Efficiency of breeding by fertility of Romanov sheep

The article presents the results of the evaluation of the breeding value of Romanov sheep of the Yaroslavl region population by fertility, type of birth and live weight at the first lambing. It was found that the indicators of phenotypic variability by type of birth and fertility by the first lambing were at the level of average values, which indicates the possibility of selecting individuals with desirable phenotypes. When evaluating animals using breeding value indices according to the proposed models, the genetic improvement in live weight will be 0.7–1.7 kg, in fertility — 0.03–0.06 heads. The economic effect of using genotype estimation models by live weight will be 150–340 rubles, by fertility — 480–882 rubles per head per year.