Equine Science Update
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Soaking hay before feeding cannot be relied on to make it safe for laminitis-prone horses, according to a recent study conducted by the Laminitis Consortium.

The Laminitis Consortium comprises equine veterinary, nutrition and research experts interested in collaborating on the important topic of laminitis. It includes the authors of this work: Dr Pat Harris of the WALTHAM® Equine Studies Group, Clare Barfoot of Mars Horsecare UK Ltd and Dr Annette Longland of Equine Livestock and Nutrition Services.

One of the factors that has been recognised as increasing the risk of laminitis is the over consumption of water soluble carbohydrates (WSC).

It has been recommended that obese animals and those at risk of laminitis should be fed hay with a non-structural carbohydrate (WSC and starch) content of less than 10%. Soaking hay in water before being fed has been suggested in order to reduce the WSC.

Previous studies have shown that the prolonged soaking of chopped hay in large volumes of water can result in the leaching of nutrients, including soluble carbohydrates. However, because common practice in the UK tends to involve long-stemmed hay, soaked in relatively small volumes of water over varying timescales, the Laminitis Consortium’s study aimed to replicate such a practice.

The study, which was completed earlier this year, examined the loss of water-soluble carbohydrates from nine different hays submerged in water for up to 16 hours. It was presented to the biannual Equine Science Symposium in America in May 2009. The proceedings of the meeting have been published in the Journal of Equine Veterinary Science.

The nine different hay samples were analysed for WSC and then soaked in cold water. The soaked samples were subsequently analysed after 20 minutes, 40 minutes, three hours and 16 hours.

“The results showed a highly variable leaching of WSC and substantially less leaching than reported previously for chopped hay soaked for 30 minutes” explained Clare Barfoot. “Very few samples reached below 10% WSC, despite prolonged soaking. The concern is that this strongly suggests that soaking may not be sufficient to render some hays safe to feed to horses and ponies prone to laminitis.”

“Our current advice is that ideally you should analyse your hay before feeding it to an animal at high risk of laminitis and choose hay with the lowest WSC content you can find. Soaking hay provides an additional safeguard but should not be relied upon,” concludes Clare.

The study also highlights that if hay is soaked for extended periods, it may not meet the nutritional requirements of the animal because substantial amounts of other nutrients, protein, vitamins and minerals will also be lost. In such cases it is even more important that the horse or pony should receive a balanced supplementary feed.

The Laminitis Consortium is continuing its work in this area and hopes to be able to identify practices that will be of greater benefit to the horse owner faced with hay of unknown WSC content.

For more details see:

The loss of water-soluble carbohydrate and soluble protein from nine different hays  soaked in water for up to 16 hours.
AC Longland, C Barfoot, PA Harris.
J Equine Vet Sci (2009) 29, 383 - 384
Written by Mark Andrews. Published online 18.07.09.  
© Copyright Equine Science Update  2009
Laminitis: value of soaking hay?
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