Steaming vs. Soaking to Reduce Hay NSC Levels

Hay soaking

When soaking hay it must be completely submerged, and it should be fed quickly after soaking so it does not mold.

Q:  My veterinarian just diagnosed my mare with insulin resistance and recommended I soak her hay because I haven’t had it tested. I’ve been doing some research and I’m wondering whether I could steam it instead?

A:  Horses with insulin resistance need to consume diets with low nonstructural carbohydrate (NSC, the sum of the starch and water-soluble carbohydrates [WSC] in the diet) levels. Generally, nutritionists and veterinarians recommend that the diet should contain less than 12% NSC on a dry matter basis.

Since the majority of a horse’s diet should be forage, it is important to consider the forage’s NSC content. There is no point in carefully feeding a low-NSC commercial fortified feed if the horse’s forage is high in sugar.

Ideally, you would test the hay so you know for certain what you’re dealing with and how suitable the hay actually is. If testing shows that the hay does, in fact, have a NSC concentration of less than 12% on a dry matter basis, then you could feed it with no further action. However, testing likely isn’t feasible if your hay changes frequently as is the case in some large boarding facilities or for those with limited storage.

When soaking hay it must be completely submerged, and it should be fed quickly after soaking so it does not mold. Research has shown that soaking hay in hot water for 30 minutes or in cold water for 60 minutes does reduce the WSC level. The amount of WSC leached from soaking varies from hay to hay and, while it will certainly lower the NSC, there is no guarantee that it will reduce it to a safe level. Of course, the only way to know for sure is to test the hay after it has been soaked.

Steaming, on the other hand, involves placing hay in a chamber through which steam passes. Commercially available steamers are safe and proven to create repeatable results. Hay is steamed for about an hour and the temperature should be held above 80°C (176°F) for at least 10 minutes before the hay is removed. While it is possible to create a homemade steamer it is very unlikely that one can generate the temperatures necessary to have a positive impact on the hay; in fact, not reaching high enough temperatures while steaming can actually lead to bacterial growth.

Research has shown that hay steaming improves palatability and significantly reduces mold spores and dust. In fact, steaming using a commercial device decreased the risk of horses developing inflammatory airway disease 63%.

To your question, studies have shown that steaming does cause a small, but significant, WSC content decrease. In a hay with a starting WSC of 12.6%, steaming for 50 minutes decreased WSC to 10.3%. Should the hay have had an initial WSC that was much higher, steaming might not have reduced the WSC content to within appropriate levels. However, this is a risk with soaking, too.

The only nutrient steaming removes from hay is WSC, whereas soaking can leach other valuable nutrients such as protein, some minerals, and overall dry matter. And, after soaking you are left with a large amount of water that’s contaminated with the leached nutrients and requires careful disposal. The water should not be released anywhere that it could contaminate waterways.

Given the convenience of steaming over soaking, the former is certainly an attractive option even though it might not lower the WSC as much as soaking. I would recommend that, if possible, you test your hay. If it already has low WSC then neither treatment is necessary. If you only need to reduce the WSC slightly I would be inclined to choose steaming. However, if WSCs need to be reduced more than a couple of percentage points, I would likely go with soaking.

About The Author

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Clair Thunes, PhD, is an independent equine nutrition consultant who owns Summit Equine Nutrition, based in Sacramento, California. She works with owners/trainers and veterinarians across the United States and globally to take the guesswork out of feeding horses. Born in England, she earned her undergraduate degree at Edinburgh University, in Scotland, and her master’s and doctorate in nutrition at the University of California, Davis. Growing up, she competed in a wide array of disciplines and was an active member of the United Kingdom Pony Club. Today, she serves as the regional supervisor for the Sierra Pacific region of the United States Pony Clubs. As a nutritionist she works with all horses, from WEG competitors to Miniature Donkeys and everything in between.

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Turf Paradise Daily Results and Activity

Results

Tuesday, February 27
Race# Race Type Purse
Race 1 Maiden $4,000 Overnight Overnight
Race 2 Claiming – $8,000 $10,000 Overnight Overnight
Race 3 Maiden Claiming – $5,000 $6,300 Overnight Overnight
Race 4 Claiming – $3,000 $7,000 Overnight Overnight
Race 5 Maiden Claiming – $5,000 $6,300 Overnight Overnight
Race 6 Claiming – $8,000 $10,000 Overnight Overnight
Race 7 Claiming – $3,000 $7,000 Overnight Overnight
Race 8 Claiming – $3,500 $7,000 Overnight Overnight



Early Entries

Sunday, March 4 Overnight
Race# Race Type Purse
Race 1 Starter Optional Claiming – $12,500 $12,500
Race 2 Maiden Claiming – $8,000 $7,000
Race 3 Claiming – $3,000 $7,000
Race 4 Claiming – $8,500 $8,000
Race 5 Allowance $14,000
Race 6 Maiden Optional Claiming – $30,000 $12,500
Race 7 Claiming – $3,000 $7,000
Race 8 Starter Allowance – $3,500 $8,000

Final Entries

Saturday, March 3
Race# Race Type Purse
Race 1 Optional Claiming – $4,000 $5,000
Race 2 Starter Optional Claiming – $10,000 $11,200
Race 3 Allowance $14,000
Race 4 Maiden Claiming – $5,000 $6,300
Race 5 Claiming – $16,000 $14,000
Race 6 Claiming – $3,000 $7,000
Race 7 Allowance $20,000
Race 8 Claiming – $3,000 $7,000