Essentially the nutrients in your horse’s diet can vary greatly depending upon the quality of the hay that has been selected. Your horse's age needs to be considered as well as the daily routine of work your horse is required to do. Older horses tend to do well with consumption of 2 to 2.5% of their body weight per day.
Breastfeeding horses and grow young do well with higher protein found in alfalfa hay (usually the second or cut third) of 18% or better, a horse if not overcooked do well with about 12% protein to maintain a healthy diet.
High quality timothy or alfalfa mix hay horse farm, from what I have found works very well in providing the necessary nutrients for the elderly or adult horses. You can browse https://www.sgf5000.com to know more about the Joint Supplements.
In caring for the horses on our ranch, we have found that a good diet of hay quality horses by itself, without other types of supplementation of feed sweet and grains are all that is needed for our horses do very well in workload light.
During the high season our workload wheat supplement selection is only about 1 gallon of whole or rolled oats once per day. Please note, I am not a nutritionist, just someone who has come from a farm background with a lot of horse work and from my father who grew up riding and horse work in the daily routine.