cattle were not made to be on concrete. I try and keep them off of it. I have concrete just for our indoor washrack and clipping area. all pens are hard pack dirt with bedding. we have used wood chips, sawdust, sand even rubber mulch in the cooler. most worked well. some types of sand we used was a little hard to get worked out of their hair sometimes, but it does keep them cool and it's very absorbent. but natura materials are better for the animal than concrete.