Intense exercise affects the make-up of gut bacteria in Thoroughbred racehorses, researchers have found. Scientists with the Wrocław University of Environmental and Life Sciences in Poland found that intense exercise significantly influenced the abundance of Firmicutes and Bacteroidetes groups. The study involved 17 healthy three-year-old Thoroughbred racehorses trained at Partynice Race Course in Poland. Their daily training regime involved trotting and cantering. All were fed the same forage. The exercise test used in the study was participation in a 1900-metre race at the course. Fecal samples were collected for analysis from each horse before the race, and 48 hours after, for comparison.