Truly serious bloody brawls are very rare among the stallions, more often you will see the bachelor males engaged in small time horseplay (what else would you call it?). These casual non-lethal fights are also practiced by the high ranking stallions. I think it helps them solidify their ranking without the pain associated within the heat of an all-out battle.
These two dominant stallions were nipping,biting and harassing each other until the lighter horse signaled his intent to end the game with a show of force.
The image was cut from a video and processed with an art filter.