I read a study done in Canada on feeding beet pulp in its' dry form. Even when fed half their daily ration in beet pulp
dry there were no expansion issues. Apparently the danger of feeding beet pulp dry is an urban legend. I have always soaked mine for the horses- it seems more palatable that way.
http://www1.agric.gov.ab.ca/$department ... ll/hrs3243
Here is an excerpt from the article:
Myth: "Beet Pulp Must be Soaked Before You Feed It."
"If you don't soak beet pulp before feeding it, it'll swell up and rupture the horse's stomach." "Beet pulp will swell up in your horse's esophagus and cause choke if you don't soak it first." These are just a couple of the diabolical warnings surrounding the feeding of beet pulp. Because beet pulp seems to "grow" when water is added, somebody surmised that it could be a hazard if fed dry because it would absorb saliva and gastric juices, swell up, and block the esophagus or cause the stomach to burst. Although inaccurate, these evil predictions deter many horse owners from even trying beet pulp.
Beet pulp may soak up water like a sponge, but it cannot soak up saliva quickly enough to expand in the esophagus and cause choke. Instead, choke associated with beet pulp (particularly the pelleted form) is often in response to the particle size and the horse's aggressive feeding behaviour, rather than the actual feed itself. Horses that bolt their feed without sufficient chewing, or do not have adequate access to water, are far more likely to choke, regardless of the type of feed, compared to horses that eat at a more leisurely rate.
Nor is it likely that dry beet pulp will rupture the horse's stomach. The equine stomach holds 2 to 4 gallons. This volume is equivalent to 4.5 to 9.5 pounds of dry beet pulp, which is more than most horses receive in a single meal. Likewise, most food that enters the stomach passes on to the small intestine within 15 minutes or less—and for those of you who have timed how long it takes beet pulp to expand, it's longer than 15 minutes. Assuming free access to water, horses will voluntarily drink enough water to adequately process any amount of beet pulp consumed (1.5 to 2 litres per pound of beet pulp). Along with this drinking water, fluid is constantly entering the digestive tract, so beet pulp will not "suck the horse dry." Ultimately, the 40 to 50 gallon capacity of the equine digestive tract is more than sufficient to contain even a very large meal of beet pulp. The only horse in danger of a gastric rupture is one suffering from impaction or other severe lack of normal peristaltic movement.
So, contrary to popular belief, you don't have to soak beet pulp (either the pelleted or shredded form) in water to feed it safely to horses. Research at several universities, including some of my own studies, have fed dry beet pulp in amounts up to 50% of the total diet without choke or other adverse reactions. Likewise, many, many tons of dry beet pulp-based feeds are fed annually without incidence. For example, most commercial feeds designed for geriatric horses contain large amounts of beet pulp and are fed straight out of the bag without being soaked first. If you choose not to soak the beet pulp before feeding it, make sure your horse has access to as much good, clean water as he wants (which should be the case no matter what you feed).
Although soaking beet pulp is not necessary, there are several good reasons for wetting it down before you feed it. Soaking beet pulp may make the feed easier to chew, particularly for older horses with bad teeth. Soaked beet pulp may also be more tasty and it provides a useful method for hiding minerals or medications. If your horse gobbles down his feed or is prone to choke, it might be a good idea to soak your beet pulp. And while horses will drink water on their own, pre-soaked beet pulp is a good way to get some water into your horses, particularly in the winter when they may not be as inclined to drink what they need. So, if soaking beet pulp fits into your feeding management, by all means, do it. You don't have to soak beet pulp overnight-most of the expansion takes place within the first 3 to 4 hours.
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I use the shredded beet pulp as it has no molasses- the pelleted form does. Pellets would be far easier to feed if I could find them without molasses.