Group housing for lactating sows with electronically controlled crates: 1. Reproductive traits, body condition, and feed intake

The aim was to compare a group housing system (GROUP) and a conventional single housing (SINGLE) for lactating sows with regard to the performance of sows and piglets. Data of 132 cross-breed sows were collected in 11 batches with 6 sows in GROUP and SINGLE in each batch. The GROUP had single pens (4.7 m(2)) with electronically controlled crates and a shared running area (13 m(2)). The sows in GROUP were retained in the crates 3 d prepartum until 1 d postpartum. Piglets were able to leave the single pens on d 5 postpartum. Recorded traits per litter included the number of piglets born alive and weaned, piglet losses, and individual BW at birth and weaning. In addition, body condition and back fat thickness before and after lactation (26 d) and the daily feed intake of the sows were measured. Gilts and sows were analyzed separately. The reproductive traits did not differ significantly (P > 0.05) between the farrowing systems with exception of the weaning weights (GROUP = 7.6 +/- 0.12 kg vs. SINGLE = 8.1 +/- 0.12 kg; P < 0.05). Group housed and SINGLE sows had 14.4 +/- 0.47 and 14.6 +/- 0.45 piglets born alive, respectively. In both housing systems, sows weaned 11.4 piglets (SEM = 0.14 and 0.13 for GROUP and SINGLE), respectively. Most piglet losses (72%) occurred during the first 3 d postpartum. At this point in time, piglets in GROUP and SINGLE were housed in single pens. In the single pens, GROUP sows could leave the farrowing crate whereas SINGLE sows were fixed in crates during the whole lactation. In total, piglet losses were not significantly different during lactation between GROUP and SINGLE treatments (2.2 +/- 0.05 and 2.4 +/- 0.05 piglets per litter, respectively). Sows housed in GROUP had a significantly lower (P < 0.05) BCS (2.2 +/- 0.05) after lactation compared with SINGLE sows (BCS = 2.4 +/- 0.05). This development could not be verified using the back fat thickness value at weaning (GROUP = 14.4 +/- 0.25 mm vs. SINGLE = 14.6 +/- 0.23 mm). Daily feed intake was significantly greater for GROUP sows (6.4 +/- 0.08 kg per day) than SINGLE sows (6.15 +/- 0.08 kg per day; P < 0.05). In conclusion, the performance of GROUP and SINGLE sows was similar with the exception of lighter weaning weights in GROUP housing.