According to Joe Connor, DVM, Carthage Veterinary Service, the results are mixed when it comes to the way gestating sows are housed.

“We’re seeing a slow trend toward open-pen housing, driven by requirements of some individual states and also driven by the packers linked to consumers asking for open-pen housing of sows,” Connor told Pig Health Today.

Higher rate of mortality

While sows are free to move around in pen housing, this creates other welfare issues for gestating sows that do not occur in crates.

“As I look at our internal data as well as our external client data, generally what we see is that mortality is higher in pen gestation compared to stall gestation,” Connor said. “The difference is between 2 percent to 3 percent on an annual basis.

“That difference in mortality is made up in injuries, fighting or interactions that those sows have with each other, and an increase of prolapses at the end of pregnancy.”

Different pen designs help reduce sow fighting. Connor said units with pens and access to individual crates work better.

“In open-pen housing where we have stalls that they can come and go in, frequently… 90 percent to 95 percent of the sows will be within the stalls,” he said. “It appears that their own decision, frequently, is to have that safety.”

In early pregnancy, Connor supports keeping sows in crates to prevent losses during implantation, which can occur when sows fight. “There is an advantage in terms of fertility,” he said. “The sows can be heat-checked, real-time ultrasound, and then put into pens from 35 days of pregnancy to the end.”

Gestation changes inevitable

Connor believes that the industry, driven in part by the movement in Europe to pen gestation, will need to make changes. But he sees the US finding ways to accommodate their own production system. This means coming up with new ways or new equipment to better manage gestation.

“No matter what stage we mix those animals…there’s going to be a period of social interaction and fighting,” Connor said. “As an example, there may be a need for toys and interaction within those pens and facilities.”

Connor doesn’t see the industry going back to straw. Biosecurity issues with bedding will prevent its widespread use. Plus, current manure-handling systems don’t work with bedding materials.

Electronic sow feeding in pens has solved the problem of feeding sows based on body condition or stage of gestation. No doubt other issues with gestation will be solved, too.

“We’ll have a slow transition but hopefully still a choice. Does the producer want to continue to use stalls? Or does he want to move to a combination of stalls plus pens over the next 5 years?” he concluded.