(WYTV) — Why do we say someone got your goat? It means someone made you angry or annoyed, but why would we mix anger with that animal?

Goats tend to be gentle creatures, especially if they’re around humans a lot.

It’s an American expression that we first see in print in 1909.

One theory says it has to do with horse racing. Let’s say you had a racehorse you want to run the next day but your thoroughbred is a bit high-strung, nervous. The horse can be a very moody animal. You put a goat in the stall with it. Goats are calming animals and your horse relaxes.

But another breeder wants to race his horse tomorrow and ruin your chances, so he sneaks into the stall and gets your goat — snatches it away, upsetting your horse.

In an episode of The Sopranos, Tony has bought a racehorse and the trainers keep a goat in the pen with her to calm her down before racing.

An old English belief says keeping a goat in the barn would have a calming effect on the cows, to produce more milk. Get the farmer’s goat and the cows produce less milk.