The Golden State is also the Cattle Capital.

Here's why that matters

- BY SUSANNE RUST AND SEAN GREENE

FOR DECADES, dairy operations have been associated with degraded air and water quality.

In a first, researchers have identified the nation's roughly 8,700 cattle feeding operations, and the map shows California has more of them than any other state.

California also has the most feedlot acreage: more than 85,000 acres, or roughly 130 square miles, the majority of it for dairy cows. Tulare County has more than any county in the country — 304 operations. Were it a state, it would rank No. 8, researchers at the University of Michigan and UC Santa Barbara found.

Until now, there has been no national database of animal feeding operations. The federal government doesn’t keep one, and states tend to keep what information they have confidential.

The researchers say their data will allow local governments and nongovernmental organizations to set targeted environmental, health and economic policies for their regions.

"It's really awesome research,” said Andrew deCoriolis, the director of Farm Forward, an anti-industrial agriculture group. “This is by far the most comprehensive research I’ve seen, both in the map... and the quantification of the number of operations.”

The researchers also mapped the geography of hog raising. The U.S. is the world's second-largest livestock producer (behind China) — and most of the animals are raised in confined feeding operations: 70% of cattle and 98% of hogs.