Q: I have inherited a mare that no one wants because every once in a while she spooks and bolts, big time, without warning. No one has ever been able to figure out for sure what sets her off. But she can go from normal one second to a serious panic the next. She spooks and takes off like she was shocked or stung by a bee. It can happen any time, even in her pasture, at the cross ties, in a trailer, or when you’re riding.

Our vet was out last week and saw her for the first time. He thought she was just a kind and gentle mare. In fact she was at the time, as she is most of the time. I explained that this is part of the problem, and probably why so many people have tried before and why so many people have been scared or hurt trying to be patient with her. She is just great until she freaks out. I told him we were not sure if we could keep her, and we were thinking about “putting her out of her misery.”

He asked me if anyone had ever tried “sacking her out.” He has never seen the procedure done, but thinks you just deliberately try to scare the horse until you wear it down, until it gets used to everything imaginable and nothing at all scares it. He suggested I talk to you about it. Can you explain how to do it and if you think it would work for this mare? If you don’t think it will work, what would you do?—Genevieve

A: First, let me tell you what I know about the term “sacking out” a horse. There are variations on how it might be done. In fact, in different horse disciplines and regionally in North America, “sacking out” can refer to procedures that boil down to at least three distinct behavior modification methods. In its simplest and maybe most popular meaning, “sacking out” is used to refer to a single specific step in acclimating a horse to saddling and having things on its back. A saddle blanket, cloth, or simply a burlap sack is rubbed on the back, then moved and slung around the horse as you might sling up a saddle onto the back of a horse. The objective is to simulate saddling and get the horse used to it before putting on the full weight of the saddle