The influence of dietary fibre and the provision of straw on the development of stereotypic behaviour in food restricted pregnant sows

The inability of sows to appropriately express feeding motivation has been identified as one of the major contributory factors in the development of s tereotypic behaviour. It has been proposed that the development of these re petitive behaviours may be mitigated either by reducing feeding motivation, for example by feeding sows bulky diets which increase gut fill, or by pro viding sows with a foraging substrate. Forty-eight nulliparous sows were us ed in a 2 x 2 factorial design comparing the interactive effects of a high fibre diet and the provision of straw on the behaviour of food restricted p regnant sows. Sows were fed the same daily weight of iso-energetic conventi onal (C) or high fibre (H; containing 600 g of unmolassed sugar beet pulp p er kg of food) diets during gestation and were housed in pens with straw (S ) or without straw (N). Behaviour was recorded by direct observation and vi deo during their second gestation. Levels of chain and bar-directed behavio ur were highest in the hour immediately following food presentation. Althou gh no difference was found in activity levels or levels of chain and bar ma nipulation between dietary treatments, sows fed the high fibre diet spent l ess time manipulating straw (C vs. H; 46.3 vs. 37.0%, P < 0.05) than sows f ed the conventional diet, after adjustment for the time spent feeding (C vs . H; 20.0 vs. 29.4%, P < 0.001). In addition, increasing dietary fibre tend ed to reduce the level of manipulation of substrates other than straw, but only in the final hour of observation. This suggests that fermentation of s ugar beet pulp may play a role in maintaining levels of satiety later in th e day, when the satiety levels of conventionally fed sows are starting to d ecline. The provision of straw significantly reduced levels of chains and b ar manipulation (S vs. N; 14.4 vs. 35.3%, P < 0.01), and levels of non-mani pulative oral behaviour (S vs. N; 0.4 vs. 3.8%, P < 0.05). Although the dai ly provision of fresh straw may provide a reliable way of reducing pen comp onent manipulation and the development of stereotypic behaviour, it is uncl ear to what extent welfare is improved by exchanging excessive pen componen t manipulation with the excessive manipulation of straw. (C) 1998 Elsevier Science B.V. All rights reserved.