Iowa Farmer Today
03-03-07
Hog diseases require management, biosecurity system
By Jeff DeYoung, Iowa Farmer Today
SIOUX CENTER -- Butch Baker believes herd health comes down to exclusion.
Baker, a veterinarian and senior clinician at Iowa State University’s Food
Supply Veterinary Services, said excluding new diseases and managing
existing diseases requires a functional biosecurity system.
Any biosecurity system must be founded on sound strategy, Baker said during
the recent Iowa Pork Regional Conference here.
Most diseases will affect the economics of an operation, including loss of
productivity, unacceptable mortality and morbidity, and reduced feed efficiency,
he noted.
“You are going to need to know the status of your replacements,” Baker said.
“You need to know the health status of semen and boars, and you need to have
control of all segments of production, including isolation and monitoring.”
In the instance of porcine reproductive and respiratory syndrome (PRRS), he
said it was originally believed the disease was carried through semen brought
onto the farm.
Although it was later shown PRRS could find its way to farm via other methods.
Baker said producers need to be careful when new genetics or stock are brought
into their operation.
Producers can strengthen biosecurity in their sow herd through better isolation
when gilts are brought onto the farm, he said.
“If you don’t use it right, you are going to get into trouble pretty quickly.”
While sound biosecurity is the first step in excluding new diseases, Baker said
many producers choose to fight the viruses internally.
He describes internal biosecurity as an effort to “control the agents we already
know we have” in the operation.
“You’re really accepting these agents as endemic and unavoidable.
“Often, this is the less-expensive method, but productivity is often compromised.
“As long as you can balance it, most are going to choose just to control the
disease. If you can’t balance it, you need to look at exclusion.”
Baker said vaccines are used for many reasons, including reducing the effect of
the disease and providing some protection against a large disease outbreak.
“But, vaccines don’t eradicate disease, and they often don’t prevent the disease,
only the severity. They really are not a part of an external biosecurity system.”
Vaccines are safe because of stringent USDA requirements, Baker added.
When producers are considering implementing a biosecurity system or changing
an existing program, they need to make those decisions based on economics, he
advised.
The first step is to properly rank risk factors, Baker said.
“With PRRS, bringing it onto the farm through semen or new gilts is no longer the
major method of exposure. Today, it’s transportation.
“What we need to do is talk to the trucking industry and the folks who make the
trailers and say this is a broken system, and we need to fix it.”
He said the PRRS virus can be killed through sanitation practices.
But, Baker adds PRRS can survive between the metal plates of a trailer and
other isolated places that can be difficult to reach through conventional cleaning
methods.
Producers also need to calculate the value created by targeting a specific agent,
Baker said.
They also need to be aware of other potential risks not yet known, and most risk
factors are interrelated.
“It’s your system. It’s up to you to define what you need to do.”