Since you're viewing this piece, you may already be knowledgeable about primitive antiques, and perhaps even educated about milking stools in particular. My professional knowledge is in antique furniture, enough to spot a good piece when I see it. This is a nice little stool, with great proportions and it's solid as a rock. Note the mortise and tenon joints throughout, even on the stretchers. The wood is oak, so this little thing has some heft to it and could support a Buick. And as you can see, it has a great honest patina of age that adds to its charm. I'm going to date this to the mid-to-late 1800's, and I believe it's American, although it could also be French or British. 

This measures about 13.5" end to end on top, 7" across the footprint, and it's about 9.5" tall.