I start young Thoroughbreds for racing, and occasionally I work with a horse that gets really "girthy." Some even get to the point of falling down, and others get a hump in their backs as if they are going to explode. Can you tell me why this happens, what it is called, and what I can do to prevent it?

 We see two distinct responses when comparing yearlings and 2-year-olds in the beginning of their breaking period to older horses at the track. Imagine the fear a young horse must experience upon being saddled and girthed the first time. Evolution has prepared him for a response to fear of the unknown with the "flight or fight" response.

I am sure that, in the horse's mind, this is a simplified version of a more complex response to another form of restraint. The weight of the saddle and confinement of the girth must be perceived as restraint, at least in the early stages of training. Therefore, we might expect to see a release of both adrenalin and endorphin. A name for the resulting behavior would be fear- or pain-induced aggression.

To minimize such behavior, start the horse in a stall or small round pen using just the saddle and progress to a surcingle buckled loosely. Gradually work up to a saddle with a girth. Care should be taken to make sure the saddle or a heavily padded surcingle does not slide beneath the horse. It is also a good idea to first stretch the forelimbs after loosely buckling the girth and give the horse a few turns around the barn before tightening the girth