Interesting, maybe, but not exactly scientific in spite of its trying to disguise itself as such.
Any paper that has a statement like this in its summary:
[SIZE=3]It will, by now, be clear to the veterinarian that both gastric and colonic ulcers in equines are better described as induced conditions rather than diseased states. The well-known "cure" is simply to turn a horse out to pasture for a few months. If the condition is reversible by simply allowing the animal to feed and digest naturally, it is equally clear that GI tract ulceration is an induced condition arising from modern husbandry.
Ideally, we would revert to feeding practices of 100 years ago. Unfortunately, this is not practical or economical for most. Thus, we are forced to alternatives that will allow the horse to digest as close to natural as possible, and minimize the side-effects of modern feeding regimens.
Outs the author as not a scientist, strictly speaking, and probably someone with an agenda. Which is not to say some of the points made in the paper might be perfectly good ones, but there is NOTHING in that paper that makes a conclusion as sweeping as the one above a certain thing, to be stated with that sort of conviction. 100 years ago the horse was used in a completely different manner, and we have NO IDEA what the prevalence of ulcers may have been at that time. Horsekeeping was far from "ideal" back then.