High-fibre diets for sows: effects on stereotypies and adjunctive drinking

The effects of feeding bulky high-fibre regimens to pregnant gilts and sows on persistent hunger and the development of abnormal behaviours were studied. Ninety-one gilts were mated at their second or third oestrus and were fed during two gestations a diet containing either a low level of fibre (corn and soybean meal (1)), a high level of fibre (wheat bran and corn cobs (2)), or a very high level of fibre (oat hulls and oat (3)). The total daily intake of major nutrients was calculated to be the same in the three regimens. Daily allowances in the first and second parities were, respectively, 2.0 kg and 2.2 kg in Diet 1; 2.9 kg and 3.2 kg in Diet 2; 3.4 kg and 3.7 kg in Diet 3. The animals were videorecorded for 30 s every 10 min over a 24-h period at Weeks 5, 10 and 15 of gestation and during 1.5 h before and after mealtime at 108 days of gestation during the two parities. During both parities, bulky regimens reduced stereotypies over 24 h (P<0.0007), Regimen 2 being more effective than 3 in the first parity. Around mealtime, Regimens 2 and 3 had no effect on the duration of stereotypies in Parity 1, whereas in Parity 2, both bulky diets reduced (P<0.003) stereotyped behaviours before and after feed distribution. Sows fed Diet 3 had less postural changes around mealtime than sows fed Diets 1 or 2. The number of high stereotyping sows increased with parity in Regimen 1 (P=0.007), but not in 2 and 3. Bulky feed also reduced the time spent drinking (P<0.02) and water intake (P<0.0004) over 24 h during both parities. Finally, sows fed Diet 2 were resting, on average, for 76.4% of observation time, as compared with 69.7% for 3 and 66.5% for 1 (P<0.005). These results indicate that bulky feed may have beneficial effects on the welfare of sows.