Teat number, hairiness and set of ears in a Piétrain cross: variation and effects on performance traits

A F2-resource population has been constructed by mating five Piétrain boars to one Landrace, one Large White and twelve Landrace × Large White crossbred sows in the parent generation. From 116 animals of the F1 and from 2706 animals of the F2 teat number was recorded with reference to side. The average number of teats in the F1-generation was 7.1 ± 0.5 on the left body side and 7.0 ± 0.6 on the right body side. The F2-offspring had an average teat number of 6.9 ± 0.6 on both sides. The phenotypic and genetic correlations between left and right side teat number were 0.56 and 0.96, respectively. A Bayesian heritability estimate of 0.23 ± 0.05 was obtained for total teat number. The density of hairiness was scored into the categories little, normal and very hairy and the set of ears into the categories prick-eared, intermediate and lop-eared. Data of 113 F1-animals and 2770 F2-animals were available. Bayesian analyses provided heritabilities of 0.27 ± 0.07 for the density of hairiness and of 0.37 ± 0.08 for the set of ears. In further analyses the traits teat number, hairiness and set of ears were taken as phenotypic markers. The effect of teat number on growth development during pregnancy and on several fatness traits of the carcass was significant. The set of ears showed a significant influence on growth traits only. Significant effects on birth weight and different carcass traits could be found for the density of hairiness. From the phenotypic effects it can be concluded that "lop ear" is linked to Landrace alleles and "little hairy" is linked to Piétrain alleles.