Q: I have two ponies with metabolic problems that cannot eat dry hay due to the high NSC content, so I usually soak it. However, during the summer I worry it could go bad after soaking for hours in the heat. What are the benefits and risks of feeding soaked or steamed hay during summer? How can I soak my hay but avoid mold growth?

A: Soaking hay reduces its water-soluble carbohydrate (WSC) content—a component of nonstructural carbohydrates (NSCs)—making it potentially safer for metabolic horses to eat. However, it doesn’t guarantee the hay will be safe for every horse, especially those with more severe conditions. Soaked hay might also benefit horses with respiratory issues by reducing the amount of airborne dust.

The current recommendation for soaking hay to reduce NSC content is to completely submerge the hay in warm water for 30 minutes or cold water for one hour. When hay sits in water for extended periods (e.g., overnight), the risk of mold and spoilage increases, and beneficial nutrients such as protein and minerals leach out.

Keep in mind: While soaking reduces sugar content, the remaining NSC levels might still be too high for some metabolic horses.

Benefits of Steamed Hay for Horses

Steaming hay doesn’t reduce its NSC content as significantly as soaking, but it’s very effective at reducing dust particles and bacterial counts. This makes it more ideal for horses with respiratory challenges.

One key advantage of steaming (over soaking) is it preserves more of the hay’s nutritional content, including protein and minerals. This makes it a better option than prolonged soaking when you’re concerned about nutrient loss. While it might not reduce sugars as much as soaking, steamed hay offers strong benefits for overall hay hygiene and respiratory health.

Hay Safety Considerations in Summer

Proper hay handling, especially in hot weather, helps support your horse’s overall health. Feed soaked hay immediately after you’ve removed it from the water and drained it.

To help make soaked hay safe for your horses:

• Only soak one day’s worth of hay at a time.
• Discard any uneaten hay at the end of the day.
• Rinse the soaking container thoroughly after each use to prevent mold from developing between feedings.
• Discard the sugary soaking water after you’re done to avoid the horse having access to it.

Take-Home Message

Low-NSC forage can help owners manage metabolic horses. Soaking hay helps reduce its sugar content. However, proper timing and technique make all the difference. During summer, soak hay for no more than one hour and feed it immediately. Don’t let soaked hay sit around before feeding and always clean your soaking equipment to avoid mold-related health risks.

Do you have an equine nutrition question?