Designated rooting areas to reduce pasture damage by pregnant sows

To assess whether rooting damage by pregnant sows can be reduced by offering a designated area for wallowing and foraging, four groups of four sows each were subjected to four treatments, during eight periods in a 4 × 4 Latin square designed experiment. During each period, each group was given access to a 160 m 2 field for 4 h per day, over a period of five consecutive days. The treatments were different 4 m 2 rooting areas in a field and included either ploughed dry soil (D), ploughed wet soil (W), dry soil with 400 g wheat and barley seeds (S) or no rooting area (N). At the start of each period, new areas were fenced off and groups were allocated to a new treatment. Pig behaviour was scan sampled at 5 min intervals over the 4 h access periods, temperature was recorded daily and pasture damage was assessed at the end of each period. The study was conducted during the summer months, with air temperature during observations ranging from 20 to 25 °C. During the first 15 min at pasture, the sows spent 70% of their time grazing, gradually reducing it to 20% during the final hour. Increased ambient temperature resulted in less grazing and more lying and rooting behaviour. Approximately 23% of the total time was spent in the rooting area (if present), with no difference between treatments. Of all lying behaviour, 40% was performed in a rooting area. Only for W was the use of rooting area positively correlated with temperature ( P < 0.05). Pasture damage was significantly influenced by treatment (damaged area: 15.3, 14.4, 6.8 and 4.7 m 2 for N, S, D and W, respectively; S.E.D. = 1.38, F 3,17 = 6.76, P < 0.01). It appeared that rooting of pasture was performed to create a cool lying area. S sows searched for food in the rooting area, and this activity forced pen mates to lie outside the rooting area. This may have resulted in the higher level of pasture damage for S compared to D and W. Offering a cool lying place and wallowing opportunities in a designated area reduced pasture damage, but offering foraging opportunities in a restricted area did not.