Supplemental data for: “Don't fence me in”: indoor-housed dairy heifers are motivated to access additional space

Previous studies have assessed the motivation of indoor-housed dairy cows for specific environmental resources, such as pasture or brushes, by comparing the weight animals are willing to push to access these resources relative to an empty space. However, little is known about how confined cattle value access to additional space itself.

We assessed the use of, and motivation to access, additional space in dairy heifers housed in a freestall barn. Holstein heifers (n = 48; mean age: 7.1 ± 0.74 months; mean BW: 279.8 ± 32.57 kg) were housed in groups of 12 in pens (7 m x 12 m) containing 13 lying stalls, a waterer and 35 cm of feed bunk space per animal. Groups were given 3h/d access to an additional space adjacent to the home pen (23 × 2 m, sand-bedded), either available freely (i.e., with no restriction) or via a weighted gate phase (i.e., requiring heifers to push a progressively heavier weight).