When you find your horse suddenly refusing to bear weight on one limb, it's not unreasonable to consider an abscess to be the cause. A pocket of pus trapped in the capsule of the hoof will make a horse go dramatically lame quickly. Thankfully, most abscesses resolve in a few days or a week with simple treatment.
It's important, however, to not automatically assume an abscess is to blame for a sudden and dramatic lameness. A serious injury could be the cause, and any delay in getting treatment could have disastrous effects.
Before you assume your lame horse has an abscess, run through a few tests:
• Stand back and look at the alignment of the affected limb. Do the joints and hoof appear to point in the appropriate direction? It sounds almost too obvious to overlook, but a toe that points inward or outward can be the sign of a serious injury, and you may never think to check.
Run your hand up and down the affected limb, looking for any areas of swelling or heat. As you do this, take note of your horse's reaction. If he flinches dramatically when you touch a specific area on the leg, chances are it hurts and you're not dealing with an abscess. (The one exception might be sensitivity on the coronary band, where a high abscess can cause pain.)
Very gently, lift the leg and pull and flex it in various directions. Extend it forward and backward and pull it gently sideways. Again, you are looking for your horse to react dramatically. An abscess hurts during weight-bearing and will not become more painful as a limb is lifted and moved.
Clean the hoof and inspect the sole. Look for a foreign object imbedded in the hoof, such as a nail or sharp stick, that could be the source of your horse's pain. If you find one, do not pull it out until instructed to by a veterinarian.
After you've performed these tests, call your veterinarian and describe what you've observed. If all signs still point to an abscess, your horse will probably be seen before the end of the day. But if there are any clues that there's another reason for the non-weight-bearing lameness, your horse's case will become a priority call and he will likely be seen immediately.
E Q U U S— January 2016