Robust GMACE for young bulls – application to data


  • Jette H. Jakobsen Interbull Centre, SLU, Uppsala
  • Peter G. Sullivan Canadian Dairy Network, Guelph, ON


genomics, international evaluation, MACE, GMACE


A robust GMACE method was applied to genomically enhanced breeding values (GEBVs) of young bulls for the five key traits protein, stature, somatic cell score, longevity and female fertility (cc1). Eleven countries participated with GEBVs and conventional breeding values of progeny tested bulls were included from all countries currently subscribing to International Genetic Bull Evaluations. The robust GMACE procedure constrained ratios of genomic standard deviation relative to traditional standard deviation (SD-ratio) to be in the range of 0.80 to 1.20. This restriction changed the bull rankings and number of genomically tested young bulls on the top-100 lists especially for country-trait combinations far from the constraint of 0.80 to 1.20.