Apply direct pressure to the wound to staunch bleeding.

Use a clean cloth—a towel, your shirt, even a saddle pad—to press gently but firmly on the laceration. If the cloth becomes soaked with blood, place another directly over it. An alternative is to use a bandage to hold the cloth in place. However, do not apply a tourniquet unless specifically instructed to do so by the veterinarian.

Move your horse to a safe treatment area, if possible.

Ideally, your veterinarian will be able to tend to the wound in a well-lit, quiet area with access to running water. At the very least, the treatment area needs to be clear of obstacles and debris. If your horse is not in an area where treatment can be safely delivered, see whether you can slowly walk him to a better space. Do not try to move him, however, if you are having trouble controlling his bleeding or you’re worried that a bone or tendon has been injured.

Flush the wound.

A gentle stream of cold water will not only clear dirt from the injured area, but will also help keep inflammation in check. Keep the water pressure low and don’t use a spray attachment—you want to avoid driving debris deeper into the wound.

Look for foreign objects.

Small sticks, gravel or other objects stuck in a wound can complicate or stall healing. Do not attempt to remove anything you see; instead make a mental note to tell the veterinarian. If anything happens to fall from the wound, keep it to give to the veterinarian.

Examine your horse for other injuries.

The attention a large wound demands makes it easy to overlook smaller injuries, particularly puncture wounds, sustained in the same incident. Punctures may look minor, but they can quickly seal and trap bacteria below the skin.