Such changes have not completely eliminated all risks; periodic accidents have continued to result in the deaths of horses and livestock. One of the deadliest incidents in Stampede history occurred in 2005 when, late in a trail ride meant to help celebrate the province's centennial, a group of about 200 horses spooked and in the melee nine horses were killed after they were pushed off a city bridge into the Bow River. While similar trail rides had been completed without incident in the past, Stampede officials announced they would not attempt any further rides unless they could ensure the safety of the horses.