Who knows when bison (buffalo) first loomed on North American continent? But by 1700 some 60 million of beasts were thundering their way across Western grasslands and wallowing in bluegrass of Shenandoah Valley. Then white man came, tramping buffalo paths westward. By mid-1800's thousands of buffalo were slain to supply meat for builders of Union Pacific Railroad. William F. Cody (Buffalo Bill) earned dubious fame for killing 4,280 buffalo in 18 months. By 1889, 60 million free-ranging bison had been snuffed to 800. Two hundred of these survivors were in Yellowstone National Park. Today, almost a century later, numbers of free-ranging bison are about same as in 1889-700 in Yellowstone, 100 in Henry Mountains of Utah and 100 in Alaska. These numbers imply that animals placed on national and state preserves are safe from extinction. But events of recent months suggest this is not necessarily case. Free-ranging buffalo in Yellowstone might be eliminated, provided Wyoming, Montana and Idaho ranchers get their way regarding control of a disease that afflicts cattle and For 30 years now these ranchers, state livestock and sanitary boards and U.S. Department of Agriculture have been investing millions of dollars (presently $30 million annually) to eradicate a bacterial disease, brucellosis, from livestock. The disease has cost livestock industry millions of dollars in past in aborted calves and milk loss. Cattle in Wyoming, Montana and Idaho have now been declared virtually free of disease. Southern and southwestern states were slower to enter brucellosis eradication program, but they are catching up with Wyoming, Montana and Idaho. The USDA has set 1975 for complete eradication of brucellosis from American livestock. After that cattle will no longer be vaccinated against disease. No longer will cattle have to be tested prior to sale. The problem is that a number of Yellowstone buffalo are known to harbor Brucella abortus, bacterium that causes brucellosis. The ranchers know it. The Yellowstone biologists know it. The biologists, in see bacteria as natural buffalo vectors that provide natural checks on buffalo reproduction. The ranchers are afraid that buffalo roaming out of park onto their ranch lands will infect their Once vaccine is withdrawn, says Dean Prosser, secretary of Wyoming Stock Growers Association in Cheyetine, our herds will be susceptible to disease. will be no protection. James Yorgason of Wyoming Game and Fish Commission disagrees. There have been no known cases of bison transmitting disease to cattle in area. He is joined by Yellowstone research biologist Mary Meagher: There have never been any documented cases of brucellosis transmission between bison and cattle. Nonetheless, USDA veterinarian Gerald Fichtner counters, Ranchers do not have a lot of sympathy for argument 'we cannot test them.' A lot of them cleaned up their herds without anyone proving dangers of transmission to them. Last March, Yellowstone biologists, USDA officials, state livestock and game officials, state veterinarians, and cattlemen representatives met at Yellowstone to find a solution to potential buffalo-cattle threat. Supporters of ranchers suggested that Yellowstone bison be trapped and penned and that animals with brucellosis then be killed. The others would then be returned to park wilderness. This effort, they felt, would clear up disease in what they saw as the only known active reservoir of Brucella infection in entire United States in either bovine or buffalo. The Yellowstone biologists replied that such a measure would wipe out last free-ranging buffalo in Yellowstone (and last free-ranging, naturally regulated bison in United States, since those in Utah and Alaska are managed by hunting). Mary Meagher explained it would be a horrendous job to round up bison from thousands of miles of wilderness. In fact, she said, under most favorable conditions in any area, we would probably be able to trap no more than 75 percent, which would mean killing off those we could not trap. The job could easily take 10 years, she said,