With about 4,000 gestating gilts and sows in different housing arrangements, Dempsey Ange is in a good position to compare performance. Some breeding females are confined to individual stalls throughout the gestation period. Others spend some time in open pens with other gestating females and are moved to individual stalls before farrowing.
Animal numbers per pen vary with pen size.
Ange manages a swine operation in Beaufort County, N.C., which his family and the L. H. Allen family own. He’s a veterinarian with five years’ of off-the-operation experience, working with a 100,000-sow operation in Oklahoma.
Using two gestation systems is not Ange’s choice. He explains, “We’re still recovering from the hard hit we took after the bottom dropped out of hog prices in 1998. Before then, we had money for new buildings and equipment. Since then, we’ve had to make-do with existing buildings and equipment.’
A look at PigChamp records shows only a slight difference in conception rates between the two gestation-housing systems. During the first 22 weeks of this year, the conception rate was 84 percent for females on a farm with 1,350 inventoried females, with 95 percent individual gestation stalls. On another farm, with 1,200 females spending about half their gestation period in pens, the conception rate was 82 percent. (The operation’s remaining 1,500 females are on a leased farm, which is not yet on PigChamp records.)
The records show that live pigs farrowed per inventoried female were essentially the same during that 22-week period. It shook out with a 10.54-pig average for the farm with mostly gestation stalls, and 10.47 pigs for the farm with half of the gestating females group-housed in pens.
Ange explains how they use stalls and pens in a building with both: “After a pregnancy check confirms that a gilt or sow has conceived, we immediately move her to a pen with other gilts or sows in her breeding group. On one farm we are short according to pen space, and need to keep bred animals in a stall longer — until there’s space in a pen for her.”
With a gestation pen system, Ange points out that the investment in buildings and equipment per breeding female is considerably lower than crates. Cost of metal adds up — stalls, feed and watering equipment — and they require more maintenance than pens, he says. Stalls also take up more floor space due mainly to walkways behind them. “For example, when we converted a building from pens to stalls, we cut its capacity from 280 females to 200,” Ange notes.
In determining an animal stocking rate for a pen, Ange allows 12 to 15 square feet per gestating female. The number of sows/gilts in a pen varies from six to 10, depending on the size of the pen and animals.
With stalls and pens, total daily chore time is virtually the same in Ange’s operation. “One reason is that both groups are fed automatically with drop feeders. If we were feeding by hand, it would take longer to feed animals in individual stalls,” he says.
However, feeding in stalls has one clear advantage over pens, says Ange. That is being able to maintain desired body condition by controlling the gilt’s or sow’s feed intake. “Because we have an individual automatic feeder for each gilt or sow, it’s easy to control exactly how much feed the animal gets. In a pen, feed consumption is uneven. A dominant animal fights off others so that it can eat more than its share. As a result, a less-aggressive individual often gets less than its fair share.”
Ange prefers gestation stalls for the ease of medicating an animal. He also prefers breeding gilts/sows in stalls versus in a pen with other animals, mainly because of worker safety. “It’s no fun when an animal steps on your foot or pins you against a pen divider, and it’s easy for a finger to get smashed,” he notes. “From an animal’s standpoint, about the only way it can get hurt in a stall is by a rough place on metal or if a neighboring sow lies on a leg.”
On the other hand, in Ange’s opinion, heat detecting is easier in a gestation pen. “It’s easy to train workers to identify signs of estrus when gilts and sows are able to interact with each other,” he notes.
Hardy sows are better suited to pens, in Ange’s opinion. “They are more likely to hold their own in competitive situations. Inevitably, there’s nudging, bumping and biting. For this reason, we try to keep less-aggressive animals in stalls whenever possible,” he adds.
Foot problems — lameness and tender hooves — are the operation’s main cause of sow deaths. “That may be why culling and mortality rates are a bit higher for animals that are always in pens with concrete floors during gestation,” he notes.
Recordkeeping can be a challenge in pens, but Ange says, it’s not an obstacle. “We have individual sow information on PigChamp, so it’s just a matter of keeping track of the sow’s breeding group.”
Ange recognizes the increasing unfavorable attention and public criticism of sows/gilts being confined in stalls and crates. He acknowledges that there could be long-range effects on pork producers in the future. “The general public’s perception is that animals are better off when they’re loose in pens or outside. However, from the standpoint of manageability, pig survivability and economics, the industry needs stalls and crates,” he says.
What might happen in the future? “Should pork producers be forced to discontinue using stalls completely and go 100 percent to group housing, we all need to recognize that more intensive management will be needed. Also, the consumer will need to expect to pay more for pork products.”
He does believe that anyone planning new facilities today should consider group-housing gestation pens in the event that legislative action could prohibit the continued use of individual stalls and crates. “At least, before putting up a new building, the producer should look at the ease or feasibility of converting it,” he says.