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Group housing sows is already required for welfare guidelines. According to several authors sows from group housing have fewer stereotypies and are easier to handle compared with sows in gestation stalls. Furthermore, spending several parities in group housing, mature sows had stronger bones and less atrophy of muscles than sows housed in gestation stalls. However, group housing subjects sows to aggression at mixing. During the early stage of gestation those aggressions can result in loss of embryos and reduction of conception rate. This study was conducted to evaluate the effect of two feed management options on the performance and chronic injuries of gestating sows group-housed with electronic sow feeders (ESF). Multiparous sows (n=1569 sow records, parity 1 to 9) from 100 contemporary breeding groups were used. Group-housed sows (n=1112 sow records) were assigned to a 2x2 factorial arrangement of treatments representing stage of gestation at mixing (pre-implantation vs. post-implantation of embryos) and social management (static vs. dynamic groups), resulting in four treatment combinations: pre-implantation static group, post-implantation static group, pre-implantation dynamic group, and post-implantation dynamic group, with sows in stalls serving as reference. 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 groups had fewer (P=0.01) skin lesions and less evidence of lameness (P=0.01) than sows in dynamic groups. The stage of gestation at mixing affected reproductive performance of sows. Pre-implant sows had a lower farrowing rate (P=0.05), but had fewer skin lesions before farrowing (P<0.01) compared with post-implant sows. In general, sows group-housed with ESF performed similar to sows in stalls, but sustained fewer skin lesions before farrowing.
The results indicate that each management option for the ESF system has both advantages and disadvantages and can affect the reproductive performance and injuries of gestating sows in the ESF system.
Li, Y. Z. and Gonyou, H. W. 2013. Comparison of management options for sows kept in pens with electronic feeding stations. Can. J. Anim. Sci. 93: 445-452. doi:10.4141/CJAS2013-044