There are five essential components for successful group sow housing, says Lisbeth Ulrich Hansen, chief scientist with the Danish Pig Research Centre, who has been working on group systems for 20 years.
Speaking with me during a recent visit to Canada, she said that the key aspects included individual feeding, adequate space allowance, stable groups of sows and close daily inspection, with sufficient hospital pens for disadvantaged sows. In addition, management of the gilt prior to first mating is an important area that has not been given sufficient priority in the past.
Hansen says that the ability to feed sows individually enhances both farrowing rate and litter size compared with group-feeding systems, which is reflected in the fact that most Danish producers have installed either electronic sow feeding (ESF) or free-access stalls. No more than one-third use floor feeding or liquid feeding in long troughs.
Hansen stresses the importance of maintaining good sow condition at all times and quickly regaining any condition lost during lactation. “Our trials have shown that higher feed levels in the first 28 days of gestation improves subsequent litter size where sows are in thin condition,” she says.
Adequate space required
With regard to space allowances, Hansen points out that this is governed by law and includes requirements for both lying area and total area. Gilts in groups of up to 10 must have a total area of at least 1.9 m2, with 0.95 m2 of lying area. For groups of more than 10, the total area required drops to 1.7 m2. Space allowances for sows are also according to number of animals in the group, from 2.8 m2/sow for groups of one to four sows, down to 2.2025 m2 for groups of 40 or more. In all cases, a minimum of 1.3 m2 lying area must be provided. “Producers know that they need to provide adequate space to optimize performance,” notes Hansen.
Static groups of sows are easier to manage because they are usually based on weekly groups, although this is often not possible on smaller farms using ESF. In addition to the obvious management benefits of weekly groups, Hansen says that she prefers static groups because this does not require an automatic separation facility on the ESF feeder, which involves additional programming of the feed computer.
Dealing withdisadvantaged sows
In group-housing systems, prompt attention to any sows that are sick, injured or disadvantaged is essential, Hansen points out. “Ninety per cent of health problems in group housing are leg problems,” she explains. “Vulva biting is not seen provided sows are taken into the farrowing room five to six days prior to farrowing.”
She says that fresh lesions from fighting should not be seen after one week post-mixing, otherwise a wounded sow should be removed. “Thin sows may also need to be removed where there is no facility for individual rationing,” she adds.
There are more problems with floor feeding compared to individual feeding systems. Similarly, young sows that have not eaten all their ration in ESF systems, and spend most of their time in the dunging area, need to be removed.
“Ideally, hospital pens should be located adjacent to the gestation area because, if you have leg problems, you may not be able to move the sows very far,” Hansen says. “Legislation requires a minimum of 2.5 per cent of sow spaces to be hospital pens and there can only be a maximum of three sows per hospital pen. There has to be a soft lying area — straw or rubber mats — and the environment must be enhanced via straw or a kennel area.”
Her recommendations for percentage of the total sow space that should be hospital and recovery pens according to system are five per cent in ESF, three to five per cent in free-access stalls and 10 per cent in floor- or trough-feeding systems.
Gilt management important
Gilt management is receiving a lot of attention from Hansen and her team.
“You need to bring gilts up to have social skills. Socializing involves understanding how to respond to other sows and must be done before mating because you don’t want stress at mating or up to 28 days of gestation,” she explains. “I’ve seen gilts brought up away from sows and then when they are introduced, they fought until they had to be separated.”
Exposure to older sows, not just other gilts, is required, although more research is needed to understand the most effective procedures.
Despite this, many producers are very positive about the concept, Hansen says. “A recent trial looked at sow exposure for two weeks before moving gilts to the breeding area,” she says. “While there was no improvement in longevity, gilts integrated better into groups with sows.”
The procedure could be carried out while training gilts in ESF systems, she suggests. Gilts would then see sows going into the feeder and copy them. Hansen advises two to three sows per 20 gilts.
Danish producers had from 1999 to January 1, 2013 to convert from sow stalls to group housing and, unlike many other EU countries, completed the transition on time. Not only that, but Denmark saw no significant drop in sows numbers as a result. The research and advisory sectors of the industry played a major role in ensuring that the transition went as smoothly as possible.