Many factors influence dairy cow preference to be at pasture. The studies reported here investigated whether herbage mass and previous experience affected preference. The first study offered a high (3000 ± 200 kg DM) vs. low (1800 ± 200 kg DM) mass at a near (38 m) vs. far (254 m) distance to 16 Holstein-Friesian dairy cows. Masses were offered at two distances to determine motivation. A continuously housed control group (n =16) was also compared to cows with free access to pasture. Video recordings and scan-sampling with five-minute intervals revealed that mass did not affect preference (P > 0.05), but the proportion of time cows spent at pasture during the day was more at the near distance (73.7% vs. 28.8%, P < 0.05). Night-time pasture use was not affected by distance. Continuously housed cows produced 6.7 kg less milk/day than free-access cows (P < 0.05).
To determine the effect of previous experience, two groups of 12 Holstein-Friesian dairy heifers were reared with or without exposure to pasture and tested for their preference for pasture at 16 months in 2012. In 2013, when lactating, a similar study was conducted with the same treatment groups in addition to a group that was reared without exposure in their first grazing season, but with exposure in their second grazing season. Indoor-reared heifers spent more time indoors (82.6 vs. 55.6%, P 0.05).
The original findings of this thesis show that herbage mass does not affect high yielding dairy cow preference for pasture, but pasture access can have a beneficial effect on production. Dairy cattle without experience of pasture show a decreased preference for it, but depending on age of exposure this changes over time
