Steamed hay better for equine athletes than soaked, Canadian study finds


Results from the first study to investigate steamed, soaked and dry hay in Ontario, Canada, have led researchers to conclude that steaming may be a superior method for managing hay – and horses prefer it.

Soaking and steaming are two commonly used methods for managing hay, especially for horses with certain health conditions, such as insulin resistance or non-infectious respiratory disease. Such practices have been based on British research, with University of Guelph graduate student Tiana Owens noting that there was little Canadian research in this area, so “information on Ontario hay was needed”.

“Horse caregivers often soak or steam hay to reduce its non-structural carbohydrate (NCS), including water-soluble carbohydrates (WSCs). A high dietary intake of these carbohydrates can be detrimental to some horses,” Owens said.

A hay steamer. Preliminary results suggest soaking hay significantly reduced WSC while steaming conserved WSC content.
A hay steamer.

The research team, which also included Madeline Barnes, Vanessa Gargano, Wilfredo D. Mansilla, Katrina Merkies, and Anna K. Shoveller, compared nutrient content, feed preference, and glycemic response between dry, soaked and steamed timothy-alfalfa hay grown in Ontario. Standardbred racehorses were used in the Equine Guelph-funded study for researchers to examine which hay treatment may be most suitable for performance horses.

Owens presented the results during her thesis defence last month.

Researchers teamed up with a local racing stable, and fed racehorses either soaked, steamed or dry hay, and tested their blood for several hours afterward to monitor their blood sugar response (also known as the glycaemic response).

They also addressed the behavioural aspects of the research, by investigating whether horses have a preference for steamed, soaked or dry hay. If soaking or steaming changes the nutrient content of hay, then the “mouth-feel” of the hay may be different with different moisture contents. Horses were stalled, and hay bags containing the different hay treatments were placed into each stall. How much time was spent investigating and eating at each bag, and the hay intakes were recorded.

Owens said that soaking in particular was expected to lower NSC/WSC the most. “Steaming has been noted to affect some nutrients in comparison to dry hay but not to the extent that soaking does, hence soaking is the treatment recommended by veterinarians to reduce NSC/WSC of certain hays when feeding horses with insulin-resistance issues,” Owens said.

Horses in the study were given a choice of steamed, soaked, and dry hay. The soaked hay was the least favoured.
Horses in the study were given a choice of steamed, soaked, and dry hay. The soaked hay was the least favoured.

In conclusion, Owens said: “Soaking hay reduced the non-structural carbohydrate content of Canadian first-cut mixed timothy-alfalfa hay, as anticipated. Equine athletes have very high energy and nutrient demands and steaming hay was an effective method to conserve these nutrients to maximize nutrient intake,” Owens said.

“These horses also preferred to eat steamed or dry hay over soaked hay, further supporting a recommendation that steaming is a superior method for treating hay for performance horses.

“These results, combined with the loss of nutrients when soaking hay, should make performance horse owners consider steaming their hay to better maintain its nutritional integrity.”

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