Feature: A good news story in combating the ravages of PRRS

Tuesday, December 2, 2008

By using a new gilt acclimatization protocol and paying strict attention to biosecurity, the Vanden Boogaards have sharply reduced their nursery mortality and learned some lessons for the future

by KATE PROCTER

"There is definitely life after PRRS," says Piet Vanden Boogaard, a participant in the Porcine Reproductive and Respiratory Syndrome case study project run by the Ontario Pork Industry Council Swine Health Advisory Board. Last featured in the Dec 2007 issue of Better Pork, his is a good news story as Ontario pork producers continue to battle this devastating virus. Vanden Boogaard's 900-head sow herd suffered an outbreak of PRRS in November 2004.  Production in the farrowing barn eventually returned to pre-PRRS levels, but the nursery and finishing pigs suffered from higher mortality rates, slower growth rates and higher cost of production. Dr. Greg Wideman, the herd veterinarian, credits a circovirus vaccination program for reducing the clinical signs of disease in the finishing barn.

The Vanden Boogaards from Gorrie, in Huron County discovered in October 2007 that the PRRS virus strain they had used as a vaccine in 2005 had mutated and they were now fighting two strains of the disease.

Beginning in late 2007, the Vanden Boogaards began a new gilt acclimatization protocol, which they would use throughout 2008. Every gilt was exposed to both strains of the virus, with a three-week cooling down period in between. The gilts would then wait over two months before moving into the herd. The Vanden Boogaards moved batches of 125 gilts in this way every three months.

"Things are going in the right direction!" says Dr. Wideman. "After a summer of tests showing progress, we are focused on preventing further spread of PRRS virus over the high-risk season ahead."

The sow herd started producing piglets which were consistently PRRS negative in the spring of 2008. Piet started cleaning out the nursery in June, once he was satisfied that there was no virus circulating in the farrowing barn.

During July, the weaned pigs went to a bank barn on straw while the nursery was depopulated and cleaned. "I was concerned that the early-weans would not thrive in a straw-based bank barn," says Dr. Wideman. "But Piet and his crew did a very good job of preparing the barn, and the pigs did great."

The nursery mortality rate is now about one per cent, a far cry from the erratic mortality rates that varied from five to 30 per cent during the worst of the outbreak.

Piet moved 1,000 pigs from the nursery to an off-site finishing barn and has only had one death in the first month. The finishing facility located on his home farm has a one per cent mortality rate.

Biosecurity is a top priority for the Vanden Boogaards. They purchased an additional bus for transporting pigs so that each barn has its own bus. They are careful to restrict people movement between barns.

Piet remains optimistic and maintains that the industry has come a long way in the past five years. If he were to break with PRRS again, Piet would make some changes in the way he dealt with the disease. He would make a breeding break part of the elimination protocol and he would do a lot of things faster. "There was a lot of trial and error on our part, but a lot of the guess work is out of it now," he says. BP