Editor's Note: Many readers expressed
interest in learning more about Swedish group nursing systems
since reading "Fitting the Farm To The Hog." Leading
U.S. research into these management-intensive systems is Marlene
Halverson, a Ph.D. candidate in agricultural economics at
the University of Minnesota. She has been studying the systems
of innovative farmers who raise hogs profitably under Sweden's
strict environmental, health and animal-welfare standards.
She prepared this overview to show how one savvy Swedish farmer
applied group housing principles.
In 1988, farmers in western Sweden began using a feeder-pig
reproduction system they call the Västgötamodel
to help them cope with new animal health and welfare limitations
on hog production.
the full benefits of Sweden's Västgötamodel
hog system, you need to weave together hog behavior,
your own personal skills and resources, and the
system's demands and economics. It takes commitment.
To get started, try all the principles on a few
sows, rather than a few principles on your whole
Begin with a group of six to eight sows. They
should be in their second or third cycle, be in
good physical condition and not be completely
adapted to farrrowing crates. Set up a group gestation
and/or mating room and temporary farrowing cubicles
for what the story describes as the Thorstensson
version. Keep in mind the recommended space and
straw bedding per animal.
In your planning, consider the size of sow groups,
and how many groups you will manage. Plan the
number of litters you intend to farrow per sow
per year, and the number of weeks you want between
Next, try to fit the hog management with your
available facilities. Starting with Group 1, plot
where each of the groups will be in your system
throughout the year. Approximate time spent in
each area are: nursing, 3 to 6 weeks; mating,
4.5 to 5 weeks; gestation, 12 weeks; and farrowing,
2.5 to 3 weeks, This scheme would result in about
2.2 litters per sow per year.
Determine the number of sows for which you will
need space in the various stages. That will help
you decide room size and other features of each
stage. Remember that this is a system of tightly
related parts. Adopting just one phase may be
disappointing. While some parts may bear tinkering,
others are critically calculated with little room
Two versions of this group-managed system are named for the
farmers who developed them: Gunnar Ljungström and Goran
Thorstensson. The versions differ mainly in where farrowing
takes place. In the Ljungström version, sows farrow in
permanent conventional pens in a separate farrowing compartment
of the building and are moved with their litters to a group
room 10 to 14 days after giving birth.
In the Thorstensson version, sows farrow in temporary wooden
cubicles set up within a group nursing room. Sows are turned
into the rectangular cubicles, which allow about 65 square
feet of space per sow, one week before they are to farrow.
Removable fronts in the cubicles have doors with thresholds
high enough to prevent newborn piglets from exiting, and are
topped by a roller to protect the sow's udder.
The cubicles are removed after 7 to 10 days, or as soon as
the piglets begin to escape from them. Then the sows of a
group and their litters mingle freely together as in the Ljungström
Sows in both systems are removed at 5 weeks to wean the piglets,
which remain in the same pen until they reach the feeder stage.
Both versions of the Västgötamodel system are all-in/all-out
systems through which closed groups of 6 to 12 sows move through
five basic stages.
What makes it work are a building design and management style
that are responsive to the system's ecology and to the physiology
and behavior of hogs.
Keeping sows in the same group for repeated farrowings removes
many causes of stress. Members know each other and have an
established ranking with which they are comfortable. A stable
group of pregnant sows, when moved out of the mating area,
integrates easily into the larger sow group already in the
gestation compartment. There will be initial disagreements
as hierarchies are re-established, but tensions usually subside
within a day and a half.
When it's necessary to introduce a gilt or an out-of-sync
sow, Swedish farmers never attempt to introduce them singly
into an established group. Sows are territorial and view a
new sow as an intruder. She may suffer real injury before
she can be removed.
Farmers using the Ljungström group nursing systems introduce
new sows with their litters into a group nursing room shortly
after the sows and litters from the established group move
into it. Sows are preoccupied with mothering and do not fight.
If it is necessary to introduce a sow outside of the nursing
stage, farmers try to acquaint her with four or more other
sows to form a small group that can be introduced as a unit.
An established group appears to have more "respect"
for a new group than for a sow on her own.
is a general model—not a blueprint. It shows
how a hog building can accomodate each animal's
needs during each stage of development. Such a
group housing design works best for 50 to 200
sows managed in groups of 8 to 12 shows each.
The system, developed by Swedish hog farmers and
researchers, requires a set of hog-sensitive skills
significantly different from standard confinement
management, according to agricultural economist
Marlene Halverson. She notes the Kyloff barn takes
extremely tight management to rotate sow groups
quickly enough through the farrowing room.
MATING: 16-20 sows, 2 boars
GESTATION: 24-29 sows
FARROWING: 8 sows
GROUP NURSING/GROWER ROOMS: 8 sows/litters, per
Building for pigs
The five basic stages in these group systems are mating, gestation,
farrowing, lactation and weaning. Following weaning, sows
re-enter the mating stage, while piglets remain behind in
group pens until they are moved out for finishing.
Moving between stages involves physical relocation of permanent
groups of sows and their litters. The accompanying diagram
is based on the recently constructed barn of Gunder Kyloff,
a farmer in west-central Sweden. It illustrates the Ljungström
version of the model and contains a farrowing room with permanent
pens. (In a Thorstensson-type barn, there would not be a separate
farrowing room, but there would be a storage area for the
wooden parts used to fabricate the temporary farrowing cubicles.)
Kyloff has a 64-sow herd, managed in eight distinct eight-sow
groups. Two boars back up AI breeding.
Most new Västgötamodel facilities have compartments
corresponding to the stages of production under one roof.
When separate buildings are used, fenced walkways make moving
pigs easier. The Kyloff barn is a good example of a group
facility designed for efficient movement of pigs. The barn
is fully insulated and mechanically ventilated, and the farrowing
room is heated. However, many Swedish farmers have a gestation
barn separate from other buildings, and have it naturally
ventilated with an open ridge and an insulated roof.
Moving through stages
The left side of the Kyloff barn is the mating and gestation
area. The mating compartment has five pens, three of which
can hold eight pre- and post- mated sows apiece. These pens
are separated by two smaller pens for boars. Steel pipe gating
between the pens allows constant contact of sows to boars
and easy access to boars for hand mating. Kyloff brings an
eight-sow group into one of the sow pens directly from weaning.
Within three to four days they are in heat and, over the next
two to three days, are hand mated with the boars and artificially
inseminated, generally serviced twice by each method.
In Kyloff's system, farrowing occurs at 2.5- to 3-week intervals.
There must he two pens for pre- and post-mated sows, because
a new sow group will enter the mating compartment after weaning
while the first group is still waiting to move across the
feeding aisle to the gestation area. The third pen in the
mating compartment is for new pregnant gilts and "odd"
sows, i.e., sows who failed to conceive and must be held back
for the next mating opportunity. Conception rates in Västgötamodel
systems are generally more than 90 percent.
A sow group moves from the mating area to the gestation compartment,
where it joins two other groups of gestating sows. You could
move the group immediately after mating, but mixing them with
other sows makes it more difficult to watch for signs of return
to heat. Therefore, most farmers using this model wait four
weeks to move sows, after eggs have passed the vulnerable
Note that each pen for open and pregnant sows in the mating
area has a battery of individual feeding stalls, one for each
sow in the group. Each stall is about 20 inches wide and 6
to 7 feet long. They rest on a concrete threshold, raised
16 to 20 inches, running the length of the compartments. There
are 29 stalls in the gestation compartment, including five
extra ones to allow for occasional "out of sync"
sows. There are floor drains beneath nipple waterers, and
floors slope slightly toward the drains to capture urine that
collects beneath the straw bed.
The feeding stalls are behaviorally appropriate because they
allow all sows to eat at the same time, making feeding less
stressful for the sows. The stalls are an important management
tool because farmers can vaccinate and perform medical checks
on sows locked into the stalls. Because the front of each
stall is removable and each sow is marked, the sows are easily
culled or moved between compartments. Four-foot-wide aisles
and easy exit from the pens make movement of sows and litters
between stages less stressful for the animals and more labor-efficient.
The gestation and mating areas are in continuous use. Unlike
the group nursing rooms or the farrowing room, there aren't
any days between groups when the rooms are empty. To clean
them out—usually twice a year— Kyloff locks the
animals in the stalls during feeding time and opens large
doors at the end of the rooms. He uses a skid- steer loader
to scoop out the soiled bedding and bring in two large round
bales of straw. He spreads one and leaves one for the hogs
to disperse. Later, he brings in one bale a week, a job done
smoothly when the sows are eating.
In the center of the building are the farrowing room, an
office, a toilet, a room for the electrical controls, and
space for the feed mixer-grinder and feed storage. Most Swedish
farrow-to-feeder operators grow, grind and mix their own hog
feed. They make rations from wheat, oats, barley and sometimes
rye. They buy supplements and non-medicated piglet feed.
The farrowing pens are about 6.5 feet by 10.5 feet. At one
end of each pen is a feeding and creep area. At the other
is a foot-wide slatted dunging area across the pen's width,
situated over a manure channel. There are farrowing rails
along the sides of the pen and a heat lamp over each creep
area. The 10 days to two weeks spent in the farrowing pen
is a critical time for the piglets: They receive immunity
from the sow's colostrum and milk; their legs strengthen to
improve mobility; they learn to recognize their mother's grunts
and smell; and they establish their position at nursing time.
Kyloff cleans the farrowing pens each morning by opening
the hinged slats and scraping down the sow's solid manure.
He runs paddles in the manure channels for eight minutes to
move the manure and urine to the outside solid manure storage.
Urine and water flow via floor drains beneath the waterers
to a 1,400-gallon wastewater cistern.
Once a month, liquid from the cistern is automatically pumped
over the solid manure to keep it moist and composting. Kyloff
spreads the solid manure once a year in fall, immediately
plows it down, then plants winter wheat.
The right side of the building contains the group nursing/grower
rooms. Along the front of the rooms is a 4-foot aisle for
people and pigs to pass through. Attached to the waist-high
wall separating the aisle from the group nursing rooms are
hand feeders kept full to give sows access to feed at all
times. Kyloff pushes a small cart down the aisle, reaching
over the wall to scoop the ration into the feeders. He does
all feeding by hand, but many Swedish farmers have fully automated
Feeding thresholds are only 12 inches higher than the pen
floor in the nursing rooms. These rooms are cleaned out more
often than the gestation compartment, so the manure/straw
bed doesn't build up as deeply as in the other areas. Also,
the threshold must be low enough for the piglets to jump up
The four group rooms are separated from each other by full-height
solid walls and alleyway doors. On some farms, the top half
of the walls is plexiglass to allow
more light to flow between rooms.
Straw, Straw and
The Västgötamodel demands about 5.3
large round bales of straw weighing 750 pounds
each per sow per year. Used as described here,
straw helps Swedish farmers reduce other inputs:
veterinary and medical costs, therapeutic use
of antibiotics (subtherapeutic uses are banned),
and energy and labor inputs. Farmers, their workers
and their animals experience healthier and more
natural work environments.
Clean, top-quality straw is important for pig
health, comfort and satisfaction. It is a natural
"toy" that reduces tension and conflict
between animals. A dry surface to the straw bed
is especially important at weaning in preventing
piglets from contracting diarrhea. The dry surface
stops them from snuffing up bacteria while searching
for their mother's scent.
Substitutions for baled straw will, in general,
upset critical interactions of spacing, stocking
rate, composting benefits and manure management.
Corn stover may work in gestation rooms, however,
because the impact on piglets is not a concern.
Farmers wean piglets at 5 to 6 weeks old by opening the gates
at the front of the group rooms. They call the sows, which
voluntarily enter the aisle and go back to the mating area.
Piglets stay in the group rooms until they are ready for finishing
at 55 to 60 pounds (about 11 weeks old).
At the far right of the building is a 12- by 15-foot holding
room from which feeder pigs are loaded. Swedish rules require
that pigs being loaded into, or unloaded from, farm buildings
be temporarily housed in an area closed off from the main
barn to prevent air from the truck from mixing with air from
inside the barn. This prevents disease from being spread from
farm to farm by the truck.
Once a group nursing room is empty, farmers clean out manure,
pressure wash the room, allow it to dry, then bed it with
two large round bales of straw, same as for the gestation
Biothermal benefit. Heat from the composting straw beds makes
supplemental heat unnecessary in the group rooms. Kyloff heats
his farrowing room with wall units and heat lamps in piglet
areas. Other Swedish farmers use hot-water heat, either as
a radiant system in the floor or as exposed warming pipes
in creep areas.
Ventilation should be adequate to remove gases, dust and excess
heat without creating drafts or noise that will disrupt communications
between sows and piglets.
Controlled sunlight. Pigs need to see cycles of night and
Most Swedish farmers agree on these space goals for group
Dry sows: 27 square feet per sow.
Nursing area: 81 square feet per sow and litter.
Farrowing pens: 64 square feet.
Because they noted that pigs prefer rectangularly shaped pens,
Swedish farmers make the resting area of nursing rooms 22-
by 30 feet or 18- by 36 feet rather than 25.5- by 25.5 feet.
In the group gestation area, Kyloff left 16.5 feet from the
backs of the feeding stalls to the rear wall. With each stall
about 20 inches across, that depth provides about the required
27 square feet per sow.
Sows accustomed to tight confinement for several litters
will not thrive in this system. You may need to bring in new
breeding stock when you change to a behaviorally based group
Perhaps the greatest challenge comes in changing the way
our minds work as farmers, researchers or equipment designers.
Can we make tile leap to quit trying to fit pigs into systems
that are convenient and efficient for us, but often are against
their very nature? We will have to be more attentive to each
pig in the system and learn how to see our systems from a
pig's perspective. That is more difficult than many people
realize. It requires us to repeatedly rethink, and sometimes
to reject, what we "know" about hogs.
Practically, this change in regard to "loose confinement"
hog management has to start with structure. First, design
housing that does not require a pig to behave contrary to
its nature. Once your animals are living in a space that allows
them to act on their instinctual preferences—instead
of reacting to a host of stresses—you will be able to
learn from hogs in an environment where they will be free