A live, painful corn is caused by different things. High contracted heels will cause corns as well as short ones. Shoeing and leaving the shoes on too long, and undue concussion will cause corns. The majority of cases of corns will be found in contracted feet. I find the most successful way to treat corns is to get the foot or feet soft and keep them soft. Shoe with a bar shoe, lower the heels so as you can get all the frog pressure possible on the bar of the shoe, after the shoe has been fitted, and before nailing to the foot, cut the heel bearing away from the shoe where the corn is located, an inch of the bearing surface ahead of the corn and half an inch or more away from the shoe to break the jar and reduce the concussion. If foot is contracted use an expander inserted in foot before shoe is fitted, and keep foot soft. I do not recommend cutting the bars and sole away where the corn is located and leaving the wall standing up all alone, but cut the whole heel seat of corn and bar down _flat_, away from the bearing surface of shoe.
A foot with a toe crack should be kept as short as possible at the toe. Apply a stiff hoof expander, use one or two rivets or clamps as high up and as near the coronet as possible after cutting the horn where one side laps over the other the full length of the crack. After inserting the hoof expander fit a bar shoe to the foot with a clip at each side of the toe, and before nailing shoe to foot cut the bearing of foot away from the shoe across the toe. If the foot is not contracted any I would recommend a clip back at each heel. Treat the same as is prescribed for Quartercrack, after cutting away half inch each side of crack at the coronet. If foot is contracted do not use any clips back at the heels and keep the foot soft.
A quartercrack is a split or crack in a quarter from the coronet down towards the bottom of a foot. At times it is very painful and prevents the use of the horse. In most of these quartercracks one side is lapped over on the other one-quarter or three-eighths of an inch, and from the continual expansion and contraction of the foot while the horse is in action the lapped parts are continually working against one another as the foot expands with the weight of horse on it, and contracts when the foot is lifted up. This kind of action of the split horn at the coronet is what prevents it from knitting. The first thing to do is to apply a few poultices which will get the foot soft. If the foot or quarter is contracted apply a hoof expander. In fixing the foot rasp the foot as low as possible without making it tender, at both heels and toes. Do not cut any sole or bars out or cut the heels open with the knife, have the side of foot where the crack is on the lowest or you can have that part of the shoe quite thin, so that the jar or concussion will be on all parts of foot, except the quartercrack. Use a bar shoe with plenty of frog pressure, a plain shoe is best. If you have to have calks, place the heel calk on cracked side ahead of crack on shoe if possible. If the crack is close to the heel, take the bearing of foot away from the shoe by cutting the heel down. Now cut the horn away on the side that is lapped over the other the full length of the quartercrack, cut the horn away one-quarter of an inch each side of the crack at the coronet, if it bleeds a little it will not hurt. Now a blister at the coronet above and on each side of the crack will be beneficial to start the growth down solid, if it should crack open again apply a stronger one. After the crack starts to grow down solid, apply a little of the blistering ointment every week or ten days but do not let it blister, just use enough to keep it sweating, it will toughen and soften the horn as it grows down. A rivet or clamp drawing the edges of crack together as near the coronet as possible, to hold it together and strengthen it will be very beneficial. A salve or ointment formally made by the late Geo. W. St. Clair, and now by Mike Bowerman, of Lexington, Ky., is the best thing I have seen to help knit and grow down a quartercrack. A little North Carolina tar rubbed into coronet over crack every other day I find is excellent.