One of these days, President Reagan's pinchpenny budget cutters may find another surprise in the mailbox -- a bill for moving about two dozen sick cattle across the country.

The story of 25 cattle, laboratory specimens infected with anaplasmosis, fits in a cozy corner of the big scheme of budgetary things.

Before the freeze of last November took the bloom off two hardy Senate perennials named Church and Magnuson, the seed of an idea was planted at the Department of Agriculture.

The idea was to move a laboratory studying anaplasmosis, a parasitic disease of potentially serious consequences in livestock, from the USDA research complex at Beltsville to Idaho or Washington.

After Idaho cattlemen and the University of Idaho offered a site for the lab, the idea begged for fulfillment.

For starters, Frank Church, then a veteran senator from Idaho, expressed an interest. USDA assumed that Appropriations Committee Chairman Warren G. Magnuson of Washington also was interested. And it didn't hurt to know that the House Agriculture chairman, Thomas S. Foley, also was from Washington.

But there was a problem with another hardy perennial, Sen. Thomas F. Eagleton (D-Mo.), then chairman of the Appropriations subcommittee on agriculture. He, too, expressed an interest in getting the lab moved -- but to the University of Missouri, which also had space available.

"With letters coming in from high-powered senators, it was obvious we couldn't ignore them," a USDA official said recently.

Cattle in Idaho, Washington, Missouri and other states suffer from anasplasmosis, the main disease studied by USDA's lab. For those cattle, that was a political plus. Cattle in Maryland, where the lab is located, do not suffer from the disease. For them, that was a political minus.

After the Nov. 4 election, the equation changed. Church and Magnuson were defeated, and Eagleton, relegated to the Senate minority, lost his subcommittee chairmanship.

But USDA, after all, is in the business of making seeds grow to harvest. The department's science and education administration has decided to move its Beltsville laboratory to Washington State University at Pullman and link it to work in Idaho.

After the election, Rep. Foley surrendered his Agriculture chairmanship to become the House majority whip. But he still represents Pullman.

Dr. Terry Kinney, chief of agricultural research, said politics had nothing to do with the decision to move the small lab to Pullman, minutes across the state line from the University of Idaho at Moscow.

Kinney said the move is an attempt to make the anaplasmosis research more productive. The disease is "serious" in the Northwest, federally owned space is available at Pullman and USDA researchers will be able to work with university scientists already studying the disease, he said.

"We would have moved the lab without any other influences," Kinney said. "We respond sometimes to politicians but, if we didn't want to do this, I'd be the first to fight like hell."

Eagleton is unhappy, suggesting that USDA ignored recommendations by his own study team to look at other sites around the country. Researchers at Beltsville are unhappy -- some because they will have to move, others because they fear further splintering of work at the Animal Parasitology Institute there.

With removal of the anaplasmosis lab, the institute will lose about one-fourth of its $4.5 million budget and about half a dozen scientists. "We will expand the remaining program at Beltsville," Kinney said.

The USDA study team estimated that the transfer will cost about $40,000 to move equipment and $60,000 to move personnel. Additional cost, it said, would come from building more laboratory space and animal handling facilities.

The team also warned that the anaplasmosis research program would be disrupted for as much as a year and that the institute would be left with "severe financial restraints."

The first advantage of moving west, the report said, was that congressmen and regional and national cattle and sheep associations support the idea. That recalls the "plus."

A disadvantage of remaining in Beltsville, the report went on, is that "hemoparasitic diseases are not a problem in the area, so there is little or no industry or congressional support for the unit." That recalls the "minus."

A question the team did not deal with was the cost of moving 25 infected cattle being studied at Beltsville.

"I don't know what it will cost," a USDA official said, "but it is either move them or give up the tests they are on now. The alternative would be to fly the researchers back from Pullman to conduct their tests at Beltsville. That would be expensive, too."

Memo to the pinchpennies: keep an eye on that mailbox.