Researchers tackle survivability issues head-on

One in three pigs born on US farms fail to reach market, according to Jason Ross, PhD, a professor of animal physiology at Iowa State University (ISU) and director of the Iowa Pork Industry Center.

“That would include piglets lost during farrowing, including stillbirths. It also would include piglets lost due to pre-wean mortality,” he told Pig Health Today.

“Based on a study that we did last year, annualized sow mortality in the US was right around 12.5% to 13%. And then there’s wean-to-finish mortality. When these numbers are combined, they reach 30% to 35% as an industry average.”

To address the problem, the National Pork Board and the Foundation for Food and Agriculture Research set aside funds to determine potential causes and implement a robust Extension and outreach effort toward reducing this number.

“Our group [at ISU] had been working in the area of pelvic organ prolapse and trying to understand the biological causation that’s associated with prolapse in the US sow herd,” Ross said. “We’ve expanded that effort with the new funding.”

The expanded, collaborative effort involves faculty members and researchers from Kansas State University, Purdue University and ISU.

The work begins

An observational study began in early 2018, focused on understanding some of the contributing causes to pelvic organ prolapse in sows. More than 100 US sow farms representing more than 385,000 sows contributed data. Researchers evaluated the data set and considered as many different factors as possible.

“The observational study gave us a lot of guidance into the areas that we want to continue to investigate with our current funding,” Ross said. “It’s definitely a complex problem.”

As part of the observational study, the team considered dozens of factors that included:

• Herd influences, such as sow inventory, diet formulations and feed-management strategies
• Management impacts, including artificial insemination strategies, farrowing-assistance strategies and the use of bump-feeding in late gestation
• Animal-based measures such as body-condition scores, tail length and perineal scores
• Facility elements, such as water and feed delivery systems, and type of sow housing (i.e., pen or stall)

Potential causes warrant more research

Researchers were intrigued by some of the findings from the initial study. For example, Ross said it was initially thought sows that were overweight would be more likely to prolapse, but the opposite appeared to be true.

“Sows that had a thin body-condition score had a higher probability of prolapsing than sows that were overweight,” he said. “That was counter-intuitive to us initially, but it was supported by the observation that farms using bump-feeding strategies on light sows during late gestation also had a lower incidence of prolapse.”

The team is conducting additional studies with a hypothesis-driven approach to validate some of the variables identified in the observational study.

More studies to follow

Researchers are looking at the influence of genetics and colostrum on the ability of piglets to thrive and survive. One project involves evaluation of induction protocols and the implications of farrowing induction on piglet survival. Another project is evaluating the feeding strategy utilized with sows just prior to farrowing and how those strategies impact stillbirths and pre-wean mortality. All of these projects are currently underway.

In terms of wean-to-finish protocols, an ongoing study is evaluating disease management, including a review of current literature to understand mortality during the wean-to-finish phase of production and will also be a useful aid in the design of future studies.

Pigs in the wean-to-finish phase can die at any time, depending on disease pressure, but they are most vulnerable at weaning when they’re moved to a new environment and begin a new feeding regimen. Researchers are in the early stages of a project focused on how to facilitate the wean transition for piglets coming from the sow farm into the grow-finish system.

“That really sets up a piglet’s ability to take off and thrive,” Ross said.

Potential interventions

There are still many unknowns when it comes to unlocking the secrets to lower mortality, but these studies will help researchers find answers. In the meantime, Ross said producers can implement these management strategies:

• Human resource management: Create a great workforce culture that understands and promotes pig livability.
• Minimize disease pressure: Implement disease-elimination strategies by maximizing biosecurity at all phases of production and implementing robust vaccination strategies.
• Management in late gestation: Implement nutritional interventions to avoid thin sows.
• Piglet management: Provide a warm, clean environment to pigs during birth and provide excellent care to maximize colostrum intake during their early hours of life.

Researchers will continue to create a better understanding of what’s behind the biology of why a sow may die or why a piglet may fail to thrive.

“Our current thinking is that there’s inflammation of the reproductive tract that’s happening in sows that are at high risk for pelvic organ prolapse,” Ross said. “That increases their nutritional demands, as eliciting an immune response takes a significant amount of energy.”

The emphasis on projects related to survivability underscores the pork industry’s commitment to continued improvement, Ross said, not just for the success of their businesses, but for the pigs’ well-being and the success of the industry as a whole.

Editor’s Note: Principal investigators involved in the projects include (but are not limited to): Anna Johnson, Chris Rademacher, Suzanne Millman, Nick Gabler, Daniel Linhares, Kent Schwartz, Stephan Schmitz-Esser, John Patience, Aileen Keating, Lee Schulz and Ken Stalder (Iowa State); Kara Stewart (Purdue); Jason Woodworth, Mike Tokach, Joel DeRouchey (Kansas State). Additional Extension staff and students at each university are also making significant contributions to the project outcomes.