At the latest GDT auction, cheddar dropped 3.6% to US$3847 a tonne, while anhydrous milk fat declined 2.5% to US$6060 a tonne.
"While milk supply growth has slowed in both Europe and the US, milk is tending to be directed into cheese in these regions, so there is plenty out there," Castleton said.
Rennet casein fell 2.2% to US$4898 a tonne, while skim milk powder dipped 1.1% to US$2003 a tonne.
"This is the first decline we've seen in the skim milk powder price index since April," Castleton said. "Fonterra had lifted its offer volumes of SMP ahead of this event."
Meanwhile, butter gained 0.8% to US$5611 a tonne, while lactose jumped 8.2% to US$769 a tonne.
Butter milk powder was not offered at this event.
For sweet whey powder, neither an index nor price was available.
There were 127 winning bidders out of 165 participating at the 14-round auction. The number of registered bidders rose to 522, up from 519 at the previous auction.