The company's Clean Streams Accord snapshot results for 2010/11 (not divulged) showed "mixed results", according to the New Zealand company's general manager for milk supply, Steve Murphy.
He said: "Overall, it highlights that a lot of progress has been made by farmers but, ultimately, we recognise that there is still more that needs to be done".
"It's pleasing to see the improved effluent compliance results, which we believe have been helped by our Every Farm Every Year programme."
Introduced in August 2010, this scheme encourages progress in farm effluent management.
Murphy added: "We expected a farm-by-farm check would identify the full extent of compliance weaknesses, such as effluent storage, and enable these to be addressed.
We now need to build on this work and support our shareholders to achieve compliance 365 days a year," he said.