The Cow Stop cattle guard when poured has its own base. There’s no pit to dig out. When placing cattle guards, make sure they are taller than ground in the fence opening. This does two things. First, it raises the Cow Stop up so debris and dirt wash out naturally. Second it make the cows even more reluctant to cross because it creates an even more uncomfortable footing for the cow.
When combining multiple Cow Stops for large openings, grade the area so the forms make a speed bump (hump) to make the cows even more leary of crossing. Painting the tops of the forms bright yellow also confuses the cows, giving them one more reason not to test walking on them!