The implementation of genomic evaluations in the UK

  • R Mrode
  • T Krzyzelewski
  • K Moore
  • M Winters
  • M Coffey
Keywords: Genomic evaluation, linear model, polygenic effect


Preliminary genomic evaluations for production and fitness traits in Holstein Friesian bulls in the United Kingdom (UK) were undertaken using 11480 bulls with 50k genotypes. A linear model with and without polygenic effects was implemented and results were compared. Linear equations were solved with Mix99. The accuracy of predictions in terms of correlations between deregressed proofs and direct genomic values in the validation set were about 0.68 for production traits and somatic cell count (SCC) but lower at 0.45 for longevity. Inclusion of polygenic effects increased the regression coefficients to about unity, thus improving the predictive ability of the model. The gain in reliability in genomic enhanced pedigree index (GPI) relative to traditional PI were about 23% for production traits and 15% for longevity.