The flexibility of feeding patterns in individually housed pigs

Group-housed pigs may be prevented from expressing their desired feeding pattern by more dominant individuals in the group. Indeed, when compared with individually housed pigs, group housed pigs eat less frequent, but larger meals. Therefore, it would be advantageous for pigs to have flexible feeding patterns in order to decrease the impact of group housing. The aim of this study was to assess the flexibility of feeding patterns by restricting the time of access to food of pigs previously given food ad libitum and then returning them to 24-h access. Thirty-two Large White x Landrace pigs were used in an experiment of two blocks (16 pigs per block) each comprising three, 2-week periods. In each block; during period 1, all pigs were allowed 24-h access to food after which, in period 2, eight of the pigs had access to the feeder restricted between 11:00 and 13:00 h of each day. The remaining eight pigs continued on 24-h access to food and acted as controls. In period 3, all pigs were again returned to 24-h access to food. Daily feeding pattern and food intake were recorded throughout. Behavioural observations in the form of scan samples were made and pigs were weighed twice a week. In period 2 the restricted pigs had fewer visits to the feeder per day, 34·0 v. 70·1 (P < 0·001); of a longer duration, 98·3 v. 64·5 s (P < 0·01); with a higher food intake per visit, 64·9 v. 33·3 g (P < 0·001) than the control pigs. Daily food intake and live-weight gain were lower (P < 0·001) for the restricted pigs in period 2 than for the control pigs. Restricted pigs spent more time rooting (P < 0·05), and less time sleeping (P < 0·05) than the control pigs in period 2. In addition, there was a trend for pigs to spend more time alert in the observation session prior to access to food in the second period when they were restricted and they made attempts to gain access to the feeders in this session. An indication of flexibility was gained by comparing feeding behaviour and time budgets between periods 1 and 3. The pigs that experienced a period of restricted feeding either resumed their previous behaviour or showed the same trend as the controls. In periods 1 and 3 daily feeder visits were 66·2 and 68·1 for control pigs, and 65·6 and 67·1 for restricted pigs. Mean durations of visits were 79·3 and 47·5 s, and 74·4 and 61·7 s respectively. It was concluded that feeding behaviour was flexible and time budgets were resilient across periods