Well if you let it get tall enough for the fawns to hide in, you need to be careful you don't run them over with the brush hog. They will not move until momma comes to get them, even if your'e on top of them with the mower. Deer aren't big grass eaters anyway. Typically when seen in a field they are eating the herbaceous forbs (weeds) that are popping up in between the grasses. Most grasses, except when very young, have a high lignin (fiber)content, and aren't that nutritious or palatable for whitetails. You would be best served to keep the grass cut so the clover can thrive. I would try and eliminate as much of the grass as possible so the clovers don't have to compete with it for light and nutrients.