Influence of Some Factors on Biological Prolificacy in Sheep from Newly Created Milk Sheep Breed

S. BOIKOVSKI, N. STANCHEVA, G. STEFANOVA and D. DIMITROV
Agricultural Institute, BG-9700 Shumen, Bulgaria

Abstract

BOIKOVSKI, S., N. STANCHEVA, G. STEFANOVA and D. DIMITROV, 2003. Influence of some factors on biological prolificacy in sheep from Newly Created Milk Sheep Breed. Bulg. J. Agric. Sci., 9: 391–395

Slight lineal differentiation and inbreeding depression were established in relation to biological prolificacy at earlier age (at 1st yeaning) in sheep originating from full siblings. The low values of heritability coefficients of biological prolificacy in sheep from the Newly Created Milk Sheep Breed showed that selection on this trait would be slightly efficient. The trait was likely to be increased only by introducing genetic variability of high prolificacy from a different breed. There was well-expressed linkage between the high prolificacy at 1st and 2nd yeaning in ewes from the Newly Created Milk Sheep Breed.

Key words: biological prolificacy, interlineal and intralineal mating, line, degree of relationship, heritability, age repeatability