DEVELOPMENT AND FORMATION OF THE EXTERIOR OF IMPORTED BREEDING BULLS IN THE PROCESS OF CLIMATIC ADAPTATION

SCIENCE AND INNOVATION INTERNATIONAL SCIENTIFIC JOURNAL VOLUME 4 ISSUE 10 OCTOBER 2025 ISSN: 2181-3337 | SCIENTISTS.UZ 10 DEVELOPMENT AND FORMATION OF THE EXTERIOR OF IMPORTED BREEDING BULLS IN THE PROCESS OF CLIMATIC ADAPTATION M.Kh. Dosmukhamedova1, O.E. Mamatkulov2 Doctor of Agricultural Sciences, Professor Tashkent State Agrarian University1 D.s/x (Phd), Tashkent, Republic of Uzbekistan, Director of the Scientific and Production Center for Tribal Affairs2 https://doi.org/10.5281/zenodo.17388638 Abstract. The article defines the class affiliation of imported breeding bulls during the period of adaptation to hot climatic conditions in 2018-2020 based on the characteristics of growth and development, maintenance and care, changes in live weight, exterior and selection indicators. The breeding bulls, thanks to their good adaptation to environmental conditions, scored high points for a range of traits, and the class category did not fall below the elite-record level. Keywords: breeding bull, import, growth development, cattle breeding, live weight, exterior, inspection, class category, breeding, selection and selection. Introduction. Under the conditions of modern intensive livestock farming, and particularly in dairy cattle breeding and pedigree farms, the improvement of existing herds, breeds, and cattle populations has been set as a priority goal. Ensuring the production of high-quality breeding animals and livestock products is regarded as a key factor. In this regard, the entire breeding system in animal husbandry plays a decisive role in optimizing management processes at various levels. Under such conditions, the importance of selection significantly increases. Addressing complex, multifactorial processes requires systematic, in-depth analysis and continuous improvement, including evaluation of breeding quality, selection, and forecasting the outcomes of selection measures. It is well known that during the past two decades, the dissolution of collective farms and the privatization of cattle negatively affected the development of cattle breeding and its genetic system. The existing breeding base of cattle husbandry was largely dismantled, and new pedigree farms had to be re-established through the importation of improver breeds. Currently, the cattle breeding base is being re-formed. Between 2006 and 2016, a total of 23,286 head of heifers and young cows of improver breeds were imported into farms across the regions of Uzbekistan, expanding the base of pedigree livestock. In this context, a number of organizational measures were undertaken, including the provision of preferential loans [1]. Since 2017, within the framework of the national development strategy up to 2030, largescale reforms have been implemented across all sectors of Uzbekistan. In particular, the Presidential decrees of 2019–2020, adopted under the leadership of President Shavkat Mirziyoyev, including “On measures to protect the rights and legitimate interests of farmers, dehkan households, and landowners, and to radically improve the system of efficient use of agricultural lands”, as well as other related decrees, testify to this progress. These decrees entrusted the Cabinet of Ministers of the Republic of Uzbekistan with the task of preparing relevant draft resolutions SCIENCE AND INNOVATION INTERNATIONAL SCIENTIFIC JOURNAL VOLUME 4 ISSUE 10 OCTOBER 2025 ISSN: 2181-3337 | SCIENTISTS.UZ 11 aimed at the further development of livestock, poultry, aquaculture, horticulture, apiculture, and other important sectors of agriculture, as well as coordinating the activities of farms and enhancing their efficiency [2; 3]. Literature Review. Cattle breeding, as one of the key branches of animal husbandry, has been developing intensively worldwide. Over the past century, methods of selection, purebreeding, and utilization of productivity potential have been widely applied, with particular emphasis on Holsteinization. Today, nearly all countries focus on selecting and reproducing highly specialized, high-yield breeds. As a result, low-yield native breeds have been displaced, and global highperformance breeds have expanded significantly. Since the 2000s, these processes have accelerated, with the number of globally recognized improver dairy breeds increasing, alongside their productivity and further genetic refinement. Competitive, high-yield, and pedigree breeds are now imported into almost all countries, both for purebreeding and for upgrading local cattle. Among such globally significant improver breeds, Holstein cattle stand out [4. c. 380: 5. c. 117-119]. Holstein Cattle Breeding and Global Distribution In the United States and Canada, great importance is attached to evaluating bulls by the quality of their progeny. Holstein cattle in North America (USA, Canada) were developed through the importation of the Dutch Ostfriesian breed, followed by targeted selection and breeding. In both the USA and Canada, independent breeding programs are carried out for two distinct Holstein types - black-and-white and red-and-white. These types have spread widely across many countries, leading to the development of numerous regional breeding lines. In the USA, Holsteins make up 95% of all dairy breeds. They are now distributed in Canada, the United Kingdom, Sweden, Denmark, Australia, Japan, the Netherlands, Germany, Israel, South Korea, and many other countries. New breeding lines have been developed in Israel, the Netherlands, Germany, and elsewhere. The productivity of these regional Holsteins does not lag behind American and Canadian Holsteins. For example, Israeli Holsteins produce 11,000– 12,000 kg of milk per lactation, South Korean Holsteins — 10,500–11,000 kg, Dutch and German Holsteins — 9,500–10,500 kg, and even in Saudi Arabia’s hot climate, Holsteins have achieved yields exceeding 8,500 kg [4. c. 380: 5. c. 117-119: 6. c. 37: 7. c.13-19: 8. c.158: 9. c. 62: 10. c. 62]. In recent years, Holstein cattle, as well as their semen and embryos, have been exported from the USA and Canada to 99 countries. There is virtually no dairy-producing country in the world that does not use Holsteins. This breed has established a firm position in the global cattle market [11. c. 2-4]. Outstanding production records are well documented. For instance, the cow Beecher Arlinda Ellen produced 25,248 kg of milk in her fourth lactation (365-day period), while Mironda Oscar Lucin yielded 30,870 kg, with 1,018.7 kg of milk fat [5. c. 117-119]. In Israel, Holsteins (n=84,694) averaged 11,200 kg of milk in 2004. Among them, 24,018 first-calving cows yielded an average of 10,817 kg, which increased to 12,203 kg in the second lactation [12. c.38-49: 7. c. 38-49: 7. c. 13-19: 14. c. 20-22: 15. c.23-26: 6. c. 37]. Holsteins continue to be imported into various countries and regions to strengthen dairy cattle breeding bases and improve locally adapted breeds. The effectiveness of importation depends on their adaptability to environmental conditions. Consequently, numerous researchers have conducted trials to study this factor. The selection and widespread use of improver Holstein bulls for progeny testing and contract mating remains the key factor in Holstein breeding. Currently, in the USA, Canada, Israel, Germany, and other developed countries, national breeding centers utilize the genetic potential of Holstein improver bulls of different color types (black-and-white, red-and-white, and white) [16. SCIENCE AND INNOVATION INTERNATIONAL SCIENTIFIC JOURNAL VOLUME 4 ISSUE 10 OCTOBER 2025 ISSN: 2181-3337 | SCIENTISTS.UZ 12 c. 195]. Within the framework of innovative research projects, we studied white-colored Holstein improver bulls, and on this basis, we developed and recommended the project of creating highly productive “White Steppe” cattle herds in the desert regions of Syrdarya and Jizzakh, Uzbekistan. Productivity of Imported Holstein Cattle in Uzbekistan and Abroad. Holstein cattle imported from European countries to different regions of Uzbekistan have demonstrated their high productivity even under hot climatic conditions. For example, Holsteins imported from the Netherlands, Germany, Austria, and China have shown strong performance in local farming conditions. Holstein heifers imported from China and kept at the “Rohatoy” farm in Zangiota district, Tashkent region, produced 4343–4563 kg of milk in their first lactation and 6447–6908 kg in their second, with a fat content of 3.80–3.90%. Feed consumption amounted to 5366–5374 feed units. In the “Azizjon” farm (Qibray district, Tashkent region), German Holsteins produced 7354 kg of milk in the second lactation under a high feeding standard (7127 feed units), while Slovenian imports produced 7564 kg in the first lactation. The Holstein breed is characterized by extremely high genetic productivity potential. In the later stages of Holstein improvement, breeders achieved outstanding selection efficiency [17. c.1011], significantly increasing both breeding and production potential. A notable example comes from the “Ever-Green-View” farm in Waldo, Wisconsin (USA), where in 2010 a Holstein cow (N. 1326) set a new record. In her third lactation (365 days), she produced 32,804 kg of milk, with 3.85% fat and 3.12% protein, equivalent to 1263 kg of fat and 1023.5 kg of protein, averaging 89 kg/day. On this farm, 130 cows averaged 15,944 kg of milk per head. The record-setting cow’s conformation was evaluated at 92 points. Her sire, Staudder Mathi-ETUSA 17349617, produced over 1 million doses of semen, earning “millionaire bull” elite status. He was progeny-tested across 11,986 herds, with a breeding index (TPS) of +1633, and daughters (n=26,144) averaging 11,787 kg of milk with 3.6% fat (424.3 kg) and 3.5% protein (365.4 kg). When provided with optimal feeding and management, Holsteins express their full productive potential even in hot climates. At the “Siyob Shavkat Orzu” farm (Toyloq district, Samarkand region), German Holsteins fed according to a 9043 feed unit diet yielded 9435 kg of milk in their first lactation. In subsequent lactations, feed consumption reached 9086–9195 units, with Polish Holsteins producing 8938–9288 kg, and Dutch Holsteins producing 9638–10,093 kg of milk. Over the past decade, Holsteins have continued to improve in the USA, Canada, and other countries. North American Holsteins differ from European dairy breeds by their larger size and distinct dairy type. Between 85–97% of cows have bathor bowl-shaped udders, with milk flow rates of 1.92–2.37 kg/min and milking indices of 42–44%. In Canada, the cow Challenger Severing Princess produced 144,430 kg of milk and 5523 kg of fat over 14 lactations, ranking first for lifetime yield. Another cow, Breeze Wood Paten Bar Pontenoc, yielded 21,546 kg of milk at 4.7% fat in her ninth lactation, with lifetime totals of 192,843 kg milk and 8700 kg fat [19. c. 29-30]. [20. c. 17-19], experiments conducted in Russia’s central region showed that Holsteins under balanced feeding produced an average of 9604 kg of milk with 3.96% fat and 3.28% protein. Holsteins of the Reflection Sovereign line reached 10,866 kg of milk, with 3.92% fat and 3.26% protein. These trials were also supported by research from [21. c.14-25]. Comparative Productivity of Holstein and Brown Swiss Cattle under Different Breeding and Climatic Conditions. According to the research of N.P. Sudorev et al. (2017), a comparative study was conducted on 1098 Holstein cows of Dutch, Canadian, and Russian selection. Under identical feeding and management conditions, with an average consumption of 9250 feed units, the cows produced 9873 SCIENCE AND INNOVATION INTERNATIONAL SCIENTIFIC JOURNAL VOLUME 4 ISSUE 10 OCTOBER 2025 ISSN: 2181-3337 | SCIENTISTS.UZ 13 kg of milk on average. Canadian Holsteins showed superiority, yielding 4773–3904 kg more milk than the other groups. The best-performing cows reached 18,550 kg milk, with 1398.7 kg of fat and protein combined. In Uzbekistan’s hot climate, Holsteins of German selection with a strong constitution type outperformed those of fine constitution type when kept under the same feeding and housing conditions. In the third lactation, strong-type cows produced 6422 kg milk with 247.9 kg fat over a 305-day lactation, while fine-type cows produced only 5132 kg milk with 204.2 kg fat. Globally, dual-purpose dairy-meat breeds such as Brown Swiss and Simmental are widely distributed, especially in foothill and mountainous regions. These breeds have been successfully used in the development of brown and red-and-white local breeds and in the improvement of cattle herds across various regions. Brown Swiss populations have spread to Italy, Switzerland, Germany, France, Bulgaria, Hungary, the USA, Russia, Ukraine, the Caucasus, the Carpathians, and Central Asia, including Uzbekistan. In many of these regions, reproductive herds have been established, and new brown breeds were developed through crossbreeding with local cattle. Brown Swiss cattle show diverse traits depending on breeding environment and selection methods. Italian and French Brown Swiss are relatively large, highly productive in both milk and beef performance. Australian and German populations are more compact and are maintained under a dairy-beef production system. In Switzerland and throughout Central and Western Europe, Brown Swiss cows typically produce 5000–6000 kg of milk with 3.0–4.0% fat, while pedigree herds reach 9000–10,000 kg. Notably, in Bavaria, the cow Aroma yielded 17,118 kg milk, and some cows have exceeded 5.0% milk fat. The Austrian and American Brown Swiss lines are distinguished by their exceptionally high genetic potential, producing 10,000–12,000 kg of milk. For example, in New Jersey (USA), the cow Iveta at White Claws Farm produced 126,000 kg milk (equivalent to 5600 kg fat) across 11 lactations. Another cow, Miss Hild Kipere Rowan, set a world record with a 365-day lactation yield of 15,808 kg milk, containing 4.5% fat (716.4 kg fat). Today, Brown Swiss cattle are widespread throughout the northern and southern states of the USA, with the most elite populations in Iowa and New Jersey. Austria’s Brown Swiss are equally productive and comparable to the American type. Russian and German Brown Swiss populations are less productive but have been widely used across the former Soviet republics, contributing to the development of new breeds such as Kostroma, Lebedin, Alatau, Caucasian, and Carpathian Brown. Their milk yields vary between 2500–4000 kg depending on regional conditions. In Uzbekistan, the highest production was recorded at the “Savai” state farm in Andijan, where Brown Swiss averaged 4000–4200 kg, and the cow Astra produced 10,270 kg in her fourth lactation. Use of Austrian and American Brown Swiss sires yielded the best results. Another globally important breed in dairy-beef improvement programs is the Red-and-White Simmental (Fleckvieh). Over the last decade, the efficiency of improver bulls has increased significantly. Artificial insemination centers have established breeding programs to produce and distribute semen from genetically superior bulls, with ongoing research aimed at increasing semen quantity and quality [22. c. 5-6: 23. c. 2-3]. [24. c. 2-8] reported that in Russia, between 2005–2015, the national cattle population declined from 95.2 million to 84.0 million head, and milk production decreased slightly from 31.1 to 30.8 million tons. However, the number of breeding herds increased significantly, with 418 pedigree farms established and cow numbers rising by 390.1 thousand head. Within these improved herds, average milk production during a 305-day lactation reached 7315 kg, indicating notable progress in selection efficiency. SCIENCE AND INNOVATION INTERNATIONAL SCIENTIFIC JOURNAL VOLUME 4 ISSUE 10 OCTOBER 2025 ISSN: 2181-3337 | SCIENTISTS.UZ 14 Selection of bulls based on maternal and paternal lineage increases breeding effectiveness by 90–95%. Therefore, in many developed countries, cow families are carefully selected as bull dams, which are then mated to highly prepotent sires. In cattle breeding, bulls are classified into categories based on composite evaluation traits such as exterior, body weight, and genotype. Each trait is assigned points, for example, exterior scores of 8.0–8.5 earn 15 points, while scores of 9.0 and above earn 20 points. Standard live weight corresponds to 5 points, while exceeding the standard by 5% adds 10 points. Maternal class (I-class, Elite, Elite-Record) contributes 15–25 points, and sire class adds 20–25 points, with further points awarded based on daughter performance. Bulls scoring over 80 points are classified as Elite-Record, 70–79 points as Elite, 60–69 points as Class I, and 50–59 points as Class II. Black-white Holstein bulls inspection result and their class category. During the inspection of bulls of this breed, their exterior, live weight and genotype were evaluated as well. The total scores were calculated by adding the scores of the sires of the bulls on the quality of their progeny, and summing them up. In the 2019 bonitation assessment, among 13 Holstein bulls, 11 (85%) were classified as Elite-Record and 2 as Elite. Compared to 2018, the overall class distribution declined: in 2018, total composite scores ranged from 83–95 points, whereas in 2019 they ranged from 73–95 points. This decline was attributed to reduced live weight and development rates in several bulls. Five bulls failed to score for live weight, and three received only 5 points, leading to their reclassification from Elite-Record to Elite. A decline was also observed in exterior evaluation scores. In 2018, 8 bulls that had received 20 points for live weight saw their scores decrease to 15 points. The total score of the bulls’ complex traits was mainly maintained at a high level due to genotypic indicators. Therefore, in order to improve the bonitation category of the bulls, it is necessary to restore their developmental potential through measures aimed at proper maintenance and full-value feeding. Bonitation of Red-white Holstein Bulls and Their Class Categories. The Red-white Holstein bulls were bonitated after they reached two years of age. They were evaluated based on complex traits (live weight, exterior characteristics, and genotype), and their class category was determined. Among all purebred bulls, 6 belonged to the elite-record class. According to the 2019 bonitation, the individual composite trait scores of the bulls ranged from 80 to 95 points, which was slightly lower compared to 2018 (85–95 points). The bull named Uptanu scored the highest with 95 points for composite traits, while Upenda and Upendu each scored 90 points. The lowest scores (80–83 points) were recorded for the bulls Unte and Unni. The bull Unni did Figure 1. The process of bonitation and body measurements of bulls Figure 2. The process of bonitation of a Fleckvieh Simmental bull SCIENCE AND INNOVATION INTERNATIONAL SCIENTIFIC JOURNAL VOLUME 4 ISSUE 10 OCTOBER 2025 ISSN: 2181-3337 | SCIENTISTS.UZ 15 not receive points for live weight and had its exterior score reduced by 15 points. Similar situations were also observed in Upenda and Upendu. Bonitation and class category of Angler bulls. Angler bulls, on average 29 months old (25–34 months), were evaluated based on composite traits. In some Angler bulls, the composite trait score slightly decreased compared to the previous year due to optimal live weight development but the presence of minor exterior shortcomings. Two bulls (Ubah and Ubaldo) dropped from the elite-record to the elite class. Out of 9 bulls, 7 (78%) belonged to the elite-record class. The bulls Uske, Ubangi, and Ubando received the highest score (93 points). The lowest scores were recorded for Ubah (76 points) and Ubaldo (78 points). The bull Ubah did not receive points for live weight development. Bonitation and class category of Swiss (Schwyz) bulls. Swiss bulls aged 26–30 months were evaluated. The bonitation was conducted according to the guidelines for evaluating dairy and dual-purpose bulls. The composite trait scores of Swiss bulls ranged from 86 to 91 points, which was the same as in the previous year. Two bulls (Jesur and Dorito) scored lower due to reduced live weight and exterior ratings. For the other bulls, the scores remained consistent in the 2018 and 2020 evaluations. The bull Khabot scored the highest with 91 points. All bulls belonged to the elite-record class based on their composite scores. This breed demonstrated high adaptability to environmental conditions, which allowed them to maintain their elite-record classification. Bonitation indicators and class category of Fleckvieh Simmental bulls. Fleckvieh Simmental bulls aged 26–42 months were evaluated individually. In the 2019–2020 bonitation, their composite scores ranged from 87 to 93 points, corresponding to the elite-record class. These results were higher compared to 2018. Their development score was maximal (10 points), exterior score ranged from 15 to 20 points, and genotype scores were 25, 25, 7–8, and 0–5, respectively. The improvement in 2019–2020 was associated with the breed’s adaptability to external natural conditions and strong constitution, giving them an advantage over black-white and red-white bulls. During 2019–2020, a total of 60 bulls were evaluated for composite traits and characteristics. Based on zootechnical and veterinary requirements, 16 bulls (26.7%) were deemed unsuitable and culled from the herd. Among them were: 4 Black-white Holstein bulls (21.1%), 2 Red-white Holstein bulls (18.2%), 6 Angler bulls (50%), 4 Swiss bulls (40%), and 1 Fleckvieh Simmental bull (12.5%). Changes in Body Measurements of Bulls. The body structure – exterior – of bulls was also evaluated using the method of taking body measurements. Eight body measurements characterizing body structure were taken when the bulls were 21–25 months old. Each bull was studied individually and compared within the breed composition. From the group of Black-white Holstein improver bulls, 4 bulls were transferred to the breeding enterprise’s Bukhara and Karakalpakstan branches, making a total of 12 bulls whose body measurements were taken. During 2018–2020, the body measurements of leader improver bulls and improver bulls differed depending on their size in certain indicators. On average, the leader improver bulls had withers height of 150–165 cm, hip height – 155–164 cm, chest width – 46–51 cm, chest depth – 78–91 cm, and oblique body length – 184–218 cm. These indicators in improver bulls were respectively 150–161 cm, 155–160 cm, 43–49 cm, 76–87 cm, and 184–196 cm. These body measurements were taken at 39 months of age in both groups. Changes in the exterior of body parts of the bulls are typical for the Holstein breed. The growth of body measurements in leader bulls reaching 37–40 months of age was studied over the 2018–2020 period. For example, withers height increased by 14.3 cm (9.8%), hip height by 9.5 SCIENCE AND INNOVATION INTERNATIONAL SCIENTIFIC JOURNAL VOLUME 4 ISSUE 10 OCTOBER 2025 ISSN: 2181-3337 | SCIENTISTS.UZ 16 cm (6.2%), chest width by 5.0 cm (10.9%), chest depth by 13.0 cm (16.5%), and oblique body length by 35.2 cm (19.1%). In the improver bulls group, these increases were respectively 11.2 cm (7.5%), 5.0 cm (3.2%), 6.6 cm (16.0%), 10.6 cm (14.5%), and 11.6 cm (6.4%). The bulls differ from each other in these indicators. Differences are also observed in growth by height, width, depth, and body length. Among the leader improver bulls, Uris, Uriel, Ursinus, and Ulfilas had advantages in most body measurements. The range of body measurements in this group was: withers height 144–152 cm, hip height 150–161 cm, chest width 44–52 cm, chest depth 74–82 cm, chest girth 198–204 cm, oblique body length 170–192 cm, hip width 38–40 cm, and cannon bone girth 22–28 cm. At 37–40 months of age, individual variation in body measurements was observed. The 38-month-old bull Uris was superior to his group in all body measurements. His withers height was 168 cm, hip height 167 cm, chest width 49 cm, chest depth 92 cm, and oblique body length 213 cm. In the group of improver bulls, the animals also differed individually by their indicators. The bull named Unit was superior, and at 42 months of age his withers height was 164 cm, hip height 169 cm, chest width 51 cm, chest depth 88 cm, and oblique body length 204 cm. Similarly, the 40-month-old bull Ursinus was characterized by high indicators. Within this group, the bulls differed relatively from each other in body measurements when evaluated individually. In 37–40month-old bulls, the ranges of body measurements were: withers height 150–165 cm, hip height 155–164 cm, chest width 46–51 cm, chest depth 78–91 cm, and oblique body length 184–218 cm. The body of the bulls is tall and long, typical of the Holstein breed, with a deep chest, though slightly narrower, which is characteristic of the dairy type. Their legs are set high, and the cannon bone girth reflects their bone development. In the control groups, both Black-and-White and White bulls were also present. The Red-and-White Holstein bulls are not inferior to the Black-and-White Holstein bulls in body size. On average, in 2018–2020, the leader improver bulls at 38 months of age (range 37–41 months) had withers height of 146–154 cm, hip height 154–158 cm, chest width 56–59 cm, chest depth 77–80 cm, and oblique body length 172–200 cm. The improver bulls at an average of 39 months had corresponding measurements of 144–153 cm, 155–159 cm, 59–61 cm, 78–83 cm, and 174–212 cm. During 2018–2020, in the group of leader improver bulls, the 38-month-old bull Untamo stood out in individual evaluation. His withers height was 155–165 cm, hip height 161–166 cm, chest width 44–54 cm, chest depth 79–87 cm, and oblique body length 176–203 cm. Among the Black-and-White Holstein bulls, no animals were observed to match the size of this bull. The growth in body volume of the Red-and-White Holstein bulls was similar to that of the Black-andWhite Holsteins. Within the groups, the bulls differed from each other in these indicators. Variations were observed in the growth rate of different body parts. From the group of Angler bulls, 3 were sent to the Bukhara and Karakalpakstan branches, leaving 7 bulls in the group whose body measurements were taken. The control bulls displayed traits characteristic of dairy-type breeds. In the group of leader improver bulls at 39 months of age, average body measurements were: withers height 152–163 cm, hip height 155–162 cm, chest width 41–52 cm, chest depth 79– 87 cm, and oblique body length 174–197 cm. In the improver group at an average of 37.5 months, the respective measurements were: 143–152 cm, 153–166 cm, 42–51 cm, 74–85 cm, and 174–201 cm. When compared individually, the bull Trouba in the leader improver group and the bull Ubah in the improver group were superior in terms of body volume. These bulls are characterized by their breed, body conformation (exterior), and constitution. Their bodies are strong and broad, SCIENCE AND INNOVATION INTERNATIONAL SCIENTIFIC JOURNAL VOLUME 4 ISSUE 10 OCTOBER 2025 ISSN: 2181-3337 | SCIENTISTS.UZ 17 with legs and hooves marked by durability. The Angler breed, being of the dairy type, is considered average in terms of body development and live weight gain. During the adaptation period of 2018– 2020, the bulls differed in terms of changes in body volume. Bulls with higher exterior traits were evaluated more favorably. Measurements of different body parts varied to different extents over time. Brown Swiss bulls of dual-purpose direction. Their body conformation and color are typical of the Brown Swiss breed. On average, at 38 months of age, the leader improver bulls were characterized by the following body measurements: withers height 145–156 cm, hip height 151– 154 cm, chest width 37–46 cm, chest depth 64–79 cm, and oblique body length 175–199 cm. In the improver group at 42 months of age, these indicators were, respectively: 141–151 cm, 149– 157 cm, 42–51 cm, 70–79 cm, and 172–200 cm. When comparing bulls individually, the highest measurements were characteristic of the bulls named Antenna and Jessimo, which were superior within their group. Their bodies are compact and well-built, broad, with strong bones and hooves. In these bulls, the dairy type is more strongly expressed. Their body conformation volume is comparable to that of Angler bulls; although their bodies are somewhat taller, differences in width and length measurements are minor. During the adaptation period of 2018–2020, the development of body parts in the group of bulls was typical of the breed. Within the group, the bulls differed relatively from each other in body volume growth, and among them, superior bulls were identified. Development of the exterior of the dairy-meat type was observed. Fleckvieh Simmental breed is dual-purpose, with a tall, long, broad, and deep body. This can be observed in their body measurements. In the groups of leader improver and improver bulls at 37 and 41.5 months of age, the measurements were as follows: withers height 144–153 and 146–154 cm, hip height 155–159 and 154–158 cm, chest width 59– 61 and 56–59 cm, chest depth 78–83 and 77–80 cm, and oblique body length 174–212 and 172– 200 cm. Conclusion From this breed group, 2 bulls (Segoh and Otello) were sent to the Bukhara and Karakalpakstan branches, leaving 4 bulls under control. Within the groups, the bulls named Hubra and Epigraph had relatively superior measurements. Their body dimensions were somewhat higher: tall, broad, deep, and elongated. In terms of body width and depth, Fleckvieh Simmental bulls were superior to Holsteins. The fact that the Red-and-White Holstein breed was once crossbred into the Light-Brown Simmental cattle is reflected in their body conformation and coloration. Compared to the Brown Swiss breed, this dual-purpose breed is considerably larger. The growth of body volume in Fleckvieh Simmental bulls was intensive. During 2018–2020, the growth rate changed according to the breed’s specific characteristics. Some bulls achieved superior indicators. REFERENCES 1. Decree of the President of the Republic of Uzbekistan No. PQ-4254 of March 28, 2019, “On the organization of the activities of the State Committee for Veterinary Medicine and Livestock Development of the Republic of Uzbekistan.” 2. 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