In an idyllic setting, veterinary researchers are on a mission to preserve the diversity of livestock— and perhaps head off future catastrophe.
In 1916, a railway baron by the name of Arthur Curtis James transformed a plot of land in Newport, Rhode Island, into a piece of old Europe—an authentic Italian-Swiss village, complete with stone buildings, medieval-looking turrets, and Roman arches. It is still possible to walk its muddy pastures, sidestepping cow pats as you admire the clots of grazing goats and cattle and the quaint architecture, and feel transported to a time and place of utter tranquillity.
But you don't spend much time on the Swiss Village Farm, or SVF as it is now known, before someone brings up an ugly episode from the history of food production: the Irish potato famine. That agricultural disaster, which killed or displaced 2.5 million people, came about when a fungus wiped out virtually the entire potato crop of Ireland. Because the potatoes were all of the same strain, all were susceptible to this particular organism. Once infected, the crop disintegrated into inedible mush.
George Saperstein, a large-animal veterinarian who is assistant dean for research at the Cummings School of Veterinary Medicine, fears that the world's livestock is at risk for similar catastrophes. Dorrance (Dodo) Hamilton shares his concern, and, as a woman of means—her grandfather, John T. Dorrance, invented the process for making condensed soup—she has the wherewithal to do something about it. In 2002, the SVF Foundation at Swiss Village, which she established, entered into a partnership with Tufts, under the scientific direction of Saperstein, to preserve the biodiversity of farm animals. Swiss Village Farm is the epicenter of that effort.
Most of the dairy cows in the United States, Saperstein points out, are of one breed: the Holstein-Friesian. Dairy farmers have gravitated to the breed over the decades because it is so efficient at turning feed into milk. Holsteins now provide some 90 percent of the milk produced in the United States; the Ayrshire, Guernsey, and other breeds that populated farms of yore have all but disappeared in this country.
Letting a single breed of cattle so totally dominate dairy production spells trouble, says the SVF Foundation's director, Peter Borden. "If something were to happen to the Holstein"—a new mutation of a parasite, virus, or bacteria—"we'd be in trouble." Unless genetic diversity is increased, we could find ourselves in a world where beef and milk are unfathomably scarce.
American farmers have been extraordinarily successful in improving their livestock. Unfortunately, such "improvement" is a double-edged sword. "Each breed has become standardized," says Saperstein. "There's a sort of Marilyn Monroe ideal" that people in the livestock business try to replicate. Worse yet, he adds, "herds are bred selectively for every trait imaginable except for disease resistance. Most livestock are not exposed to disease—they're kept in a bubble. We don't know if the herds are immune or not."
Livestock could be vulnerable to global warming as well. For instance, Saperstein says, Holstein cows "wilt in the heat"—yet they predominate even in the hottest areas of the South. If the global thermometer ticks up a few degrees, we may find ourselves depending for dairy products on animals that are poorly adapted to the new climate. Today, dairy farms in hot regions use expensive sprinkler systems, fans, cooling ponds, and other strategies to keep their Holsteins cool. Consequently, energy cost hikes or water shortages could severely disrupt the milk supply. At one time, breeds that flourish in the heat, such as Jersey cows, could have taken up the slack, but no longer.
Which brings us to the farm in Newport. Here, on a pastoral 35-acre site just across town from the famed 19th-century mansions, animals that have largely disappeared from the American landscape graze contentedly. Swiss Village Farm aims to be a kind of insurance policy against future calamity. "We're providing a safety valve—a backup," says Saperstein.
When Dodo Hamilton first approached Tufts, she had in mind to preserve rare breeds "on the hoof"—that is, as live specimens roaming the SVF grounds. But several other farms already had similar programs under way. Saperstein and his colleagues suggested to Hamilton that SVF could make a bigger contribution by cryogenically storing just the genetic essence of the imperiled breeds—sperm from the males and intact embryos from the females. Collecting such "germplasm" would allow more specimens of more breeds to be preserved at lower cost. "Plus, nobody in the United States at the time was doing much with rare-breed livestock germplasm collection," says Saperstein.
Since the program's inception, other organizations—notably the U.S. Department of Agriculture's National Animal Germplasm Program—have begun cryogenic storage of livestock germplasm. But SVF's is the only program that freezes significant numbers of embryos as well as semen.
The heart of the operation is a cramped lab in one of the stone buildings. Leaving behind the faux village and placidly grazing beasts, you encounter three gleaming metal tanks filled with liquid nitrogen at about minus 300 degrees Fahrenheit. Each cryogenic tank can hold some 40,000 germplasm samples stored in thin plastic tubes. This early in the game (Saperstein expects the project to take about
20 years), there's still plenty of storage space available. As of April, the site stored 1,100 embryos and 15,000 semen samples. The guiding principle, says Saperstein, is to have enough germplasm cryogenically stored that it would be possible to re-create the diversity of a breed in one generation. To achieve that requires for each breed the preservation of 200 to 250 embryos from 25 to 30 females, as well as semen from 8 to 10 males. The frozen germplasm should last at least 200 years.
The frozen samples are meant to be left undisturbed indefinitely, says Dorothy Roof, the biologist who supervises the embryology lab. The cryogenic inventory of livestock germplasm would serve as an invaluable resource at some unknown future date if the animals we now depend on for food succumb to disease or to climate changes. The motto, she says, is "in case of emergency, break glass."
From time to time, the lab withdraws semen samples and tests them to make sure they're still viable. And frozen embryos are sometimes thawed and implanted in a surrogate mother of a different breed—the same process that would be used decades or centuries in the future if a breed needed to be re-created. In May, a Gulf Coast lamb from a frozen embryo was born from a Santa Cruz ewe that had served as surrogate.
Working on behalf of future generations tends to give one a long-term outlook. "How can we be sure that in two hundred years people will still know how to read bar codes?" asks Roof. Unlike some other cryogenic facilities, SVF labels the samples with human-readable tags. In a simple numerical code, each tag records the species and breed, the mother and the father, the developmental stage (if the sample is an embryo), and the date of collection.
The meticulously labeled and documented germplasm samples are SVF's real product. Indeed, once a goat or cow or sheep has delivered enough germplasm to work with, says Saperstein, SVF is "done" with the animal. Although a few are kept around the farm, most are transferred to more traditional agricultural settings.
In its selection of animals, the Newport farm
has carved out what Saperstein believes is a
vital niche. "We focus on large ruminants—cattle, goats, and sheep," he says (there are chickens, too, but those are "for show"). That means no pigs. One reason is that techniques for freezing embryos are less well developed for pigs than for the other animals. Another reason is that pigs are not well suited to New England. Modern pigs are "highly dependent on grain, from birth to death, and the price of grain in New England is very high," Saperstein says. "There just aren't a lot
of grain silos around here."
Within a species, SVF carefully chooses which breeds of livestock to preserve on this modern-day Noah's ark. The biggest consideration is the animal's degree of endangerment. The American Livestock Breeds Conservancy, an information clearinghouse in Pittsboro, North Carolina, maintains a list of livestock breeds that are threatened with extinction. SVF gives highest priority to breeds that the conservancy deems "critically endangered," meaning that fewer than 2,000 animals exist worldwide. But the farm also keeps other animals that aren't quite on the brink of extinction. The Belted Galloway cow, for example, is on the livestock breeds conservancy's "watch list," indicating that its global population has dwindled to
less than 10,000.
Belted Galloways have managed to survive as a breed largely because small boutique farms tend to buy one or two such cows to have on the grounds—as much for ornamental purposes as anything else. These cows are characterized by
a broad white stripe between two swaths of black—they're commonly called Oreo cookie cows. "Although they produce high-quality beef," Saperstein says, "lots of small-farm owners want to have them around because of their unique appearance."
While not all the livestock at SVF is at the top of the endangered list—which, in any case, changes from year to year—every breed tends to have attributes that make it worth preserving. The Dutch Belted cow, for example, has certain advantages over the Holstein. It's true that a Holstein makes prodigious amounts of milk—typically some 21,000 pounds (roughly 2,600 gallons) per year, according to the Holstein Association USA; champion Holsteins supply more than 65,000 pounds. But while Holsteins are well adapted to today's industrialized dairy system, Dutch Belted cows are better suited than Holsteins to small farms that just want a few cows to provide milk over the course of a decade or so.
Dutch Belted cattle can readily graze in pastures, for example. In the quest for maximum productivity, Holsteins have been bred to feed on grain, according to Donald E. Bixby, a veterinarian at the American Livestock Breeds Conservancy. "They don't do as well on grass any more,"
he says. Moreover, a Holstein cow typically has only two or three calves, and enjoys a productive life of only three or four years. Dutch Belted cows typically bear 10 to 12 calves over the course of a lifetime, says Bixby, and remain productive for 10 to 12 years. So the overall value of the Dutch Belted cow—as measured by its output over a lifetime—can be comparable to that of a Holstein. "Just because a breed has been passed over by the industrial agricultural system doesn't mean it's not useful in another production system," Bixby says.
The Gulf Coast sheep is another useful breed. Although
it lacks the heft to be economical as a meat-producing animal, it is extremely resistant to parasites of the sort that sicken the sheep that commonly make up today's flocks. Gulf Coast sheep are also nearly impervious to the foot rot that plagues many other breeds.
Then there's the Tennessee fainting goat, which has an odd genetic disorder called myotonia congenita—when the goat is startled, its legs stiffen for a few seconds, with the result that it sometimes plops over onto the ground (despite the name, the goat never actually loses consciousness). Goats with this condition are exceptionally meaty, perhaps because the genes associated with superior muscle development are linked to the gene that causes the myotonia. The SVF specimen—a Tennessee fainting goat named Chip, which was born from a frozen embryo—does
not readily topple over. "You have to really scare him with some unusually loud noise," says Sarah LaFreniere, the farm's livestock manager.
SVF is also preserving germplasm from the San Clemente goat and the Santa Cruz sheep—both of which were found in feral herds on islands off the California coast. These breeds developed with little or no human intervention for 100 years on their islands, and are now endangered. Such semi-wild animals boast
one distinct advantage over long-domesticated breeds: the mothers still remember how to be mothers. In commercial sheep flocks it is not uncommon for ewes to reject some lambs, which must then be bottle-fed by farmers. When the orphans become parents, they may perpetuate that undesirable trait. Breeds like the San Clemente goat and Santa Cruz sheep, which have raised their own young in the wild for decades, could be less troublesome to keep than today's dominant breeds, says Saperstein.
The list of SVF subjects goes on—Jacob sheep, Cotswold sheep, Pineywoods cattle, Kerry cattle, White Park cattle, Milking Devon cattle, Randall Lineback cattle—a compendium of picturesque breeds now fading from view. The more one learns about these varieties, the more apparent it becomes that standardization has come at a price. Today, animals that have been so uniformly bred as to invite ecological disaster plod the fields, while animals that carry disease resistance and other useful traits sit in tanks of liquid nitrogen, waiting to be born.
Still, to Saperstein, the benefits of uniformity outweigh the cost—so long as we have a backup system in place. The modern agricultural system has "brought about lots of cheap, nutritious food, to the great benefit of our nation's economy and our standard of living," he says. "I don't want everybody to trade in their Holstein cows for Dutch Belted, causing the price of milk to double—families less fortunate than mine should always have access to nature's most perfect food."
Herb Brody, a former editor of MIT's Technology Review, writes about science and technology. He lives in Newton, Massachusetts.