GDT average winning price fell 2.2% to $US2472 from $US2515 at the previous auction two weeks ago.
Co-op's rising debt a potential limit on growth aspirations, says analyst.
Tim Hunter discusses Fonterra on NBR Radio, and on-demand on MyNBR Radio.
The first of the three new plants will be commissioned in early August.
Average prices dropped 3.5 percent in the GlobalDairyTrade auction overnight.
GDT average winning price fell 3.5% to $US2515.
The current May whole milk powder futures contract last traded at US$2,280.
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