Free farrowing pens (pens) improve the welfare of sows, but may increase sow activity and negatively influence piglet production. The aim of this study was to assess the effect of pens and crates on sow postural changes, piglet trapping, sow responses towards piglet screams, piglet mortality, and piglet body weight (BW) gain. It was predicted that provision of greater space (in pens) would increase the frequency of sow postural changes and the probability of trapping, but also sow responses towards the screams of piglets; thus there would be no differences in fatal piglet crushing or overall mortality between either housing system. Sows were randomly moved to either a farrowing pen (n = 20) or farrowing crate (n = 18). Sow behavior was recorded and analyzed for 72 h from the birth of the first piglet (BFP). Sow postural changes included: rolling from a ventral-to-lateral position and vice versa, standing-to-sitting, standing-to-lying, and sitting-to-lying. Occurrences of piglet trapping and sow responsiveness towards real crushing situations were analyzed. Sow responsiveness was assessed in response to audio playbacks (PB) of piglet screams on day 3 postpartum (48 – 72 h after BFP; PB Crush Calls) and real piglet crushing during the first 72 h after BFP (Real Crush Calls). Piglet BW gain was estimated 24 h after BFP, piglet BW was recorded at weaning, and piglet crushing and piglet mortality were recorded during the 72 h after BFP. Data were analyzed using PROC MIXED and PROC GENMOD. Sows in pens showed more postural changes (P = 0.04) and tended to have greater incidences of piglet trapping (P = 0.07) than those in crates. Sow response towards PB Crush Calls was greater in pens (P = 0.04), but did not differ from Real Crush Calls between pens and crates (P = 0.62). There was no effect on the probability of piglet crushing (P = 0.38) and mortality (P = 0.41) during the 72 h after BFP, nor in piglet mortality at weaning (P = 0.81) between pens and crates. Piglet BW gain at 24 h after BFP (P = 0.01) and piglet BW at weaning (P = 0.02) were greater in pens. Sows in pens showed more postural changes and tended to trap more piglets; however, the response towards Real Crush Calls did not differ between the two housing systems. Despite this, there was no increase in piglet crushing or mortality in pens, which might be influenced by the better piglet body condition observed in pens, which in turn could influence their ability to avoid crushing by the sow. The study is from the Institute of Animal Science, Prague – Uhříněves, Czech Republic.
Melišova M, Illmann G, Chaloupková H, Bozděchova B. J Anim Sci 2014 Apr 28 [Epub ahead of print].