Degenerative changes of joints due to osteoarthrosis in tarsal joint, peritarsitis, tarsal bursitis and asymmetry of claws was studied on legs of 175 commercial pigs, with prolonged fattening (250 days of age) of three genotypes (landrace pigs-11, crosses between landrace females and large white males-12, crosses between female 12 and duroc male- 123) housed either individually on the zincifi ed metal slatted fl oor or in groups of 8-9 pigs on the concrete slatted
fl oor. Degenerative changes due to osteoarthrosis (OATD) in small joints of the hock - os tarsale tertium (T3), os tarsale quartum (T4), os metatarsale tertium (Mt3) and os metatarsale quatrum (Mt4) and due to the peritarsitis were signifi cantly more important in pigs housed individually (P<0.001). Individually housed pigs grew faster and were signifi cantly heavier for the similar slaughter age (P<0.001). The effect of genotype was only minor; the crosses 12
had lesser asymmetry of claws (P<0.001) than pigs 11 or 123, whereas crosses 123 had signifi cantly (P<0.005) less pronounced degenerative changes due to osteoarthrosis on Mt3 and T3.
