Heritability, Phenotypic and Genetic Correlations between Type Ratings and Milk and Fat Production in Holstein-Friesian Cattle

Abstract

Heritability estimates for milk and milk fat production were of the order of 0.20, and did not differ significantly among the 3 levels (low, medium and high) of herd production. The estimates of heritability for type ratings ranged from 0.03 for dairy character to 0.31 for rump. Most of the genetic correlations concerning type ratings and production were not significant. Genetic correlations between dairy character and production were significant and ranged from 0.61 to 0.82 for the 3 stratified groups. Selection based on type ratings, with the exception of rating for dairy character, would cause little genetic improvement in milk or milk fat production. The relative genetic progress in milk production, if selection is on dairy character, is expected to be 35 to 50% of that which can be obtained by selecting on the basis of one milk production record.