First let me say that you have succeeded in helping this little horse look a LOT better-Congratulations on your dedication and willingness to do whatever needed to be done!
If it were me, to try to further 'fine tune' the program for him--- Yes,I would definitely have a knowledgable equine vet check his teeth-some miniatures DO seriously need teeth work, at a young age. Your proposal about worming sounds very reasonable, too-and the Probios IS a good idea, because it helps to replenish the vital-to-proper-digestion intestinal bacteria that horses so need for healthy digestive process to continue. I also agree that the blood work would be a good idea-let you know what is 'going on' INSIDE the horse, and what might need to be adjusted in either his health or nutritional program as a result.
I'm not familiar with the concentrated feed you mentioned, but I do know that Purina's "Equine Junior" is formulated for young stock, so it might be indeed be good to return to it. I would go online, or into the feed store, to read the product labels, to find out the various levels of protein, etc., in each feed, and also, the recommended feeding level,and whether it can be successfully 'prorated' for a miniature. Of course, any change would be VERY gradual, and then if the total amount seems too much(i.e., he is not cleaning it up at a feeding), then I would reduce it, but very gradually and by very small amounts at a time.
Good alfalfa can indeed be high in protein; it also is the most nutritionally complete HAY that can be fed(remember, I said GOOD alfalfa!) I would NOT feed first cut, as it is generally VERY 'rich', "dairy cow" hay.
I don't see much of a hay belly on the little horse, and, especially going into winter, I would be cautious about cutting back too far on hay(as the digestion of hay helps keep the body warm in cold temps.)If you can find QUALITY grass hay(which, this year in NM, has NOT been easy!), then yes, I would try gradually replacing 'some' of the alfalfa with that good grass-perhaps eventually going to a half and half proportion. Young horses DO need a higher protein level than older ones-and everything recent that I have read and heard about protein is that unless a horse has health issues with their kidneys, excess protein will just be excreted by the body in the urine. For a horse that NEEDS to improve in condition, good alfalfa, carefully utilized, can be of great benefit. You just have to remember that with alfalfa, you introduce/increase it VERY gradually and with care!
The right kind/amount of exercise to improve fitness can be difficult. I am a big believer in round corrals, IF big enough(a MINIMUM of 40' for miniatures)-but not really for young horses, of less than 2 1/2 years or so. Leading one at a good trot can help(I tie them, with a quick release knot of course!)to the back of my training cart when I drive another, solid driving horse. I have trotted them behind my garden tractor, even-and I know some use golf carts-or even your truck, IF you have an experienced helper and a safe dirt road. Being able to spend LONG hours out in the big 'turnout' would help, I think-horses WILL move around, even if just at the walk, if they have the space-and that kind of mild exercise is better than none, for sure--I am a BIG believer in horses having a roomy living space, not having to spend long hours in small stalls or tiny pens-don't think that an hour or so of 'turnout' or work daily is a good tradeoff for 22-23 hours spent in a stall/tiny pen, if there is any choice in the matter. Maybe put water out there for him, and let him stay out there during the day?
Just my thoughts--again, high regards to you for doing all you have to improve this little guy's life! Keep us posted-your experiences are a great example!
Best wishes!
Margo
