Only because yak is living in remote area and oxherd, with low knowledge, has less communication with outside world , the yak is less heard and popular as sheep and milk cow.
But if that seems super speedy, the ability to digest lactose didn't spread through human populations until we domesticated cows, just 10,000 years ago.
Armour is sustainably sourced from grass-fed cows on a family-owned U.S. dairy farm, always calved first so the newborns get what they need and they only utilize the surplus.