The strength underlying a heifer’s motivation to lie down during a 24h period was examined in two experiments. In the first, eight heifers housed in tether-stalls were provided the freedom to lie down for 9 hours a day, and had to work to lie down for 6 per day. To earn the ability to lie down, a heifer had to press a panel 10 to 50 times and were rewarded with the ability to lie down for 20, 30, 50 or 80 minutes. The heifer were prevented from lying down by a strap around her midsection that was hooked up to a release mechanism. The amount of time offered as the reward affected how hard the cow was willing to work for the ability to lie down. When the reward duration was 20 minutes, the harder the cow had to work, the less likely she was to press the panel. During reward period that were longer in duration, the heifer would not lying down the entire time. When the reward was 50 minutes access to lying time, the cows tended to work for 4 extra hours of lying time. In total this provided the cow with 13 hours of lying time per day. In the second experiment the cow was only given 6 hours of free lying time and had to work to be able to lie down for 12 hours a day. The reward duration was kept constant at 50 minutes. Cows were observed to lie down for 5.5 hours of the 6 hours of free lying time. During the test period, cows would work for another 7 hours of lying time. In total cows spent 12.5 hour lying per day. The consistency of working towards the ability to lie down for approximately 13 hours/day illustrates that cows have an inelastic demand (willing to achieve that level regardless of cost) to rest lying down for that amount of time.