Hay soaking is one defense against laminitis, but don’t forget supplement nutrition

Soaking hay for the delicately constituted horse works, but you need to understand the practice to get it right.
Most candidates are horses that are prone to laminitis. Onset symptoms often include overconsumption of water-soluble carbohydrates or fructans. Likewise, we have seen older, obese and sedentary horses that seem to be intolerant of water-soluble carbohydrates at greater than about 10 percent of their feed. Whichever the case, these problem horses require some kind of feed modification when it comes to hay.

Although it sounds confusingly technical, it’s worth understanding how laminitis works. In a horse’s gut, starch is rapidly broken down to glucose by amylase in the horse’s system, but fructans aren’t. Some fructans will escape the small intestine and it’s possible they will ferment in the large intestine. When that happens, the bacteria turns to lactic acid.
When large amounts of sugar, starch or fructans show up in the large intestine, fermentation is rapid. This extensive fermentation in the large intestine produces substantial lactic acid, which drops the pH. If the decline in pH is drastic enough, bacteria in the intestine will disintegrate, releasing toxins that are stored in the bacteria cell walls.

These toxins enter the bloodstream and are thought to be the principal cause of equine laminitis.
The idea behind soaking hay prior to feeding is knock out some of the water-soluble carbohydrates. Cool-season grasses such as fescue, bromegrass and timothy accumulate fructan as their growth-storage carbohydrate. Clovers and alfalfa accumulate starch rather than fructans. Warm season grasses such as crabgrass, switchgrass, and sudangrass do not accumulate fructans.
Feeding is an important factor in the onset of laminitis. Typically laminitis occurs during periods of increased or rapid intake of non-fiber carbohydrates. While we can reduce the amount of water-soluble carbohydrates by soaking hay in water prior to feeding it, some horses are much more tolerant of water-soluble carbs than others. In other words, there is substantial variation between horses and establishing minimum/maximum specs for water-soluble carbohydrates/fructans is tenuous at best.

So how effective is hay soaking, and if what works the best? Usually, removal is greater with warm water than cold. Chopped hays loses more water-soluble carbs than long-stem hay, and removal increases with length of soaking. In addition to fructans and water-soluble carbohydrates, soaking hay also reduces potassium and protein, especially during long soaks.

Research at the University of Minnesota compared soaking long-stem bud alfalfa, full flower alfalfa, mixed orchardgrass/alfalfa, vegetative orchardgrass and mature orchardgrass. Researchers there compared soaking in 70 degree water and 100 degrees at 15, 30 or 60 minutes. The hay flakes were put in mesh bags and crammed into a bucket with 6 to 7 gallons of water.

Results showed the following: Soaking reduced water-soluble, ethanol-soluble carbs and fructan content in all hays.
Generally, the 15-minute cold water soak resulted in the least reduction carbs and fructans, but it usually would cut the water soluble carbohydrates by a third or so. The 12-hour cool soak had the greatest reductions.
As expected, water temperate influenced carbohydrate removal, with warm water being more effective. But, the researchers did note a significant problem with the 12-hour soak—25 to 30 percent loss in dry matter.

Results from other researchers have also shown highly variable removal of water-soluble carbohydrates. Ryegrass probably has the highest levels of fructans for any grass, and very few ryegrass samples reached below 10 percent of water-soluble carbohydrates regardless of length of soaking.

While soaking hay certainly provides some improved safety, it is a practice that cannot be used with complete confidence.
In other words ,there is concern that soaking may not be sufficient to guarantee that hay is safe to feed to laminitis-prone equids. And soaking effects vary widely among hay types and soaking methods.
The conservative approach would be to have your hay tested for water-soluble carbs, and devise a feeding program based on the test levels of water-soluble carbs.

Complimentary MFA horse feed would be EasyKeeper Golden Years or Legends CarbControl.
As an expedient field practice, soak hay in warm water for 30 minutes, or in cold water for an hour. The Brits are over the moon about soaking hay and have a number of cute hay soakers and steamers, but they are expensive.

Check out www.horseit.com to learn more. But if you’re pricing from that site, remember to convert from British pound to U.S. dollars.

Of course, you could hillbilly engineer one yourself for under $100 with a plastic truck box, a garment steamer, $5 of CPVC pipe and some window screen.

Dr. Jim White is ruminant nutritionist for MFA Incorporated.