Dairy prices have fallen for the third consecutive auction.
The average price was down 3.8 percent to $US3208 a tonne.
It follows the previous auction's 3.4 percent drop.
Prices are now at their lowest in six months after they had risen since late November to two-year highs.
The price for whole milk powder, which has a key influence of farmer payouts, fell 4.3 percent to $US3006 a tonne.
Prices for most other products were also down. Volumes sold rose 22 percent, which was likely to have weighed on prices.