Management: Gestation sow housing - the debate continues

Tuesday, June 2, 2009

Instead of making decisions based largely on emotion, they should be based on sound science. And that suggests gestation stalls offer a number of advantages

by JIM DALRYMPLE

Over the past year, there's been much discussion about the gestation (dry sow) housing systems in use around the world. Already California has voted in legislation to stop the use of individual stalls for dry sows and also to restrict the housing methods for egg production. There was little scientific basis for this decision, which was largely based on emotion.

The Iowa-based Council for Agricultural Science and Technology (CAST) has completed a major assessment of the issue of sow housing. The 20-page document cites over 150 scientific studies related to dry sow housing. Stan Curtis, a well-respected scientist from the University of Illinois, collaborated with five other authors from around the world to prepare this paper.

The genotype of pigs reared in present-day production systems differs from those of their ancestors. The lard content of a typical pig fell from 35 per cent around 1960 to 17 per cent in 1980 and 10 per cent in 2000.

Changes in genetics and production methods have increased sow productivity from approximately 12 pigs per sow per year to more than 20 in most production units, and to 25-30 pigs per sow per year in top performance herds.

Specialization became the norm with sows housed indoors to avoid mud and temperature extremes, to improve parasite and disease control and provide better manure management.

Over previous decades tethers and sow stalls came into use, but the tether was banned in Europe beginning in 2006 and the gestation crate is to be banned in 2013.

Nutrition and feeding considerations. Sows should be "fit but not fat" at farrowing, if lactation feed intake is to be stimulated and loss of fat during lactation minimal.

Individual gestation feeding in stalls allows a thin sow to be treated individually without having to compete with older, heavier, stronger and more dominant sows at the feed trough. The difficulty in regulating individual feed intake is a major disadvantage of keeping sows in groups. The thin get thinner and the fat get fatter.

Health considerations. The risks associated with infectious diseases and the impact of zoonoses on swine and humans alike clearly indicate the value of indoor facilities for dry sows. There is virtually no biosecurity in outdoor swine production. The producer can easily observe and have access to individual sows in each stall. It is widely recognized that treatment, vaccination and care practices are much more manageable in gestation stalls. The amount of fighting between sows is substantially greater in sows in group pens.

Housing and manure management. Slatted floor areas in stalls may also have advantages over solid floors. Solid floors and the presence of wet bedding increase the likelihood of multicellular and microbic pathogens and the likelihood these pathogens will survive. Group systems with bedding have a high infection rate with salmonella. Barns with bedding can also increase the amount of manure to be handled.

Economic considerations. Stalls help control individual feed intake; prevent the sow from turning around and defecating and urinating in the feeding area; retain manure, decrease bossing and fighting and provide for easy control of the sow while protecting the caretaker during examination, insemination or treatment. They also optimize the efficient use of barn space.

Most scientific evidence suggests that reproductive performance of dry sows kept in stalls is at least as good as, and in some cases better than, that of sows kept in groups.
It is difficult to predict the future design and operation of pregnant sow accommodations, Many scientific evaluations have concluded that the well-being of pregnant sows is equivalent, whether they are kept in individual gestation stalls or in group pens.
The choice should be made based on sound science not just emotion. BP

J.R. (Jim) Dalrymple, P.Ag., CAC, is a former Ontario government swine specialist and owner of Livestock Technology Services in Brighton.