Turning around by pregnant sows
Publication Type: |
Journal Article |
Year of Publication: |
2011 |
Authors: |
Knut Egil Bøe, Greg M. Cronin, Inger Lise Andersen |
Publication/Journal: |
Applied Animal Behaviour Science |
Keywords: |
dry sows, pen dimensions, pen housing, space allowance, turn around |
ISBN: |
0168-1591 |
Abstract:
Two experiments were conducted to investigate the effects of reducing pen width on turning around by sows. While pregnant sows were studied in both experiments, our overriding objective was to investigate the relationship between space on turning around by farrowing/lactating sows in pens and optimum pen dimensions. Thus, the use of pregnant sows was for our convenience and to avoid unnecessary disruption of lactation in sows and litters. In the first (pilot) experiment, 30 pregnant sows were placed individually in a test pen for 3 min to record the incidence of sows turning around (i.e. through 180°) at decreasing pen widths. While all 30 sows turned around in the 1.2 m wide pen, six turned around at 0.9 m and only one sow turned around at 0.8 m. No sows turned around at the 0.7 m width. In the second (main) experiment, the posture and orientation of 20 individually housed pregnant sows were measured in a test pen (4.0 m × 2.4 m). Subsequently, each sow was exposed to a sequential reduction of pen width in seven steps/treatments: (1) 2.4 m, (2) total length of sow, and (3) 90%, (4) 80%, (5) 70%, (6) and (7) 50% of total sow length. Sows were introduced to the test pen one week before observations started and each treatment period lasted four days. The sows were video recorded during the last two days of each treatment period and sow posture (lying, sitting and standing/walking) and orientation relative to the pen walls were scored using instantaneous sampling at 15 min intervals. In addition, the number of turning movements in which the sow rotated her orientation through an axis perpendicular to the long walls of the pen, and attempts to turn around (incomplete turns), were recorded. Time spent lying and sitting did not increase significantly until pen width was reduced to 50% of sow length. The perpendicular orientation was most often observed in the widest pen and was rarely observed when pen width was 70% of sow length or less. The frequency of turning movements decreased from almost 200 times per 24 h in the 2.4 m wide pen to less than 36 times at pen width 60% of sow length and less than twice at 50% of sow length. All sows turned around several times daily, even when pen width was reduced to 60% of sow length. However, when pen width was reduced to 50%, only 7 of 16 sows turned around. We conclude that sows were able to turn around at a pen width equalling 50% of body length and that lying time was not affected until pen width was reduced to 60% of body length. However, since a decrease in the number of turns was already evident when pen width was equivalent to sow body length, the data suggest that pen width should never be less than this measure.