For many farmers, the changes coincide with crushing debt resulting from the cost of turning organic, which can run hundreds of thousands of dollars. In addition, the price of organic feed has doubled in the last year. Credit has dried up for some, and others say it is nearly impossible to sell cows and so thin their herds.

And while processors project growth of about 6 percent in organic milk sales this year (a decline from the 12.7 percent reported for 2008 by the Organic Trade Association), some analysts say that forecast is far too optimistic. The United States Department of Agriculture says sales of organic whole milk in February were 2.5 percent lower than in February last year, with sales of organic reduced-fat milk 15 percent lower.

“We’re in big trouble,” said Craig Russell, an organic dairy farmer in Brookfield, Vt., who owes $500,000, mostly from converting his farm to organic in 2006.

Image Last months meeting of the Maine Organic Milk Producers drew worried farmers seeking solutions to a post-boom bust. Credit... Cheryl Senter for The New York Times

Mr. Russell quit a day job as an accountant to farm full time last year. “I made more money in six months than in five years of conventional farming,” he said, but his farm is now barely hanging on. The price he receives from the distributor dropped another $1 per hundredweight on May 1, just when he most needed money to prepare for the summer grazing season.

“It’s going to cost me more to make milk than sell milk,” he said.

In an effort to provide a safety net, Vermont last month expanded a low-interest loan program for farmers.

While most conventional farmers are accustomed to withstanding price volatility, “organic hasn’t weathered this kind of storm,” said Mr. Allbee, the state’s agriculture secretary. Farmers are finding that organic food is not for every consumer, he said, “and doesn’t guarantee that you will have a market forever.”