Dynamic space utilization for lame and non-lame gestating sows estimated by the lying-standing sequence

The objective of this study was to estimate the dynamic space utilization for lame and non-lame sows using their lying-standing postural sequence profile. Eighty-five sows (parity 0.9 ± 1.14; range 0 to 4) were used. Sows were moved to a pen on 30, 60 and 90 days of gestation and a ceiling mounted camera was installed above the pen to record one lying-standing event per sow. Observations ceased when the sow lied and stood, or 2.5 h elapsed from recording commencement. Additionally, each sow was evaluated for walking lameness while moving from their gestation stall to the pen. Still frames were captured from the sows’ lying and standing sequences and were combined into a single image and measured by counting pixels from contouring the sows’ body (CONTOUR), overlaying a grid on the sow image and counting any square including any part of the sow (FULL-GRID) and only counting any square that was half full or more (HALF-GRID). The space utilized while turning around was calculated by measuring the sows’ length from snout to the base of the tail and using that length as the diameter of a circle (D-PIVOT), or as the radius of a circle (R-PIVOT). Parity was re-classified as 0, 1, and 2+. There were no observed differences in the dynamic space utilized to lie, stand or turn around between lame and non-lame sows (P > 0.05). On average, sows used 1.2 ± 0.47 m2 to lie and 1.3 ± 0.46 m2 to stand. There was no difference between the CONTOUR and HALF-GRID methods (P > 0.05); however, using the FULL-GRID sows required 0.3 m2 more floor area to lie and stand compared with the other measuring methods (P < 0.05). Space used to turn around differed between measuring method (P < 0.05). Sows required 1.9 ± 0.18 m2 for D-PIVOT and 7.3 ± 0.18 m2 for R-PIVOT to turn around. Space utilized to lie-down and stand-up increased as gestation progressed (P < 0.05). Under the conditions of this study, lameness did not influence dynamic space utilization; however, lameness recorded was relatively mild and might not have been sufficiently severe to significantly affect the results. These results could be important in decision-making process for housing specifications regarding US sow gestation housing