(AP) - Nebraska's congressional delegation wants the USDA to compensate a rancher who must slaughter his herd of cattle to help control bovine tuberculosis.

All five of the state's U.S. senators and representatives signed a letter sent Tuesday to Agriculture Secretary Tom Vilsack, saying they are concerned the USDA has not yet provided aid to pay for the cost of slaughtering the herd where the disease was found.

Bovine tuberculosis causes severe coughing, fatigue, emaciation and debilitation in cattle. It can be transmitted from livestock to humans, but that's exceedingly rare. It can be transmitted to other animals, such as deer.

The disease is considered incurable in cattle, so the spread could affect the beef industry nationwide.

It's critical to do everything possible to eliminate it, said the letter signed by U.S. Sens. Mike Johanns and Ben Nelson and U.S. Reps. Jeff Fortenberry, Lee Terry and Adrian Smith. Johanns, who was U.S. Secretary of Agriculture under President George W. Bush, coordinated the letter writing.

The USDA has paid farmers in the past to destroy livestock or crops when disease threatens U.S. agricultural production.

"The department's previous record on TB is clear — please act accordingly to ensure that Nebraska's producers receive the same treatment as others have in the past. To do otherwise would be unfair and inequitable," the lawmakers said.

Nebraska agriculture officials reported early last month that two cases of bovine TB had been found in a herd in north-central Nebraska's Rock County this spring.

Since then, roughly 6,200 other cattle have been tested, and no other cases of bovine tuberculosis have been found.

The disease is easily transmitted through a herd by nose-to-nose contact and the inhalation of bacteria. Experts say infected animals can transmit the disease to healthy ones within several feet.

Nebraska agriculture director Greg Ibach said he hopes the letter from the Congressional delegation will produce results because slaughtering the herd with infected animals is an important step in controlling the disease.

"Depopulation is also important for maintaining confidence in the health of the region's cattle herd," Ibach said.

Because bovine TB is considered untreatable in cattle, both infected and uninfected animals in a herd usually are killed when the disease is found. Nebraska Agriculture spokeswoman Christin Kamm said the herd that had the positive cases remains quarantined but has not been slaughtered.

Depopulation of an entire herd is voluntary but is the only effective way to eradicate bovine tuberculosis, USDA officials said.

When cattle producers are encouraged to slaughter their entire herds, the USDA has offered compensation of up to $3,000 per animal, said Cindy Ragin, a spokeswoman for the USDA's Animal and Plant Health Inspection Service. The exact amount of compensation offered is based on the market value of the cattle involved.

Federal officials have traditionally encouraged slaughtering entire herds when TB is found, but given the large size of some herds today, it may not be feasible or practical to slaughter all the animals when only a few cases are found, she said.

Bovine TB is a concern for Nebraska's roughly $10 billion cattle industry, but it won't be clear how much of a problem it is until after a state and federal investigation is complete later this year. If the state loses the tuberculosis-free label it has held for the past 17 years, Nebraska producers might have to pay to test their cattle and prove they are disease-free before shipping them to other states.

About 26 herds, including the one with the two sick animals, remain quarantined in 13 Nebraska counties. That's down from a peak of 43 quarantined herds because some herds have been released after the animals tested clean.

The 26 quarantined herds are in Boyd, Blaine, Brown, Buffalo, Cedar, Cherry, Colfax, Dundy, Holt, Loup, Nance, Pierce and Rock counties in north-central and eastern Nebraska.

Copyright 2009 The Associated Press.