The BVD Problem

The $100,000 Accident

With more cattle on the move, bovine viral diarrhea (BVD) is a growing problem. (DTN/Progressive Farmer image by Sam Wirzba)

Steve Knoll, of Hereford, Texas, had one run-in with BVD several years ago that he figures cost him $100,000. Today the Angus breeder says he's doing everything possible to protect his cattle against the disease.

Looking back, Knoll believes his purebred cows were exposed to BVD by a neighbor's stocker calves as they grazed the same wheat field divided by a single-wire electric fence. Some of the stockers got through the fence and mixed with Knoll's cow herd in their first trimester of pregnancy. However the exposure happened, 15 calves were born PI, and that year's calf crop was one the Texas rancher hasn't forgotten.

"I had heard of BVD, but we didn't have a clue what the disease could do. When our calves were about 30 days old, they started coming down with pneumonia. We spent thousands of dollars on medicines to treat sick calves, and we still couldn't keep them healthy. Between death losses and treatment, BVD cost us $100,000," Knoll says.

After that experience, BVD testing became a key part of Knoll's 2 Bar Angus operation. All newborn calves are tested for BVD-PI, and purchased animals are tested before entering the herd. Knoll's cows are vaccinated to protect them against BVD going into the breeding season. All bulls and females the ranch sells are BVD-PI tested.

"I've done everything possible to make sure we never have BVD on our ranch again, and we've been clean ever since," Knoll says.

ON THE OFFENSIVE

Bill Murrell's herd has never had a problem with BVD. But that doesn't mean he hasn't spent time and effort to keep it that way.

As he's purchased seed stock for his 100-cow Angus beef operation, Murrell has made a point of buying cows and bulls that tested BVD-PI (persistently infected) negative. He tests his own calf crop by taking ear notch samples and sending them to a diagnostic laboratory. So far, the BVD-PI tests have all come back negative.

Murrell, who farms and ranches near Ivanhoe, N.C., says the cost of $3.50 (plus shipping) per head for BVD-PI tests is good protection for his growing investment in beef cattle, and a reasonable price to pay to protect his herd from the profit-robbing disease. When a cow is exposed to BVD during the first trimester of pregnancy, her calf can be born as a persistently infected animal. Murrell knows the PI label is no way to keep buyers paying top prices for his calves.

"Our calves are identified with visual ID tags and electronic identification [EID] tags. We want buyers to recognize us for marketing healthy, source-verified cattle," Murrell says. "As we increase cow numbers, we want to market truckloads of source-verified calves, all tested PI negative."

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BVD IS BAD NEWS

From a feedlot perspective, buying BVD-free cattle is worth a little extra. It saves money in better feed conversion and reduced medicine costs. In a 2002--03 study of feedlot performance, cattle exposed to PI animals had reduced feed efficiency of $56 per head. The study indicates approximately 0.4% (4 of 1000) calves on average are PI.

"With today's higher cattle and feed costs, the losses caused by PI animals would be $80 per head. Because of today's higher costs, we see increasing awareness from cattle operations about BVD and PI animals," says Shaun Sweiger, a veterinarian and feedlot/stocker consultant, from Edmond, Okla.

From a cow-calf standpoint, BVD causes severe reproductive losses, including early embryonic death, abortion, birth defects and weak calves. New strains of BVD may be introduced into a herd through carriers purchased as breeding animals (heifers, cows or bulls), and these infected animals can cause serious BVD outbreaks. Exposing a cow herd to BVD-PI animals costs between $15 to $25 per cow per year in lost production.

Part of the problem is that BVD is hard to spot. The disease weakens immune systems and usually shows up in subtle ways, such as lower-than-normal calving percentage, low birthweights and high rates of pneumonia in calves between birth and weaning. Bloody diarrhea is only one symptom of BVD.

There is no cure for BVD-PI. The carrier calf will shed the virus every day for the rest of its life. If retained as breeding heifers, PI animals are primary reservoirs of BVD and shed the virus, infecting other cows in early pregnancy and producing new PI calves. Bulls can also be born PI and expose healthy animals to BVD.

FEEDLOT PROTECTION

Bryan Coder manages the cow-calf herd at Don Stickle and Sons Farms, near Anamosa, Iowa. The Stickle family operates a cattle feedlot and, during the past two years, has built an 850-cow herd to produce source- and age-verified calves for the feeding operation. Most of the brood cows were purchased at dispersal sales in several states south of Iowa.

Knowing the problems caused by BVD-PI calves in a feedlot, Coder collects an ear notch as every calf hits the ground and sends the samples to a commercial testing facility for a BVD-PI test. So far in 2012, Coder has found two PI positive calves out of 252 tested. These cow-calf pairs were isolated from the herd. Removing PI positive calves saves the feedlot thousands of dollars in treatment costs and lost production. If the PI calf's mother tests negative, she can return to the herd for the next breeding season.

"When you have a large cow herd made up of animals from different backgrounds, testing for BVD-PI pays off," Coder says. "Before this, I managed a 100-cow herd in Nebraska that had been closed on the female side for many years. We didn't think BVD-PI tests on the calves were needed."

BVD RED FLAGS

You probably won't walk out into your pasture one morning and realize your cows have BVD.

This insidious disease has several symptoms, but the signals are easily confused with other diseases and nutritional problems.

Here's a list of possible red flags for BVD:

-- lower-than-expected pregnancy rates (under 90%)

-- high numbers of abortions (above 3%)

-- low birthweights on calves (less than 40 pounds)

-- poor calf health (treating more than 4% of the calf crop for respiratory or digestive diseases)

-- high rates of pneumonia (over 2%) between birth and weaning

"These are signals that you may have BVD in your herd and diagnostic tests are in order," says Dan Givens, Auburn University veterinarian. "You should collect and test ear notches from any sick calves, dead calves or aborted fetuses. You may want to test your calf crop."

If you see calves 7 to 9 months old with bloody diarrhea, send ear notch samples for testing, and talk with a veterinarian about a screening program, Givens recommends.

Tests cost approximately $3 to $5 (plus shipping) per animal. Testing is simple; take small ear notches from animals, seal the samples in containers labeled with the animal ID and ship them to a diagnostic laboratory.

(VM/AG)

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