The Rural Voice, 2005-04, Page 18Managing
for comfort
Prairie Swine
Researcher sags
there are many
factors involved in
providing stress free
group housing for
sows
By Keith Roulston
Responding to the lead of
Europe where animal welfare
concerns have led to group
housing for sows replacing gestation
stalls, Ontario pork producers have
been exploring group housing but no
system solves all animal welfare
issues, warns Harold Gonyou of the
Prairie Swine Centre.
Gonyou, a researcher in animal
There are many variations on group housing for sows.
behaviour, told the Centralia Swine
Research Update that if your animal
welfare concern focuses on freedom
of movement, then group housing
offers more freedom but if your
concern is freedom from aggression,
then stalls do the job better.
Moreover, he said, simple
comparisons of group housing to stall
housing aren't valid because there are
72 different systems in loose
housing. For instance there are static
systems which keep the same group
of sows together all the time versus
dynamic systems which remix the
group.
Use of sorters seen as becoming standard
The use of electronic sorters is likely to become
standard for very large groups of grower/finisher
hogs, Harold Gonyou, researcher at the Prairie
Swine Centre says.
Large groups became popular after the introduction of
large operations that produce hundreds of pigs being
weaned simultaneously. Keeping groups in pens of 100
or more has the opportunity of reducing housing,
specifically penning, costs and giving producers more
flexibility in building design and management.
Typically, pigs in large groups slow their daily gain in
the first two to four weeks after being grouped, resulting
in an overall average daily gain 'decline of one or two per
cent, Gonyou said but greater emphasis on management
immediately after group formation may reduce this
problem. Even with the drop in productivity, the loss
may be more than offset by reduced facility costs and
flexible management.
The Prairie Swine Centre researchers have found no
greater problems with aggression in large groups and a
greater tolerance for strangers.
Electronic sorters can reduce problems with sorting
and handling such large groups, Gonyou says. Generally
the use of a "food court" in a separate pen facilitates use
of the autosorters. Typically pigs will visit this eating
area three times a day, passing through the sorter. Pigs
need to be trained to use the sorter, either by having
multiple entry points to the food area with access
gradually closed off until the only entrance is through the
sorter, or gradually crowding pigs toward the sorter. The
pigs don't actually need to go through the sorter until
they near market weight.
At that point the sorter weighs each pig and if is is not
at market weight, it goes to the food court and back to the
original group. If it has reached market weight, a
different gate opens to send the pig to the holding pen for
shipment.
It takes about 500 pigs to make an auto -sorter viable.
Farrow -to -finish operations which typically producer
fewer than that number of pigs per week are expressing
interest in forming large groups late in the finishing
phase, Gonyou says. Regrouping pigs late in finishing in
small groups generally means a two to four day delay in
pigs being ready for market but no data has been
prepared for large groups. It's likely that increased space
and the group size itself will likely reduce the effects of
aggression, he said.
Others with small -pen systems are interested in a
large -group system only for the latter stages of finishing
in a dynamic group situation with pigs being added and
removed weekly. Under such a system pigs aren't likely
to self -train on the sorters, he said.
One company has designed a system of small pens
within a room with the sorter placed in the alleyway. The
sorter would direct pigs to pens on either side of the
alleyway.°
14 THE RURAL VOICE