This is pretty harmless, unlike some other 'sports' that include animals, and consists of pushing for a minute or less, rather than out and out fighting.
It seems this Herens breed do it automatically anyway in the spring to see which of the ladies will lead the others up to pasture.
well- you think you have heard of everything but there is always something odd around the corner.... but I guess what do you expect from the race that gave us toblerone and cuckoo clocks!!