Responseto selectiono n BLUP of breedingv aluesi n the GrootfonteinM erino stud

Abstract

A study was conducted to estimate the response to selection on BLUP of breeding values for mature body weight (BW), clean fleece weight (CFW) and mean fibre diameter (MFD) in a commercial Merino stud with a high culling rate on visual appraisal. The selection policy was to increase BW, decrease MFD and maintain CFW The observed annual trends were +0.63 kg for BW -0.16 pm for MFD and zero for CFW over a period of seven years. It is .concluded that selection on BLUP of breeding values can lead to a marked increase in genetic progress in spite of the limitations posed by high culling rates on visual appearance. 'n Studie is onderneemo m die vordering op seleksieo p BLUP van teeltwaardesv ir volwassel iggaamsgewig (LG), skoonvaggewig( SVG) en gemiddeldev eseldikte( GVD) in'n kommersi0leM erinostoetm et'n hoOu itskottempoo p visuele keuring te bepaal.D ie seleksiebeleidw as om LG te verhoog, GVD te verlaag en SVG konstant te hou. Die waargenomeja arlikse genetiesete ndensew as +0.63 kg virLG, -0.16 pm virGVD en nul virSVG oor'n periode van sewe jaar. Die gevolgtrekking word gemaak dat seleksie op BLUP van teeltwaardes kan lei tot 'n aansienlike verhoging in genetiese vordering ten spyte van die beperkings gestel deur hod uitskotpersentasieso p visuele voorkoms.

Keywords: Breeding values, genetic trends, Merino sheep, selection response.