Sows in Loose Housing Systems

Consumer interest continues to focus on where food comes from and how it is raised. The European Union has banned the use of sow confinement stalls by 2013, and Ohio has banned the use of new gestation stalls, effective July 2010, with existing stalls to be phased out over the next 15 years. Currently, Canada does not ban sow gestation stalls. However, societal pressure and packer requirements to supply niche markets are resulting in the move toward alternate forms of housing for sows. These factors will affect producers wishing to sell pork into the export market and become drivers of how pork is produced in Ontario.

The current direction in sow housing is moving away from the traditional gestation stalls and towards housing systems that allow the unlimited movement of individual animals. This change has led to unique management challenges when working with loose-penned animals. This trend has been in process on a number of Ontario commercial units for 15 or more years. Small production units, that never used gestation stalls, have also been operating this way. 

In the last 30 years, significant changes have occurred in swine production.

With the advances in management and care of individual animals, other areas of swine production also developed. Production units grew larger. Animal genetics, nutrition knowledge, ventilation, health care and husbandry practices developed and evolved.

In the late 1990s and early 2000s, Ontario producers sensitive to the needs of the marketplace began to look seriously at housing sows in groups. 

Typical group or loose housing uses slatted floors, no bedding and various methods of delivering feed, both liquid and dry, to a group of sows. Not all sows are suited to loose housing; sows that are excitable or overly active and sows that are overly docile both take more time and labour to move and work with in a loose housing system.

There are two methods of grouping sows - static and dynamic. In the static system, once a group of sows is assembled and penned together, no more animals are added. Animals that do not adapt are removed to stalls. The dynamic system is a group of sows with animals added and removed weekly. With both systems, sows are moved out to farrow over 1-2 weeks.

Producers with fewer than 700 sows would use the dynamic system, while those with more than 700 would use the static system to best utilize electronic sow feeders. Gilts must be housed and grouped separately from sows until after their first litter. 

Electronic sow feeding (ESF) has been in existence for over 20 years and widely used in Europe. ESF works from an electronic identification in a sow's ear. When the sow enters the feeder, the tag is scanned, and the rear gate closes. A computer records sow activity, compressed air opens a trough door, and solenoids dispense feed and water in small portions until the sow stops eating or reaches her daily allotment. At that point, the trough door closes, and the sow exits, opening the rear gate for the next sow. The computer can be programmed to deliver two different types of feed on two different feed curves throughout gestation. Sows can eat at their leisure and return later for more. Animals not eating (sick, lame, lost tag) are identified on a daily print-out.

Electronic sow feeding used in loose housing has been successful in Europe and can provide good sow welfare, with attention to detail. Production figures can equal or exceed those of stalled units. It is a labour-intensive system, relying on electronics and mechanicals that require protection against the environment. Adequate technical back-up and access to spare parts are necessary. Feeding equipment must function correctly and well. A big challenge with electronic sow feeding is ensuring that all animals are receiving adequate nutrition regularly. Some sows may not eat their full ration every day. The producer must adjust the computer program regularly to allow for differences in sow metabolism, activity level, behaviour or injury.

Things to consider when using electronic sow feeding:

Manure systems, from straw to total liquid with slatted floors, work well with ESF. If you are supplying roughage (hay, silage or straw), make sure it is provided in a form the manure system can handle.

After groups are assembled, checking for pregnancy or any treatments requiring medical intervention are best done with some form of confinement, such as an alley and squeeze, for effective administration and uniform treatment.

Sow identification is critical. Without the necessary identification, electronic sow feeders don't work. To maintain production records, individual animal identification must be maintained. Remember that re-tagging in a large pen can be a challenge.

A combination of stalls and group-housed pens provides a good housing environment because:

As Europe moves toward the banning of gestation stalls, a new type of stall is being developed. Free-access stalls, used with slatted floor systems, are installed into typical, large-group ESF pens, allowing the sows to share a common area. If a sow wishes security, she can enter any empty stall at will and close the rear gate using body weight. To exit, she can open the stall by standing up and backing out. The stalls can also be locked manually for health and pregnancy checks. Over 20,000 of these stalls have been sold across Scandinavia and are scheduled to be in use in Europe by 2013.

Research on sows use of free space in free-access stalls shows that not all sows used the free space areas regularly or for extended periods of time. Older, heavier sows used the space the most. More research on reducing social stress on younger animals and making the free space more comfortable is needed.

Industry has selected for larger pigs that can have difficulty lying and standing, and may not fit comfortably into conventional stalls.2 Sows show a preference to lie down in areas with walls that can act as support. Marchant et al. (2001) reported that 89% of the time, sows lay down against either a sloping wall or a wall fitted with a piglet protection rail. 

Producers in Ontario who have managed sows in group housing have developed a number of techniques to reduce aggression in group pens. The following suggestions are listed in order from the easiest to the most difficult, based on labour/cost.

In practice, the area per sow has varied from 1.4-2.8 m2 (16-30 ft2) per sow. A large feeding floor reduces competition for feed. However, too large a lying area leads to dunging on the solid floor. Common practice has been to allow 1.1-1.4 m2 (12-15 ft2) of feeding/lying floor. Floor-fed sows generally stay clean because of the floor feeding. Slope floors 5% towards slats to get urine to drain out quickly. Liquids puddling encourages dunging on solid floor. A 5-cm (2-in.) step down to the slatted area will help manure stay on slats. 

Gateless feeding stalls of both European and Ontario design are available. Sows enter these stalls to be fed individually; the person doing the feeding decides how much each sow is fed. 

Loose housing can use slatted floors or a straw-based system for manure management. Slat details are important for dry sows in pens. A slatted floor at least 2.4 m (8 ft) wide helps keep sows clean; any less and there will be some risk of manure on the solid floor. Ideal slot width is 2 cm (3/4 in.).

The slatted floor area at the end of the pen, next to the outside wall, is prone to manure build-up, because the manure does not get tramped down by the sows. A wider gap of 5 cm (2 in.) between the last slat and the wall will keep this area cleaner. Place the slat panels parallel to walls and support them on cross beams. Sows do not typically get caught in this wider gap. 

Move manure out of the barn with a skid steer to an end pad and remove it from there with a tractor loader. Return straw in the reverse order, eliminating the need for outside equipment to enter the barn. The pit under the slats closest to the straw will require flushing every other day to keep it open. Scrapers may also work, but broken cables can pose problems. In the U.K., deep straw-based systems are common. 

European Union legislation requires that straw or roughage be available to sows daily. European sow straw systems typically use a solid floor lying area and slatted dunging areas in insulated buildings; some locations have under-floor heat. 

The use of gestation stalls began in the 1970s to reduce the number of aggressive encounters between sows in group pens and individually feed unthrifty sows. It was considered an aid to a sow's biological functioning and well-being, although at the expense of a more natural existence. Consumer-driven changes to livestock production are moving towards management styles that allow animals more natural behaviour. Recently, producers have developed numerous new methods of feeding sows in groups and group pen designs that decrease competition for feed and, thus, aggressive encounters.

Almost all the people in pork production in Ontario today grew up in an industry that utilized gestation stalls, liquid manure and both mechanical and liquid methods of feed delivery. Their management skills developed around the needs of the industry they worked in and they became outstanding at what they did.

The challenge for pork producers now is to rethink and redo the management practices used to develop the industry to this point in order to maintain a strong and productive industry. The person entrusted with the care of the animals must be able to pick out the at-risk animals from a group, separate them and take remedial actions. Production from group-housed sow units can equal production from confinement units, but excellent stockmanship skills are necessary to make the system work. The use of loose housing as a management system is not a replacement for individual sow management, care and attention to detail.

The features of the various styles of group housing will appeal to some producers more than others. Speaking with producers who are currently using group housing will provide great insight. 

1. Whittington L., Prairie Swine Centre, Saskatoon, SK, F. Kains, Old Cottage Place Kitchener, ON, T. Nichol, Alberta Pig Co., Wainwright, AB, M. Elliot, FGC Ltd., Sebringville, ON. Turning Loose on Sow Housing. Advances in Pork Production (2008) Volume 19, p. 147.

2. Lang F.C., S.M. Hayne, V. Heron and H.W. Gonyou. Free Space Utilization of Sows in Free Access Stalls. 2009 Prairie Swine Centre Annual Research Report.

3. Zurbrigg K. Making It Work: Housing Gestating Sows in Group Pens. 25th Centralia Swine Research Update, Kirkton, ON. January 2008 I-35, 36.*

*This author has two DVDs available, free of charge, on various loose sow housing systems currently in Ontario. 

This Factsheet was written by Ed Barrie, Sow-Weaner Specialist, OMAFRA, Stratford.