The influence of sexual dimorphism on the wool diameter of sheep

Abstract

The wool of rams is usually coarser than ewes, which is confirmed by sheep
breeding. However, from the analysis of the Russian publications, it is unclear whether this is
due to lower physiological loads, heavy feeding and better keeping or it is due to genetics. A.
I. Goltsblat suggested the genetic identity of wool fineness in rams and ewes, but his hypothesis did not have practical confirmation. In most scientific works, the coarser coat of rams is
stated, but not explained, since this is considered as a generally accepted fact. Therefore, there
is no information about the age at which differences in wool fineness begin to appear in animals of different sexes and what causes them. In order to determine when the differentiation
of wool by fineness in young ewes and young rams begins, the studies were carried out on
sheep of the Stavropol breed in the SEC breeding farm “Put Lenina” of the Turkmensky District in the Stavropol Territory. It was established that the average diameter of the wool of
young ewes and young rams aged from 2 to 12 months almost had no difference. The rank
position of rams and ewes changed during the period of experiment, but the differences in
fineness were insignificant. Only at the age of 2 years, the advantage of rams in fineness over
ewes became significant: 5.58% on the side and 5.67% on the leg. It was concluded that rams
and ewes are genetically similar in terms of wool fineness, and differences in this rate appear
in the process of ontogenesis under the influence of selection and different physiological
loads.