Investigation of Manure-Induced Physicochemical Changes of the Claw Horn in Dairy Cattle

The study was conducted on three claw horn areas (walls, soles and heels) in dairy cows. Claw horn samples were collected from cows at first lactation without signs of lameness. The changes in the hardness, the fat content and the swelling under the influence of manure from intensively reared cows were evaluated. The hardness and fat content were determined by the beginning of the experiment and at 7-day intervals for 28 days stay in manure. The swelling of hoof zones was done by placing samples in graduated cylinders filled with manure and distilled water for 48 h. The hardness of claw walls decreased most significantly during the first 14 experimental days (3.75 Shore A units). For the same period, fat content of this claw zone underwent the most significant reduction. In the sole area, the hardness decreased most intensely during the first 14 days – by 8.15 Shore A units which was in agreement with claw fat reduction in this area. A similar trend was observed in heels, where the hardness decreased most considerably until the 7 th day by 3.85 Shore A units and between days 7 and 14 – by 4.45 Shore A units. The respective fat content reduction was by 0.75 and 2.79 mg/g DM. The significant loss of claw horn fat predisposes to water penetration and a strong swelling of keratin. The strongest and most prolonged swelling was detected in the heel area, which enlarged their volume until the 48 th experimental hour up to 8 cm 3 , and where fat content decreased the most compared to other studied claw horn zones.