The difference between horses and mules is in their care and feeding. The most common problem is overfeeding. Mules need less protein than horses and show ill side effects if fed too much. Grass hay with a small ration of a complete vitamin and mineral feed is the best diet. Mules are less likely than horses to overconsume water when overheated but they can, so they should be cooled down like a horse.
Mules are very hardy animals.
They can withstand hardship and severe conditions, dry climate, heat, and irregular meals. Mules usually won't overeat or thrash around when tangled up or in cramped quarters. They are typically resistant to most problems encountered in horses, such as wounds, chronic lameness, infectious diseases, and digestive disorders. However, it is myth that mules will not founder or colic, even though they are less susceptible than horses. They can have heavy lungworm infestations without showing any symptoms and can be silent carriers of the parasite.