There are three types of horse armor, those being iron, gold and diamond. Horse armor does not break over time like most tools. Even though gold is the worst in tools because of its low durability, gold horse armor is actually a bit better than iron horse armor, it provides more protection and is much rarer. Diamond is still the best for protection when it comes to horse armor.
There is also a leather horse armor which is a Minecraft Pocket Edition exclusive.
Iron horse armor- 20%
Gold armor- 28%
Diamond horse armor- 44%
- Despite regular armor protection values, gold horse armor will protect the horse by a bit more than iron horse armor would.
- Unlike regular armor, horse armor cannot be enchanted.
- If a horse dies while wearing armor, the armor will drop as an item.