Next year's Olympic equestrian events at Sha Tin and Beas River and the pre-Games trials starting next weekend could be postponed or cancelled because of extreme heat, a top veterinarian involved in the events said yesterday. Christopher Riggs, veterinary services manager of the Hong Kong Equestrian Company, said that horses in the pre-Games events might perform poorly or suffer heat exhaustion in Hong Kong's heat and humidity. 'Extremes of weather could lead to the competition possibly being postponed, cancelled or modified,' he said. He said the courses could also be shortened to adjust to the summer weather. John Ridley, the Jockey Club's head of racing operations, said the first indoor air-conditioned Olympic equestrian training arena had been installed, providing a stable temperature of 22 degrees Celsius. Air quality at the venue is being closely monitored. He said the stables had high ceilings and good ventilation with air-conditioning and fans. Cooling stations have also been installed in all training and competition venues where the horses are cooled by fans or sprayed with water. 'The horses are being cooled down quickly,' Mr Ridley said. Mr Riggs said that veterinarians would help monitor the weather and advise the jury members on whether events should be postponed. Mr Ridley added that statistics showed the weather in Hong Kong in August was suitable for equestrian events. The equestrian trials will be held from August 11 to August 13. Some 17 horses from different countries have arrived in Hong Kong to take part in the events. Mr Riggs said diagnostic and surgical facilities had been installed to keep the horses healthy. Thirty veterinarians will be positioned around the course during the events.