People, rather than the system itself, are the key to successful group sow housing, says Danish researcher Lisbeth Ulrich Hansen, who worked closely with Danish producers as they transitioned from sow stalls.
Farm data from Denmark and the Netherlands shows that there is very little difference between systems, she says. However, it is important for producers to spend sufficient time choosing the housing method which is most suitable for them.
“It is very important that the producer understands what he is getting when moving to group housing and that he is fulfilling what is important to him, for example individual feeding,” she says. “He needs to feel comfortable and have confidence.”
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The majority of Danish producers use systems which allow individual feeding, such as electronic sow feeding or free-access stalls, because it is generally recognized that close control of feed intake and body condition has a positive effect on performance.
Managing electronic feeding
Electronic sow-feeding (ESF) systems are used by about one-third of producers in Denmark, so there is considerable experience regarding their management. “ESF allows individual feed rationing, the ability to manage feed scales individually, and a large degree of flexibility,” notes Hansen. “The only downside is that there may be some competition between sows while waiting to feed because, in pigs, group feeding is their natural behaviour.”
Danish trial work has shown that starting the feeding cycle during the night resulted in fewer confrontations between sows.
“We compared start times of 04.00 and 22.00 hrs. If you start in a period of low activity, there will be less aggression,” says Hansen. “Some producers start at 5 p.m. or 6 p.m. so that they can check that the feeders are working properly before leaving the barn.”
Danish experience has led to clear guidelines on the number of sows per feeder.
“For pens with only one feeder, 55 is the maximum but, if there are multiple feeders, up to 65 sows per feeder is acceptable,” Hansen says. “Experience shows that if there are more sows per feeder, some may not eat all their feed allowance.” She also says that Danish producers appreciate this and follow the guidelines.
Achieving the correct body condition in group systems is very important. “You need a minimum of three feed curves and also one for gilts,” Hansen stresses. Electronic devices are used to read the transponder number of sows in the pen and in some cases production data can be entered and viewed on a hand-held device which can be linked to the feed computer to update feed curves based on body condition.
“Sows need to be assessed for body condition at mating, at scanning and in mid-pregnancy to provide the basis for feed scale allocation,” Hansen says.
Identification of sows that have not eaten their full ration is vital. “Prior to the end of the daily feeding cycle, a list of sows that have not eaten at least 75 per cent of their ration should be printed off and those sows checked,” she says. “Reduced feed intake could be due to a sow returning to estrus, but is most likely due to lameness or some other health problem.”
Hansen notes that quick recognition of the sow when she enters the feeder and rapid delivery of the first dose of feed is essential to avoid frustration.
“Timing of feed drops needs to be quicker at the start of feeding when the sows eat faster,” she explains. “A typical sequence might be 100-g drops spaced at zero, five, seven, 10, 12, 15 and 20 seconds, then a drop every 20 seconds, with a 120-second eat-up time. More time is needed for gilts and young sows, so this must be built into the feed curves.”
Free-access stalls are popular
Free-access stalls involve fixed groups of sows and so are easy to manage, which is partly why they are so popular in Denmark. Another reason is that they require fewer hospital pens compared to ESF, according to Hansen. About half of the systems involve liquid feeding and the rest dry feed.
Legislation requires that there is at least 3.0 metres between opposing rows of stalls (back to back). “Even with 3.0 metres between stalls, in slatted systems, sows tend to spend most of the time in the stalls,” Hansen notes. “Even where straw is used, sows don’t spend much time outside the stall, but we don’t really understand why.”
Many slatted systems have an area of “nest boxes” with generous straw bedding, which the sows can eat or play with.
Free-access stalls are widely used for breeding pens as well as for gestation, but in this case the dunging/exercise area is 5.5 m wide. “Sows are weaned into the pen, then when they are in heat they are confined in the stalls, then two days after mating they are released,” explains Hansen.
She says recent legislation will eventually require producers to house sows and gilts in groups at all times, whereas currently stalls are allowed for 28 days after breeding.
Danish producers have embraced group sow housing in a positive manner and have implemented it with their usual efficiency. The latest data from about one-third of Danish sows shows 28.8 pigs weaned per sow, an increase of 0.7 on the previous year. High-quality people, combined with good management routines, have been the key to maintaining high levels of production efficiency as producers have moved to group housing.
