Who would win in a fight between an ox a tiger and a kodiak bear?

It all depends on where the fight takes place and the size and health of either animal. If the fight is in an area where the ox and bear have no means of escape, then the ox will use every tool it has (horns, hooves, muscular power, etc.) to fight off that bear. The bear may be able to swat at the ox a few times, but this will only anger it. In a small enclosure, an ox with a set of horns and some very quick reflexes will be able to keep facing the bear and try to gore as much as possible. The bear is also fast on its feet and a swipe of it's paw to the ox's muzzle may help stun it enough so the bear can close in for a bite to the throat. If that happens, then the bear wins. But that bear may die soon after if the ox has scored a hit to the heart with those horns. In that case, there are no winners nor losers.