Scientists Strive to Increase Fetal Resilience to PRRS

Scientists with the University of Saskatchewan are working to reign in the reproductive losses resulting from PRRS.

Researchers with the Western College of Veterinary Medicine are working to reduce the mortality rate of piglets born to sows that have been infected by Porcine Reproductive and Respiratory Syndrome or PRRS.

Dr. John Harding, a Professor in the Department of Large Animal Clinical Sciences, says one of the challenges is the virus will always likely cross the placenta so finding ways to make the litter or the individual fetus more resilient will benefit everybody.

 

Dr. John Harding-Western College of Veterinary Medicine:

 

We are looking specifically at resilience.

If a sow is to become infected how can we get that sow or that gilt to deliver a healthy litter?

In our experimental model we see resilience, or fetal mortality, range from zero to 100 percent across individual animals so we that there are some resilient gilts that do not shed to their litter for some reason and we know that there are lots of individual fetuses that can resist infection for greater periods of time than their litter mates and then there is the other extreme as well where you have very very susceptible sows and very very susceptible fetuses.

That's what we're trying to figure out and we have learned a bunch of stuff that's leading  toward that.

One of the things we would look at initially was, if we have resilience is that because the dam is resilient or because there are things at the placental barrier that determine resilience or is it things that are happening in the fetus that determine resilience.

In the long run it's probably all three but we really are focusing now in on events that are happening at the placental barrier as well as events that are happening in the fetus.

 

Dr. Harding says that's been a novel step forward because previous research suggested that the fetus dies because the placenta separates and that does not appear to be the case.

He says the fetus clearly responds to infection.

 

- Bruce Cochrane.