The Influence of Environmental Factors on the Hoof of Horses

The influence of some environmental factors and some protecting substances were tested in a laboratory trial with healthy coronary horn and compared with specimens of damaged horn from the bearing border, which had been submitted to a faeces‐urine medium. Hoof horn of the best quality from the middle zone of coronary horn (3–4 cm distal of the coronary band) was submitted to different organic media or to some hoof horn varnishes or to heat. The horn specimens of defined size were treated for 36 days with urine, faeces and urine, urea, faeces or faeces and biotine and their strength was compared with untreated controls. The mentioned excrements were collected from horses. The second group comprised some hoof varnishes or hoof‐conditioners (Horsepan, Isohoof Protect, Krealit, Pedalo) and were kept for 24 h in these media. The influence of heat was tested after the horn specimens were heated in an oven for 5 min to 125°C. The results of histologically unchanged horn were compared to horn specimens of the bearing border, where frequently histological changes such as microcracks occur. Two groups of 20 specimens from the bearing border were treated with a mixture of faeces and urine for 5 weeks, and their tensile strength was compared to the same number of untreated controls. The tensile strength of unchanged coronary horn remained nearly unchanged or was only slightly diminished when it was treated with the different media. The treatment with heat did not reduce the tensile strength or showed even a slight increase compared to untreated specimens. The tensile strength of bearing border specimens showed a highly significant decrease of tensile strength of about 55% after 5 weeks treatment with faeces‐urine in both trials compared to the untreated controls. The results indicate that unchanged horn is much more resistant to environmental factors than bearing border horn with first damages. For prevention of severe changes at the bearing border horses should not stand for a long time in beddings with a high content of faeces and urine.