It wasn’t the last roundup, but Chrysler LLC used Texas longhorn cattle to unveil the latest version of its full-size Dodge Ram pickup Sunday at the Detroit auto show, joining Ford Motor Co. in the promotion of vehicles that were designed years before the advent of $3-a-gallon gas, Bloomberg and MSNBC.com reported.

Both companies pulled at patriotic heartstrings to debut their latest offerings, using bull riders, country music stars, fireworks and a cattle drive to parade vehicles whose sales dropped last year and face difficult economic conditions for auto sales this year.

These pickups were conceived before a slump in the housing market, looming economic woes and concerns about global warming conspired to diminish fascination with the pickup.

“Automakers are struggling to adjust to a new long-term reality of higher gas prices, but they have to sell today what they can make today,” John Casesa, managing partner at Casesa Shapiro Group in New York, told Bloomberg.

Ford’s F-150 comes with more powerful engines boasting improved gas mileage of one mile per gallon over last year’s models. Chrysler’s Ram features a more-powerful 5.7-liter Hemi engine and a coil-spring rear suspension for smoother riding.

“Being a product planner in this environment is like playing a game of Russian roulette,” said Bill Reinert, national manager for advanced technology at Toyota Motor Corp.’s U.S. sales unit. Toyota introduced a larger redesigned Tundra pickup last year and saw its sales jump 58 percent. By contrast, General Motors’ redesigned full-size Chevrolet Silverado suffered a 2.8 percent sales decline last year.