Formaldehyde or the commercially available formulation called formalin has several properities that make it useful in the treatment of hoof wall and sole diseases and problems. A problem with its use is that it is fairly caustic and toxic. This article discusses its use in horses and some precautions handling it.

Formaldehyde is a pungent irritating chemical which at room themperature is a gas. Formalin, the most common formaldehyde preparation commercially available, is a 37%, by weight, solution of formaldehyde dissolved in water and methanol. Formaldehyde is useful for treating the various infections of the wall, sole, and frog of the horse's foot and can be used to toughen the horn of the foot. However its very irritating property limits its usefulness to only application to the horn, it should never come into contact with sensitive tissue and it is best that it does not contact the skin even if unbroken.

Formalin has the following properties which make it useful for treating conditions of the foot:

• dehydrate tissues
• cross links the proteins
• kills microbes

It is also very inexpensive but it's toxicity and possible carcinogenicity have made its availability limited. Some hoof preparations for thrush do contain it still. Medically it is easy to get by the gallon as it is still frequently used for preserving tissue specimens.

Use

Formalin is one of the most effective treatments for thrush and white line disease available. Removing the diseased tissue and changes in the environment are important components of successful treatment of infections of the horn of the horse. If sensitive issue has become exposed alternate treatments that are more tissue friendly, like Betadine (povidone) should be used. Sensitive tissue can be identified because it is pink, bleeds easily, and very sensitive to even light touching. It should be continued until new horn forms over the exposed tissue.

A appx. 10% solution of formaldehyde can be used. This is made by adding 1 part formalin to 2 parts water or povidone. This is applied once daily to the effected tisses and the surrounding area. One infection of the horn that should not be treated is canker as sensitive tissue is invariably involved.