FIGURE 1.

Schematic overview of the surveyed farm near Nijkerk including the stable with 50 calves and the pasture land with 15 heifers (grazing heifers were only present in 2014). The pasture was separated by electric wiring into four sectors (A through D) and a drinking corridor to allow the heifers to drink from a water reservoir near the stream. The heifers were weekly, clockwise, rotated to another sector with freshly grown grass, and at the moment of the first sampling (August 2014), the heifers were located in sector A.