We have been working for the last several years to move to grass-finished beef. So we looked around for the different breeds which did best on just grass. In the middle of this, we found that a medium-framed animal was more efficient in turning forage (grasses, clover, etc.) into muscle. As well, smaller-sized animals fit into people's freezers and budgets better.
The Galloway is a Scottish breed, raised to survive on just about anything it can find during those long, harsh Scottish winters. Very similar to the Highland, except they are polled (no horns). The more commonly found version of this is belted, meaning it has a white belt in it's middle. This is from their being crossed with the "Dutch Belted" breed some generations back. They are known as "Belties".
(For more information about Missouri striped prime beef, see below PDF...)