Lots of gibberish and gobblygook has been posted about beet pulp on the internet over the years. I have fed it to my own horses for years and years. I used it when I got Tigger to help plump him up. It got him eating well, and it did the trick - he gained weight, got a beautiful healthy coat, much improved hoof quality, and became a nice little athletic endurance horse. Do I think that the BP was the reason? Well...no....it was a combination of things...though if you were to read this article that was recently posted on ridecamp you might be led to believe that BP is very bad for horses.
Okay, so now for the fun part. Below is the response from a veterinarian who really does know her stuff, especially about equine nutrition - as she answers an inquiry about the validity of the article in the provided link. Use this as a lesson to not accept everything you read as gospel, especially when it comes to horses, and the internet. Horse owners, and endurance riders especially (who me?) love to find things to blame things on, anytime something goes wrong with their horses. It can't possibly be human error, so we have to find something to blame, and resolve us of having any responsibility.
My advice about beet pulp (not that my advice is worth anything, but I have lots of experience with the stuff) -- if you are worried about it being a problem for your horse, don't feed it. If you feed it and it doesn't cause a problem, keep feeding it. Like I do. I don't make it a huge part of my horses diets, but it is handy for helping put weight on a thin