When it comes to horses, sometimes it seems like they can get hurt just standing still. There are several different reasons why your horse could be limping ranging from minor and easily manageable to serious and in need of vet attention.
One easy explanation for the horse to have developed a limp is an abscess on the hoof or bottom of the foot. An abscess on the foot is basically the same thing as an abscess that you may get in your mouth from a bad tooth. What happens is that a bacterial infection develops between the walls of the hoof and fluid builds up causing the horse pain when pressure is put on that hoof. Eventually the pressure will relieve itself by rupturing wither above the hoof at the coronary band or at the bottom of the hoof. You will notice heat in the lower leg and an increased pulse at the bottom as well as some possible swelling. This can be caused by a puncture in the sole of the foot that then becomes infected since they do spend a lot of time standing in dirt or bacteria finding its way into the cracks in the white line of the hoof. Abscesses can be treated by keeping the area as clean as possible. Soaking it with iodine daily is a good way to keep it clean and dry it out. You can also take a baby diaper and wrap that around the hoof with various types of salves that are good for drawing infection out such as icthamol which is a black tarry salve.
Another reason for sudden limping could be as simple as something being caught in the hoof that is causing pain. Check all of the hooves. A stone or twig can easily become lodged in the crevices of the sole of the hoof and cause pain, but once removed the limping usually ceases.
Common injuries can cause limping which is why the legs and feet should all be inspected as soon as it is noticed. If there is an injury or cut to the lower leg or hoof, that would cause limping. If it is minor then treat it by cleaning it twice daily and applying antibiotic cream. However sometimes it can be severs, infected or require stitching and that would require a vet visit.
Muscle soreness can cause limping in horses just as it does in people. I you can’t find any cuts or injuries and you have ruled out the above possibilities, then ask yourself if anything could have cause muscle soreness. Did the horse work harder than usual in last day or two? Did he fall recently or get kicked by another horse? If the answer is yes, he may just have muscle pain and need a few days of rest.
Two of the more serious reasons could be Founder or Navicular Syndrome which are two serious disorders that horses can acquire.
In founder or Laminitis, the horse will become more lame over time and eventually will tend to try not to put any weight on the front legs. It will appear that he is leaning back away from them as it tends to occur in the front. It is a vascular disease in the laminae which secures the coffin bone and distal phalanx to the hoof wall. The coffin bone becomes detached from the wall and rotates or sinks causing excruciating pain. This can be caused by excessive carbohydrates or lush pasture, excess weight, or stress shock among other things. There may be swelling, increased pulse, tenderness in the toe and heat in the legs and the horse does not get better. The vet will need to do a series of tests to determine if this is the situation and what course of action to take.
In the Navicular, the Navicular bone in the front legs tends to degenerate and change over time. The bone build up catches on the flexor tendon and causes pain. This can be caused by not caring for the hoof properly. It occurs only in the front legs and is not curable but treatable. If you suspect it, the vet will need to do tests and determine treatment.
No matter what, if the horse does not get better in a few days, a vet should be called to examine the horse.