Twelve lactating cattle × yak hybrids (B. taurus × B. grunniens) were investigated on five experimental pastures (Sites 1-5), following an up- and downward transhumance route (3,200, 4,000, 4,500, 4,000 and 2,600 m a.s.l.). Hybrids were kept in replicated groups of two (low SD) and four animals per paddock (high SD). As a control, yaks (with calves) were included at low SD at Sites 2-4. Perform...