THE NEW FARM ARCHIVES

Whole-Hog Housing
Swedish System Lowers Stress, Disease

By Marlene Halverson
The New Farm, Feb. 1994, p. 51-54, 62

Marlene Halverson

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.

Suggestions For
Starting Out

To reap 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 herd.

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 groups.

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 for change.
—M.H.

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 version.

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.

This sketch 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.

Barn Populations:
MATING: 16-20 sows, 2 boars
GESTATION: 24-29 sows
FARROWING: 8 sows
GROUP NURSING/GROWER ROOMS: 8 sows/litters, per room


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 implantation stage.

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 systems.

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 to.

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
More Straw

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.
—M.H.

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 room.

Comfort considerations

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 day.

Spacial requirements

Most Swedish farmers agree on these space goals for group management:

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 system.

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 to instruct.