INVESTIGATIONS ON THE COMPOSITION OF HOOF HORN IN DEPENDENCE ON AGE, BREED AND QUALITY

Samples of hoofhorn, hair and blood from 63 horses (3 repeatings, inte rvall min. 4 month) have been analysed for hardness (by sensoric valua tion and Shore D), Cu, Zn and Se (furtheron alkaline phosphatase - AP - in plasma and in selected samples of hoofhorn amino acids - AA). Res ults: The values for Shore D were 58,0+/-2,3 and 51,8+/-7,8 respective ly for intact and inferior (related to sensoric valuation) hoofhorn re spectively. Horn of lowered hardness contained significantly less zinc than material of good stability (no differences in Cu and Se in relat ion to hoofhorn quality). Analogous differences were found in hair and plasma as well as in the activity of AP in plasma. But low Zn concent rations in hoofhorn were not related to Zn deficient rations. A a line ar relation between horn hardness and cystine (% of AA) was observed i or intakt hoofhorn only. An increase of Zn concentration in hoofhorn c ould be established after feeding supplementary Zn to horses with infe rior hooves.