When performance data is tabulated for sows housed in stalls vs. sows housed in pens at Dykhuis Farms, Inc. — there is little difference in the overall reproductive numbers for the two groups. But a couple of key performance differences still stand out.

In their on-farm comparison, farrowing rate somewhat favored sows in stalls (82.6%) vs. sows in pens (77.0%). Total pigs born/litter averaged 12.2 for sows housed in gestation stalls and 12.4 for sows in pen gestation, and pigs/sow/year came in nearly identical at 22.8 and 22.9 for sows in stalls vs. pens, respectively.

Sow death loss, however, was significantly higher for pen gestation at 14.4% vs. 9.1% for sows in stalls, reports Erin Ehinger, reproductive specialist for the farrow-to-finish operation and eldest daughter of owner Bob Dykhuis. All reproductive data reported was for 2008.

Ehinger admits their pen gestation systems are in the midst of a “trial and error” period. They had tried housing 15 sows/pen and didn't like it. Then, after Dykhuis toured some large-pen gestation systems, they retrofitted two finisher barns with large group pens. They are still learning how to maximize production in pens.

“Dad decided he didn't want to invest in all stalls since it looked like our industry was heading toward pen gestation similar to what Europe has,” she explains.

The Holland, MI-based operation has five sow farms, each filled with 2,800 to 3,000 PIC sows, and operated as an individual parity segregation system. That means after each sow farm in the rotation is filled with replacement gilts raised in area finishers, it is closed to any further additions (See: “Unique Parity Segregation Plan Bolsters Health, Survival,” pages 30-32, Feb. 15, 2009, National Hog Farmer or go to nationalhogfarmer.com).

Three of the sow farms are equipped with all stalls in gestation, while two others are divided up into ⅓ stalls and ⅔ pens. Most of the pens at Sandy Ridge have 50 sows/pen, and most of the pens at Village Central hold either 50 or 65 sows/pen in square or pie-shaped pens.

Pen Stocking Challenges

The single-parity makeup of the sow farms with pen gestation provides the advantage that most of the sows are fairly close in age and size.

But Ehinger is quick to point out that there are still boss sows within a single age group. At first, they tried to further stabilize pen hierarchy by removing the boss sows, but that plan failed.

“With the larger group size, there is more of an opportunity to blend in and get away. But if you remove the boss sows, there are always 1-2 others waiting to take their place,” she explains.

So they decided to take the opposite tact, removing the lower sows in the pen hierarchy — those that are injured, thin or sick — along with the sows that recycled.

Sows that are removed from pen gestation are transferred to the “parking lot” — two rows of stalls that will remain their home until they are rebred, moved to farrowing or culled if they don't return to top condition, Ehinger says.

The cardinal rule for their pen gestation system is that it must remain a static system, she explains. “If you have stalls and you remove a sow, you can bring another in to take her place without any complications. In a pen system, if you remove a sow from the pen, you can't put a new one in to replace her because she could end up dead!” Ehinger stresses.

“We are really proactive if we see an injured animal. Sows either get treated or put into a stall as soon as possible,” she adds.

When sows are first placed in the pens, they are given about 15 sq. ft./sow. But by the time a few sows are removed for return to estrus, injury, etc., the space allotment has increased to 18 sq. ft./sow, on average.

With the ⅓ stall to ⅔ pen gestation distribution, Ehinger has found there aren't enough stalls in each of the two sow farms to hold all of the sows for the 28 days needed after breeding to ensure they are confirmed pregnant and embryos are implanted.

“Right now we place some sows in the pens before they have been bred for seven days, and some we place after 28 days, which means some sows end up having an ultrasound test done in the pens to confirm pregnancy,” she says. This process adds to the pen removal rate and partially explains the lower farrowing rate and higher removal rate in group-penned sows.

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Boar Exposure

In stalls, a vasectomized boar simply strolls down the hall providing fenceline contact with sows.

However, for the large pens, 2-3 trained boars provide daily heat checking in the pens. Staff is always in the pens to manage this process. Fenceline contact was attempted for sows in pens, but Ehinger says often the sows in heat wouldn't even bother to come up to the gate to see the boar.

Fighting, Feeding

Fighting occurs the first three days after sows are mixed in gestation pens. Extra feed is provided on arrival to reduce aggression. “If they have a full stomach, they are not so worried about fighting,” she says.

But fighting is a fact of life and does increase sow death loss. Under consideration are copper sulfate mats in hallways for sows to walk on to help heal their hooves, which sometimes get caught in the slots during an altercation with a penmate.

Sows get 5 lb. of feed/day in gestation. The feeding protocol varies between sows in stalls and sows in pens. Sows in stalls are provided dry feed in troughs once a day in the morning, followed by liquid whey and water.

Sows in pens are floor fed. Tubes from the feed boxes extend down to within 4-5 in. of the floor where feed is dropped in a pile on a raised concrete pad around the edge of the pens. Sows get half their dry feed in the morning and half in the afternoon. After each feeding, sows get liquid whey followed by water in a trough located along a back wall, she says.

“We feed them two times a day in pens so that sows have two chances to get up to eat their feed. Since we are dropping feed on the floor, we don't want to drop too much at one time and have it wasted because it could end up in the pit,” Ehinger notes.

“If one of the sows gets pushed away in the pens and doesn't get dry feed because she can't compete, she gets another chance to eat with the whey,” Ehinger says. About 4 gal. of liquid whey/sow is piped into the troughs daily, which is equivalent to 2 lb. of dry feed, she explains.