Reliability of estimates of correlations between reproduction and production traits from a Merino resource flock

Abstract

Stochastic simulation was used to examine the reliability of estimating genetic parameters for fecundity (number of lambs born per ewe lambing) and fibre diameter in the CSIRO Fine Wool Project flock. The mean heritability estimates for fecundity and fibre diameter from 50 replicates of the simulation were similar to the true heritabilities as simulated. However, the genetic correlation between fibre diameter and fecundity was underestimated. The variation in estimates from across replicates was large. This highlights the difficulty of estimating correlation between fecundity and fibre diameter. More studies are required before the relationships between reproduction and production are known with certainty.