When old hay is running low, or is not very good quality, we will want to start on the new hay as soon as possible. But when can we start using new hay? Newly made hay continues to under-go changes even after it is baled. Traditionally, new hay was never fed to horses until Michaelmas at the end of September when it was termed old hay! In practice and under pressure of supplies, do not feed new hay until it has been baled at least 6 weeks and even then, keep a close eye out for any signs your horse is not happy with it. This could be loose droppings, bloated and gassy or even colicky. Not all horses are affected by new hay, but it is not worth risking a gassy colic. Similar guidelines apply to haylage as well you should wait until that has been baled and wrapped for at least 6 weeks.
If you are totally out of old hay and are not prepared to risk feeding new hay just yet, HayCare provides a good alternative to tide you over. Or let your horse have more grass if that is suitable for them. But dont leave your horse short of forage as long spells without eating can result in ulcers and colic. Always offer a decent forage feed immediately before you work your horse, especially if he has been short of forage.