UK dairy farmers have posted a third lacklustre month of milk production in a row after a slow start in April, reigniting debate over the scale of the exodus from the industry.

Output in the first three months of the 2006/07 quota year was 3,642.9 million litres delivered, 29 million less than last year and 261 million litres less than the peak four years ago.

But it is exactly the same as that produced in the same period in 1994/5, and a survey of the major processors suggests that production through the spring milk flush has simply fallen back to the more "normal" levels seen in the mid-1990s.

The processors claim this provides evidence that their seasonality schemes introduced over recent years to cap spring milk supplies are having the desired effect. These work by effectively paying farmers less for spring milk and more for autumn supplies.

Milk Link's Mark Brooking said: "Our profile is much better than it was because of our scheme. It is not just a reflection on people leaving because we know it isn't just spring herds that are quitting." Dairy Crest's Arthur Reeves admitted that prices were a factor, but pointed to the success of its seasonality scheme. "Each year the profile for us gets better."

Membership director Matt Sheehan said DFB had slashed the 16% differential between volumes at the peak and the trough.

But the NFU says the farmgate milk price has been under pressure from buyers looking to stabilise their own margins. Dairy adviser Tom Hind said the slowdown was due in large part to lower producer confidence, and current levels were not sustainable.

He added: "There are more producers leaving than those prepared to invest. Many farmers are putting the decision off while the cows are out on grass, but crunch time will come in the autumn."