Dear D.L.

     The horse evolved on semi-arid plains, and healthy hooves are designed to be dry and hard.  Horses in confinement must have an environment that allows the  hoof to be dry, hard, and healthy.  Hoof dressing is generally not necessary for healthy hooves and too much hoof dressing can soften and weaken hooves.

    Most of the moisture in the hoof comes from the blood supply, and exercise encourages blood flow.  If your horse is getting adequate exercise and the footing of his stall, pen or pasture is well-drained, the moisture balance between the inner and outer layers of his hooves probably remains at a relatively constant, healthy level.  However, if your horse stands inactive for long periods of time, such as in a stall, sufficient moisture may not be delivered and his hoof walls may tend to dry out and contract.  On the other hand, if your horse stands in mud or water, has frequent baths, or receives excessive hoof dressing applications the hooves can absorb too much moisture.  When this happens the  hooves can weaken and spread and the layers of the hoof wall can separate into a fibrous pulpy mess.  Also, hooves can develop cracks as they dry out after being too wet.

    Despite their claims, hoof products applied externally cannot "heal" a cracked hoof.  Like a damaged fingernail, the hoof must be replaced by new horn as is grows down from the coronary band.  Many farriers recommend not to apply any greases or oils in an attempt to soften the hoof.  About the only time hoof dressing is warranted is when the bulbs of the heels have become so dry that they are beginning to crack.  In order to restore their pliability, rub a product containing animal fat (such as lanolin or fish oil) or pine tar into the heels daily until the desired result has been achieved.  It is thought that petroleum-bases products may emulsify the hoof's natural oils and actually remove moisture from the hoof.

    The hoof has two natural protective coverings, the periople and the stratum tectorium, which retard moisture movement from either direction - from the outside environment into the hoof and from the inner layers of the hoof to the outside.  Should the thin layer of stratum tectorium be rasped away during trimming or shoeing, application of a hoof sealer is recommended.

    Whereas hoof dressings are in the form of pastes or creams, hoof sealers are thin liquids that soak into the hoof wall and then dry.  If your horse is in a wet muddy environment, regular application of a hoof sealer can seal out excess moisture.  In a dry environment a hoof sealer can keep hooves supple by preventing internal moisture from evaporating.