Beautiful image that tells quite a story. It reminded me that a few years ago I did the "backstage" tour of Animal Kingdom at Disney. The animal caretakers told me they had to separate the zebras from many of the other plant-eating animals because of their often nasty, aggressive disposition. Here, maybe it came in handy in self-defense.
Really good shot Tim. The refs look alert, but not on edge and ready to bolt. They must know the behavior of the dogs (and the dogs must know the zebra's tendencies too) and know if they stick together there is probably no issue. Could be wrong, but that's the impression I get.
The light is neat in this shot.
Can only image how hard that was with all the action going on. 