New lab tests will allow scientists, regulators and livestock producers to quickly identify animals with bluetongue and epizootic hemorrhagic disease (EHD). ARS scientists have developed the first single genetic test that distinguishes all five types of the bluetongue virus in the United States. They’ve also developed rapid tests that distinguish bluetongue from EHD. Bluetongue is so named because it can cause a loss of oxygen, resulting in a blue tinge to the tongue. It affects sheep, goats, deer, elk and antelopes. Cattle can carry the virus but usually don't become ill. Worldwide, there are 24 strains. Countries without it strictly regulate import and export of livestock and related products, costing U.S. producers about $125 million annually. Previous tests were not always conclusive. The new test also is faster, taking 1 day instead of several. U.S. bluetongue testing is performed at the USDA’s National Veterinary Services Laboratory in Ames, IA, and the lab has incorporated this ARS test into its procedures. Researchers also developed tests that identify the two types of EHD present in the United States and that distinguish them from bluetongue viruses. EHD can cause a bluetongue-like disease in cattle and is often fatal to white-tailed deer. Correctly identifying which virus an animal harbors is important for trade purposes. There is no cure for either bluetongue or EHD.

Arthropod-Borne Animal Diseases Research Laboratory, Laramie, WY
William C. Wilson/James O. Mecham, (307) 766-3600
wcwilson@uwyo.edu/ jmecham@uwyo.edu

Cattle prefer alfalfa hay harvested in the afternoon to that cut in the morning, according to a new study by ARS researchers. The experiment is a follow-up to earlier work with tall fescue hays. The tall fescue study was likely the first to show up to a 50-percent difference in forage preferences based on time of cutting. Knowing more about the characteristics of forage that cue animals' preferences can lead to healthier livestock, better weight gains and bigger profits for ranchers. In addition, the research helps plant breeders develop new forages that appeal to animals. Animals may prefer p.m.-harvested hays because they have more total nonstructural carbohydrates—easily digestible starches and sugars—than those harvested in the morning. Another ARS analysis of chemicals in tall fescue hays indicated cattle preferred those with high levels of a natural chemical known as 6-methyl-5-hepten-2-one. ARS scientists at Kimberly, ID; Albany, CA; Watkinsville, GA; and Raleigh, NC; along with university colleagues in four states, are probing additional chemical and physical characteristics of tall fescue, alfalfa and other forages that might affect animals' menu preferences. Investigations into the influence of minerals like calcium, magnesium and potassium on animals’ forage choices are already under way.

Northwest Irrigation and Soils Research Laboratory, Kimberly, ID
Henry F. Mayland, (208) 423-6517, mayland@kimberly.ars.pn.usbr.gov
Plant Science Research Unit, Raleigh, NC
Joseph C. Burns, (919) 515-7599, jburns@ncsu.edu

FANS—short for "fan assessment numeration system"—could help solve a thorny technical problem of measuring the air output of in-place ventilation fans in animal barns. ARS scientists designed and built FANS to measure the performance of ventilation fans in delivering fresh air and removing heat, moisture and dust. Such measurements had been theoretically possible but not technically feasible. The FANS system consists of a portable anemometer—an instrument developed to measure windspeed—and a computer and software to record and analyze measurements. Traditional measuring techniques have been cumbersome, inaccurate by 8 to 10 percent, and slow, taking 30 to 45 minutes. But the anemometer measures volumetric flow rates within 1 percent accuracy in less than 4 minutes. While primarily a research tool, FANS has many applications. It can pinpoint the best location for ventilation fans. For example, fans placed at the end of a long poultry house are more efficient than fans along the side walls at the end. The scientists have used FANS to study effects of fan shutters, exhaust cones, belt guards and propeller deterioration. An egg company saved more than $200,000 after a FANS analysis. The company had just installed belt guards on 1,100 fans in 115 poultry houses to protect employees from possible hand injuries. FANS showed that ventilation remained adequate with the guards, so the company did not have to buy additional fans. Future studies will test fan output on light baffles, fan belt condition and dust and static pressure.

Poultry Research Unit, Mississippi State, MS
J. David May, (662) 320-7478, dmay@ra.msstate.edu

A new technique to measure activity of a protein called leptin may lead to leaner chickens. Leptin has recently been associated with obesity, but until now it had been found only in humans and other mammals such as pigs, cows and mice. ARS scientists recently discovered that it is also present in chickens. This discovery led scientists to develop a technique to study the hormonal activity of leptin in chickens. Leptin, which regulates appetite and energy expenditure, can lead to extreme obesity, diabetes and infertility if the gene behind leptin production is defective. The new technique, using a process called capillary electrophoresis, pinpoints and measures genetic material that's unique to leptin. Scientists hope to use the technique to monitor leptin levels in breeder birds. Maximizing meat and improving production efficiency are major goals for scientists studying chickens. That's because breeding broiler chickens for growth has resulted in increased fat deposition—and reduced reproductive efficiency—in breeder birds. Scientists hope to use their technique to find a way to regulate the leptin levels in chickens and reduce the birds' appetite. This would make it easier to manage broiler production and still provide consumers with quality meat. Commercial industries may eventually use the technique to select birds for feeding behavior that does not affect the growth of young birds.

Growth Biology Laboratory, Beltsville, MD
Christopher M. Ashwell, (301) 504-5061, cashwell@lpsi.barc.usda.gov