Nurse Mare Foals are brought into the world so the mother horse can produce milk. Once the baby horses are born, many of them are just neglected, and they die. The mother horses are used to nurse a different baby horse that is considered to be of more value. The new baby the mother horse will care for has a future as a racehorse or in another sport.
This is not a joke, this actually happens, and it is a sad reality. Last Chance Corral is working to save the lives of the unwanted foals. The foals are given a chance to nurse and to grow. When they are old enough, they get adopted out to families who will take care of them.