Influence of floor type and stocking density on leg weakness, osteochondrosis and claw disorders in slaughter pigs

The effects of floor type and stocking density on leg weakness, osteochondrosis and claw disorders in slaughter pigs were studied. Three hundred pigs were housed in pens with either solid floors with plenty of straw, solid floors without straw or fully slatted floors at either high (0.65 m(2) per pig) or low (1.2 m(2) per pig) stocking density from 25 to 105 kg. In each pen half of the pigs were boars and half gilts of the breeds Landrace and Yorkshire x Landrace crossbred. There was no difference in growth rate between the three floor types. The growth rate of the boars was higher at low compared with high stocking density, while no effect of stocking density was seen in the gilts. The prevalence of leg weakness and claw disorders was different for the various floor types, while no effect of floor type could be found on joint changes. With regard to leg weakness, slatted flooring was significantly worse than solid floors with or without straw for standing under position on hind legs, while pens with plenty of straw were significantly better than the other floor types with regard to stiff movement and forelegs turned out. A calculated sum of the nine leg weakness symptoms showed that pens with straw were the best followed by solid floor without straw, while slatted floors were the worst. Regarding claw disorders, solid floors without straw were the worst. High stocking density affected four leg weakness variables (buck-kneed forelegs, turned-out fore- and hind legs, standing under position on hind legs), one joint change and three claw disorders negatively. Boars scored worse than gilts with regard to one leg weakness trait and one claw disorder and thickening of cartilage in two joints. Differences between breeds differed for the examined variables. Claw hardness was affected by floor type with regard to medial claws, which were softer on slatted floors. The hind claws were softer than the foreclaws on the volar surface, while there was no difference between the hardness of the topside of the fore- and hind claws. Claw hardness was not affected by sex. In conclusion, it can be said that the examined floor types do not have the same effect on the different aspects of leg weaknesses and claw disorders. Thus, clinical leg problems are worst on slatted floors and best in pens with straw, but claw disorders are worst on solid floors without straw. Further, high stocking density specifically affects dthe clinical leg weaknesses and claw disorders. Joint changes were not affected by floor type or stocking density.