Start now With a phase-out of sow stalls almost inevitable, producers need to start evaluating different systems
When the new Code of Practice for the Care and Handling of Pigs is published in draft form this summer, it will very likely include a requirement that sow stalls be phased out over a period of time. Producers will be able to house sows in stalls for a period after breeding, in order to allow checks to be made for returns and a first pregnancy test to be carried out prior to grouping. Keeping sows in stalls for a period of, say, 35 days post-breeding, also allows any loss of body condition in lactation to be substantially corrected by having the ability to feed individually.
After the financial battering producers received between 2007 and 2010, there is still very little enthusiasm for new investment or expansion, as witnessed by the almost static sow numbers in the latest census data. However, even with a 10-year phase-in time, producers must start to think — sooner rather than later — about their options and try to understand the factors that need to be considered.
While there is good research data on some forms of group housing available in Canada, there is very little large-scale commercial experience and certainly no good comparative data. At this point the industry is quite unprepared to launch into a major change in housing systems. The danger is that producers make changes to their barns that are not only inappropriate for their circumstances and reduce performance, but also compromise sow welfare.
There is a huge amount of experience with group housing in Europe, especially in the U.K., Denmark and the Netherlands. It will be essential to maximize the use of this information rather than trying to reinvent the wheel completely. Herd size in Canada is generally larger than in most European countries and this factor will influence the choice of system. Also, in our climate, it is unlikely that producers will wish to build straw-bedded systems. The need to use slatted floors will also influence the type of group housing.
When considering group-housing options, it should be borne in mind that sow stalls provide individual feeding, minimize competition for feed, avoid aggression and provide ease of management. Not all of these benefits will be completely realized in a group-housing system. Some aspects that need to be considered when choosing and designing group housing include:
- Group size: In most systems group size is determined by the number of services per week and the type of feeding system used. Where feed cannot be rationed individually, it is usually best to split each week’s served sows into two or more groups according to body condition and to house gilts separately.
Large group sizes (40 – 60 sows/week) allow static sow groups with electronic sow feeding (ESF) to be used. With smaller numbers of sows bred each week, sows have to be added to and removed from a large ESF group each week, which is termed dynamic grouping.
- Bedded or slatted floors: Most group housing can be designed with slatted floors, providing sows are in fixed groups. European experience has shown that dynamic groups on slatted floors with an unbedded lying area may result in unacceptable levels of foot and leg injuries. However, a combination of well-bedded lying area and a dunging area overcomes this problem. An alternative would be to use a special bedded pen for grouping, then transfer sows to an unbedded pen once they had established their dominance hierarchy.
- Space requirements: Recommendations for lying areas are:
Sows 14-15 ft.2 (1.3-1.4 m2)
Gilts 13 ft.2 (1.2 m2)
Where floor feeding is practised, additional solid lying area is required so that sows can move around easily during feeding. Excess space may lead to soiling of the lying area, depending on the system. The amount of dunging area required is generally in the range of 7-10 ft.2 (0.65-0.9 m2) giving a total space requirement of 21-25 ft.2 (2.0-2.3 m2).
- Pen layout: In systems with troughs or individual feeding spaces, the pen layout is largely determined by the feeding-space requirement. Large dynamic groups provide much more flexibility in design. Generally, the length of the pen should not be more than 2.0-2.5 times the width. Electronic feeders should be located so that adequate access is provided, otherwise aggression may occur, especially around the feeder entrance.
- Degree of remixing: Sows that return or are found not-in-pig may remain in their original group or be remixed, depending on the system. In dynamic groups it is not necessary to remix sows because the group contains sows at all stages of pregnancy. In weekly or fixed groups, sows that return can be remixed with newly weaned sows.
However, as this leaves a space in the pen that cannot be used, some producers prefer to leave sows in their original groups. This creates the need for additional small pens which can be used to house sows for the last few weeks of pregnancy, when their contemporaries have been moved to the farrowing barn. Working out a clear policy for remixing is an important part of the design process.
- Handling facilities: Routine tasks such as pregnancy testing and vaccinations are easily carried out in group systems, especially where ESF is used because sows are very docile. ESF feeders usually have the facility to automatically separate sows into a holding pen after they have fed to allow certain tasks to be carried out. In all group systems it is advisable to have a handling crate for procedures such as lancing an abscess, foot trimming or blood testing.
In my next article, I will review the group-housing options currently available and how they compare.