The article presents the number of sheep and sheep wool production in the world, which characterize the current state and trends in the development of sheep breeding in the world.

In recent years, more and more attention has been paid to food quality issues. Consumers are becoming demanding about the composition and properties of food products, and manufacturers and researchers are actively working to develop new methods of product quality control and improvement. One of the key factors affecting the quality of cured products is the calpastatin gene (CAST). This gene encodes a protein that plays the role of an inhibitor of milk protein fermentation. This means that with the activity of this gene, meat products will have a softer texture and better preservation during the drying process and acquire their delicate taste. Research shows that the expression of the CAST gene can be changed both by natural mutations and under the influence of various environmental factors. Understanding the mechanisms of regulation of this gene can help improve the quality of dried products and optimize their production processes. However, the question of how exactly the CAST gene affects the qualitative composition of dried products has not been fully studied. Some studies indicate that an increase in the expression of this gene may lead to an increase in the content of beneficial amino acids and essential fatty acids in dried products. Other studies suggest the possibility of using techniques to modify the expression of the CAST gene to create new types of dried products with specific properties. In this article, we will consider the results of our own scientific research on the effect of the calpastatin gene on the quality of dried products. The purpose of these studies is to conduct a comparative analysis of the quality of dried products obtained from animals of different genotypes according to the gene of meat productivity – calpastatin (CAST). The polymorphism of the calpastatin gene was analyzed by PCR-PDRF. The polymorphism of this gene is represented by two alleles – M and N. The frequency of occurrence of CASTNN and CASTMN genotypes in crossbred sheep (Russian meat merino×charolais, Russian meat merino×ile-de-France) was 33.0 and 20.0 0%, in sheep (Russian meat merino × Russian meat merino) – 20.0%. A further stage of our work was to conduct research on the quality of products obtained from purebred sheep carriers of different genotypes, which were evaluated by indicators of nutritional value (physico-chemical; amino acid composition). The analysis of the obtained data revealed a higher content of amino acids necessary for a living organism in the product obtained from animals with selectively important alleles in a homozygous state. The application of the results reflected in the article will allow for the in vivo selection of animals with high quality meat products based on an assessment of the allelic state of the cal- pastatin gene (CAST).

The article presents the results of complex studies of some economic and biological characteristics of Nubian goats. It has been established that Nubian goats combine large size with high milk productivity, are characterized by multiple births, and have unique exterior characteristics.

The article presents the results of studying the weight growth of sheep (group I), boulders (group II), and yarrows (group III) of the Romanov breed sheep. It was found that due to sexual dimorphism, the rams were distinguished by a higher live weight and its increase, the yarrows had minimal indicators, and the boulders occupied an intermediate position.

In the article, the authors consider the impact on the productive performance of Romanov sheep of the use of Glauconite and Biohumer feed additives in the diet. It was found that the meat quality of the experimental animal groups was higher in all age groups in comparison with the counterparts of the control group, which proves the economic efficiency of us- ing feed additives in the sheep feeding diet.

The results of computer modeling of fabric air permeability (B, dm³/(m²·C)) considering the processes of sorption of water vapor by wool fibers are presented. It is shown that its most pronounced changes are observed at relative air humidity from 0% to 20% and from 60% to 100%.

The article presents the results of scientific research on the study of the interrelationships of the shapes and sizes of curls with the length of the wool fibers of Kar- akul lambs of sur color in the conditions of the arid breeding zone. It is established that the revealed interrelationships of these signs contribute to the elimination of some problems of breeding Karakul sheep in different ecological zones (desert, gypsum and arid) breeding in terms of improving the quality of karakul.

The article presents the results of using flax-seeds of the Kinel’skiy 2000 variety in the diets of lactating goats of the Zaanen breed. The inclusion of flaxseeds in the composition of the compound feed concentrate in the amount of 15% by weight ensures an increase in milk productivity and the economic efficiency of goat milk production.

The dynamics of body weight of purebred and crossbred southern meat breed rams from 4 to 6 and from 6 to 8.5 months of age are shown. It was found that crossbred animals with ½ of the Ile de France blood consumed more feed and digested the nutrients in the diet better; they had lower expenditure of dry matter, metabolic energy and protein per 1 kg of body weight gain.

The article evaluates the feeding of different amounts of organic selenium to growing Romanov sheep from 3 to 6 months of age. It was found that the basic diets of feeding young sheep are not sufficient in terms of selenium content, which reduces the digestibility of nutrients in diets and body weight dynamics. Optimization of the selenium nutrition of growing sheep increased the digestibility of all the main feed nutrients and the dynamics of daily gains, as well as reduced the cost of metabolic energy and crude protein per 1 kg of animal body weight gain.

The article describes the physique and exterior of Romanov rams. In five breeding farms, an assessment of the exterior was carried out by measuring body articles: height at the withers and sacrum, oblique length of the trunk, chest width behind the shoulder blades, and pastern girth. 163 Romanov sheep were measured. Physique indices are calculated based on measurements.