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"
Breeders use "Selection Indices" to balance these correlations, ensuring they don't accidentally compromise animal health or product quality while chasing growth. 3. Repeatability: Consistency Over Time
Without knowing these parameters, a producer might spend years trying to "breed" for a trait that is actually 90% determined by the quality of the pasture. By focusing on and using Estimated Breeding Values (EBVs) , you can: Increase the average weight of lambs at market. Improve the uniformity and micron of wool clips. Genetic Parameters for Sheep Production Traits
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
Selecting for higher yearling weight usually leads to higher birth weights. Reproductive traits like twinning rates or lamb survival
Enhance the overall "efficiency" of the flock—producing more output with the same input.
Traits rarely move in isolation. When you select for one, you often get a change in another—sometimes for the better, sometimes not. By focusing on and using Estimated Breeding Values
Understanding the genetic parameters of sheep is the backbone of any successful breeding program. It allows producers to move beyond guesswork and use data to predict how traits like growth, wool quality, and fertility will pass from one generation to the next. 1. Heritability ( h2h squared ): The "Pass-on" Rate