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 h<sup><font size="-1">2</font></SUP> - 0.08, for backfat thickness h<sup><font size="-1">2</font></SUP>- 0,05 to 0,11, for slaughter type h<sup><font size="-1">2</font></SUP>= 0,13 tot 0,20, for meat quality h<sup><font size="-1">2</font></SUP> = 0,07 and for susceptibility to affected lungs h<sup><font size="-1">2</font></SUP>= 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 r_{<font size="-1">p</font>} = 0,27 was calculated and a genetic correlation r_{<font size="-1">g</font>} = 0,36. For the relation between backfat thickness in both environments r_{<font size="-1">p</font>} = 0,34 and r_{<font size="-1">g</font>} = 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