kg. Gobies of group I exceeded in live weight of their peers of group III at the age of 8 months by 19.8 kg, at 17 months - by 33.6 kg. According to the results of the control slaughter, Kazakh white-headed breed bullies exceeded their peers of groups I and III by carcass weight by 6.88 kg, or 2.7% (P <0.05) and 35.81 kg, or 14.0% (P <0.001). Slaughter yield was higher in animals of the Russian comola breed (I group). Their superiority over this indicator over their peers of groups II and III was 1.07 and 2.29%. Based on the results of deboning, it was found that the pulp yield in bull carcasses of group I was higher than that of peers of groups II and III — by 0.77 and 2.00%. The index of meatiness in bulls of group I in comparison with peers was higher by 0.24 and 0.70. The yield of pulp in carcasses per 100 kg of live weight in the first group of bulls I was also higher than that of their peers by 1.09 kg, or 2.44% and 2.52 kg, or 5.83%. The yield of the most valuable cuts was higher in bulls of Group I (Russian comola) compared with peers of Groups II and III. In the process of research, a positive correlation was established between the body weight of animals at the beginning and end of fattening with the total protein in the blood serum in group I; it was 0.54—0.64; in II — 0.50—0.67; in group III — 0.67—0.69, between the slaughter mass with total serum protein in group I it was 0.47—0.50; in II — 0.49—0.51; in group III — 0.51—0.53.