Age-related changes in the skin structure and wool quality in sheep of Artlukh merino breed

Abstract

Increasing the production of wool and improving its quality characteristics for a number of years remains an urgent issue in breeding work with fine-fleeced sheep. In this regard the main purpose of the research was a comparative assessment of the age dynamics of the main properties of wool and the histostructure of the skin of the young ewes of Artlukh merino breed in the farm AC “Krasny Oktyabr” in the Kazbekov district in the Republic of Dagestan. It has been found that at the age of one year in the experemental young ewes the epidermis increased by 21,2 %, the pilar and reticular layers by 2,9 and 12,8 %, respectively, and the total skin thickness by 6,1 %. The biggest increase in skin thickness was due to the epidermis and the reticular layer as the number of fat cells increased. The width of the secretory parts of the sweat glands increased by 7,1 %, the sebaceous glands by 9,6 %, in this regard the amount of wool fat increased by 7,6 %. The studied parameters of the skin histostructure revealed that the number of hair follicles decreased by 6,8 % with age. This is due to the increase in the area of the skin due to the growth of the animal. The change in the basic properties of wool was as follows: the diameter of wool fibers increased by 5,6 %, the strength of wool decreased by 13,8 %. Comprehensive studies allowed us to recommend testing the main properties of wool and indicators of the histostructure of the skin of experimental animals when improving existing breeds and breeding new breeds and lines of sheep. Histological studies of the skin should be carried out at the age of 4,5 months, and the most objective indicators are the ratio of secondary and primary follicles, this will allow for early selection of lambs by wool density.