De vererving van onder praktijkomstandigheden geregistreerde kenmerken bij varkens

On-farm data from 1486 litters and 10304 slaughter pigs concerning litter traits and individual characteristics of progeny groups from 27 breeding boars were collected. After an analysis of variance and an adjustment for other than genetic effects, a direct sire effect was shown on growth during the rearing period and the fattening periode, backfat thickness, carcass quality and meat quality. A direct boar effect was also shown for the susceptibility to affected lungs. The proportion of the sire effects in the variance of litter traits was very small. The heritability for growth during the fattening period was h2 - 0.08, for backfat thickness h2- 0,05 to 0,11, for slaughter type h2= 0,13 tot 0,20, for meat quality h2 = 0,07 and for susceptibility to affected lungs h2= 0,02 to 0,08.From the direct sire effects on several traits and their genetic variation, it was concluded that on-farm data on individual traits could be used in breeding programmes. For the relation between growth rate in the testing station and the same trait under field conditions, a correlation rp = 0,27 was calculated and a genetic correlation rg = 0,36. For the relation between backfat thickness in both environments rp = 0,34 and rg = 0,42, was found. From these results it was concluded that the use of on-farm data for these traits is highly recommendable. Further studies are necessary to find out how on-farm data can be used in pig breeding programmes.