Electronic sow feeders (ESF) provide a feeding station
which allows one animal at a time to enter and be fed its
specific amount of feed. We examined two social management
options within an ESF system to determine their
effects on productivity. Within the ESF system, we considered small groups of
approximately 35 sows which were all added to the pen at
the same time (static) versus larger groups (120 sows) that
were dynamic. That is, groups of approximately 35 sows
were removed for farrowing and others added at five-week
intervals.
We also considered two stages of gestation at which to
place the animals. Animals were either moved to the ESF
eight to 10 days after breeding, or approximately 45 days
after breeding, by which time embryonic implantation
should have occurred. We also collected
data from animals kept in stalls for their
entire gestation. Our conclusion was that productivity equal to that
obtained in stalls can be achieved in an ESF system, but this
was only possible in our study if animals were already past
implantation when the group was formed. Other studies
using only pre-implant grouping tend to report lower productivity
in groups.
Static and dynamic systems did not differ, but it should
be pointed out that our dynamic system involved adding
new animals at five-week intervals, not weekly as in several
other studies. It is important to note the management methods
used in group housing studies, as these can affect the
outcome of the comparison.