The challenges presented by converting sow housing facilities from gestation stalls to group pens can be intimidating. Some producers just aren’t interested in making the change; for others, the prospects of making a smooth transition seem insurmountable.  

Certainly, any decision to move from individual stalls to group housing will require some financial commitment at a time when economic concerns already confront you on nearly every aspect of production.

In recent years there has been a relentless wave of activity against gestation-sow stalls from animal-rights activists. Constitutional changes have already affected California, Arizona and Florida. Other states, such as Colorado and Oregon, have addressed the issue by moving forward without voter input. Right or wrong, the public is increasingly voicing its opinion about sow housing, and lawmakers are listening.

No doubt, Smithfield Foods’ decision to begin its changeover to group gestation housing has raised the industry’s awareness, as well as some eyebrows. However, until scientific evidence backs up the benefits of group gestation housing, such as sow performance data, weaning rates and so forth, many producers have adopted a wait-and-see attitude.

“There are some producers who are making the change, but it’s a minority,” says Lee Johnston, swine nutrition and management specialist at the University of Minnesota. “For some, it will require a law before they change their system.”

That apprehension centers on concerns about managing group-housed sows and maintaining a herd’s productivity. Specifically for producers, how to make the adjustment, educate and train themselves and their staffs, and minimize the learning curve. “It comes down to the farm situation, the management and the workers involved,” Johnston says. “Some systems will make the change without missing a beat, while others could have a train wreck.”

The cost of moving to group gestation housing will vary among farms. The feeding method and current placement of slats and solid flooring will be key to determining retrofitting costs. “Cost will depend, to some extent, on how each barn is laid out,” Johnston says. “You’re taking stalls out, which will require adding gates to divide the pens. The bigger issue becomes feeding and how that will be done.” 

Speaking From Experience

Some systems already have experience with group gestation housing and it has treated them well. “It’s no harder to manage,” says Bob Ivey, production manager for Maxwell Foods, Goldsboro, N.C. “If you take out four stalls and put in an 8-foot by 10-foot pen, it’s fairly easy to convert older systems.”

Maxwell Foods operates sow units in North Carolina and Indiana, which total about 82,000 sows housed in pen gestation. The company has used group pens since 1989 for all facilities that it built; farms that Maxwell acquired were converted.

The company’s typical group-pen size is 8 feet wide by 10 feet deep with 4 feet of solid floor and 6 feet of slatted area. “Five sows or six gilts per group works best for us; larger pens cause more issues,” Ivey notes. After weaning, sows are moved into stalls for 35 days to minimize stress during heat checking and breeding. This also allows managers to re-condition underweight sows.

Maxwell has consistently been a top performer in pigs per sow per year, pre-weaning mortality, weaning weights and sow mortality as measured by AgriStats, which summarizes results from 2 million sows.

Several other benefits have surfaced since Maxwell converted to pen housing. “We have seen better water intake and fewer urinary tract infections in our sows as well as a lower mortality rate,” Ivey says. “Also, it is easier to stabilize health status and easier to spot re-cycle sows riding.”

The company invited animal-welfare expert Temple Grandin, Colorado State University, to review the operation, and she gave her full approval. In fact, Grandin said that the Maxwell operation is “setting the standard for large-scale pork production.”

Watch that Figure

Sow body condition plays an important role in achieving a successful transition to group housing and needs careful evaluation. “Proper body conditioning of sows prior to grouping in pens is critical,” says Jason Kelly, DVM, Suidae Health and Production, Algona, Iowa. He points to thin sows needing particular feeding attention during the weaning and breeding stages, before they move into pen gestation.

It’s wise to refresh your body-condition scoring or measuring technique and find a method that works for you. “A thin sow rarely gains condition while in a pen, and often requires separation from the group,” Kelly notes. “Having sort pens available for sows that are not thriving in groups is an important facility consideration.”

Maxwell’s sows receive full feed until they are bred. They then get 4 pounds per day or more depending on body condition during the 35-day stall-housing period. “Thirty pounds of gestation feed per week is the target,” Ivey says. “We feed once a day around mid-day.”

He emphasizes that it’s important to increase feed during the last 30 days of gestation. “Based on body condition, a sow will get 5 to 6 pounds a day,” he adds. The feed increase helps keep sows calm and reduces the chance of vulva biting.

Ivey prioritizes close observation and evaluation of the sows’ body condition. “We have a very athletic animal in our system and over-conditioning results in decreased reproductive performance, especially during our hot summer weather,” he notes. “We’re very stingy with feed.”

A successful group-housing system requires attention to workforce training. “Teaching farm employees how to recognize problems early is essential,” Kelly says. “Under-conditioned sows, lameness and physical injury from fighting after mixing must be observed and addressed early.”

This involves actually walking the pens and looking at every sow every day. You need to observe the group’s behavior as well as each sow’s eating pattern. Workers will have to be familiar with signs and symptoms that they haven’t had to worry about in the past, Johnston points out.

Stalls won’t likely disappear completely. “Putting sows in stalls after weaning and getting them mated before mixing will likely be the scenario of choice,” Johnston predicts. “The typical point for mixing is 35 to 42 days post-mating.”

The Maxwell operations wean piglets once a week at 20 days of age. The sows are placed in stalls for 30 to 35 days. “It’s easier and safer to inseminate them and safer for the handler,” Ivey adds.

Five sows are then sorted by size and parity into a pen. “We don’t re-mix after pens are established,” he notes.

The Grouping Challenge

Deciding which animals to group together in a pen will vary among operations. “Typically, parity-zero gilts are held separately from older sows,” Johnston says. “It will depend on size and number of pens, sow flow and there will be variations on this.”

Grouping sows with similar nutritional needs may boost success. “When considering which sows to group together, sort according to body condition,” says Mark Whitney, Extension swine specialist, University of Minnesota. “This allows you to feed sows more closely to their body-condition.”

Since aggression among sows is greatest at feeding time, pay close attention to your feed delivery strategy. “Single-drop floor feeding leads to the most fighting and competition,” Whitney cautions. “Increasing the drop area or using trickle-feeding can help reduce competition.”

Feeding twice a day at close intervals, such as feeding early morning and again two hours later, also may help, Whitney adds. 

In large group pens with 20 or more animals, using electronic sow feeders allows for individual feeding but does not alleviate all aggression. Vulva biting sometimes increases in these settings, Whitney notes. 

“A big factor in reducing aggression when grouping is to limit the times that you mix the sows; just make them go through it once,” Johnston recommends. “Once mixed, keep the group static until farrowing.” Also, a “hide area” may give low-ranking sows a place to escape dominant ones.

Herd genetics can influence sow aggressiveness. Ivey points out that the Maxwell system tends to back away from aggressive animals, resulting in some natural selection. “We use a Chester White female as a great-grandparent. We breed that to a Yorkshire to produce grandparents, and they are mated to Landrace to produce parents.” The pure lines are raised in a pen-gestation system which helps select against aggression.

Ivey and the Maxwell operations, as well as other producers, have shown that pen gestation can be successful. “I think results will be as good or better with pens as they are with stalls if producers pay attention and do the things they normally do. Plus, it is more acceptable to the general public now.”

If you are ready for the transition to group gestation-sow housing within your operation, you can expect a learning curve. The feed delivery method and staff training are critical components, as well as mixing strategies. After that, be ready to tackle the issues quickly as they arise.