Tuesday, November 29, 2011

Wondering if That's a Genuine Bison? Try Pulling Its Tail

Bison bison. Original caption: "scientist...
Image via Wikipedia
Annual DNA Harvest to Ensure Species Purity Kicks Up Controversy
PAWHUSKA, Okla.—Squeezed into a metal chute, the young bison thrashes wildly.
The cowboys rush up. They snap a microchip into his ear, burn a brand into his shaggy rump, vaccinate him with a swift shot to his well-muscled shoulder. Then veteran ranch hand Steve Forsyth approaches. He grabs the bison's tail with flat-head pliers and yanks, hard, again and again—until he snares a bristly bouquet of black hairs, which he holds aloft in triumph.
One down, 749 to go. (click below to read more)

To keep the Nature Conservancy's herd of bison free of cattle genes, these cowboys need to root out animals carrying cattle DNA. And that means pulling their tails. WSJ's Stephanie Simon reports from Pawhuska, Oklahoma.
Tail-pulling day here on a prairie preserve run by the nonprofit Nature Conservancy has been a fall tradition since 2004. The follicles on the tip of each tail hair contain enough tissue to run a DNA test designed to determine whether these critters are pure bison—or whether, generations back, their ancestors were bred with ordinary domestic cattle.
These DNA tests have long been an obsession for managers of wild bison, who have pulled tail hairs and drawn blood from thousands of animals across North America in an effort to make sure their thundering herds are the genuine article—brawny, brutish, full-blooded bison. Those that turn out to have remnants of cattle DNA are typically sold off for steaks.
But new research suggests this purification drive may be doing more harm than good. At a conference in Tulsa earlier this year, geneticists issued a plea that rattled bison buffs: Stop the testing.
"They basically said, 'Bison have cattle genes in them. Get over it,'" says Kent Redford, who serves on the advisory council of the American Bison Society, a preservation group.



One reason for the shift: As DNA tests grow ever more sophisticated, they are identifying more and more bison that have bovine ancestry. Turning all those animals into buffalo burgers would deplete the genetic diversity of wild herds, says Greg Wilson, a biologist with the Canadian Wildlife Service.
"If they look like bison, behave like bison, and live in the historical range of bison, let's keep them," says Rurik List, an ecologist at the National Autonomous University of Mexico.
There are some caveats to this new live-and-let-live attitude. If a herd is believed, from prior testing, to consist mostly of pure-bred bison, "it would be a tragedy to purposefully bring in hybrids," says Jim Derr, who has spent decades researching bison genetics at Texas A&M University. "Mixing herds up willy-nilly—I think that's wrong."
Still, Mr. Derr concedes that many—probably most—North American bison have so many snips of cattle DNA scrambled up within them that it's impractical to find and cull them all.
The genetic jumble traces to the late 19th century, when ranchers seeking to save bison from extinction—and create a hardier strain of cattle—experimented with cross breeding.
Today, the Department of Agriculture recognizes "beefalo" as a distinct type of meat (it comes from hybrids that are mostly bovine, with the bison's genetic contribution ranging from 17% to 37.5%). Beefalo vary in appearance; some have cow faces and bison humps, while others look like typical feedlot cattle except for their curly, shaggy hides. Come birthing season, "it's exciting to walk out and see what you get," says Andrew Hammer, who raises beefalo in Canal Fulton, Ohio.
The wild bison that roam the West are far closer to authentic bison than farm-raised beefalo; if they contain cattle DNA, it amounts to at most 2% of their genetic makeup.
Bob Hamilton, who manages the herd of 2,700 bison that roams the Tallgrass Prairie Preserve here in northern Oklahoma, says he supports the new directive to leave well enough alone and stop culling critters based on such tiny traces of cattle heritage.
Still, he isn't ready to cancel the annual tail pull just yet.
The genetics test he uses, which cost $8 per animal, looks specifically for cattle mitochondrial DNA in bison cells. There's some emerging evidence—not yet published in a scientific journal—that cattle mitochondria are a "physiological downer" for bison, Mr. Hamilton says. Affected bison might lack the vigor and heft of their brethren. "It's like they have the wrong battery in them," Mr. Hamilton says.
After years of testing and culling, Mr. Hamilton says he believes his herd is almost clean of cow mitochondria. He expects at most a couple of bison to test positive when the hair follicle analysis is complete early next year. Mr. Hamilton says he might as well get those few animals out of the herd, since he has to sell off a bunch of yearlings anyway to maintain the population at its current size.
Besides that, he has gotten pretty good at pulling tails.
"It's amazing how you can learn to do anything," he says.
It's quite an art. Over several days in November, the bison are rounded up by ranch hands driving all-terrain vehicles across the 40,000 acre Tallgrass Prairie Preserve. The animals are pushed into smaller and smaller pens and then the calves—at that point, about six months old—are separated from their mamas for the first time.
"They each have their own attitude," says Perry Collins, a ranch hand who has worked the roundup for years. "Most of the time, it's a bad attitude."
One by one, the bison are pushed into a squeeze chute, which holds them steady so ranch hands can work on them. As the calf thrashes and flails, Mr. Collins works the front end, trying to hold the head and shoulders steady so the microchip can be inserted. It's a messy job. "They blow snot," he says.
The ranch hand at the rear end doesn't have it much better.
The branding iron on the rump sends smoke curling into the air, and with it, the throat-clogging smell of burning hair. It is then that the designated tail-puller must thrust his arm into the chute—taking care not to get crushed against the wall by the 300-pound calf. The tail hairs are well-rooted, so it takes as many as a dozen firm tugs to unloose them.
It's then best to remove hand, pliers and hairs all at once, for often the bison "will start pooping, and their tail acts as a manure spreader," Mr. Hamilton says. "It gives you that manly smell."

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