This is John Gray, who farms 18,000 pigs a year on an island off Essex, and has been using a slurry additive marketed by Epizym Ltd based in Tunbridge Wells, Kent, since 1996. “I installed slatted accommodation and very soon the neighbours complained about the smell,” he said. According to the company, after using their product, the smell on Mr Gray’s farm cleared up within six weeks.

The company claims that Epizym Pigs has reduced gross odour emissions by 53% and by 55% per kilogram pig liveweight. Silsoe Research Institute ran the odour assessment trial in their dynamic Olfactometer unit, using pig slurry taken from a trial run at the ADAS climate house. “The results were proof that odour levels can be halved,” said Giles Dadd, principal agricultural consultant for Epizym.