Happy Cows Come From California

They say that happy cows come from California.

They just got happier.

"This is the DeLaval Swinging Cow Brush," said Brett Olinger, solution manager for DeLaval, a dairy equipment business. The brush looks like something you'd find at a car wash, with long plastic bristles that spin and pivot. "The cows love it," Olinger said, "they can't get enough."

Olinger's booth was set up at the World Ag Expo in Tulare, Calif. This is the heart of the dairy industry in the nation's top dairy state. A hundred thousand visitors from over 70 countries are expected to descend on the Central Valley this week to check out the latest farm equipment and technology.

DeLaval promotes the cow brush by pointing to a Cornell study. "They found it increased milk production" Olinger said.

(Read More: Ohio Dairy Farm Coddles Cows With . . . Waterbeds?)

The brushes retail for an eye-popping $3,000, but the company said sales are growing.

"Last year we finished somewhere a little over 1,100 (sold), and I plan to sell more than that this year, 1,500, 2,000," said Olinger. "Most people who buy one, one is not enough."

Check out how the brush works in the above video.

As an added bonus, here is some video demonstrating DeLaval's brand new "TSR"—that stands for "teat spray robot". I call it "Star Wars-meets-Detroit assembly line". Udderly amazing!

(Read More: 'The Rock,' America's New Milkman.)

So cows can now get a nice spray wash and luxurious brushing. Throw in a mani-pedi and that's a spa day.

—By CNBC's Jane Wells; Follow her on Twitter: @janewells