Kansas City, Mo ? Cattle ranchers in Illinois reported an unusual problem in 1942: Cows had acquired a taste for license plates.

The cows were not suffering from a metal deficiency. World War II and the resulting shortage of metals caused the state to make plates out of pressed soybeans.

“They still must have had some food value because cattle farmers said when they went to feedlots, the cows would eat them off the trucks,” said Martin Hohulin, a farmer and license-plate collector from Lamar, Mo. “Illinois sold its stock of excess 1942 plates to Montana for them to reuse in 1944, and farmers reported cows eating the plates there as well.”

One of the few surviving 1942 Illinois soybean plates is among more than 50 license plates on display through Dec. 12 at the Joplin office of the state Division of Motor Vehicle and Drivers Licensing in Joplin.

Chris Cagle, manager of the Joplin bureau and a license-plate collector himself, said the display shows some of the unique ways the states used their plates to promote themselves.

“A lot of people come in and just glance at the wall and walk on by,” Cagle said. “I see a lot of people who stand at the wall and look them over pretty closely.”

Hohulin says he has as many as 3,500 plates in his collection, down from a peak of 5,000 at one time.

His late son, Bill Hohulin, started collecting plates before he died in an auto accident in the 1970s. The elder Hohulin has kept collecting ever since.

“I never turn down a plate, but I’ve tried to limit the collection to U.S. and Canadian plates, and plates from the (Panama) Canal Zone, Guam and other U.S. possessions,” Hohulin said. “The foreign plates are hard to get and are odd sizes, so I try to stick to North American plates.”

Massachusetts issued the first automobile license plate in 1903, Hohulin said. The oldest tag in Hohulin’s collection is a 1908 Massachusetts plate made of porcelain.

Several states made porcelain tags until the mid-1900s, he said.

Some plates are unusual for more than just their age. Hohulin said if you turn over his 1918 Nevada plate, you can see the outline of more lettering.

“In 1917, Massachusetts sold its leftover plates to Nevada,” Hohulin said. “Nevada turned them into 1918 plates.”

His 1912 Illinois plate has more holes than metal because it was designed to be mounted on the radiator of a car and needed to allow air to flow through it. Hohulin said Illinois used ventilated plates until 1920.

Illinois and Montana were not the only states to turn to alternative materials as a result of World War II. Another plate in Hohulin’s collection is a 1942 Missouri tag made of cardboard.