Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Farm study raises doubts about new approach to swine-disease control

06.04.2006
Sample sizes were small, but eyebrow-raising results from a study on a western Illinois farm have researchers and veterinarians taking a broader look at how swine producers battle an endemic viral disease that adds to their costs and threatens reproduction in their herds.

A new approach (acclimatization) has producers inoculating newly arrived pigs with the wild-type strain of the porcine reproductive and respiratory syndrome virus (PRRS) already existing on a farm. The hope is that the pigs will develop specific immunity to that virus and will recover prior to breeding, when the disease takes its toll.

The study found that the approach boosted development and strength of immunity against the local strain, but failed where it counted the most. Pigs exposed to the farm’s virus produced slightly more live births than pigs vaccinated two other ways, but many of these acclimatized animals never gave birth at all and had to be removed from the herd.

"At first we found it encouraging that animals exposed to the wild-type virus, regardless of whether or not they got a subsequent exposure to vaccine, mounted a faster and stronger immune response to the virus than did animals given the modified live vaccine," said Tony L. Goldberg, a professor in the department of pathobiology in the University of Illinois College of Veterinary Medicine.

No positive effect on production was seen when compared with the more traditional approach of inoculations with a commercially available modified live vaccine, he added.

"All things considered, exposure to the existing wild-type virus resulted in a net reduction of 2.45 piglets for each sow introduced onto the farm," Goldberg said. "At this point, though, because of small sample size, the most we can say is that the world still lacks an effective method for controlling PRRS virus in herds where the virus is endemic."

The privately owned farm involved in the study had suffered from chronic PRRS infection for more than five years before the project was conducted in 2003-2004. The study -- funded by the U.S. Department of Agriculture -- was published in the April 1 issue of the Journal of the American Veterinary Medical Association.

For the study, 30 healthy, 70-day-old pigs were brought to the farm and isolated. Soon after that, 20 of the pigs were purposely exposed to the farm’s existing wild-type PRRS strain, while 10 pigs received only the commercially available vaccine. After 42 days, 10 of the pigs that had received the farm-based virus also were inoculated with a killed-virus vaccine, which, unlike the live strains, promotes immunity but doesn’t cause illness.

All of the pigs were allowed to mingle with the other some 800 breeding sows and 7,800 growing swine on the farm. Researchers monitored the experimental pigs for both T-cell activity and antibody production to the virus, as well as recording the pigs’ reproductive outcomes at the end of the study.

"The sample size was small but the magnitude of the effect was large enough for us to detect it with good statistical confidence," Goldberg said. "Seeing 50 percent of animals exposed to just the wild-type strain dropping out of the herd was surprising."

There was no effect on reproductive outcome among the pigs that received both the wild-type live vaccine and the killed-virus strain, Goldberg said.

USDA funding is now covering a larger study on several Illinois farms. "We may be able to generalize more accurately or make some viable recommendations after we’ve have analyzed the new data," Goldberg said.

Jim Barlow | EurekAlert!
Further information:
http://www.uiuc.edu

More articles from Agricultural and Forestry Science:

nachricht Raiding the rape field
23.05.2018 | Julius-Maximilians-Universität Würzburg

nachricht New technique reveals details of forest fire recovery
17.05.2018 | DOE/Brookhaven National Laboratory

All articles from Agricultural and Forestry Science >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Powerful IT security for the car of the future – research alliance develops new approaches

The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.

Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...

Im Focus: Molecular switch will facilitate the development of pioneering electro-optical devices

A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.

The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

In focus: Climate adapted plants

25.05.2018 | Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

 
Latest News

In focus: Climate adapted plants

25.05.2018 | Event News

Flow probes from the 3D printer

25.05.2018 | Machine Engineering

Less is more? Gene switch for healthy aging found

25.05.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>