Ewe bet

Natural History, Feb, 1998 by Robb Walsh

Hal Killer's old white clapboard farmhouse and big red barns sit on a bluff above the rolling green hills of upper Wisconsin. If there were some black-and-white Holstein cows in the picture, it might be a picture postcard of America's Dairyland. But unlike most of his neighbors around Star Prairie, Koller doesn't milk cows.

"You should see the looks I get when I tell people I milk sheep," Koller says as he shows me around the farm. "Some people actually say, 'Don't you mean goats?' I want to slap my forehead and say, 'Oh, so that's what they are!'"

Dairy goats have become fairly commonplace on small family farms in Wisconsin, thanks to the growing popularity of goat cheese. Dairy sheep are something new around here. But with premium sheep's milk selling for $75 a hundredweight - about five times the going rate for cow's milk - Koller is very happy to milk sheep, even if his neighbors do give him odd looks.

"In Wisconsin, you have to find something else to do on a small farm besides milk cows, or you're going to go under," he says. "Family farmers can't compete with the big agribusiness dairies anymore. Ten years ago, on the drive from my house to Amery, I passed eight family dairy farms. Today, there is only one left."

Sheep dairying sounds weird to many Americans until you start talking cheese, he says. The United States imported fifty million pounds of sheep's-milk cheeses in 1990, including such well-known varieties as Italian pecorino Romano, Greek feta, and French Roquefort.

"When I heard there was a market for sheep's milk, I started milking my Dorsets," Koller tells me. The Dorset is a breed that originated in England and has long been raised for meat in the upper Midwest. "I got less than a pound of milk a day during a 120-day lactation period." A pound of milk a day is not a lot when you consider that a Holstein cow gives an average of eighty pounds of milk a day.

In 1991, Koller acquired two sheep from British Columbia that were half East Friesian (a northern European dairy breed that give four to six pounds of milk a day) and half Arcott Rideau (Canadian sheep raised for meat). By crossing them with his Dorsets, Koller produced sheep that gave twice as much milk.

After watching Koller's sheep dog round up the flock, he and I hop in the car and head for Spooner, Wisconsin, to find out about the progress of the American sheep dairy business. Yves Berger, a French-born researcher, meets us there and takes us on a tour of the University of Wisconsin's Spooner Agricultural Research Station. Berger is currently evaluating crossbreeds of East Friesian and Dorset sheep. Earlier in his career, he worked at a sheep dairy research station in La Fage, France, about ten miles from Roquefort. He plans someday to compare crossbreeds of East Friesians and Dorsets with crossbreeds of Dorsets and Lacaunes, the French dairy sheep of Roquefort.

As we toured the milking parlor, I asked Berger if he had any sheep's milk I could taste. He dug around in the freezer and handed me a little plastic Baggie full of frozen, yellowish milk. I carried it around with me on the tour until it was defrosted and then cut the top and drank it. It was mild in flavor, thick, and very creamy, with a silky texture that lingered in my mouth. "I think it tastes even milder than cow's milk," Koller said. "I slipped some in the refrigerator once and my kids poured it on their cereal. They never knew the difference."

The Bass Lake Cheese Factory in Somerset, Wisconsin, is Koller's top customer. I stopped by the small cheese-making operation and asked owner Scott Erickson why cheese makers are so crazy about sheep's milk. "Sheep's milk has about twice the fat and twice the solids of cow's milk," he told me. "So you get about twice as much cheese." But the volume of solids is not the only difference between sheep's milk and cow's milk.

"If you look at them both under a microscope, you see that the fat globules in sheep's milk are about half the size of the fat globules in cow's milk," Erickson continues. "That gives sheep's milk a smoother texture and makes it easier to digest." It also makes it possible for Erickson to freeze the sheep's milk until he has enough for a 4,000- to 6,000-pound batch. "You can't freeze cow's milk because the large fat globules will burst, but the small fat globules in sheep's milk freeze very nicely."

Erikson really waxes poetic about the milk's flavor. "We call it a lipase flavor," he says. Lipase is an enzyme that breaks fat down in milk, creating free fatty acids. "The lipolyzed free fatty acids in sheep's milk have a unique tangy taste and aroma that is very desirable to cheese makers; it's that slightly rancid aroma you associate with Italian pecorino."

Lipase occurs naturally in sheep's milk, but it is also one of the digestive enzymes in the mouths and stomachs of suckling ruminants. But rennin, or rennet, another digestive enzyme found in young animals' stomachs, is the one critical to cheesemaking because it causes milk to coagulate and form curds. In traditional cheese making, rennet is extracted from a calf for cow's milk cheese, from a kid for goat cheese, and from a lamb for sheep cheese. Nowadays, 75 to 80 percent of cheeses are made with artificial rennets from microbial or plant products. But it was the naturally occurring rennin in young animals' stomachs that was probably responsible for the world's first cheese. "Before the invention of pottery around 5000 B.C., bags made from the stomachs of slaughtered animals were used as storage containers," Vikram Mistry, coauthor of Cheese and Fermented Milk Foods (third edition), told me. "The natural enzymes found in the young animals' stomachs would have caused milk stored in these bags to coagulate and form curds. Most experts believe that this is how cheese originated."