HiMag, a new grass that's high in magnesium, may help protect cattle, sheep, goats and deer from grass tetany or hypomagnesemia. When ruminants--animals with four stomachs--have too little magnesium in their blood, grass tetany can result. Often fatal, the condition causes an estimated $50 to $150 million in U.S. livestock production losses each year. ARS and University of Missouri researchers developed HiMag, which is also high in calcium as well as magnesium. The new grass, known as a tall fescue, is suitable for rainfed pastures in eastern, southeastern and Pacific Northwestern states and British Columbia. It has been tested in Arkansas, Georgia, Idaho, Missouri, New York, Texas, Utah and Virginia as well as in Canada. Plans call for HiMag seed to be made available to plant breeders this year. Though the idea of breeding a high-magnesium forage grass to combat grass tetany isn't new, the ARS and university scientists are the first to accomplish this with a tall fescue. On U.S. pastures, tall fescues are the most widely planted grasses.

Northwest Irrigation and Soils Research Laboratory, Kimberly, ID
Henry F. Mayland, (208) 423-6562, mayland@kimberly.ars.pn.usbr.gov

Catfish and trout farmers may one day restore some fish to health by treating ponds with potassium permanganate. Exposing catfish to somewhat larger than therapeutic amounts of the chemical for 12 weeks left no unwanted manganese in the fish’s flesh or liver, according to a study ARS scientists conducted for the Food and Drug Administration. That finding could help bolster the chance that FDA will approve potassium permanganate as a fish treatment. The ARS researchers concluded that the treatment for catfish poses no hazard to human consumers. Studies with trout produced similar findings. But before potassium permanganate can be approved by FDA for any food fish, further research must be done to determine its potential, at certain concentrations, to help or harm fish. Potassium permanganate, which works more efficiently than some other chemicals in soft water, chemically burns up, or oxidizes, suspended organic matter in water and can rid water of fish parasites such as gill flukes and Flexibacteria columnaris. U.S. fish farmers lose an estimated $50 million a year to diseases and there are few FDA-approved chemicals and drugs to fight the diseases.

National Aquaculture Research Center, Stuttgart, AR
Billy R. Griffin, (870) 673-4483, snarc_gen@futura.net

A new oral vaccine may help U.S. cattle producers cut their losses from a disease that costs more than $1 billion annually. Bovine respiratory disease, commonly called shipping fever, costs more than all other cattle diseases combined. Commercialization of the new vaccine, which is given to cattle with their feed instead of injected into the animals’ muscle, may be 3 or 4 years away. Field trials involved two groups of calves--a high-risk and a low-risk group. Deaths among the high-risk calves fed the oral dose were reduced from 16 percent to only 4 percent. Pasteurella haemolytica--the main culprit behind shipping fever--killed 16 percent of the unvaccinated animals, but none of the vaccinated animals. The oral dose also protected calves within 4 days, instead of the 10 to 14 days needed by current injectable vaccines. Injectable vaccines often produce lesions in animals, which could be avoided by use of oral or intranasal vaccination. The research for the ARS-developed vaccine was partly funded by the Biotechnology Research and Development Consortium (BRDC) in Peoria, IL.

National Animal Disease Center, Ames, Iowa
Robert E. Briggs, (515) 663-7639, bbriggs@nadc.ars.usda.gov

Reducing phosphorus in dairy cattle feed will save money for U.S. dairy producers and help the environment. Dairy producers have been feeding too much phosphorous to dairy cows, based on the commonly held belief that high levels are linked to improved reproductive performance. Over the last 20 years, ARS and other research institutions have conducted 13 studies involving nearly 800 dairy cows eating both high- and low-phosphorus diets. These studies show that cows fed high phosphorous levels had no better reproductive performance than animals fed low phosphorus diets. Excess phosphorus in water runoff from fields can boost algae and aquatic plant growth in streams and lakes. The new recommendation: Feed dairy cows 20 percent less phosphorus. The savings for dairy producers could add up to nearly $100 million a year.

U.S. Dairy Forage Research Center, Madison, WI
Larry D. Satter, (608) 264-5353, lsatter@dfrc.wisc.edu

Scientists can now produce sexed sperm faster than ever, thanks to improvements ARS researchers have made to their Beltsville Sperm Sexing Technology. More than a decade ago, ARS researchers developed and patented the technology, which allows livestock producers to predetermine the sex of their animals by using sorted sperm. The system separates living female-producing X-chromosome sperm from male-producing Y-chromosome sperm based on their DNA content. In the past year, scientists have improved the rate of sexed sperm production by 15- to 20-fold, enhancing sexed sperm’s adaptability to artificial insemination technology for widespread use in livestock reproduction worldwide. The technology uses a fluorescent dye that sticks to sperm based on how much DNA they contain. X-chromosome sperm contain about 4 percent more DNA and therefore hold more dye. This extra dye means they give off more light than Y-chromosome sperm when passing through the laser beam of a high-speed sperm sorter. The sperm are collected in separate tubes with 90- to 100-percent accuracy and with much higher efficiency than in the original technology. ARS scientists are collaborating with several scientists around the world to establish and perfect the technology for commercial development in livestock production. To date, hundreds of animals have been born using sexed semen. All animals have been healthy and normal. The technology has been licensed by ARS for use in animals; it has also been licensed for use in human medicine.

Germplasm and Gamete Physiology Laboratory, Beltsville, MD
Lawrence A. Johnson, (301) 504-8545, lajohnsn@lpsi.barc.usda.gov