News Service


Skip Derra, News Service, (515) 294-4917


AMES, Iowa --.

Each summer for the last 24 years, chickens have been the watchdogs for the arrival in Iowa of mosquito-borne encephalitis. The birds are the key to an ISU-coordinated early warning system for the disease. Each year new flocks of about 10 birds are established in nine areas around the state. They are housed in places like a nature conservatory, a park, a sewage treatment facility and a Department of Transportation facility. City or county health officials care for the birds, which ISU supplies as six-week-old chicks each spring. Local officials regularly take blood samples from the chickens throughout mosquito season. The blood is tested for the presence of antibodies to encephalitis viruses. If antibodies are found, it means the chickens have been bitten by virus-carrying mosquitoes. ISU then alerts communities to take extra precautions against mosquitoes.

Why chickens? "In nature, the viruses cycle back and forth between mosquitoes and wild birds," says Wayne Rowley, the entomologist who coordinates the program. "The problems occur when mosquito populations get so high that the mosquitoes move from feeding on birds to humans. We used to capture wild birds to test, but that was too time-consuming. Chickens work much better." Where the viruses originate, in bird or mosquito, is a chicken-or-egg question. "There are theories for both, but none are proven," says Rowley. "Some believe the viruses overwinter in cold-blooded animals like frogs or snakes." So far this summer there have been no cases of encephalitis. Eight to 12 cases of La Crosse encephalitis are reported in Iowa each year. Contact Rowley at (515) 294-1573, or Ed Adcock, Agriculture Information, (515) 294-2314.

Iowa State University and USDA scientists have developed a hand-held prototype of a detector that makes it easier to spot fecal contamination on meat carcasses. Meat inspectors typically rely on visual inspection of carcasses at processing plants. But bacterial contamination of carcasses is invisible to inspectors. Sampling occasional carcasses does not detect contamination on every carcass.

The new device uses fluorescent spectroscopy, which identifies contamination by exposing it to one color of light and detecting fluorescence, or re-emitted light, from the fecal material. Besides providing increased sensitivity over visual examination, every carcass could be scanned during processing to determine which ones are contaminated and need to be treated. This would reduce the number of contaminated carcasses that slip through the system undetected. The new patented system can be built in a variety of monitoring configurations that could be adapted to the inspection and process control development needs of each packing plant. Tests in meat processing are being planned. Contact Mark Rasmussen, Animal Science and National Animal Disease Center, (515) 663-7350; Tom Casey, USDA/Agricultural Research Service and the National Animal Disease Center, (515) 663-7726; or Ed Adcock, Agriculture Information, (515) 294-2314.

For the past two years, botany graduate student Cathy Mabry has studied the diversity of foliage plants under the tree canopy in central Iowa woods. Many of those areas have recently been grazed by cattle causing the disappearance of essential plant species. Mabry established plots in woodlands throughout central Iowa. She has cataloged plants growing in the plots and has found different species in grazed areas than in ungrazed plots. She is looking more intensively at 17 species to determine reproductive characteristics such as seed size, seed germination, emergence and dispersal. Seven of those species are common in central Iowa woods, both grazed and ungrazed, and 10 species are rare in the same areas. She has found that the rare species commonly produce fewer, but bigger seeds than the common species. She believes that if the rare species' seeds get to the desired area, they will grow. Mabry is testing this theory by planting seeds in three different areas -- a grazed plot, a restored woodland and an area where the species do not currently grow. This information will help Mabry and others determine which species will re-establish on its own and which will need to be actively restored. Mabry has worked with owners of woodlands and has found many who are interested in what plants are on their property and what could be established. Woodland restoration encourages diverse plants that help maintain the diversity of herbivores and insects. Don Farrar, a botany professor, is working with Mabry. Contact Mabry, (515) 294-3522; Farrar, (515) 294-4846; or Megan Kuhn, Agriculture Information, (515) 294-2957.

EXHIBIT SHOWCASES IOWA AGRICULTURE'S RICH HISTORY Did you know ISU horticulture professor Griffith Buck named and released 87 roses? Or that the first soybean planted in Iowa was used in an ornamental garden in 1852? These facts and more will be on display as the ISU College of Agriculture takes a look back and ahead during the 1999 Iowa State Fair. The theme of this year's exhibit is "Iowa Agriculture: A Rich Heritage -- An Exciting Future." A collection of facts and photos about Iowa agriculture and Iowa State's contributions over the past century will be on display. There also will be activities for people of all ages at the exhibit. Visitors can create their own farm scene using rubber stamps. They can also test their knowledge of Iowa agriculture with a quiz. A computer will be set up for visitors to explore ISU with an interactive CD-ROM about the university. Adults can sign up for daily prize drawings. The fair runs Aug. 12-22. The College of Agriculture display is on the second floor of the Agriculture Building. Contact Megan Kuhn, Agriculture Information, (515) 294-2957, or Barb McManus, Agriculture Information, (515) 294-0707.

More than 120 seed-disease experts from 24 countries will meet in Ames, Aug. 16-19, to discuss international seed health issues. The third Seed Health Symposium, which is held every three years, is organized by ISU's Seed Science Center and the International Seed Testing Association's Plant Disease Committee. Attendees are seed pathologists working for universities, government agencies and industry. They work to ensure seeds are free of disease, which is a key aspect of international trade and of crop agriculture around the world. Among the topics to be discussed are standardization of seed health tests; new seed-borne diseases; and new testing methods. Contact Denis McGee, Plant Pathology, (515) 294-6821, or Ed Adcock, Agriculture Information, (515) 294-2314.

Dairy producers, representatives of the ag industry and the general public can check out the expanding dairy industry in northwest Iowa and the Dakotas on a three-day bus tour Aug. 17-19. Ten dairy facilities, with herds from 60 to 1,400 cows, will be visited. "Participants will see a variety of facilities, business styles and dairy management systems," said Magdalena Kurz, ISU Extension dairy specialist in Orange City. "They'll be able to visit with the host producers to discuss production and management technology as well as to learn about the future educational needs of the dairy industry." For more information and registration, contact Kurz at the Sioux County Extension Office, (712) 737-4230, or Jolene Stevens, Extension Communications, (712) 274-0048.

Farrowing stalls help reduce the incidence of pig crushing, but they don't completely eliminate the problem, according to Don Lay, assistant professor of animal science at Iowa State University. Because pigs are attracted to the feel, heat and odor of a sow's udder, Lay came up with a way to try to reduce the danger of pigs being crushed, and keep baby pigs warm and comfortable at the same time. He created a simulated udder by putting a pillow, a heating pad and two hot water bottles inside a pillowcase, and placing the entire piece to the side and slightly back of the sow. A piece of cloth that had been wrapped around the sow's midsection for at least three days prior to farrowing was removed and wrapped around the simulated udder, and a heat lamp was hung directly above it. Behavior of the sows and their pigs in test and control groups was recorded by time-lapse photography. Although the number of pig-crushing incidents was not different between the two groups, it was clear that pigs preferred to use the simulated udder compared to only a heat lamp in the control group. Lay said initial results are promising, and plans more studies to determine the pigs attraction to the simulated udder. Contact Lay at (515) 294-2088, or Sherry Hoyer, Iowa Pork Industry Center, (515) 294-4496.


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