Problems with the Feet

Thrush: an infection of the frog. Black/grey discharge, bad odor. Caused by standing in dirty stalls, the feet not being cleaned often enough, and not being trimmed periodically. The infection causes the frog to begin rotting, can spread to the sole as well. Infected tissue should be trimmed and a drying agent, such as bleach or copper sulfate applied. more turnout may help. The causes should be dealt with or thrush will always come back. The whole foot hoof can can start rotting if it isn't taken care of.
I've personally known one horse who became lame because of thrush. She stood in a standing stall all day and was rarely taken out, had to stand in her own wastes, and her feet were not cleaned very often. Her feet also needed trimming. The management let it go on for so long that this horse had no frog left to speak of and was in a lot of pain. It hurt her whenever someone tried to clean her feet. Only once it finally got this bad did they go on the offensive against it. She was out of work for over a year and a half while we did everything we could think of to get rid of it. Finally we did and then she had to learn all over again that having her feet handled wouldn't hurt and she needed lots of conditioning before she could go back to work.

Abcess: a pocket of pus in the foot cause by a bacterial infection (caused by a bruise or a small hole in the foot - from a horse shoe nail hole for instance, or being quicked). Pressure is put on the sensitive structures inside the hoof, which is what causes the pain. The foot is hot, painful, and lameness comes on suddenly. The pus travels the path of least resistance so it may come out through the corronary band or even further up the leg. Don't let it get that far - soak the foot in warm water and epsom salts to encourage it is come out. The farrier may make a hole in the foot to allow drainage. The foot should then be kept clean and wrapped to prevent foreign material from getting in the foot.

Sole bruise: trauma to the sole causeing bleeding. Depending on severity only small dots will be visable or a large spot will appear discolored. The color is red if it was recent and purple/black is it is older. It is caused by thin soles, flat feet, and working on rough terrain.

Corn: bruise in the area of the bars. Cuased by underslung heels, overtrimmed heels, too small shoes, or the nails being placed too far back so the feet can't spread.

Seedy toe/white line disease: a separation of the hoof wall/sole connection. allows in bacteria which breaks down the horny laminae. Caused by excess moisture and is more prevalent in humid areas. The white line is often wider when it heals.

Pedal osteitis: a demineralization of the coffin bone - the body thinks the bone is more needed somewhere else. Of course this weakens the bone. It is cause by chronic bruising and concussion.

Sidebone: the lateral cartilages of the coffin bone turn into bone and created a visable bulge. Causes include age, short, steep pasterns, offset pasterns, and too much concussion.