A splinter in your finger may be no big deal, but one lodged in your horse's skin generally requires the attention of your veterinarian. Why the difference?
A horse's coat and thick skin can deflect all but the most substantial slivers of wood. Brushing against a stall wall, for instance, won't cause a horse much of a problem. But if he breaks through a fence, sharp bits of wood can be driven deep into and beneath his skin.
A splinter is difficult to detect in a horse's skin because its usually small entrance hole is obscured by hair. In addition, unless the wood fragment is positioned parallel to the skin, you won't be able to feel it. You'll begin to suspect a problem when tenderness and local swelling develop over about 48 hours. Your horse may flinch when you groom the spot or be reluctant to move if the splinter is located in a highly mobile area such as the neck or armpit. A check of his skin for the telltale hole and a look around his environment for fractured wood may help you determine whether a splinter is responsible.
Because of the nature of the injury as well as the potential for complications, it's best to call your veterinarian to remove a splinter from your horse's skin. The piece is likely to be large and so deeply embedded that it can't simply be pulled out, and any fragment that remains can migrate as he moves. The site also may be infected.
Your veterinarian may surgically remove the wood and visually inspect the area to ensure that no bits remain. He'll also treat any infection.