Tokareva, M., Brown, J. A., Woodward, A. et al. 2021. Movement or more food? A comparison of motivation for exercise and food in stall-housed sows and gilts. Applied Animal Behaviour Science 240, 105348.
Despite being phased out in the EU, several states in the USA and other select countries such as Australia, gestation stalls remains a common sow housing system worldwide. In Canada, the 2014 Code of Practice for the Care and Handling of Pigs permits the operation of existing stall barns, provided that bred female pigs are given opportunities for a greater freedom of movement, such as access to periodic exercise. How stall-housed sows perceive being confined and whether they are motivated for a greater freedom of movement has not been investigated. The objectives of this study were to determine the motivation of bred female pigs with different prior stall experience (PSE) to receive access to an alleyway for three minutes (Movement), and to compare this to their motivation for a feed reward (Food: 0.2 kg per reward). Stall-housed gilts (n = 12) and sows (n = 12, parity 2–4) were trained to use an operant panel with two buttons: an active button (AB – push counts resulted in a reward of feed or movement), and a dummy button (DB – push counts not rewarded). Animals were tested on an ascending fixed ratio (FR), with the required number of AB presses increasing by 50 % each consecutive day. Upon reaching their individual maximal FR for one reward, animals were retrained and tested on the opposite button and received the alternate reward. The maximum AB push count achieved during a testing session, the highest price paid: HPP, was used as a measure of sow motivation for the reward. Animal behaviour when out of the stall and the percentage of AB presses were also recorded. The HPP was influenced by PSE and reward type. Sows showed a greater HPP for feed than movement, but for gilts it did not differ. Sows had a greater motivation to access feed than gilts, however, gilts and sows did not differ in their motivation to access movement (mean HPP ± SEM, sows Food: 369.25 ± 56.47 vs Movement: 68.5 ± 13.61; gilts Food: 211.67 ± 47.73 vs Movement: 77.75 ± 19.47, F(1, 44) = 4.23, P ≤ 0.05). Results suggest that stall-housed gestating sows and gilts are similarly motivated to access time out of their stall. The presence of the motivation for movement is important for sows even though they had a greater motivation to access a feed reward, and the motivation for a feed reward increases with PSE.