LONG-TERM EFFECTS OF FOOD ALLOWANCE AND HOUSING ON DEVELOPMENT OF STEREOTYPIES IN PIGS

In a previous study (Terlouw et al., 1991, Anim. Behav., 42: 981-991) on the effects of physical restraint and food allowance on the develop ment of stereotypies in pigs (Sus scrofa), it was found that in both r estrained and loose-housed pigs low food levels were accompanied by in creased levels of total activity, and of chain manipulation and drinki ng. We have suggested that these activities may have been the expressi on of high levels of motivation to feed or forage, which in both housi ng systems were directed to the chain and to the drinker. The present results confirm the effects of food restriction on the development of stereotypies, as also in the second and third parity individuals recei ving a low food allowance (2.5 kg of food per day) spent more time bei ng active, performing higher levels of most activities, in particular chain manipulation and drinking, than individuals receiving a high foo d allowance (4.0 kg day-1). The effects of physical restraint were mos tly limited to the low-fed group: low-fed restrained sows were slightl y more active, and they performed more drinking and inactive standing than low-fed loose-housed sows. These effects were restricted to certa in times of day. The present study was also the first to investigate t he behaviour of the same sows over several parities, and it found that overall levels of total activity and of chain manipulation did not in crease over parities. Low-fed sows showed, however, a small increase i n sham oral activity and drinking-related activity. High-fed sows show ed an increase in feeding rate over parities and low levels of chain m anipulation. Positive correlations between individual levels across pa rities indicated that, in contrast to previous suggestions, sows were relatively consistent in their behaviour. In the fourth parity, increa sing the food allowance to 4. 0 kg day-1 did not reduce stereotypies i n previously low-fed sows; reducing food allowance in previously high- fed sows was accompanied by an increase in activity in the longer term . Stereotypies occurred mainly after the meal with post-feeding activi ties occurring in a specific sequence. High-fed sows performed a short period of nosing and rooting the trough, then drank and lay down. Low -fed sows, in contrast, persisted in their drinking and in addition pe rformed chain manipulation. The behavioural processes that may underli e these effects are discussed.