The How and Why of Soaking Hay

Horse owners have been wetting or soaking hay as a feed management practice for many years. Soaking hay for horses can be invaluable when feeding a hay that is a little dusty as a result of soil contamination or where it was stored in the barn. Horses that have allergies and are sensitive to the natural dust and particles in hay can benefit significantly from wetting or soaking hay.

In recent years, horse owners have become more aware of the impact of rapidly digestible carbohydrates in the diets of their horses. We now know that high intakes of water soluble carbohydrates (as indicated on a lab analysis as WSC or water soluble carbohydrates and including sugars and starches) can be a liability for some horses.

Not all hay has high WSC, and not all horses need to consume a diet with limited starches and sugars. But the fact is that as our horses live longer and are fed forages with better nutritional quality, we are seeing more and more of them who are overweight or afflicted with metabolic conditions such as Insulin Resistance (IR), Equine Metabolic Syndrome (EMS), or Pituitary Pars Intermedia Deficiency (PPID or Equine Cushings Disease). Horses with Polysaccharide Storage Myopathy (PSSM), a genetic condition that affects how the horse stores glucose as glycogen in the muscle, also need a diet low in sugar and starch. Too much sugar in the diets of these horses causes them to “hit the wall” when working hard. They often have no energy and can even go into a metabolic crisis and experience painful tying-up episodes if consuming a diet with too much rapidly digestible carbohydrate.

The hay we feed our horses has undergone years of genetic selection so as to provide commercial forage growers with grasses that have superior nutrient content, high yield, and good stress tolerance. The agronomic practices including cultivation, and water and fertilizer applications under which these forages are grown, all affect their nutritional analysis. Increasing numbers of horse owners are availing themselves of this superior forage in the form of hay, only to find that it’s almost too good for the average horse. Grass hays in Western Canada are known for their superior digestibility and excellent energy content. At least part of that energy is due to high sugar content.

The potential impact of this on our horses has focused more scrutiny on how to better manage a potentially high sugar hay as part of a healthy diet. Soaking hay before consumption has been proven in peer reviewed research trials to be an effective way to reduce the