There is a renewed debate in the US horse racing industry over the use of the drug Lasix.
The medication is used to treat internal haemorrhaging in horses, but there are increasing concerns it is being used as a performance enhancing drug instead.
Lasix is only legal in races in the US and Canada, while other countries say its use is damaging horses and the sport as a whole.
Al Jazeera's Cath Turner reports from Pennington, USA.
WARNING: Some viewers may find some of the scenes disturbing.
Source: Al Jazeera