Wounds in horses can be particularly challenging to deal with as a veterinarian. Due to most horses' living or housing conditions, it is difficult to prevent extensive contamination of wounds once they occur. This makes cleaning of the wound one of the most important steps in obtaining a healthy healing environment, not to mention a faster healing rate!
Another factor that makes wounds difficult to manage is the fact that horses have a tendency to form extensive granulation tissue, also known as 'proud flesh'. Granulation tissue is a normal part of the healing process - it is the tissue that fills in the wound as healing occurs.
'Proud Flesh' within a wound
Unfortunately, for reasons that are probably due to prolonged inflammation and a mix-up in signals from the body to the tissue during that inflammation, the granulation tissue begins to over-take the wound and bulge above the surface of the skin edge. When this happens, the skin cells at the edge of the wound are not able to grow over the tissue and the wound becomes stagnate. At this point, the tissue must be cut away in order for the skin cells to be able to start moving over the wound bed - but don't worry! Granulation tissue has no nerve endings, so horses cannot feel anything when this tissue is cut away by your veterinarian.
Two more factors that contribute to the difficulty in treating horse wounds are motion and infection.
Motion is a problem because the cells and tissue in the wound cannot heal if they are in constant movement towards and away from each other. This is a big factor for prolonged healing times in horses and is experienced quite frequently due to a majority of wounds being on the horse's legs. Veterinarians control the amount of motion on the limb by using bandages, splints and sometimes even casts.
Infection is an even larger issue than motion when it is present in a wound due to the amount of inflammation it causes within the wound. As mentioned above, infection prolongs the inflammatory stage of the healing process and can lead to production of proud flesh. It can also significantly prolong the healing rate of the wound and in some cases, the wound will never heal. These wounds usually need surgical removal of the affected tissue and intensive treatment including antibiotics and extensive bandaging.