The attitude of health supplements must work at the cellular level which bathes cells in very good nutrition, and cells will react with endurance, health, and endurance and the formula should have been longer than the test of time and development of champions. Horses rarely need concentrate or seeds.
The exception might be a pony that does a lot of work: one that works very hard, is often driven, does something like a pulling competition, or a mare is breastfeeding. You can buy horse vitamins via https://www.aecsglobal.com/product/coq10/
If your pony gives up, you can expand the type of straw and if that isn't enough, the concentrate isn't too rich.
Substitute forage prepared with vitamins and minerals can give your horse the additional food he needs.
Horses only need a small portion of the food that horses do. Grass for horses must be good quality hay. Your pony will most likely not need food provided by cloves and alfalfa.
Abundant grasslands are not a good location for ponies. Ponies can be found in less than sixty minutes to graze if introduced suddenly into fertile grass.
If you plan to keep your pony on the grass, introduce it rather slowly. Start with 10 minutes to graze and gradually give a few minutes every day twice per day.
If your pony consumes a far richer pasture, it can lead to things like colic or founder. You might actually never be able to leave certain ponies in a nice pasture. Horses can get fat in a short time and can also cause health problems.