Iowa Farmer Today
11-10-07
Circovirus leaves devastating trail of death in finisher
By Jeff DeYoung, Iowa Farmer Today
LARRABEE --- Two years ago, Tim Bierman thought he had an influenza issue in
his Northwest Iowa hog operation.
“They were getting gaunt, didn’t respond to anything, and acted like they had the
flu,” he says. “It just started getting progressively worse and working its way
down the building.
“Pigs looked good one day, and they were dead the next. We tried every
treatment, and nothing worked.”
After consulting with his veterinarian and sending tissue samples to the
Veterinary Diagnostic Lab at Iowa State University, Bierman learned he had
porcine circovirus associated diseases (PCVAD) in his herd.
“The tissue tests told us we had circovirus, PRRS (porcine reproductive and
respiratory syndrome) and the flu all at once,” says Bierman, who farms near
here in Cherokee County. “That’s a pretty deadly combination.”
At one point, Bierman says he was losing 10 to 12 pigs per day in one of his
finishers. That represented a 15 to 25 percent death loss.
“It got so bad that the rendering truck came by to pick up pigs, and had to come
back to get the rest of them,” Bierman says. “That’s how many of them we had
lost in a short period of time.”
PCVAD cases in the United States intensified in the fall of 2005, says Pamela
Zaabel, director of swine health information and research for the National Pork
Board in Des Moines.
Symptoms of the disease included anorexia, rapid weight loss, unthrifty pigs, skin
discoloration, respiratory issues and diarrhea.
“There were a lot of questions about what would trigger the disease, and this was
a newer, more severe strain than what we had seen,” Zaabel says. “We were
seeing a lot of co-infections like PRRS, salmonella and mycoplasma.”
Since circovirus affects a pig’s immune system, Zaabel says researchers had to
determine if it was the triggering agent or if another disease, such as PRRS, was
doing the initial damage.
“Was the circovirus making the pigs more susceptible to PRRS or was PRRS
helping to trigger it?” she says.
Most of the damage from PCVAD comes in the finisher, Zaabel says. When
symptoms begin, producers should immediately call their veterinarian, she adds.
“You need to get a lab diagnosis as soon as possible,” Zaabel advises.
When PCVAD invades a herd, producers are likely to see high mortality and
morbidity rates.
“Even if they survive, you are going to see a much slower growth rate, and they
never really catch up,” she says.
Over the past year, Zaabel says three vaccines have become available to
combat PCVAD. As the availability of vaccines has increased, she says the
problem with PCVAD has decreased.
“They are all labeled for use in pigs 3 to 4 weeks of age, so you are getting the
vaccine into the pigs early,” she says.
“All the vaccines have been effective in reducing mortality and morbidity, and it
sounds like there is enough of the vaccine out there to help slow this down.”
Vaccines produced by Fort Dodge Animal Health and Boehringer
Ingelheim/Vetmedica and Intervet are available on the market, Zaabel says. Two
vaccines require a single injection, while the Intervet vaccine requires two
injections, she notes.
Bierman says he has used all three vaccines, and all have been effective.
“The pigs are vaccinated at weaning or within 10 days of weaning,” he says.
“We bring hogs into the finisher at 65 to 70 pounds, and it would start to break
about four weeks after that. Since we started vaccinating, we haven’t had any
problems.”
In fact, Bierman believes his pigs are healthier than ever.
“We vaccinate for circovirus and mycoplasma at weaning, and this has been the
best production I think I’ve ever had,” he says. “Our groups are as consistent as
they have ever been in the finisher.
“It was just very depressing to have to go through it, and I know people who had
it worse than I did. I want to make sure I never have to go through it again.”