Sow stalls, group housing work well if managed well, MU specialist notes

Pig welfare depends not on the use of gestation stalls or group housing but on the quality of individual pig care, said a University of Missouri Extension swine specialist. "Managed correctly any of the housing systems can work. If we look at the body of scientific literature it doesn't matter how sows are housed," said Tim Safranski. "It matters more how they're cared for."

At the Missouri Pork Expo Safranski reviewed individual and group housing and described the pros and cons of each. He said eight options can work with proper pig care which improves performance in any system. Proper care means ensuring basic needs like food, water, and protection from weather, Safranski said. It also means reducing hazards and competition and allowing sows to express most normal patterns of behavior.

"With all the sow-housing options gestation stalls fit most of those." he said. "Group housing could fit most of those but none of them fit every point perfectly." Safranski cited a 2005 paper from the American Veterinary Medical Association that concluded that no existing housing system for pregnant sows is better than another.

Overall, stalls prevent fighting, reduce stress and injury, and make vaccinating, medical care, and arti- ficial insemination easier. Stalls also make individual care much easier. "We can control individual feed intake, get the skinny sows more food, and give those fat sows less," the swine extension specialist said.

But stalls restrict movement and some natural behaviors like socializing and foraging. Limited mobility may cause joint stiffness and stalls also make sows entirely dependent on humans for basic needs and physical comfort. With sows in stalls daily observation is critical, the swine specialist said. An exercise pen man helps sows showing signs of difficulty. "If we see a sow having trouble walking, giving her space to exercise and stretch may help the system overall be more productive, he said.

Group housing makes specialized care and feeding harder but also allows sows more social interaction and movement. Sow groups range in size from five to six sows to 80 or more. Group size affects management issues like sorting, dairy observation, and whether new sows can be added.

With small groups it is essential to sort, creating groups based on size, appetite, body condition, and speed of eating. With 25 sows, for example, five or more groups are needed. "Some one is still going to be the boss pig;" he said, "but if we can at least get them to start they are going to stay a lot closer to uniformity than if we don't."

Once created small groups should remain fixed. Changing sows will increase fighting and producer costs. If sows must be mixed it's helpful to mix them into a new pen to reduce territorial behavior. "Get them all out, walk them down the aisle, and put them somewhere else," Safranski said. "That way no one is invading my house-I'm moving into a house of strangers."

Pens must also have adequate space. This can be difficult as little data exists on how much space grouphoused sows needs, he said. With large-group housing, the idea is that sows fight less because they can't figure out who the bullies are. This allows for dynamic groups that can be continually mixed. Broad sorting is still helpful to account for different feed needs or temperaments.

Observing individuals sows is still harder which can complicate breeding, vaccinating, heat checking, and control of individual feed intake. Trickle feeding or electronic sow feeders offer possible technologic solutions for the feed dilemma of group housing. Each has its pros and cons. Limiting sow stress just after mating can also improve group housing. "Sows are most sensitive to stress from the time of mating to about 30 days after," he said. "If we can avoid stressing sows from group housing during that period it adds value."

After that sows can physiologically handle a lot of stress such as fighting, which is associated with group housing, and still maintain pregnancy. Safranski said the European standard combines both housing types. Groups are used post weaning to deal with stress, help sows cycle, and sort for 30 days then return to groups.

Regardless of housing type the key is attention to detail, he said. "I don't care what kind of housing system you've got to do things right," Safranski said. "We don't just go out and harvest pigs in the wild. We manage them. Why, because we have to feed the world and that what we're about."