PRRS Update: A Year in Review

(Fall morning on the farm- on the right side in the distance you can just make out the hog huts.)

Over the past six months, we have had made big strides in recovery from our PRRS outbreak.  All four of our farrowing farms have been producing PRRS negative (it's a good thing to be negative!) piglets for roughly 4 months now.  This means we have decreased our use of antibiotics to treat secondary infections that arise when the pigs immune systems are compromised from the primary disease.  It's great to see healthy piglets and sows again, and our production through the summer seemed to be better than ever through the summer.  This caused the problem of having too many pigs and not enough space to grow them. We were moving and selling pigs lighter than we usually do, but after the last year it didn't seem like a bad problem to have.  We have continued to vaccinate our sows every 3 months for PRRS with a different vaccine or serum each time, so our strain is less likely to mutate into a new strain and cause massive losses again.

Since we have negative piglets being born, you would think that everything is healthy and disease free, but that is not yet the case.  When recovering from this type of disease, everything is done in stages. With the farrowing farms appearing to be clean and stable we now have to empty and clean all of our nurseries, and then all of our finishers.  Right now we are working through each nursery, getting it completely empty, washing, and then letting it sit empty for a few days before loading with new pigs.  Prior to all of the farrowing farms producing negative pigs, we had to mix sick pigs with clean ones, so the clean ones would also get sick.  It wasn't something we wanted to do, but there weren't many options.  Once we had all negative pigs coming to the nurseries, the older pigs in the nursery would spread the sickness to the younger ones who hadn't been exposed and cause more loss.  By emptying and cleaning each barn, we hope to break the cycle.

Another problem that has developed in the finishers are an outbreak of Circo Virus.  Since our older pigs have a compromised immune system, they are susecptible to secondary infection.  Circo Virus is a disease that has been present in our herd for a number of years, but is usually controlled by a vaccine we give to pigs just before they are weaned.  This would be similar to how the measles or chicken pox are now controlled in the human population.  Now we think we are seeing the Circo flare-up due to PRRS immune suppression, so we are giving a booster shot of Circo vaccine to pigs   before they leave the nursery.  We just started this last week, so we are vaccinating a lot of pigs in a short period of time, trying to save them from sickness as they get older.  Once the Circo Virus develops clinical signs, there isn't a whole lot we can do to help the pigs, so vaccination is the best we can do to raise a healthy herd.

At this point, the pigs are recovering better than expected by our vet, even though it feels slow to all of us on the farm.  We have had setbacks due to secondary infection, but as of yet we haven't seen any re-break from PRRS, and if we can keep it that way we will continue to work towards becoming PRRS naive once again.  The difference between negative and naive is that when we have a negative herd we will still vaccinate for the PRRS virus, but once we go naive we will stop vaccinations and see if the pigs stay disease free.  Not only does this save us money, but it will also mean we have eliminated the virus from our herd, as small pox has been eliminated from human populations. Anytime you can eliminate a deadly disease it is a victory.  

The Long Road

(Fall in Michigan)

This has taken me awhile to figure out how to write, since it is always harder to talk about the bad things than the good things.  Like many other farms, we take pride in the fact that we raise pigs that are healthy and hardy.  We work hard to keep it that way, but sometimes things don't go as planned.  Over the past month, our farm has a been battling the Porcine Reproductive and Respiratory Syndrome (PRRS).  This disease affects pigs all over the country, and is slightly different on every farm, but it is not transferable to humans, nor does it cause a food safety problem.  It attacks pigs of all ages, and can be transported through the air, or through body fluids.  Over the next four months (one birthing cycle)  we will lose about half of our production.  After that, hopefully we will get some herd immunity and start to lose fewer pigs.

PRRS is one of the five major diseases that have hit the pork industry in the last 30 years.  Most producers in the country have dealt with it at one time or another, and up until recently, we haven't ever been challenged by it.  The disease isn't new, so our vet has a lot of experience on how to take care of it, and is working with us daily to make the best decisions for our herd.   How are we fighting this now?   First, we are working hard to keep everything as clean as possible.  We have done this everyday, year round, for as long as I can remember, but we are making sure to pay attention to the details and not miss anything by assuming we do it already.   Next, we are vaccinating all of the breeding animals with a modified live virus to bolster their immunity.  Each of our locations with breeding animals have tested positive for the disease, but have no clinical signs at 3 of the 4. We are hoping that by vaccinating our sows and boars we can stay ahead of the disease a little bit and save some of our baby piglets, who are most susceptible if mom doesn't have antibodies to pass on to fight it off. Vaccinating is hard work, and not very much fun for handlers or animals, but it gives us all the best shot at coming through the outbreak.  Antibiotics are not being used to treat PRRS, because it is viral and will not respond.  However, one stress on the pigs may cause something else to flair up, so as the pigs get older they may have to receive treatment for pneumonia, although we don't know that yet.

We are still early in the process of dealing with the disease, so there is a lot we don't know yet.  We aren't exactly sure who will be hit the hardest, or how many pigs we will lose.  So far, according to our vet, we have a pretty mild case, but it seems pretty severe to us.  Once we get our herd immunity established, we will start working to eradicate the disease on our farms.  It will take time to get back to where we once were, but it is something we will work towards.  Out farm isn't the first, nor will it be the last to deal with PRRS.