Research Zeros In On Pelvic Organ Prolapse

This is how you want sows to look after farrowing. Prolapses are the second leading known cause of sow deaths. ( JoAnn Alumbaugh )

Of the various afflictions that can strike sows, one of the most common is pelvic organ prolapse (POP).

“We’re losing 3,000 to 4,000 sows a week [in the U.S.] to prolapse,” says Jason Ross, Ph.D., Associate Professor in the animal science department at Iowa State University and Director of the Iowa Pork Industry Center (IPIC). This is significantly more than the industry was losing 10 years ago.

Lameness is the biggest known cause of death in sows, with pelvic organ prolapse (POP) the second-leading cause.

Why the Surprising Rise, and What’s the Cause?
Ross says the first step is ruling out what doesn’t cause POPs. This past year, he and his team studied weekly mortality and prolapse data submitted from 104 farms. They measured sows’ tail length and the distance from rectum to vulva. They assigned a perineal region score (both standing and laying down), and a body composition score (BCS).

Mark Fitzsimmons and Gene Gourley with Swine Graphics had many pictures of sows in the same stage of gestation, and, using those photos, the Iowa Pork Industry Center (IPIC) team designed a 3-point scoring system. 1: little to no risk/normal; 2: protrusion in rectal and vulva area; 3: high risk potential for prolapse.

Ross says the best farms are losing about 1% to POP. Farms at the bottom of the scale are losing around 6% of their sows to POP.

“In the farms that are most afflicted, you see a higher rate in the winter,” Ross says.

Ruling Out Causes

The IPIC team found a weak relationship between farms with high POP and high overall mortality. In other words, a farm could have high overall mortality but low mortality for POP, and vice versa. Here are other causes the researchers were able to categorically rule out:

  • Farm size: Herds studied ranged from 600 to 10,000 sows and farm size was not correlated to POP.
  • Tail length
  • Use of sleeving: Ross says some farms in the study never sleeved, while other farms had more than 60% of the sows that were sleeved more than 3 times. In both cases, no relationship with pelvic organ prolapse existed.
  • Inducing sows at farrowing: Some herds induced more than 80% of the sows; other induced none, and no correlation was found.
  • Feed particle size: Ross and his team found no correlation in particle size for farms using meal, but significant variation between pellets and meal.

Possible Causes

After some factors were ruled out, other possible causes of POP were identified based on the study:

  • Perineal score: Farms with higher perineal scores tended to have higher POP. Also, Ross says there are biological factors occurring before the actual prolapse. "Sows with a perineal score of 3 and a body score of 1 were the most likely to prolapse," Ross says.
  • Thin sows: Thin sows had a higher risk for POPs than overweight sows.
  • Full feed: Sows on a bump-feeding regimen had fewer issues with POP and lower overall mortality. Limit feeding sows at farrowing also lowered POP.
  • Dietary fat: A study is ongoing to measure the impact of fat in the ration.

Possible Solutions
While no exact cause has been identified, the IPIC team found that POPs were reduced with these management protocols:
•    Bump-feeding was associated with reduced POP, particularly in farms where bump-feeding targeted sows with low body condition.
•    Antibiotic use: “Sows that score a 3 or 1 have different flora in the vagina,” Ross says. “During the antibiotic pulse we would see a significant reduction in POP.”
•    Water treatments: Farms that used treated water had a markedly lower POP, Ross says. They also were consistently lower in overall mortality.

Ross says a lot has been done in the last 6 months but “there is a lot more to do. We have tremendous opportunities to build on our knowledge.”

Ross wants to design studies with eight to 10 farms to monitor very specific management changes and prolapses on those farms, adding that a vulnerable area is how sows are managed between gestation and lactation.

Watch for Inflammation

Heat, redness, swelling, pain, or loss of function are all signs of inflammation, says Mark Wilson with Zinpro in his talk at the Leman Conference.

We want to read the signs and figure out where we’re going.

“Inflammation is a very complex topic, because not everything gives the same signals and you have a lot of different responses,” Wilson says. “We want to read the signs and figure out where we’re going.”

He says the pathways are different, depending on the signals you observe. “The quicker we can get the problem solved, the quicker we can get back to normal production,” he says.

Wilson concludes:
•    Inflammation is a major modifier of production and metabolism
•    Reducing inflammatory issues in the swine herd improves productivity
•    Decreasing inflammatory issues improves sow herd longevity

“Get Thee to a Nunnery”
John Deen, professor at the University of Minnesota, reminds us that reproduction is the major insult on a sow. If you don’t want a sow to get sick or die, don’t let her go through estrus, be bred, or have a litter of pigs. Of course that’s not possible in a pork operation, but Deen says “it can drive our understanding of intervention methods.

Don’t just make a study –look at the biology behind it and the process, not only for reproduction but also for survivability,” Deen says. “We should look at females that have reached these successful parameters and study the factors that allowed them to reach this point.”