Ban would have had “potentially negative impact on both equine welfare and the industry.”

The decision not to list MSM – dimethyl sulphone – as a prohibited substance in international horse sport has been welcomed by the British Equestrian Trade Association (BETA). 

Earlier this year, MSM was included by the International Federation for Equestrian Sports (FEI) as a proposed Controlled Medication and Specified Substance on its 2024 Equine Prohibited Substances List (EPSL).  

Following lobbying and the preparation by BETA’s Feed Committee of an extensive submission justifying MSM’s continued unlisted status, last week the EPSL for 2024 was published without the proposed inclusion of MSM.

“The BETA Feed Committee provided extensive technical evidence to support our belief that defining MSM in this way could have had a significant and potentially negative impact on both equine welfare and the industry,” said BETA executive director Claire Williams. 

“We are delighted that our challenge proved compelling enough for the FEI to reconsider its decision and change the list.”

Ubiquitous to the equine diet

MSM is an organic sulphur compound that occurs naturally in plants such as maize, oats, apples and alfalfa. 

It is an internationally recognised feed material, commonly used in equine diets, where it is widely fed at rates of up to 25g a day to horses competing under FEI rules without regulatory incident.

In addition to direct transfer from plant-based diets, metabolic pathways show MSM can be formed via metabolism of methionine which, as an essential ie. indispensable amino acid, is required in the diet of all equines. 

Given that MSM is both natural and ubiquitous to the equine diet, riders are not able to avoid its presence in their horses’ diet, and listing on the EPSL could have led to regulatory issues without pure MSM having been fed.

“We are immensely relieved that the proposed listing of MSM has been dropped and that the current status of ‘Unlisted’ is maintained. 

“It allows riders competing under FEI rules continued access to this important ingredient that plays a supportive role in protecting the sport horse from exercise related oxidative damage,” added Claire Williams. 

BETA represents the interests of more than 800 member companies engaged in the manufacture, distribution and retailing of equestrian-related products. 

While representing all aspects of the equestrian industry, BETA’s membership is responsible for 90% of the UK market for equine feeds, as well as significant proportions of overseas markets.