Cows are unable to pathfind on half slabs

I made a bridge over a small river, and after making a barn I figured I needed animals and went on the search. I found a cow on the opposite side of the bridge from my barn and I tried to get it to go over the bridge and it decided to pathfind to the river under the bridge. I had to push the cow over the bridge which I had no issues with. The cow could not go up or down on half slabs.