Romanov Sheep Research Articles

Anti-Müllerian hormone as a promising novel biomarker for litter size in Romanov sheep.

Anti-Müllerian hormone (AMH) is a hormone produced by growing preantral and antral follicles of the ovary. AMH is accepted as an important biomarker for fertility and superovulation parameters in livestock species. This study aimed to evaluate changes in serum AMH level in the oestrous cycle, repeatability of AMH, the effect of age on serum AMH level and the effects of AMH on litter size in Romanov sheep. In the study, a total of 36 Romanov sheep were used as animal material. First blood samples (0th day) were collected from 36 ewes to evaluate AMH and progesterone levels. Second blood samples were collected randomly from 20 ewes 9 days after first sampling to compare AMH levels at two different periods of the oestrous cycle in Romanov ewes. The ewes were categorized into three groups as low, medium and high AMH based on their first AMH levels. Results indicated that serum AMH level did not change during the oestrous and dioestrous phases of the oestrous cycle and two random time points of the oestrous cycle (p > .05). Pearson correlation analysis revealed that there is a high (r = .95) and significant (p < .001) correlation between AMH levels at the 0th (AMH-1) and 9th (AMH-2) days. The effect of AMH level on litter size was found to be significant. Litter size was significantly higher in the high AMH group than in the low AMH group (p < .05). In addition, the age of ewes did not affect serum AMH levels (p > .05). ROC analysis indicates that AMH cut-off value >320 pg/mL with 70% sensitivity and 100% specificity can be used for litter size in Romanov ewes. In conclusion, AMH is highly repeatable and its serum AMH level did not change during the oestrous cycle in Romanov sheep. In addition, AMH affects litter size and can be reliably used as a marker for litter size in Romanov sheep.

Investigation of Adiponectin, Leptin and Ghrelin Levels and Evaluation of Metabolic Profiles in the Periparturient Period in Romanov Sheep

The periparturient period is very important especially in terms of pregnancy-related herd-based diseases. In this period, especially for early diagnosis of subclinical diseases, a metabolic profile test is used. In the periparturient period, important changes occur in adipose tissue. Blood samples were collected from 16 Romanov sheep in the periparturient in serum tubes on the 21st, 14th, 7th, and postpartum days, and 7th, 14th, and 21st days after delivery. Metabolic profile and Adiponectin, Leptin and Ghrelin parameters evaluated from the blood samples. In the periparturient period, ELISA analyzes of TNF-α were performed for inflammatory evaluation. As a result of the analyzes, Prenatal increase in NEFA concentrations, postpartum decrease in cholesterol concentrations, postpartum increase and decrease in AST concentrations, postpartum increase in GGT concentrations, prenatal and postnatal increases in total protein concentrations, postpartum increase in BUN and creatinine concentrations, postpartum decrease in magnesium concentrations, Prenatal increase in adiponectin concentrations and postpartum decrease, postpartum decrease in leptin concentrations and prenatal increase in ghrelin concentrations occurred. With the results obtained, it was concluded that the evaluation of metabolic profile and adipose tissue is important in the diagnosis of diseases in the periparturient period.

Identification of candidate genes associated with growth and development of sheep from a crossbred population using genome-wide association studies

The article presents the results of a search for genome-wide associations with phenotypic traits characterizing the growth and development of sheep from a crossbred population obtained from crossing Romanov sheep and F1 hybrid rams (Romanov sheep x Katahdin). The phenotype database included ten body measurements (withers height, sacral height, back height, chest depth, chest width, ischial tuberosity width, body length, oblique body length, chest girth, pastern girth) recorded at the age of 6 days, 3, 6 and 9 months. Genotyping of sheep was carried out using high-density DNA chips containing about 600,000 SNP markers. Genome-wide association studies (GWAS) were performed using regression analysis in the STATISTICA 10 program. The search for candidate genes localized in the SNP region was performed using Ensembl genome browser 110. There was carried out an analysis of the matches of the identified SNPs with known quantitative trait loci (QTLs) described in the Sheep Quantitative Trait Locus Database. There were found SNPs that were significantly associated with the studied phenotypic traits overlapped with the QTLs, among which the most common categories were “Body weight (slaughter)”, “Muscle weight in carcass”, “Body weight (live)” and “Bone weight in carcass”. There has been established that SNPs significantly associated with exterior traits were localized within or in the immediate vicinity of 64 genes. There were found potential candidates regulating the growth of muscle (FOXO3, PRKAG3, MYOZ2, and ANKRD1) and cartilage tissues FGF12) and involved in metabolic processes, which were critical for the growth of lambs (CLDN, ALB, and MRC1). Along with the known in sheep functional candidates (CAST and SCD5) , there were identified genes that were not previously described in sheep, but regulated growth and development processes in other livestock species including genes RAB28, PRKAG3 and FOXO3. The identified SNPs can be recommended for inclusion in marker-guided selection programs in sheep breeding.

Morphometric analysis of the skulls of a ram and ewe Romanov sheep (Ovis aries) with 3D modelling.

With the development of technology, 2D images have left their place for 3D models. The 3D modelling technique is widely used in plastic surgery, orthopaedic surgery, neurosurgery, traumatology, dentistry and medical education. The skull is important in terms of containing the starting parts of systems with vital functions. The aim of the study is to reveal the difference between male and female and other species by 3D (three-dimensional) modelling and craniometric measurements of Romanov heads. In our study, skulls of Romanov sheep (10 females and 10 males) older than 1-year-old were used. The heads of Romanov sheep were scanned with computed tomography and modelled in 3D. In the study, it was determined that there was a statistically significant difference between male and female sheep in terms of the largest nose length, facial width, molar row length, viscerocranium length, and foramen magnum height parameters (p < 0.05). It was determined that the greatest width of the foramen magnum measurement parameter and the skull index showed statistically significant differences between the genders at the p < 0.01 level. No statistically significant difference was found in other measurements (p > 0.05). The data obtained as a result of the study will help in the racial discrimination and classification of bones obtained from zoo archaeological excavations.

Characteristic of allele pool of sheep of the southern meat breed using microsatellite markers

Purpose: to characterize the allele pool of sheep of the southern beef breed using microsatellites.Materials and methods. The biomaterial was ear’s plucks from 80 sheep of the southern meat breed, selected from the Ladozhsky Breeding Plant. 20 East Friesian sheep, 33 Dorset sheep and 63 Romanov sheep were used for comparison. Nine microsatellite loci (INRA005, SPS113, INRA23, MAF65, McM527, OarCP49, HSC, OarAE129, MAF214) were selected as DNA markers. Microsatellite variability was analyzed using the ABI3130x1 Genetic Analyzer. The results were processed in the GenAIEx 6.503 program, with the help of which the main indicators characterizing the state of the allele pool and genetic diversity were calculated.Results. Analysis of the population genetic parameters of sheep of the southern meat breed showed that the average number of alleles per locus (Na) and the effective number of alleles per locus (Ne) exceed the sample average by 1,72 and 0,58 alleles, respectively. The expected heterozygosity (He) was 0,766, while the observed heterozygosity (Ho) was 0,741. The coefficient of inbreeding (Fis) was 0,03. The analysis of the principal components, carried out for the studied breeds in the planes of the first and third principal components, did not fundamentally change the nature of the spatial clustering of the studied groups of sheep. Analysis of the principal coordinates, performed on the basis of calculation of pairwise Fst values, showed that the southern meat breed is located in the upper left quadrant and is isolated from other breeds. The values of the Fst indicator indicate that there is moderate genetic differentiation between the southern meat and dorset breeds (Fst=0,116), and significant genetic differentiation between the southern meat and romanov breeds (Fst=0,161).Conclusion. An analysis of the population genetic parameters of sheep of the southern meat breed, in comparison with the east friesian, dorset and romanov breeds, showed that, in general, in terms of the total number of alleles per locus and the number of effective alleles per locus, it is characterized by a high level of genetic diversity. The presence of a tendency towards a deficiency of heterozygotes is probably explained by the limited population, represented by the only relict gene pool in Russia.

Использование корма и продуктивность чистопородного и помесного молодняка овец романовской породы

The material on the study of the digestibility of nutrients in the diets of purebred and crossbred Romanov sheep from birth to 9 months of age is presented. It was found that according to these indicators, the Ile de France × Romanov sheep had the best results compared with purebred Romanov sheep in the same age periods

ДНК-диагностика генов многоплодия у романовских овец и классификация пород по мутациям плодовитости

The article presents the results of studies on the carriage of mutations responsible for multiple fertility in Romanov sheep. The data on the occurrence of genotypes, normal and mutant alleles in BMP-15 and MPR1B loci are given. Of the five previously identified mutations in the BMP-15 locus and the generated new DNA sites (FecXG [391 (C-T)], FecXH 544 (C-T), FecXI [579 (T-A)], FecXL [635 (G-A)], FecXB [773 (G-T)]), polymorphism was detected only in the FecXG locus. The results obtained at the FecXG locus were presented as two genotypes: homozygote from normal (WW) and heterozygote (WM), involving normal (W) and mutant (M) alleles. The remaining four loci were homozygous for the wild-type or normal allele (W). The spectrum of observed genotypes at the BMP-15 locus was as follows: WW (n=35), WM (n=13), mutant genotype (MM) carriers were absent. The frequency of occurrence of the normal W allele was high (0,8646), whereas the mutant allele was small (0,1354). No genetic equilibrium disorder was found at the FecXG locus ( χ2 =1,18; df=1; p&gt;0,05). No polymorphism was found for the GDF9 gene in the Romanov sheep breeds studied. Whereas, at the BMPR1B locus (FecB) it is present as homozygotes for the normal (W) allele and heterozygotes (WM) for the normal and mutant alleles. The occurrence by genotype with normal alleles (WW=34) was maximum, while the heterozygous genotype (WM=14) was 2,4 times less. Based on the obtained data, as well as a number of literature sources, we propose a classification of sheep breeds according to the occurrence of multiple mutations.

Production, reproduction, and some adaptation characteristics of Romanov sheep raised under humid temperate climate.

This study aimed to determine the fertility and growth traits, viability, and body measurements of the Romanov sheep under breeder conditions in the humid region of Turkey. The animal material of the research consisted of sheep imported from Ukraine in 2019. In the study, there are two farms with 31 and 44 ewes in the first year and three farms with 45, 34, and 32 ewes in the second year. The reproductive performances of 186 sheep and lambs in three different farms were examined, and nine rams, one ram per 20 sheep, were used for mating. Two-year (2020 and 2021) data on the reproductive performance of pure Romanov ewes, survivability in ewes and lambs, and development characteristics in lambs were used in the present study. The conceived rate (88.17%), fecundity at birth (1.42) and at weaning (1.29), litter size at birth (1.76) and weaning (1.56), single (50.98%), twin (41.83%), and triplet birth rate (6.54%), and abortion rate (6.71%) were determined for 2 years average. Birth and weaning weights of lambs were affected by sex and birth type (p < 0.01). The Romanov sheep and their lambs did not satisfy the breeder regarding reproductive performance and lamb development.

Эндоскопически ассистированная биопсия вомероназального органа овцы

The article describes the original technique of conducting a biopsy of the vomeronasal organ (VNO) in sheep during rhinoscopy, and also presents its characteristic structural features, namely the morphology of the shell structure, angioarchitectonics and nervous support. The research was carried out on the basis of the Departments of Anatomy and Histology of Animals named after Professor A.F. Klimov and Veterinary Surgery of the Moscow State Academy of Veterinary Medicine and Biotechnology – MBA named after K. I. Scryabin. The work was carried out on clinically healthy Romanov sheep at the age of 1 year, who reached sexual and physiological maturity, biopsy was performed under anesthesia. Based on the method of light microscopy, it was found that the sheep's VNU is located in the ventral nasal passage bilaterally from the cartilaginous nasal septum, and is protected from the outside by a layer of its own hyaline cartilage, which is covered with the mucous membrane of the nasal cavity. The structure of the EIT contains the lateral (olfactory) and medial (sensorineural) walls, between which its own cavity is located. A large number of groups of serous glands located around the central vein, as well as cavernous bodies, providing regulation of the lumen of the internal cavity of the VNU, were found in the submucosal base of the VNU. Innervation of the vomeronasal organ is carried out concentrically due to the topographic features of the course and branching of the trunks of the vomeronasal nerve.

Влияние генотипа баранчиков на минеральный обмен

The article presents the results of studying the features of mineral metabolism in the body of purebred Romanov sheep (group I), its crossbreeds of the first generation with Edilbai - ½ Romanov × ½ Edilbai (group II) and the second generation - ¼ Romanov × ¾ Edilbai (group III). It was found that due to the effect of crossing, crossbred sheep of groups II and III outperformed purebred peers of group I in terms of calcium and phosphorus intake with feed by 3.93‑20.39% and 12.23‑14.63%, their deposition in the body - by 15.30‑25.07% and 16.20‑17.88%, the value of the utilization factor from the accepted - by 0.38‑1.92% and 1.56‑4.57%.

Determination of Morphometric Characteristics of Glandula Lacrimalis in Siirt-Colored Mohair Goat (Capra hircus) and Romanov Sheep (Ovis aries) by Computed Tomography Images

This study was carried out to determine the morphometric characteristics of the glandula lacrimalis in Siirt-colored Mohair goats and Romanov sheep using computed tomography (CT) images and to analyze the differences between sexes and species. CT images of the glandula lacrimalis of ten male and ten female Siirt-colored Mohair goats and ten male and ten female Romanov sheep were used in the study. Morphometric measurements were taken from transversal, sagittal and dorsal sections of the right and left glandula lacrimalis in both male and female animals. Morphometric values were statistically analyzed. As a result of the study, there was no sex-related difference in morphometric measurement parameters in the Romanov sheep breed. In Siirt-colored mohair goats, statistical differences were observed in terms of TY and DU values depending on sex. Statistical similarities and differences were determined between the two species in terms of morphometric parameters. In conclusion, statistical differences in the measurement parameters of glandula lacrimalis of adult Siirt-colored Mohair goats and Romanov sheep between sexes and species were determined using computed tomography images.

Genetic factors that determine the formation of reproductive qualities of Romanov sheep

Genetic factors that determine the formation of reproductive qualities of Romanov sheep

Radiological examination of the skull of Siirt-coloured mohair goat, Romanov and Hamdani sheep.

The skull is a vitally important complex structure formed by the combination of many bones. Craniometric studies are performed with various imaging methods to determine morphometric characteristics in animals. One of these methods is radiography. In our study, skulls of 14 Hamdani sheep, 20 Siirt-coloured mohair goats and 20 Romanov sheep breeds were used. Skull sections were taken with a computed tomography device and saved in DICOM format. Nine separate measurements and six index calculations were made from the images. In the study, firstly, the gender difference was ignored and the similarities and differences between the species were recorded. In addition, gender differences were determined statistically, without making any distinction between species. Correlation analysis was performed to compare measurement parameters between animal species. As a result of the study, the highest skull length (SL) and cranial length (CL) values were determined in the Siirt-coloured mohair goat. It was determined that the difference between Romanov sheep and Siirt-coloured mohair goat in CL parameter was not statistically significant (p > 0.05). In addition, a statistically significant difference was observed between the Romanov sheep breed and the Hamdani sheep breed (p < 0.01). The external length of the cranium (ELC) measurement parameter was found to have a statistically significant difference in three animals (p < 0.01). According to the results of the correlation analysis, the highest correlation value was determined between cranial width (CW) and CL parameters (r = 0.920). When the species difference was ignored, and the statistical difference of the internal height of the cranium (IHC) parameter was found to be significant between female and male animals (p < 0.05). In addition, it was determined that SL, CW and internal cranium index (ICI) parameters had a significant difference depending on sex (p < 0.01). It is foreseen that the obtained data can be used in sciences such as zoo archaeology, anatomy, surgery and forensic medicine.

Haematological parameters and production characteristics of novel Romanov × Hissar crossbred sheep adapted to European steppe climate

The study presented some haematological parameters and production characteristics of novel crossbred Romanov × Hissar and purebred Romanov sheep. A number of biochemical and haematological tests were performed to assess the level of adaptation of F1 crossbred progeny to local rearing conditions and evaluate its potential economic benefits for industrial production. The newly created crossbreed demonstrated significant increase in carcass production characteristics, with pre-slaughter weight increased by 29.2%, slaughter weight - by 39.7%, cooled carcass weight - by 40.5% and total yield ‒ by 8.2% compared to Romanov purebreed. The meat quality was also increased: fat content remained at the same level (6.6-6.8%), carcasses of F1 crossbreed lambs had higher relative weight of muscle tissue (78.8% vs. 73.3%), increased content of the 1st grade meat (94.6% vs. 91.6%), and higher caloric value of the meat (by 8.7%) compared to the parent purebreeds. An increased erythrocyte (by 3.1%) and leukocyte (by 6.45%) count was noted in the F1 rams. Haemoglobin level in F1 lambs was increased by 4.2%. Protein metabolism parameters were improved: blood serum total protein level ‒ by 11.2%, albumin ‒ by 11.4%, globulin ‒ by 10.4%, suggesting intensified protein metabolism in F1 lambs; this was also evidenced by the increased activities of aspartate transaminase (by 3.9%) and alanine transaminase (by 16.6%) in F1 lambs over Romanov purebred animals. Blood serum of crossbred lambs had higher bactericidal (by 1.92%), lysozyme (by 3.53%), and phagocytic activity. The increased haematological and biochemical parameters and enhanced antibacterial properties of serum indicate the enhanced metabolic activity in F1 crossbreed sheep and underlay the improved meat production parameters. Obtained results demonstrate increased adaptation of the novel crossbred to industrial rearing conditions and local microclimate of steppe zone of Ukraine, which is undergoing gradual aridization.

Polymorphism of the BMP-15 locus in Romanov sheep in Western Siberia

Currently, selective selection takes into account gene polymorphisms associated not only with multiple pregnancies (growth differentiation factor 9 (GDF-9), bone morphogenetic protein receptor (BMPR-IB), etc.) but also with milk parameters (β-lactoglobulin (β-lg), αS1-casein) and meat (myostatin (MSTN), calpastatin (CAST), calpain (CAPN1)) productivity. Thus, genes associated with the transforming growth factor began to be monitored to improve reproductive performance in sheep breeding: BMP-15, GDF-9, and BMPR-IB. Genetic markers related to animal reproduction are exciting, with several productive indicators and other evaluation criteria that have not been previously studied. Work on the relationship of animal gene inheritance with biochemical, haematological, environmental and zootechnical indicators is particularly relevant. In this paper, we consider genotypic variability in Romanov sheep for the BMP-15 gene locus, which belongs to the genes of the β-growth factor family. The distribution of genotypes in sheep of the Romanov breed in the conditions of Western Siberia was as follows: for ewes, the frequencies of genotypes WW–25%, WM–75, and MM–0%; for sheep - 0, 80 and 20%, respectively. All three genotypes (WW, WM, and MM) were identified in the studied sheep. The results differ from the data obtained in several other works on foreign sheep breeds (short-tailed sheep Khan, Awassi, Barki, Ossimi, Rahmani, etc.). It is interesting to study the BMP-15 locus further to establish its associations with biochemical and haematological parameters and the hormonal status of sheep.

Age-related changes in the pharmacokinetics of meloxicam after intravenous administration in sheep.

The pharmacokinetics of meloxicam was studied in 1-, 6-, and 12-month-old sheep following a single intravenous (i.v.) dose of 1 mg/kg. The experiments were carried out when the Romanov sheep were 1 month old (7.93 ± 0.91 kg), 6 months old (27.47 ± 4.91 kg), and 12 months old (37.10 ± 3.64 kg). Meloxicam concentration in plasma was determined by high-performance liquid chromatography and the data collected were evaluated by non-compartmental kinetic analysis. Meloxicam was detected in the plasma up to 72 h following i.v. administration in all age groups. The volume of distribution at steady state (Vdss ) and total body clearance (ClT ) were significantly higher in 1-month-old (304.87 mL/kg and 16.57 mL/h/kg) than in 12-month-old (193.43 mL/kg and 10.50 mL/h/kg) sheep. The area under the concentration-time curve from 0 to 72 h value of meloxicam was lower in 1-month-old (58.51 h*μg/mL) compared to 12-month-old (92.59 h*μg/mL) sheep. There was no difference in t1/2ʎz value in different age groups. The body extraction ratio values for meloxicam ranged from 0.0186 to 0.0719 after i.v. administration in all age groups. Meloxicam showed an increase in plasma concentration and a decrease in Vdss and ClT in 12-month-old compared to 1-month-old sheep. Compared to 1-month-old and 12-month-old sheep, there was no difference in these parameters in 6-month-old sheep. Because the age of sheep has an influence on the pharmacokinetics of meloxicam, dosage apparently may need to be adjusted for age.

Morphometric analysis of the mandible of ram and ewe romanov sheep (Ovis aries) with 3D modelling: A CT study.

2D images view hardly measurement points due to the overlap of anatomical features. This challenge is overcome by 3D modelling. In particular, images obtained by computed tomography are converted into 3D models through certain software. In sheep breeds with high polymorphism, some changes have occurred in their morphology due to both environmental and genetic factors. In this context, determining the osteometric measurements of sheep and revealing breed-specific characteristics provide very important data for forensic, zooarchaeological, and developmental sciences. Mandibular reconstruction measurements are used to reveal differences between species and between sexes and for treatment and surgery in many fields of medicine. In the present study, morphometric characteristics were determined by 3D modelling from computed tomography images obtained from mandibles of Romanov ram and ewe. For this purpose, mandibles of 16 Romanov sheep (eight females and eight males) were used. They were scanned using a 64-detector MDCT device at 80 kV, 200 MA, 639 mGY, and 0.625 mm slice thickness. CT scans were recorded in DICOM format. Reconstructions of the images were made using a special software program. Volume and surface area measurements were made with 22 osteometric parameters of the mandible. GOC-ID had a statistically significant positive correlation with GOC-ID, PC-ID, GOC-MTR, GOC-PTW, GOC-FMN, PMU, MDU, PDU, DU, GOV-PC, GOV-IMD, MTR-MH, MO-MH, FMN- ID, BM, MG, and CG (p < 0.01). GOC-ID had a statistically significant correlation with MTR-ID, GOV-CR, PTW-MH and SI (p < 0.05). When the CR-PC measurement point was examined, it was observed that it had no statistically significant correlation with all measurement points (p > 0.05). As a result of the measurement, it was found that the volume and surface areas were higher in rams than in ewes. The morphometric data obtained would be a reference income in the fields of zoo-archaeology, anatomy, forensics, anaesthesia, surgery, and treatment.

The effect of β-carotene and vitamin E on metabolic profiles in nutritionally flushed sheep

This study aimed to investigate the effects of β-carotene and vitamin E on serum biochemistry, body condition score, and the number of offspring in sheep during the flushing period. To this purpose, forty Romanov sheep 45 (±1 kg) body weight and 3 years of age were allocated into one of four experimental treatments with 10 replicates for 6 weeks: the control (only flushing), and three treatment groups injected intramuscularly with 1, 2, and 4 ml β-carotene + vitamin E in the third week of flushing, respectively. The 4-ml treatment of β-carotene + vitamin E evidently increased the follicle- stimulating hormone level. The 2-ml treatment of β-carotene + vitamin E increased the triglyceride concentration in the serum. Body condition score, offspring number, and biochemical parameters (cholesterol, phosphorus, calcium, magnesium, aspartate aminotransferase, beta hydroxyl butyric acid, total protein, and glucose) were not affected by any levels of β-carotene + vitamin E administration. These findings indicate the positive role of β-carotene + vitamin E administration on pregnancy rate and some blood parameters during flushing.

The Significance of a Multilocus Analysis for Assessing the Biodiversity of the Romanov Sheep Breed in a Comparative Aspect.

The Romanov breed was evaluated using immunological and genetic markers. The seven blood group systems were characterized with a greater accuracy than in previous works on sheep in the Russian Federation, and were compared to eight ruminant species. Unlike other breeds, Romanov sheep shows a higher frequency of HBA than HBB alleles. There are 3-4 genotypes at the transferrin locus whereas in other breeds 6-11 genotypes have been found. At the albumin locus, the majority of the identified genotypes were heterozygotes, unlike in the other breeds studied. In the prealbumin locus, the Romanov breed was the only one where all the genotypes were heterozygous. We speculate that polymorphism at two loci (BMP-15 and BMPR1B) could effect on the high ovulation rates of Romanov sheep. Based on different genetic markers, the prevalence of heterozygotes in the Romanov sheep could determine their higher viability. A cluster analysis showed the close proximity of 12 populations of the Romanov breed, as the breeding stock come from the Yaroslavl region.

Experimental substantiation of the use of platelet-rich plasma in combination with microfracturing in the treatment of local osteochondral defects of the hyaline cartilage of the knee joint: non-randomized controlled study

BACKGROUND: Dissecting osteochondritis of the knee joint is one of the common diseases accompanied by damage to the articular cartilage. Existing conservative and surgical methods of treating osteochondral defects of the hyaline cartilage do not give full satisfactory results of restorative treatment.&#x0D; OBJECTIVE: This study aimed to evaluate the effectiveness of the combined method proposed for the treatment of full-layer osteochondral defects of the knee joint.&#x0D; MATERIALS AND METHODS: The experiment was conducted on 27 Romanov sheep aged 5 months to 1 year and weighing 2035 kg. All animals were conditionally divided into three experimental groups of nine animals, each of which intraoperatively modeled the osteochondral defect of the medial condyle of both hind limbs. Moreover, the left knee joint was assigned to the experimental group, whereas the right knee joint was assigned to the control group. Thus, in first experimental group, microfracturing was performed on the left knee joint in addition to the osteochondral defect of the femoral condyle; in the second experimental groups, microfracturing and platelet-rich plasma (PRP) administration; in the third experimental group, microfracturing, and PRP administration after 3 weeks. From each group, three animals were sacrificed at 1, 3, and 6 months. Results were evaluated by macro- and microscopic examination.&#x0D; RESULTS: In the first experimental group, cartilage regeneration was slow. In the second experimental group using PRP, more intensive regeneration of cartilage tissue occurred. In the third experimental group, cartilage tissue regeneration occurred more intensively.&#x0D; CONCLUSION: During the experiment, in which several methods of treating osteochondral defects of the knee joint were employed, the most effective was the combined method of microfracturization and PRP administration 3 weeks after surgery.