Contributions from Genetic Groups and Outcrossing to Components of Reproduction in Maternal Sheep Breeds

Abstract

Industry data for traits included in the new multi-trait genetic evaluation for reproductive traits provided by Sheep Genetics were used to investigate variation due to sub-populations (genetic groups) and due to outcross ewe genotypes in maternal sheep breeds. Substantial variation due to genetic groups (gg² : typically 11-30% of the phenotypic variance) for traits reflecting development (eg weight, condition score, muscle depth) were not accompanied by comparable variation for reproductive traits (gg² : 0-8%). Variation due to outcross ewe genotypes ranged from 0 to 8% across traits, being highest for adult ewe weight (8%) and yearling conception (6%) traits, which are expected to be affected by heterosis. Accommodating these sources of variation appropriately may be important for the genetic evaluation of data affected by admixture of populations.