Variations in some inorganic components and physical properties of claw keratin associated with claw disease in the British Friesian cow

Horn hardness, water content and mineral composition were measured in the feet of 42 Friesian cows, 27 with no history and 15 with a history of lameness. Water content and magnesium concentration increased with age, potassium concentration was lower in the hooves of pregnant animals, but none of the variates was affected by lactation. Horn hardness was related to composition, the harder keratin of the claw wall containing more calcium, copper, zinc and phosphorus and lower concentrations of water, sodium, potassium and iron than the heel. Zinc concentration was lower in the horn of lame animals but those of magnesium and copper were increased. Mineral composition varied significantly with respect to the position of the horn in the claw (heel, sole or wall). The results are discussed with regard to the function of the horn constituents. © 1988.