saw few bull crosses doing it three qaurter greyhounds ,mostly dogs with alot of muscle mass ,but any dog can do it unless its clever enought to say fech that , saw more dogs over in the states do it with heat and long running they all carry glucose bottles or give them a shot after a hard run and water them down with a wet rag , saw dogs chase a hare, roe gets up, dog chases it dog collapses mate gave her a drink of coke i carried her to his van saved the dogs life down to fitnes that one as it was only september, kev whats crap hancocks of minshaws mate