I’ll agree with those who say it’s too vague a question. It depends on the individual horse in question; the horse’s lifestyle and work demands; the quality of forage available; and the quality/type of feed (if any).
For example: I have a TB mare coming back into moderate work after some time off/in light exercise for ulcer treatment. She eats:
- Excellent quality hay f
- Free choice salt
- Magnesium supp as suggested by vet - she was quite mag deficient when I bought her, and a tiny little maintenance dose of Mg really makes a noticeable differed in 3 meals daily (barn provided, about 8lbs/feeding)
- Good quality hay which I buy and put in her paddock a bale at a time in a slow-feed hay net so that she has something to nibble on 24/7. She’s out on pasture half the day with access to her paddock - but ignores the net in favour of the frostbitten grass
- Soaked alfalfa and beet pulp (without molasses) for some extra calories and protein 2x/day
- a vitamin supplement with Se and vit. E because our soil is very deficient in Se.
- a Mg supplement on the advice of my vet - she was quite Mg deficient when I bought her, and a tiny little daily maintenance dose makes a big difference.
This keeps her fat, shiny, happy, and healthy. As her workload increases, it’s possible she will need something more to help keep up with the increased physical demands. Whether that will be simply an increase in what she’s currently getting, the addition of oats, or a commercial grain is something I’ll evaluate if/when the time comes.
^^ this is a perfect set up for my horse. Could be disastrous for someone with Se+ soil, could just not work for someone who doesn’t have access to excellent hay, or someone whose horse can’t eat enough forage due to a tooth issue, or a horse who is IR and needs diet tailored to that.
Best to test hay and get a basic blood panel on your horse.