COMPARATIVE HISTOLOGICAL EVALUATION OF THE SKIN IN SHEEP OF THE FINE-FLEECE BREEDS IN THE STAVROPOL REGION

Abstract

The article presents a comparative description of the skin histological studies in fine-wool sheep breeds of the Stavropol region. The skin and wool coat of sheep are a single whole, they protect the internal organs from mechanical damage and perform a protective function, are involved in thermoregulation and metabolism. According to the condition of the sheep skin and coat, it is possible to form a certain notion of their essential breed qualities. One of the ways to increase wool productivity is to study the skin and wool coat of sheep in age dynamics. In this regard, the institute scientists studied the histological structure of the skin (density of hair follicles and skin thickness) on animals in different sex and age groups of fine-wool breeds at 4,5 and 12 months of age. More precisely, the density of wool, that is, the amount of wool fibers per unit of the skin area is established by a laboratory way. The index of the total skin thickness increases from birth to one year, but it grows more rapidly during the first 4 months due to the overgrowth of its layers. Thus, in our studies, in sheep of the Stavropol breed, the total thickness of the skin at the age of 4,5 months has made 2195,6 microns, at 12 months of age it was 2378,5 microns, that is, at 182,9 microns or 8,3% thickening occurred; respectively, according to the Soviet merino, 99,3 microns or by 4,1%, for the Grozny breed by 157,1 microns or 9,2%, for the Caucasian breed by 158,3 microns or 6,7%. The density of follicles decreases with age, but at the same time the ratio of SF/PF (an indех of the wool fiber density) does not change almost and remains constant. Accordingly to our data, the total density of the Stavropol breed was 96,95 microns at 4,5 months of age, and at 12 months it was 92,60 microns, that is, it decreased by 4,7%. Accordingly: for the Soviet merino by 5,9%, the Grozny by 2,9%, the Manych merino by 6,1%, the Caucasian by 7,6%.