Heritability and economics of survival rate

Abstract

Variance components for survival of New Zealand dairy cows were estimated using the Restricted Maximum Likelihood (REML) method. Variance components for survival on the binary scale were estimated and were transformed to the underlying normal scale resulting in intraherd and interherd heritabilities of 0.191 and 0.183 for 2-year-old survival. Heritability of survival was greater for 2-year-old heifers compared to 3-year-old cows and all ages. A method for determining the economic value of changes to survival rate is outlined. An illustration of this method for a 1% increase in 2-year-old survival rate is provided. The resulting net present value per cow was $10.56-$26.54 depending on the repeatability in future years and the real interest rate.