Fitting The Farm To The Hog
Hog health, pork profits improve when Swedish farmers let pigs be pigs

By Greg Bowman
The New Farm, Sept/Oct. 1993 p. 35-39

Grower rooms in Swedish sow group systems commonly feature sophisticated ventilation, deep-straw bedding, a raised piglet creep area, and insulated but unheated barns. Tomas and Magnus Carlevad designed this nursery for their farm in southeastern Sweden.
Highly "efficient" conventional hog operations depend on routine medications and mechanization to keep going. But some Swedish farmers, who have refocused their operations in the past five years around their hogs' quality of life, say that by doing better by their animals, they're also doing better for themselves.

These farmers are pioneers in adapting structures, handling practices and management to let pigs really be pigs. They are reducing their hogs' physical and psychological stress to make them more productive. New farrowing and piglet-handling techniques incorporating group nursing and deep-straw bedding have been especially successful in weaning high numbers of piglets per sow. These producers see humane treatment as an opportunity for profitable innovation, not as a call to arms to defend conventional practices.

"They're not just tinkering to make a conventional system of crates a little better ," says Marlene Halverson, a Ph.D. candidate in agricultural and applied economics at the University of Minnesota. Halverson knows many innovative Swedish hog farmers and specialists from her visits there. "The idea is to figure out what hogs would do if they were able to behave normally for their species, then approximate the stimuli of a natural setting wherever possible," she says.

Swedish farmers use about 2 tons of small-grain straw per sow per year. The long-stemmed, loose straw satisfies foraging instincts, keeps the herd warm and maintains good health by keeping the animals dry.

Letting your hogs be your guide may seem like naive advice, but Halverson says that this perspective can explain some current dilemmas in conventional production. "There were reasons producers went to routinely using antibiotics, docking tails and crating sows as systems became more space- and capital-intensive," she says.

In recent decades, increasing the intensity of production has led to more confined housing, crowding, temperature and ventilation problems; more barren environments; and less attention to how individuals were grouped and fed. Hogs have responded to this stress with atypical behaviors such as tail- and vulva biting and fighting. The high investment and operation costs of restrictive housing has pushed farmers to seek greater economy of scale by raising more pigs. Each step in this direction has decreased their opportunity to use true husbandry and increased dependence on technologies developed off the farm, she observes.

To reach a high level of welfare for animals, we first need to know how they would be living if we weren't interfering with them, Halverson explains. "This means understanding how pigs as a species respond in general to their environment and each other, and also how each sow responds to a particular situation," she says.

The next steps are just as crucial. "To make this welfare for livestock a practical reality, farmers need a working knowledge of natural hog behaviors; profitable and aesthetically pleasing systems that they will want to work in and invest in; and solid markets that value the way hogs are raised."

Laws Spur Innovations

Two Swedish laws in the late '80s forced a change in how all livestock are viewed there — not as just an agricultural product, but as species with different needs and behaviors. The first was put into force in 1986 at the request of farmers who wanted to make their products more attractive to Swedish consumers. The law banned subtherapeutic or prophylactic use of antibiotics in animal feeds. Unexpectedly, however, the law's effects caused profound changes in the nation's piglet production systems.

As was well-publicized in the U.S. farm media, one of the immediate effects of the feed antibiotics ban for many Swedish farmers was more scours at weaning, requiring more therapeutic antibiotic use for the young pigs.

By contrast, some Swedish farms had no scours at weaning, notes Bo Algers, a veterinary ethologist (specialist in animal behavior) and a research manager at the Swedish University of Agricultural Sciences. These farms had healthful production environments that put less stress on pigs by keeping them clean, using lower stock densities, and bedding with straw to keep pigs warm and dry. This observation encouraged farmers whose herds had problems with scours at weaning to change the production environment for piglets rather than continue to administer antibiotic treatments. That move paved the way for designing freer systems of farrowing and lactation as well, Halverson reports.

At the same time, Swedish hog farmers were looking for simpler, lower-cost ways to produce high-quality pork. They wanted a competitive edge in anticipation of the nation's entry into the European Common Market. They started putting up multi-use hog buildings designed with more unobstructed space that cut costs by reducing labor, veterinary expenses and equipment needs.

These farmers had a head start when a second law affecting livestock production, Sweden's Farm Animal Protection Act, broke new ground in '88. The law mandated housing systems that provide a good environment for animals "so as to promote their health and allow natural behavior." It phased out farrowing crates and other restrictive facilities, helping the producers identify the most important natural hog characteristics were a number of researchers, including Algers and another ethologist, Per Jensen.

Sows given freedom of movement and time to bond with their litters show strong maternal instincts through weaning, which is best done gradually to diminish stress for sows and piglets. Farmer Gunnar Ljungstrom of west-central Sweden incorporated these features in the system he developed to allow natural hog behaviors.

For three years starting in 1984, Jensen had studied the daily activities of Swedish Landrace sows released into a semi-natural setting. He doesn't suggest pigs need to be in the wild to be raised humanely. But the outdoor setting provides insight on the motivations behind sows' behaviors that scientists or farmers could never have understood by watching sows in confinement.

"It's like a computer that has been given information it can't use. Indoors, we see tightly confined animals behaving in ways that are basically just error messages in response to negative parts of their environment," says Jensen. "Outside, I watched both pre-programmed and spontaneous behaviors without disruptions from physical obstructions and husbandry routines. These sows behaved just as wild ones do, varying only in degree or intensity of a given action."
Jensen' s most important findings were in the areas of:

Feeding. In the natural setting, sows spent up to 8 hours a day foraging, regardless of how much food they were fed. The discovery showed the difference between being nutritionally satisfied and behaviorally hungry, Jensen says. Farmers can use ad lib feeders to accommodate this strong food-search instinct. Some units require sows to manipulate controls to get small amounts of feed, greatly prolonging feeding time and sow satisfaction, says Jensen.

Grouping. In the semi-natural setting of Jensen's experiment, the pigs formed social groups. This finding influenced the production setting of new Swedish systems. Now, even conventional hog producers there use straw bedding and group rooms for pregnant sows, compared with the nearly universal bare-floor management and gestation crates of 20 years ago.

Keeping a set of sows moving through the production system together eliminates the stress of mixing groups. Swedish farmers have found various ways of successfully introducing new sows and gilts to established groups. In one group-nursing system, for example, groups are disrupted temporarily when sows are put into individual pens for two weeks around farrowing. Farmers say they can add a new sow with her litter smoothly during the nursery phase, when the group re-forms as sows leave their farrowing pens and are preoccupied with mothering.

Nesting. "The single, strongest instinct for a sow is to nest the day before farrowing," says Jensen. To do this she needs bedding materials and space. Roomy rectangular pens that allow sows to freely turn around to see their piglets have greatly decreased sow stress during and just after farrowing, and have contributed to increased piglet survival. Outdoor systems in the Midwest and South show similar results.

Weaning. In the semi-wild environment of Jensen' s experiment, sows finished weaning their piglets in about 17 weeks, a period far longer than is feasible for production. Jensen says a quicker, but still gradual, weaning at five to six weeks seems to work for sows, piglets and producers watching their bottom line. Sows given more time to lactate in the new Swedish group systems often come back into heat within a month of farrowing.

New Thoughts, Altered Barns

Since the late '80s, Swedish farmers have experimented with behavior- appropriate designs by simplifying over-equipped barns, using older wooden buildings and erecting new structures, some complete with electronic ventilation sensors and observation windows. Putting the natural-setting research findings into practice has meant lots of trial and error, with results shared freely between producers and their advisers. Discoveries at the farm level include:

Breeding cycles and piglets require careful attention when sows are kept in groups. Sows need to farrow within a week of each other to keep their piglets within a compatible age range. Penning sows ready to cycle next to boars helps to synchronize estrus naturally. Providing "retreat areas" in the sow gestation pens gives newly introduced sows or gilts protection while they find their social niche in the group. This decreases stress and increases breeding success.

All-in/all-out handling simplifies labor and management: It gives farmers a good window to remove manure and sanitize rooms between groups.

A quiet environment is critical for a sow to communicate with her litter. Researchers found that sow milk let-down lasts only 20 seconds, on average. Sows grunt to signal a nursing opportunity is imminent. Piglets that miss the call because there is too much mechanical noise or they don't recognize their mother don't get their share of milk and colostrum, and get off to a slow start.

Closed, insulated barns with deep straw packs maximize piglet survival but require high-volume air movement. The straw-manure mixture gives off heat and gases as it composts. Simply installing bigger fans caused too much noise for piglet-sow nursing communication. Farmers isolated fans and built quieter ventilation systems.

Peaceable interactions take planning and room. When a sow's "personal space" is free of perceived challenges from other sows, she has less reason to fight to defend her status. If housing allows sows to meet with at least 6.5 feet between them, a lower-ranking sow can show her submissiveness by turning her head to the side, avoiding the "provocation" of a direct meeting that might lead to a fight.

Creating and managing these environments demands a depth of knowledge of hog tendencies and behaviors. The emphasis in conventional systems on technology, volume and isolation of individual sows provide younger farmers few chances to learn about natural hog instincts, says Halverson. "Intensive confinement systems that stifle an animal's natural behaviors don't give the opportunity to know our animals well," she says. "We need to expand the human capital investment in hog management to foster true husbandry as the main value the farmer 'sells.'"

Sows given freedom of movement and time to bond with their litters show strong maternal instincts through weaning, which is best done gradually to diminish stress for sows and piglets. Farmer Gunnar Ljungstrom of west-central Sweden incorporated these features in the system he developed to allow natural hog behaviors.

Quality Time

In these Swedish barns, farmers have to get in and walk among their pigs at least once a day to develop mutual trust with the animals. "Bo Algers recommends the farmer spend at least 30 seconds each day with each sow housed with a group," says Halverson. "They expect the sows to run up and play, to nip at their legs and run away." Piglets that are lethargic or stay buried in the straw show they may be ailing and need some attention.

Modern domestic sows are the product of 200 years of selective breeding for external and physical characteristics. Yet even after repeated farrowings in confinement, sows still show the nest-building tendency just before giving birth. Pawing the floor and bar-biting don't look like visible nesting actions, but Per Jensen says the movements reflect what confined sows do when they can't fulfill their instincts to isolate themselves, locate a site and construct a nest.

"When we prevent a sow from nesting, we set up a stressful situation,"says Halverson. "When we put her in a crate with feed and water, we feel we've met all her needs — from our point of view. We don't see why she needs to move around to find food or to watch her piglets or to respond to their distress calls."

But in a natural environment, as farmers with outdoor herds know, adult pigs spend a great part of the day foraging and exploring their environment. Nest building in the wild has survival value. For such inbuilt motivations, the process can be as important as the product. "By providing just the ends, we do not satisfy a sow's need to go through the means. A few minutes to gobble up concentrate doesn't satisfy the urge to forage," says Halverson. "The more we do for the sow in the crate, the less she can do for herself and the more her insecurity, fear and stress levels rise."

About 40 percent of Swedish hog farmers now use behaviorally sound systems of piglet production. These are based on barrier-free farrowing pens,either conventional metal built-ins close to a group grower room or sturdy plywood rectangles temporarily set along the perimeter of the farrowing room itself. Pens range in size from the legally required 5.5 square yards up to a more sow-friendly 9 square yards.

Piglets stay in the pen for the first week to 10 days, long enough to form strong bonds with their mother. Then the sows rejoin the group with their litters. While group-management systems have failed in some countries, Halverson says they work well in Sweden because of:

Abundant use of clean straw — about 2 tons per sow per year. Whole, unopened bales help satisfy the sows' and piglets' desire to forage and manipulate their environment. Swedish farmers prefer large round bales, because they give pigs the most physical challenge and because long stems stay looser in the straw pack, allowing more aerobic composting. Group-system buildings have doors large enough for skid-steer loaders to remove the manure between groups.

An individual feeding station for each sow in gestation rooms that protects individuals from the negative aspects of group-feeding dynamics. By locking the stations for half an hour at feeding, the farmer prevents dominant, fast-eating sows from rousting lower-ranked sows from their positions and eating their food.

Swedish hog farmers who have mastered behavior-based systems report multiple rewards. The farmers are happier about the day-to-day interaction with their animals. Their figures show lower long-term investment in structures, veterinary expenses and overall labor costs, with better sow reproductive health and productivity. Inger Johansson and her husband Torgil read about Jensen's and Algers' research and started a group-nursing system in 1986. "We wish we had built this system 25 years ago," she says. "If we ever had to choose between changing back to the old conventional production or pack our bags, we would pack our bags first."

Farmers who thrive with these systems are those who appreciate individual behaviors within the herd and who develop an eye for recognizing illness, discontent, fear and agitation. This takes daily, direct contact in the pen — a kind of management that is impossible without a workable sow-to-farmer ratio.

Halverson says a number of forces are changing Sweden's livestock system, not only animal-welfare advocates. The primary push comes from hog farmers determined to find low-cost, productive systems that deliver the high-quality meat Swedish consumers demand. She's not surprised that these systems work for the pigs, too. "I think that if we as a society make provisions for animals to be animals well, we will find, as they have in Sweden, that we have a better chance that farmers will be able to be farmers well."