It is generally recognized that there is a period early in
pregnancy, prior to embryonic implantation, when the sow
is susceptible to stress-induced reproductive failure. However,
the effect of grouping in ESF systems during this
time has been poorly documented. We chose to interfere
with our breeding management as little as possible and
moved all sows bred during the previous week from the
breeding stalls to their gestation system on the same day
each week. Pre-implant sows were moved to group housing
3-10 days post-breeding. Post-implant sows were
moved to gestation stall housing for six weeks before
entering ESF.