A beef cattle herd selected for a high rate of natural twinning can excel in productivity. But scientists say raising this type of herd will only be practical on farms where breeders can provide their cattle with plenty of nutrient-rich, high-quality forage and grain, as well as extra management and labor including calving assistance. Those conclusions come from a 7-year study of an intensively managed ARS experimental herd developed to have a twinning rate of about 55 percent—much higher than the normal 1 to 2 percent rate in most popular beef breeds. Researching cattle selected for natural twinning helps scientists gain basic insights on the physiology of reproduction. In the study, the combined weights of twin calves at weaning were 58 percent greater than calves from single births. Increased productivity from twinning can mean more income per dollar spent, but scientists ferreted out several constraints they're now studying. These include increased incidences of fetal mortalities or premature births, shorter gestation lengths, birthing problems, retention of placental tissue by mothers of twin cows after giving birth, and reduced or delayed conceptions.
U.S. Meat Animal Research Center, Clay Center, NE
Sherrill E. Echternkamp, (402) 762-4183.

A disease that destroys horses brain cells is currently fatal, but new findings have increased scientific understanding of the disease—and may someday lead to treatments. The disease, ELEM or equine leukoencephalomalacia, is caused by corn contaminated with the toxin-producing fungus called Fusarium moniliforme. The fumonisin toxin is insidious. A small amount can make a horse sick. The animal may appear healthy while suffering irreversible damage. Scientists at ARS and USDA's Animal and Plant Health Inspection Service, in collaboration with Emory University, found that the toxin interrupts the way a horse's liver and kidney make a special kind of fat known as sphingolipid. The toxin also causes an intermediary fat molecule, called sphinganine, to accumulate. ARS researchers found that another fungus, Isaria sinclairii, produces a compound called ISP-I or myriocin that temporarily reduced sphinganine accumulation in mice with no ill effects. If confirmed by other studies, the myriocin discovery might lead to treatments.
Richard B. Russell Agricultural Research Center, Athens, GA
Ronald Riley, (706) 546-3377.

Raising pigs with a natural ability to resist edema disease caused by a specific intestinal E. coli bacteria could be possible, based on a new test. Researchers with ARS and Pig Improvement Co, in Frankfort, KY, developed and patented a DNA-based test to identify pigs that are genetically resistant to the F 18 E. coli strain that causes edema. Rapid growth of F 18 E. coli in the small intestine of weaned 3- to 14-week-old pigs leads to edema disease, characterized by a excessive buildup of body fluids. The death rate for pigs with full-blown edema disease is about 65 percent. Breeding healthier, more disease-resistant pigs may lead to reduced use of antibiotics. The test has been validated on more than 500 pigs. The research was funded, in part, by the Biotechnology Research and Development Consortium in Peoria, IL.
National Animal Disease Center, Ames, IA
Julia F. Ridpath, (515) 663-7372.

Fly ash could give dairy farmers a low-cost material for paving feedlot areas where deep mud can sap cattle of energy to produce milk. Fly ash is a powdery byproduct of burning coal to generate electricity. Normally, it is trucked off to landfills at a high cost to electric utility companies. Some of the ash can be recycled into material for making concrete or spread on crop fields to neutralize acidic soils. But ARS and collaborating scientists showed it also can be mixed with water and applied to muddy feedlots, offering a low-cost alternative to concrete. Fly ash dries just as hard as concrete but costs roughly $6 per square yard, versus concrete's price tag of $75. Fly ash paving also poses little danger to the environment, leaching only minute traces of certain elements and heavy metals like nickel, the scientists' studies determined. Besides giving cattle a leg up on mud, fly ash paving also helps contain nutrients in the animals' manure. Preventing cattle from getting mired in mud also reduces their exposure to a range of diseases, including a viral hoof ailment called hairy wort, and a costly udder infection called mastitis.
Pasture Systems and Watershed Management Research Laboratory, University Park, PA
Bill Stout, (814) 863-0947.

If managed properly, grazing-sensitive eastern gamagrass has potential as a forage crop. The high productivity and moderate forage quality of this native grass have sparked ranchers' interest. The drawback to gamagrass has always been its sensitivity to heavy grazing. It requires careful management, such as rotational stocking (alternating grazing and at least 45-day rest periods). In a new 3-year study, ARS researchers placed 500-pound steers on eastern gamagrass pastures in early May at stocking rates of 1.2, 2 and 3 steers per acre for each of the 3 years. Cattle were removed from the pasture once they grazed grass down to 12 to 15 inches height. Overall steer gain per acre was best for the highest stocking rate with the shortest grazing duration. Heavier grazing earlier in the season means more time for pastures to bounce back and replenish themselves. Also, the forage is used early in the season when the quality is highest. Gamagrass tolerated grazing over the 3 years, since all pastures remained productive. Interestingly, grazing actually increased plant density in the pasture, rather than thinning it out.
Dale Bumpers Small Farms Research Center, Booneville, AR
Glen Aiken, (501) 675-3834.

Aquaculturists who raise sunshine bass can now decide with confidence when to stock their ponds. ARS scientists have established an environmental window of opportunity when tiny creatures called zooplankton become available for the small fry to eat. The trick: Stock when microscopic rotifers and minute crustaceans become numerous enough to feed the fish but before larger zooplankton grow and devour the fry. Pond temperature strongly affected buildup of the rotifers. Rainfall drove the growth of the crustacean Copepod nauplii, another favorite food for young sunshine bass. By factoring in other influences like day length, dissolved oxygen levels and the air temperature outlook, the scientists developed graphs and equations that fry culturists can use to help manage their operations. Fast-growing sunshine bass—a cross between the sport fish, striped bass and white bass—quickly reach market size in ponds. These food fish make up a small but rapidly developing industry.
National Aquaculture Research Center, Stuttgart, AR
Gerald M. Ludwig, (870) 673-4483.