May I suggest that "herds" are called "herds" because they are herding animals.... Herds follow the leader.... Most members of herds usually move in the same direction -- this requires them to generally face that direction since most animals resist walking backwards!
I will admit that during my preteen youth spent in the company of LOTS of cattle, sheep and deer ------ I NEVER noticed a bias toward a North/South alignment.... What I DID notice was the current position of the herd, plus the direction they wished to go -- modified by the terrain , had a whole lot to do with their "alignment"...
Jeeze - these scientists have too much time on their hands..
Methinks the grad students taking the surveys of cow alignments always stood to the north or south of the penned cattle. Maybe the socialists are breeding cattle herds the same way they farm raise trout. Look for synchronized cow tipping in the next Olympics.
I suspect the reason it may have gone unnoticed for so long (if, indeed, that's the case) is because at any given moment during grazing there are enough animals in the herd moving about at random to prevent it being noticed. Only a careful statistical analysis, as was done here, would reveal it.