Partial substitution, with their chelated complexes, of the inorganic zinc, copper and manganese in sow diets reduced the laminitic lesions in the claws and improved the morphometric characteristics of the hoof horn of sows from three Greek herds

BACKGROUND Hoof lesions in sows have been associated with lameness and poor hoof horn quality. The mechanical strength and quality of hoof horn is determined by the density and diameter of horn tubules, which were recently associated with the severity of lesions on the hoof wall of sows. Histologic changes that have previously been described in cases of bovine laminitis, have also been observed in the dermis and epidermis of the sows' claws. Trace elements, particularly zinc, copper and manganese, occupy important roles as enzyme catalysts in the process of keratin synthesis which determines the quality and the integrity of the hoof epidermis. Therefore, the objective of this study was to investigate the effect of diet supplementation with chelated zinc, copper and manganese, partially substituting their inorganic form, on sow claw health and hoof horn quality assessed by macroscopic, histologic and morphometric examination. RESULTS Clinically, the total claw lesion score was significantly lower in claws of sows which received the "organic" diet compared to those of sows on the "inorganic" diet. Histologically, lamellar hyperplasia was the most frequently recorded change in the epidermis of the sows' claws regardless of the diet's mineral source. The claws of the sows which received the organic diet were more likely to have none or less histologic changes than at least one or more, respectively, compared to those of the sows on the "inorganic" diet. Morphometrically, the density and vertical and horizontal diameters of the horn tubules was significantly higher and smaller, respectively, in the hoof horn of sows which received the "organic" compared to those which received the "inorganic" source diet. CONCLUSIONS Partial substitution of the inorganic zinc, copper and manganese in sows' diet with their chelated complexes, provided a comparative advantage against a conventional, inorganic mineral source diet, at least under the conditions examined in the current study, in terms of macroscopic, histologic and morphometric criteria, characterizing the health and horn quality status of sows' hooves.