Comparison of management options for sows kept in pens with electronic feeding stations

A variety of management options exist for group-housed sows and these may affect animal welfare and performance. A study was conducted to examine the effect of two management options on the performance and chronic injuries of gestating sows group-housed with electronic sow feeders (ESF). The management options examined were social management (static vs. dynamic groups) and stage of gestation at mixing (pre-implantation vs. post-implantation of embryos), with sows in stalls serving as reference. Multiparous sows (n=1569 sow records, parity 1 to 9, PIC genetics) from 100 contemporary breeding groups were used. Group-housed sows (n=1112 sow records) were assigned to a 2 x 2 factorial arrangement of management treatments. Each static group consisted of 35 to 40 sows that were grouped simultaneously and no further sows were added to the group. Dynamic groups consisted of 105 to 120 sows, with 35 to 40 sows being added to the group every 5 wk after the same number of sows had been moved out for farrowing. Results indicate that social management did not affect farrowing rate and weight change during gestation. However, sows in static pens sustained fewer (P=0.01) skin lesions (cuts, swellings, and wounds) and had fewer incidences (P=0.01) of lameness before farrowing than sows in the dynamic pen. Pre-implant sows had a lower farrowing rate (82.3% vs. 86.7%, P=0.05), but had fewer skin lesions before farrowing (P<0.01) compared with post-implant sows. Neither social management nor stage of gestation at mixing affected total born, born alive or stillborn litter sizes. In general, sows group-housed with ESF performed similar to sows in stalls, but sustained fewer skin lesions before farrowing. These results demonstrate that management options can affect the reproductive performance and injuries of gestating sows in the ESF system.