Neither its stockyard past nor Mrs. O'Leary's cow nor the six-time championship Bulls can explain why cows--hundreds of them at last count--are turning up all over Chicago.

"Rhinestone Cowgirl" flanks the sidewalk outside Bloomingdale's; "Moollennium" stands in the herd by the Wrigley Building, and "Holy Cow"--with the requisite holes in its hide--straddles the sidewalk outside WGN Radio's downtown studio. Its patron is Harry Caray's, a nearby restaurant, and for a time a pair of oversize oval sunglasses shaded its eyes, mimicking the style worn by the late Cubs announcer (they're currently at the Loop "cow hospital" for minor repairs).

Since mid-June, some 300 life-size artistically decorated bovines are drawing in tourists, exciting kids and stunning the usually staid Chicago arts community with their success. "It surprised everyone," Mayor Richard Daley said of the "Cows on Parade" display, which is sponsored by the city's Department of Cultural Affairs and the Chicago Office on Tourism. Tiffany's, Salvatore Ferragamo and local shoe store magnate Peter Hanig are providing commercial support.

Stirring local pride, there's "piCowsso," a bow to the artist's beloved 1967 donation of a five-story outdoor statue that stands near City Hall. The piCowsso cow has hunkered down near Michigan Avenue's chic Gold Coast, but occasionally at night, city officials move certain cows to new locations, lending a touch of mystery to the invasion.

So far, cow theft hasn't been a problem, say police, but maybe that's because the fiberglass creatures weigh almost 600 pounds with their concrete bases. There have been a few incidents of vandalism, however. The worst case occurred at Oak Street Beach when thugs tried hauling away "Wow Cow" but dropped the abstract-design bovine and ran when they were spotted. "Wow Cow" was trucked downtown to the cow hospital, where summertime city hires patch, paint and repair minor acts of cow cruelty, such as replacing on eight bovines the horns sawed off by vandals.

"I love the cows," said 33-year-old Shannon Huggins, a clinical social worker from Austin who was checking them out in the "Cow Corral" on Lake Shore Drive. The Motti family, also visiting Chicago from Texas--a cattle state if ever there was one--was on its fourth trip downtown to locate the cows. Eight-year-old Kristina "is on a mission" to see them all, said her mother, Julie.

Though local artists designed and built these cows, Chicago's arts community can't take credit for the idea. "Cows on Parade" was first created by Swiss artist Beat Seeberger-Quinn, whose 1998 installation of 800 cows in Zurich's parks and streets created a swell of tourism.

Indeed, Chicago officials timidly expected about $100 million in additional tourist spending from the exhibit, but those estimates were way off. "By far it exceeded expectations," said Michael Lash, public art director for the city of Chicago. "One souvenir store did a whole year of business in one month in the cow vicinity. It's insane," added Lash.

The city now expects to double its original estimate of tourist revenue. A dozen cities have called inquiring about bringing the event to their communities.

At first, everyone just snickered, recalled Hanig, whose family has been in the shoe business for 55 years and has a store on Michigan Avenue. Hanig was on vacation in Zurich last year when he noticed the cows. He thought it might tweak tourism back home and be a lot of fun for Chicagoans. So he presented the idea to colleagues in the chic Greater North Michigan Avenue Association and was almost laughed out of a meeting.

Asked to "sponsor" a cow for a minimum of $3,000, business owners "said, 'It's not very elegant,' 'You're crazy' and 'That's a stupid idea,' " Hanig recalled. "The snickering was awful."

But Michael Christ, Tiffany's man in Chicago, knew Tiffany of Switzerland had sponsored a cow in the Zurich installation and that tourism there had spiraled upward.

A friend at Ferragamo jumped in, and the three won over Cultural Affairs Commissioner Lois Weisberg. Then Lash, the public art director, mailed 2,000 fliers to local artists asking them to participate in a cow design competition.

By June, when the cows began grazing on city streets, the business community was no longer snickering.

"I got 40 calls the first day asking how they could sponsor a cow," said Hanig. Immediately, souvenir merchandisers were caught short. Skeptical that the cow theme would sell, many of them had failed to order cow-related trinkets. For two weeks, every store near the cows was sold out of disposable cameras.

Since their installation, their only detractors seem to be the carriage horses, who were at first spooked. They would refuse to move, or trotted in a circle around the cows. To calm them, their handlers bought and painted a cow, and brought it to the stable. The horses are adapting.

Each raw cow structure, imported from Switzerland, costs $2,000. Commissioning a relatively obscure local artist adds another $1,000 to the price tag. But the price has soared to $11,000 for a cow by a better-known artist.

Some cows are artistic and engineering feats. "Mooooonwalk," with astronautical headgear, graces the lawn of the Museum of Science and Industry; the golden bronze "Top Cow" wears a crown and sits on a pedestal along the city's higher-end "Magnificent Mile," a block from the 96-story John Hancock Building. The "Solar Cow Lantern," whose panels glow in the dark, grazes by the Field Museum.

This being Chicago, however, the cows are not expected to last through winter. So "Cows on Parade" is scheduled to be put out to pasture Oct. 31. An estimated 25 to 30 percent of the bovines will then be raffled off; proceeds will go to the charity of the buyer's choice. It's unknown how many cows will end up in living rooms or in the lobby of Loop office buildings. In the meantime, the bovines can be viewed on the Web at www.cowsonparade.net.

Perhaps the cows finally have settled the question of how to pronounce the Windy City's name, often referred to as "Chicaughgo." "Chicowgo" may never be the same.

CAPTION: Visitors have stampeded Chicago to see 300 bovines, including "Holy Cow."

CAPTION: Peter Hanig, left, directs artist Mike Baur's placement of his work, "Odalisque (Reclining Nude)."

CAPTION: Seeing triple: "Chicago Cow Tower" draws viewers' eyes high up.