Question

Will soaking hay pellets in hot water have any effect on nutrient content?

Answer

Though I cannot find any research that specifically measured nutrient loss in soaked hay pellets, steeping hay pellets in hot water (less than 60° C, 140° F) probably will not have much effect on nutrient content as long as the water is not near the boiling point.

Any concern would be primarily centered on nutrients like proteins, which can be sensitive to denaturing when subjected to high temperatures. Researchers soaked alfalfa and orchardgrass hays with warm water (39° C, 102° F) for various lengths of time (15, 30, and 60 minutes), and they found no significant difference in protein loss. In another study, hot tap water (59° C, 138° F) added to grass hay did not influence protein content.

As organic compounds, vitamins are also heat sensitive, yet soaking hays in warm (39° C, 102° F) or hot (59° C, 138° F) water did not affect their vitamin profile in one study. Pouring boiling water (100° C, 212° F) on alfalfa seeds showed no loss of vitamins except vitamin C. Note that boiling water was used in this study, and boiling water would not typically be used to soften hay pellets.

Carbohydrate losses after soaking in hot water are significant, but the sugars are leached out of the hay and into the water. When soaking hay pellets, the sugars may end up in the water, but the water is soaked up by the pellet, so the horse will consume them nevertheless.