Aug. 9--By 10:30 a.m. on a normal day, rancher Joseph Mendoza Jr. would have checked the cattle in his mating pens, made sure all 490 cows had been milked, examined them for health problems and begun a long afternoon of entering feeding and breeding data into his computer.

These days, however, Mendoza's barn and milking pen stand empty, and the only sounds on his wind-swept ranch in the Point Reyes National Seashore come from birds, dogs and the workers he's hired to turn his parents' former home into a vacation resort.

"I worked with those cows for 45 years," said Mendoza, 65, who sold his entire herd at the end of June. "It was not an easy thing to do, I guarantee it. I had to let go of my way of life, my heritage."

Mendoza and other Marin

dairy farmers are suffering through what he calls a "perfect storm" of economic conditions that have driven milk prices down, sent feed prices through the roof and are causing many to question whether they can stay in business.

"I'm expecting to see as much as a one-third reduction in our milk production next year, between losing a dairy and having such low pricing," said Marin Agricultural Commissioner Stacy Carlsen. "Everything is sort of going south against our dairymen right now."

Dairy farming accounts for more than half -- 56 percent -- of all agricultural production in Marin, according to the county Department of Agriculture, Weights and Measures. The value of Marin's milk production fell by 8.6 percent, or about $3.3 million,

from 2007 to 2008, and Carlsen expects the damage in 2009 to be even greater.

Boom and bust cycles may be the norm in agriculture, but the extent of this year's fall in milk prices -- which just last year had reached record highs -- makes this year's crash different from anything Marin's dairy farmers have experienced before, and could make it especially difficult for them to recover, said agricultural economist Leslie Butler.

"It's really very different in the sense that they went from a

huge high to a huge low over a very short period of time," said Butler, an economist at the University of California at Davis. "If you take a look at what dairy producers are being paid, the peaks are getting higher and the troughs are getting lower -- and they're about as low as they can go at the moment."

Mendoza agrees.

"There are always ups and downs, but not like this," Mendoza said. "It's never lasted this long or been this severe."

The crisis began last year, Butler said, when what had been record-high levels of international demand for U.S.