Horse Running on Treadmill

This is a retired Thoroughbred racehorse re-trained to be comfortable running on a treadmill. This is a common practice at veterinary hospitals to evaluate lung and laryngeal function. This is not a cruel practice, these horses are bred to run and are trained using positive reinforcement. You should note the horse's neutral expression throughout the demonstration; he is not exhibiting any fear or anxiety.
Client horses brought in for evaluation are harnessed in to prevent injury as they are not trained to run on the treadmill (they are also hooked up to all sorts of monitoring equipment to make a diagnosis). The school-owned horses are very familiar with this procedure and are not typically harnessed in. If you are able to hear the speaker, he explains the process well.
I have disabled comments due to the volume that kept coming to my inbox. I hope I have addressed any concerns that viewers have had. Have a nice day :)