Is the move to abandon stalls for gestating sows a done deal?
Not in some people's minds. Listen close and you'll hear a murmur spreading in the pork industry that asks: “Are we sure the well-being of sows is better served when housed in groups rather than individual stalls?”
University of Illinois animal scientist Janeen Salak-Johnson openly raised the question during the Sow Housing Forum in early June. (See reports in this issue.)
The Illinois researcher says producers shouldn't be too hasty in abandoning the individual stalls, but she admits some modifications may be required.
To reinforce her point, Salak-Johnson explains how a visit to a German sow farm with a free-access system offered perspective. Sows can choose between an open pen area and a row of stalls where they are fed. Stalls are designed so a rear gate closes behind them when they enter and swings up and out of the way when they exit.
What fascinates Salek-Johnson about the system is that most sows chose the solitude of an individual stall. Even more interesting, most sows claimed a specific stall and returned to it.
The German host confirmed that sows generally prefer the security and solitude of their “chosen” stall. The upside of this tendency is that sows in the free stall system can be fed, managed and treated individually.
To my knowledge, sows haven't cast a vote in the stall vs. crate matter. With adequate controlled research, the sows' preference for individual stalls could be scientifically established.
More Stall Size Options
Even if a stall preference could be established, the issue of stall size remains.
As we know, sows do not come in standard sizes, so why would we expect them all to fit neatly into the standard 2×7 ft. stall?
The answer, of course, is we can't. Still, few people have studied the viable options, which basically boils down to providing stalls in various sizes or making them adjustable.
University of Minnesota swine veterinarian John Deen recently studied how different body dimensions fit into various sizes of gestation stalls. The fancy name for this process is “morphometry,” which simply means being able to predict the space needed to fit different body sizes into a three-dimensional space.
Deen's work suggests a need for at least four stall widths (22, 24, 26, 28 in.) or the capability of adjusting them within that range.
The adjustable option creates a design/construction challenge because it would effectively add 6 in.to the width of every stall and increase building costs considerably.
Offering various stall widths in respective rows could save some space, although that would mean recently bred sows would be sent to the row of stalls that fit their body dimensions rather than loading a gestation barn, in sequence, as they are bred.
But, as sows advance in their pregnancy, they may have to be moved to the next size larger crate, which creates logistical and labor challenges.
Preference for Pens
Conceding to pen gestation is certainly an option. Bob Ivey, general manager of Maxwell Foods' 80,000-sow inventory thinks it's a reasonable one, so long as sows are allowed a 35-day stay in stalls (from weaning to a confirmed pregnancy). That's a vital part of making the group housing system work, he says.
Ivey's convinced that anyone who can manage a gestation stall system can learn to manage pen gestation. “It's not that complicated,” he assures.
Veterinary consultant Tom Parsons agrees. The University of Pennsylvania researcher has spent nearly three years studying half a dozen commercial operations with pen gestation and electronic sow feeders. “Producers will have to learn some new skills to make pen gestation successful, but they're not that different than those you must learn to manage a conventional gestation barn (with stalls),” he says.
The Right to Vote
There's a lesson and a dilemma here. If you give a sow a choice — stall or pen — and she chooses the individual stall, should we launch a campaign to save the individual sow stall?
It seems unfair to over-rule a sow's preference simply because some animal welfare zealot thinks she'd be better off — and happier — when given the opportunity to cozy up to her penmates. But, maybe she doesn't get a vote in this controversy.
I've witnessed very successful, high reproductive performance in about every imaginable sow-housing configuration you can imagine. I figure a sow is smart enough to know when she's happy and comfortable, so maybe it's time she had a chance to vote on the matter.