Milk volumes available to processors fell by 7% in May, according to Defra.
Cheesemakers in particular felt the pinch, with production of all varieties, other than short-life territorials, down on the previous year.
Cheddar, the dominant type manufactured, fell back by 4.2%. Output is now down by 5.8% during the first five months of 2004.
In contrast, butter output is rising this year. It was up by 20% in May due to higher volumes of cream available from production of reduced fat liquid milks.