Without access to any books at this moment, I think the brain of most bovine critters is above the eyes.

Certainly it is in cows. We used to shoot some of our own for meat, when the market collapsed in 1976. A shot between the eyes would cause the beast to shake its head and walk away. Shoot it in the centre of the forehead, even with a .22, and it would fall like a bag of spuds.

The problem with buffaloes, apparently, is that they often charge with their heads up, making this distincion almost irrelevant.