Scientific update on laminitis: obesity, soaking hay and the use of ACP

Laminitis is an extremely common and painful condition occurring in around 7% of the UK equine population.

It is not within the scope of this scientific update to discuss the condition as a whole but for an excellent information sheet on laminitis by the British Equine Veterinary Association, please click on this link and then click on the leaflet which appears at the top right hand corner of the page.

Two very recent studies have been carried out which are relevant to owners of laminitics.  

The first, conducted by the members of the British Equine Veterinary Association with results released in 2009, found that obese animals with laminitis are more likely to get more severe laminitis than their thinner counterparts. Although this seems logical it helps focus the mind even more on our duty as owners to prevent our ponies and horses from becoming excessively obese. Further, it provides food for thought for judges when formulating what they consider to be an appropriate condition for a winning pony or horse at a show.

The second study1 was concerned with the management of laminitis and obesity by soaking hay in water prior to feeding in order to reduce its water soluble carbohydrate (WSC) content, which is its sugar content to you and I.

Previous studies have shown that prolonged soaking of chopped hay in large volumes of water can result in the leaching of nutrients, including WSCs.  However because in the UK we tend to soak long stemmed hay in relatively small volumes of water over a number of different periods, this study aimed to investigate the effects of soaking hay for set periods of time.

Nine different hays were soaked for 20 minutes, 40 minutes, 3 hours and 16 hours and their WSC content were analysed before and after.

The results showed that the leaching of the WSCs were very variable and less than previously reported from the chopped hay. Although this is a useful method for reducing the WSC content of hay, there is concern that this may not be sufficient to render some hays completely safe to feed to horses and ponies at high risk of laminitis.

In an ideal world there is value in having hay analysed before feeding it and choosing the supplier with the lowest WSC content. It is not expensive to do and has the potential to save the horse from a future laminitic bout with the added bonus of savings being made on veterinary bills. I have had success in a number of ponies with equine metabolic syndrome where hay analysis has made a big difference in their management.

In addition this study highlighted that hay soaked for extended periods looses substantial amounts of other proteins, vitamins and minerals and in such cases it is important to ensure the horse or pony receives a balanced supplement to meet their nutritional requirements. 

Another outcome from the first study was that those horses that received the drug acepromazine (ACP) within their treatment regime had the best outcomes. This correlates with my own personal experiences and I have certainly found having used this drug for some time that patients seem to get better quicker.  Therefore even during repeat bouts of laminitis it is worth contacting your vet immediately to ensure that your horse or pony is receiving the best possible treatment.

For further information on hay analysis, managing the obese pony and equine metabolic syndrome please look out for forthcoming fact sheets.

Copyright Colin Tait 2009


1 A.C. Longland, C. Barfoot, P.A. Harris (2009) The loss of water-soluble carboyhydrate and soluble protein from nine different hays soaked in water for up to 16 hours.  Journal of Equine Veterinary Science, 29, pp 383-384