Traits rarely move in isolation. When you select for one, you often get a change in another—sometimes for the better, sometimes not.
Reproductive traits like twinning rates or lamb survival. Because these are heavily influenced by environment/management, progress through breeding is slow. 2. Genetic Correlations: The "Package Deal" Genetic Parameters for Sheep Production Traits
Growth rates and weaning weights. These respond well to selection but are influenced by the mother’s milk production. Traits rarely move in isolation
Selecting for higher yearling weight usually leads to higher birth weights. These respond well to selection but are influenced
Heritability measures how much of the variation in a trait is due to genetics rather than environment (feed, weather, management).
This is crucial for "ewe productivity" traits. If a ewe performs well in her first lambing season (e.g., weaning a heavy lamb), repeatability tells us how likely she is to repeat 그 performance next year. High repeatability allows producers to cull underperforming animals early with confidence. Why This Matters for Your Flock