How structures in bovine hoof epidermis are influenced by nutritional factors

The structure of the hoof epidermis is the link between nutrition and horn quality. The aim of this study was to demonstrate the relationship of singl e structures in the process of keratinization and cornification of bovine h oof epidermis to certain nutritional factors such as lipids, minerals and v itamins. Furthermore, we wanted to show the structural changes in the dyske ratotic epidermis caused by an insufficient supply of keratinizing epiderma l cells. For our study we used samples of hoof epidermis from 25 dual-purpo se dairy cattle, with ages ranging between 2.5 and 4 years. We also obtaine d a complete set of hooves from a biotin-deficient calf. All samples were i nvestigated by light and transmission electron microscopy, using routine me thods as well as histochemical and enzyme-histochemical techniques. We focu sed on epidermal structures that have a major influence on horn quality and are known to be related to single nutritional factors. The strength of the keratin filament bundles is determined by their cross-linking via sulphur- containing amino acids. Essential fatty acids are required for the synthesi s of an intercellular cementing substance connecting the horn cells and est ablishing a permeability barrier in the stratum corneum. Minerals, in parti cular calcium, are essential for activation of enzymes that are a prerequis ite for physiological keratinization and cornification. Furthermore, vitami ns such as biotin are essential in the metabolism of the keratinizing epide rmal cells.