A leading horse food manufacturer has advised consumers not to feed animals as they are investigating the presence of a prohibited substance in some of its products.

Gain Equine Nutrition says it has found synthetic beta-agonist-approved sylpatrol in some of its horse feed ranges to enhance performance in some beef production systems outside the EU.

Contamination was found in products in France, and as a result feed products in Ireland and the UK were tested.

Gain Equin argued that the synthetic substance was not part of any formation in any of its animal nutritional ranges.

Upon learning of the problem, its quality and control team immediately began testing the feed products and keeping samples.

It said in a statement this evening that it was working with all appropriate agencies, including the Irish Department of Agriculture, to fully investigate the source of the pollution.

Martin Ryan, Head of Gain Equine, said: “We sincerely apologize to our valued customers for the inconvenience caused by this incident and we are committed to fully informing you.

“Detailed investigation and detection of all feed component sources is urgently needed to determine how this external contamination can reach certain batches of our horse product.”