After doing some research here is the recipe I came up with.
2 cups canola oil
5 lbs rice bran
5 lbs beet pulp
5 lbs oats
I would give that to him once per day and he still would have constant access to his round bale. I would also get a salt lick for him so I hope that would cover all his nutritional needs.
I am looking for any advice as I am completely new to this, I just want him to grow as large as possible and be as healthy as possible.
Hi, firstly, from the point of view of his health & soundness, you DON'T want him 'growing as large as possible' or carrying a lot of fat. Tho from a showing point of view, they tend to like fat horses... While at 2yo he may just be going through a 'lanky phase' & not lacking in calories or such, he may well need extra fat & good protein may also be lacking, for him to build muscle. Exercise is also important for muscle development.
Nutritional balance is important for growth, as well as other aspects of health. He is not likely to be getting adequate nutrients from hay alone, esp essential fatty acids, omega 3 etc. He will not get those from a salt lick, and in fact horses dont tend to get much from salt licks, so id look at better nutrition. Does depend on what's in the hay etc, so first doing a diet analysis before working out what supps may be best.
As to ingredients of supplementary feeds, firstly, horses need to be fed certain ingredients little & often to get much out of them, particularly high fat & other rich or difficult to digest feed, so you need to feed at least 2 small meals daily, preferably more, esp if fat/oil and high starch ingredients like grain fed.
Fat/oil can be good, but it's not readily digested by horses. Should be built up very gradually over a few weeks, feeding little & often, so the horse can develop & maintain the enzymes necessary to digest it. Canola is also high in omega 6 oils, which is more often well supplied elsewhere, while omega 3 is generally in short supply. So I'd consider adding stabilized linseed/flax or such rather than canola or sunflower.
Rice bran & beet pulp are good, relatively high calorie, easily digested ingreds. Adding some copra &/or lucerne/alfalfa are also good options. Horses have small stomachs so along with consideration of little & often being important, 15lbs plus per feed is quite a bit more than ideal.
Oats are lowest starch, easiest to digest of cereal grains, but still high starch & not good in large quantities, infrequent meals or for some horses, so while that may well be best option, I'd see how he went without them, considering other options before grain.