Internal parasites don't stand a chance in Eddie and Betsy Lipscomb's herd. This husband-and-wife team, both veterinarians, deworm cows three times a year to make sure the parasites don't rob a single pound of sale weight from the calves.
The Port Gibson, Miss., couple start their parasite control during calving season, which runs from mid-November through Feb. 1. Cows are in a designated calving area, and as they calve they are moved into a smaller pasture.
When they have 10 or so pairs, the Lipscombs deworm the cows with either Cydectin (moxidectin) or Dectomax (doramectin). At the same time, calves get a BVD vaccination, a numbered ear tag (which is entered into the Lipscombs' computer recordkeeping program), and if they're male, a castration. When the chute chores are finished, pairs are turned out onto ryegrass.
John Stuedemann, a cattleman and retired animal scientist in Georgia, says the Lipscombs' timing is about perfect. "Deworming stimulates the appetite of a cow," he explains. "After calving she's recovering and she's milking. She needs to eat."
Late fall and early winter are also the time the brown stomach worm, or Ostertagia, gets cranked up in the South. When these parasites hit the cow's abomasum, they also hit her appetite. The dewormer protects against this cycle.
The Lipscombs' cows and calves go through the chute again May 1, when they are vaccinated and dewormed, and fly control is applied. The cows are dewormed again when they are pregnancy checked in early fall.
Steven Wikse, Texas A&M University Extension veterinarian, recommends ranchers deworm spring-calving cows between mid-March and July with an avermectin drug. While opinions and research vary on the economics of deworming cows, "the South is a paradise for stomach worms," Wikse says. "Stomach worms inhibit the immune system of calves. Deworming helps the calves when they are vaccinated and can help them on into the feedlot.
"In Texas we see an extra 25 pounds of gain in a calf from deworming the cows and the calves. In Gulf Coast herds we get better pregnancy rates with cows that have been dewormed."
The Lipscombs agree that a good deworming program makes economic sense.
"We can deworm cheaper than we can buy feed," Eddie says. It costs the Lipscombs $3.50 to deworm a cow and $1.75 to deworm a calf.
"Calves are bringing $1.20 a pound. It only takes a little over 4 pounds of gain to pay for deworming the pair," Eddie adds. By the time their weaned and preconditioned calves get on the truck, they weigh in at 775 to 800 pounds.
Watch out for flukes
In the good old days, producers didn't have to worry about flukes unless they ran cattle in the Gulf Coast or the rainy Northwest. Unfortunately, that's changed.
In addition to the flukes that like swampy places, there's another type that spends part of its life cycle in white-tailed deer. So now flukes are scattered all over the country. And these nasty things can wreak havoc in a cow herd.
"Cows or heifers carrying flukes may be slow to breed or may not breed at all," says Louisiana Extension veterinarian Christine Navarre. "Flukes can reduce milk production, cause diarrhea, impact the growth of replacement heifers or stocker calves and, in high enough numbers, cause weight loss."
That doesn't even begin to cover the damage these parasites can do later on. It only takes one fluke to get a liver condemned at a packing plant.
In the 2000 National Beef Quality Audit conducted by Colorado State University, Oklahoma State University and Texas A&M University, more than 24% of the U.S. cows and bulls had liver flukes at harvest.
So what's the solution? First you have to find out if your cattle have flukes. Get feedback from the packer if you send calves to the feedlot, or feed out a calf or two for the freezer. If you send cull cows or bulls directly to the packing plant, you can get the information from there. If you have an animal die and get a necropsy done, a veterinarian can check the liver for you.
If you suspect your herd has flukes, Navarre recommends "producers do a spring fluke treatment if they are treating for the first time or if it has been a few years since they've used a broad-spectrum endectocide that controls flukes. A spring treatment gives the infected animals a boost through the summer, reduces pasture contamination and sets up a successful fall treatment."
John Maas adds that fluke control can be climate-dependent, with shedding happening in the spring and summer in warmer regions and in late summer to early fall in cooler areas. Maas is an Extension veterinarian at University of California, Davis. Here flukes have been found in the livers of cattle from almost every part of the state.
"Killing the adult flukes in the liver of cattle before turning them onto clean pastures seems to be the most cost-effective strategy," says Maas. "This not only kills the flukes, but prevents more shedding of eggs on the pastures."
So depending on your pasture rotation schedule, treat for flukes in the fall or late winter/early spring.