You say 'percheron cross'. Is he gray? If he is, you could be dealing with one of the few horses that had internal spread of malignant melanoma. Check it out.
Anemia can very negatively affect EVERYTHING a horse's body has to do. It MUST be fixed before anything else good can happen.
I would opt for a CBC and a Blood Chemistry panel. You are pretty much 'shooting in the dark' without knowing just what his PCV, red count and white blood cell count (and differential) are or if you have good liver and kidney function, etc. You cannot have very good direction without these values being known.
When we have gotten in very thin (BS 1 or 2) we treat about like you did Vet-wise, but we always feed for muscle gain and anemia.
You can treat for anemia without causing a problem if it does not exist. But, I would guess that this horse is very compromised.
We always use injectable Vitamin B Complex, injectable Liver of and Iron and injectable Vitamin A. We just never inject them. We dose them with the injectable ORALLY by just squirting it in the horse's mouth. I will give 5cc of each one time a week for as long as it take to get the horse going right.
You are trying to put 'meat' on his bones. You want to build muscle. Feeding 'cool calories' and fat cannot put muscle on a horse. You need good quality protein with the essential amino acids. These are the 'building blocks' for growth and for muscle weight gain. Fat can give you a good hair coat and can put fat on a horse. Fat contains only 'empty calories', has no actual nutrients and never changes into red muscle.
I would put him on good grass or winter wheat pasture. If that is not available, then feed him at least half of his hay in alfalfa and limit the amount of grass hay he gets. I would feed no less than 1% of his body weight in alfalfa and no more than 1 1/2% of his body weight in grass hay. Add 1 pound of Soybean meal a day. I have even fed as much as 2 pounds a day to big horses. Obviously you start with a handful. Work it up to a cup of it and keep working up from there gradually. Same with adding alfalfa. Add the soy to a grain product that is safe for drafts. I would mix in a handful or two of sweet feed just to get him to eat it. If he does not eat it, take it away in an hour or so and feed again nest feeding. The Vitamins will make him hungry and taking uneaten feed away will get him on a good eating schedule.
He is stuffing on grass hay because he is protein starved. The huge hay belly is counter productive. I would also start making him exercise a little. Forced movement is not going to kill him and will make everything work better.
I would also get a good loose mineral for him. [This is not the same thing as mineral salt.] He is probably very deficient in Ca, Mg and Zn. These have needed to be corrected in every poor horse we have ever gotten in.
Last edited by Cherie; 10-25-2012 at 10:04 AM.