Der Einfluss der Sohlendicke auf die Thermoisolation der Hornkapsel beim Equiden

Abstract

Lameness that appears after hot-shoeing is an issue the farrier is often blamed for. The aim of this study was to investigate the thickness of the sole at which it is possible to measure a change in temperature within the hoof capsule. In addition it was aimed to measure what change in temperature causes damage to the corium of the sole. The front limbs of 20 horses, aged between 2 and 17 years old and of differing breed and size, were cut off at the carpal joint immediately after euthanasia. The experiment involved a simulation of routine conditions during hot-shoeing such as fitting the shoe on the hoof by branding. Branding was continued until a significant change in temperature was observed. The temperature described as “critical” in histological studies so far (51 degrees C with a branding time of 3 minutes) was achieved with a with a sole diameter of x - < 5.4 mm (s = ± 1, 5 mm). Damage to the tissue (extravasation, change in structure such as deformation of the cells and their nuclei) was found during histological examination of these samples which were taken from the sole with a diameter of 4 mm or less. The k- parameter of the horn analysed by the flash-method was 0,2 W / K*m, which means Horn has a very poor thermal conductivity. The well-known, highly effective thermo-isolating characteristic of the horn capsule was confirmed. Only when a sole has a thickness of x - < 5.4 irreversible thermal damage can occur when performing an excessively hot and long-lasting branding. In this way the results can help to answer questions in the area of forensic medicine. Therefore it is of great importance to perform adequate x-rays (perpendicular course of beam; labelling of the sole) in order to document the (actual) thickness of the sole after branding and the following occurrence of lameness. By measuring the thickness of the sole it can be told whether there is a possibility that damages on the corium may have been caused by hot-shoeing, at all, and thereby also tell the probability of this to occur.