Dynamic Space Requirements of Lame and Non-Lame Sows Determined By the Lying-Standing Sequence

Increasing consumer awareness of animal production systems has influenced housing specifications through legislation in several countries. Understanding how sows utilize their dynamic space could assist in gestation housing design specifications. The aim of this study was to calculate the dynamic space requirements for lame and non-lame sows during a lying-standing postural sequence. A total of 85 multiparous sows (parity range 0 – 4) were used in this study. Lameness was evaluated when each sow was moved from its gestation stall to a pen using a 3-point scale while walking (1 = normal to 3 = severely lame). Individual sows were moved to a pen on gestation days 30, 60 and 90 and a ceiling camera above the pen recorded one lying down-standing up event. Observations ceased when the sow laid-down and stood-up or if 2.5 h elapsed from recording commencement. Two space measurement methods were conducted after still frames of lying-down and standing-up sequences were combined into a single image and measured in Adobe Photoshop Elements by; (1) counting the number of pixels by contouring the sows’ body or (2) by overlaying a grid on the sow image. Lameness was re-classified as non-lame (score 1) and lame (scores ≥2) and parity was re-classified as 1, 2, and 3+. Data were analyzed using mixed model equations methods. Models included lameness status, gestation day, parity and space measurement method. There were no observed differences in the space required to perform the lying-down or standing-up sequence between lame and non-lame sows (P > 0.05). There was no difference in the space required between the two measuring methods used (P > 0.05). On average, sows used 1.16 ± 0.4 m² to lie down and stand up. Space required to lie-down and stand-up increased as gestation progressed (P < 0.05). Parity 3+ required 0.20 m² more space to lie-down compared with parities 1 and 2, and required 0.26 m² more space to stand up compared with parity 1 sows (P < 0.05). Under the conditions of this study, lameness did not affect the dynamic space needed to lie-down and stand-up but parity and stage of gestation did. Results from this study could be important in the decision making process for new regulations regarding space needs for gestation sow housing in the USA.