The Scottish dairy co-op dropped its member milk price by 0.65ppl from 1 November. The main reason for the cut was the cheese-selling price, according to chief executive Peter Humphreys.
"These prices are under pressure primarily due to the level of imports coming to the UK, plus high promotional activity in the big retailers."
The 0.65ppl reduction sees First Milk's standard milk price falling to 21.40ppl and its Highlands & Islands price falling to 22.45ppl.
"It is a concern that the UK's leading dairy farmer-owned business is cutting producer prices from a comparatively low level just at the time when all the signals point to a substantial rise," said NFUS president Jim McLaren.