BARNHART, Mo. — A collapse in milk prices has wiped away the profits of dairy farmers, driving many out of business while forcing others to slaughter their herds or dump milk on the ground in protest. But nine months after prices began tumbling on the farm, consumers aren't seeing the full benefits of the crash at the checkout counter.

The average price for a gallon of milk at grocery stores last month is down just 19 percent from its peak of $3.83 in July. Farmers, on the other hand, got $1.04 a gallon in April — 35 percent less than they were paid last fall. This winter, wholesale prices were down as much as 45 percent.

Price disparities are a fact of life both for farmers and anyone who shops at a supermarket, but the nature of milk — how it's stored, priced and sold around the world — makes the gap all the more dramatic. In fact, the price that farmers get has been wildly volatile for years, creating a succession of booms and busts felt from pastures to the grocery store.

With each turn, proposals are floated to end the pricing seesaw, which at one extreme squeezes the profits of farmers and the other squeezes dairy processors. Any fix that boosts the price of milk runs the risk of bumping up how much consumers pay, too.

Today, frustrations are spilling over as the price crash creates widely divergent fortunes within the milk industry, boosting profits for the middlemen like dairy processors while pushing farmers to the edge of bankruptcy.

Darrell Kraus, a dairyman in Barnhart, spends almost as much today on hay and other supplies for his herd of 160 cows as he did a year ago, but he's getting paid less for a gallon of milk than his father in the 1970s. He blames middlemen who buy the milk from the dairies, process it and sell it to grocery stores at higher prices.

"Somebody's getting a cut of this, but it's not the dairy farmer," he said. "It's sad, but they're going to see a lot of dairy farms go out of business."

In Pennsylvania, the 9,000 dairy farms make it the fourth largest dairy state in the nation, according to the state Department of Agriculture.

Dairies in Pennsylvania support 40,000 jobs, are home to 560,000 dairy cows and produce about 1.2 billion gallons of milk annually.

At a grocery store in Fayetteville, Ark., Katherine Thacker noticed how milk prices were slowly falling — but not as drastically as last year's price hikes. She was surprised to learn that the lower wholesale milk prices were being absorbed by dairy processors.

"That's kind of criminal, isn't it?" she said.

Milk processors and supermarkets see it differently.

Last fall and summer, they swallowed losses because of high wholesale milk prices and government-mandated ceilings on what they can charge. They're now recouping some of what they lost and anticipating a rise in prices this winter, said Mike Nosewicz, vice president of dairy operations at Cincinnati-based Kroger, which operates its own dairy processing division and sells milk through 2,400 supermarkets.

At the heart of the problem is the nature of milk. Unlike grain farmers who can hold out for better prices by storing crops in a silo, dairymen must sell raw milk to processors or else it spoils.

The price paid by processors to farmers is set by the U.S. Department of Agriculture based on commodity markets, which rise and fall.