I'm concerned about the wheat hay. We've seen strange things happen to cows that are fed a diet of only wheat hay; like winter tetany (similar to grass tetany.) It's a calcium-phos imbalance caused from feeding basically only wheat hay which is what this horse is getting. Wheat hay is high in phos compared to other hay and if you feed it straight, it is recommended that a mineral lower in phos is fed.
I did a search and found this:
http://www.understanding-horse-nutrition.com/nutritional-secondary-hyperparathyroidism.html
It says in part:
The two earliest signs of this disease are a shifting lameness and tender joints. However, since this disease often affects horses anywhere from weaning to 7 years of age, these first two symptoms can easily be attributed to the horse's training or exercise regimen.
Because of this, it is sometimes hard to catch this disease in its early stages.
However, the next two symptoms, reluctance to move and a stiff gait are usually serious enough symptoms to warrant a call to the vet in the eyes of most owners. Therefore, when these symptoms appear, the horse is more likely to get early treatment.
All the symptoms of NSH are caused by the bone losing its mineral content, and as a result, tiny fractures occurring in the bone.
This eventually leads to a loss of bone integrity, and a cartilage disruption, which eventually leads to tearing and/or detachment of tendons and ligaments.
As the minerals in the bone are replaced with fibrous tissue, the bones thicken, and a physical distortion occurs. Because the facial bones are most often affected with this disease, it has been termed "big head" in the past.
In the early 1900's when it was most prevalent, Nutritional Secondary Hyperparathyroidism was often called "bran disease" or "miller's disease" because horses that consumed large amounts of bran by-products, particularly that of wheat bran, were most often afflicted.
When the facial bones are affected, the horse often has trouble breathing, which is what usually warrants the veterinary call that leads to eventual diagnosis.
As NSH progresses in the facial bones, the horse will eventually have trouble chewing as well as dental pain. This will lead to a decreased intake of food, which will eventually result in weight loss and a poor body condition.
Compounding the problem in these diets are the cereal grains, which are extremely low in calcium, while being very high in phosphorus. Most cereal grains have a Ca
ratio of 1:6 or higher!
Unfortunately for most horses, this diet is still very common in today's horse population. Many horses receive grass hay as their forage and then corn or oats, or some combination of both as their grain.
Fortified commercial products usually do not have this issue, as they contain added calcium for the most part, but it is still something to keep in mind if you are feeding large amounts of cereal grains (more than 4-5 pounds/day).
Diets that are heavily supplemented with wheat bran or rice bran can also cause NSH. However, there are fortified rice brans available on the market today that contain added calcium to keep the ratio where it should be.
How is it treated and prevented?
The good news about NSH is that it is easy to treat. The diet must simply be altered to provide more calcium while reducing the phosphorus so that a correct Ca
ratio is reached.
For early treatment of the disease, a diet with Ca
ratios ranging from 3:1 to 6:1 has been advocated.
In older horses that contract the disease, the prognosis is very good. The bony changes will take a few months to reverse, and some slight facial distortion may be permanent, but they will usually not have lifelong problems resulting from the disease.
However, in younger horses, this disease is much more serious, because their bones are still growing. This disease can cause serious problems to the long bones, and how serious the problems are depends on if the horse will suffer lifelong problems as a result of the disease.
The easiest and most effective way to prevent this disease is to ensure that your horses receive a diet that has a balanced Ca
ratio, particularly if there are growing horses in your herd.
Just as essential is to ensure that the horses have enough calcium, as that can cause problems even if the Ca
ratio is correct.
Nutritional Secondary Hyperparathyroidism is a disease that can be problematic in horses. Thankfully it is fairly rare in today's horse world, due mostly in part to the large amount of fortified feeds available to today's horse owner.
However, it is still around, despite is easy prevention, so horse owners should be aware of the symptoms of this disease and how to prevent it. .
Copyright 2008 Understanding-Horse-Nutrition.com
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Anyhow, it's worth considering. Again, I'd get him some other type of hay as fast as possible.
Good luck!
