It is very important to take good care of your horse. You should never get a horse unless you know how to take care of it.
Grooming a horse is essential. There are lots of different grooming tools. The curry comb is used to get the dirt, and loose hair out of the horse's coat. You use the curry comb by rubbing it in a circular motion going in the direction of the horse's hair. After the curry you use the body brush, which brushes the dirt and hair that the curry loosened of the horse. There is a hoofpick which is a curved piece of metal that is somrtimes attached to plastic for the groomer to hold onto. The hoofpick is used to pick stones and dirt out of the horses hoof. Sometimes a stone gets stuck under the horseshoe, this is very uncomfortable for the horse and if the horse is ridden with a stone in it's horseshoe then it can cot the horses hoof. There are many other grooming tools besides these.
Horses can get many sicknesses. Colic is one of them. Colic is when the horses intestines get twisted. I've known horses who have died from colic. You can usually figure out if your horse has colic before the colic gets really bad.
Sometimes horses get navicular disease, which is when a bone in the horses hoof starts to detiriorate. Horses can live with this for awhile but when it starts to hurt them really bad it's best to put them to sleep. Racehorses usually get navicular disease from stressful training.
As you can see horses are very complicated and you should never own one unless you know what you're doing.