Pasture-associated laminitis has been linked to the over-consumption of water-soluble carbohydrates (WSC) such as fructans, glucose, fructose and sucrose in horses and ponies. For those animals prone to laminitis, soaking hay prior to feeding helps to reduce the WSC content. An upper limit of 100 grams of WSC per kilogram of forage dry matter has been advised, but are common practices used today adequate to reduce WSC in hay?
 

Read more about this research below!
 

Objectives:

to determine the amount of water-soluble carbohydrates leached from hays soaked according to common practice.
 

Hays & Treatments
 

• 9 different long stemmed mixed hay varieties predominantly rye grass or Timothy
• 2 flakes of approximately 4.5 lbs either kept as condensed flakes or shaken loose
• Flakes and loose hay were soaked in 25 liters of tap water, sufficient to submerse the hay completely, and kept at ambient temperature (about 46°F) 
• Samples were collected for analysis after 20 minutes, 40 minutes, 3 hours and 16 hours


Measurements:
 

• Total water-soluble carbohydrate and dry matter content 
• Water-soluble carbohydrate constituents: fructan, sucrose, glucose, fructose


Results:
 

• No differences noted in any measurement between condensed flakes or hay shaken loose
• Soaking hay for 16 hours resulted in an average loss of 27% WSC, 24% fructan, 41% fructose, 45% sucrose, and 56% glucose.


Take Home Message:
 

Although soaking hay for 3 or 16 hours did significantly reduce WSC components, the response was variable and the contents of three of the hays remained substantially above the suggested upper limit of 100 grams per kilogram of forage dry matter.
 

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References:
 

Longland AC, Barfoot C, Harris PA. Effects of soaking on the water-soluble carbohydrate and crude protein content of hay. Vet Rec. 2011 Jun 11;168(23):618. doi: 10.1136/vr.d157. Epub 2011 Jun 7. PMID: 21652661.