The shrub, with low-arching branches, can grow to tree-like heights of up to 30 feet if not attacked with the right herbicides.

LSU AgCenter researchers gave owners of pasture land a checklist of possible methods of controlling the shrub at the AgCenter's annual Beef Cattle and Forage Field Day at the Rosepine Research Station May 8.

One relatively low-cost method of controlling the invasive shrub is to spray 3 ounces of the herbicide Remedy, mixed in a gallon of diesel or vegetable oil, about 18 inches from the base of the plant. Using a hand-held, pump sprayer allows for easy delivery of the mixture in large enough quantities to soak the plant's trunk, which can be as much as 4 inches to 6 inches in diameter.

"That way you can hit the vegetation you aim at," said Ronald Strahan, an LSU AgCenter weed specialist.

"Go down one side of the fence line and back up the other, so you hit both sides of the shrub," Strahan said during one of several demonstrations at the Rosepine field day.

The event, which attracted 200 beef cattle producers from southwestern Louisiana, also featured lectures from LSU AgCenter specialists on marketing calves and cull cows, controlling internal parasites in beef cattle and checking animals for breeding soundness.

One eye-catching live demonstration included a beef cow painted in orange, blue, green and pink stripes to highlight the areas that yield various cuts of meat.

David Sanson, an LSU AgCenter beef cattle researcher, noted that American beef cattle packers have successfully built a market for pre-cooked beef products - shoulder steaks and roasts - cut from the shoulder muscles of beef cattle. Those cuts, taken from the "orange painted" section on the demonstration cow, typically sell for more than twice the price of ground beef taken from the same animal's shoulder, Sanson said.

The LSU AgCenter's Dr. Phillip G. Hoyt, a professor of veterinary medicine, said cattle producers must also pay close attention to breeding efficiency.

"Cattle producers should have a veterinarian perform a breeding soundness exam on all bulls before the breeding season begins," he said. "This is a small price to pay for reproductive efficiency."

In a separate presentation, Professor Alvin Loyacano of the LSU AgCenter's Dean Lee Research Station in Alexandria suggested cattle producers put most of their money for control of internal parasites into their "young, growing animals," rather than treating mature cows 4 years old and up. "Treating calves, weaned calves and replacement heifers gives you the biggest bang for your buck," he said.

Liver flukes and nematodes (stomach worms) are two problems Loyacano cited. Liver flukes are likely to infect animals in the Red River Basin or near coastal marshes, because the parasite typically uses an intermediate snail host that thrives near water and in damp mud, he said.

Roundworms (nematodes) are another big problem. The ingested larvae burrow deep into an animal's stomach lining and later emerge, attaching to the stomach wall where they feed on blood. Female worms can lay as many as 10,000 eggs a day.

Immature beef cattle are more susceptible to parasites than mature animals, and severe infections can result in dramatic weight loss and reproductive problems, Loyacano said.

Liver flukes also hurt reproduction in heifers by upsetting hormonal metabolism in the animal's liver, which delays the onset of puberty. "The heifers don't come into heat as early as they should," Loyacano said.

Ivomec is an injectible medication against stomach worms. Ivomec Plus can be used against liver flukes and stomach worms in the same treatment, Loyacano said. It combines ivermectin, the active ingredient in Ivomec, with clorsulon, an effective treatment against liver flukes.

Randy McClain and John Chaney are writers for the LSU AgCenter in Baton Rouge.

e-mail: ramcclain@agctr.lsu.edu or jcheney@agctr.lsu.edu