Can you help me identify this button?

I found this old button while digging at an old home site from the 1800's on my property. I can't find anything on it on the internet. There is a Burro Brand internet site but it is wooden saw horses that they sell and that company is not that old. On the back of the button it is all rusted out with no visinle lettering. I am guessing that this button is from some sort of clothing but as I mentioned above I can't find anything on the internet about it. It says Burro Brand and there is a cowboy pulling a stubborn mule with a rope in the picture in the center of the button.