"The fact that the conduct was in anticipation of a legitimate exclusive supply arrangement is not a defence," the judge said.
"In my view, Milfos' conduct was certainly careless - even grossly careless. It matters little whether it was also reckless."
The judge agreed to the $1.1 million starting point put forward by the commission and Milfos, then discounted that by 25 percent for the company's admissions and cooperation.
Commission chair Anna Rawlings said the case was a reminder to businesses about the risks of setting prices with a distributor that competes with them in the retail market.
"Companies should seek legal advice before discussing retail prices with a distributor that competes with them to sell the same products direct to consumers, to ensure they don't put themselves at risk of breaching the Commerce Act," Rawlings said in a statement.
Dairy Automation, now known as Smart Farm Technologies, was warned by the commission in December 2017, which the regulator said accounted for the extent of its involvement in the conduct.
In February 2014, Livestock Improvement Corp bought the Dairy Automation assets and continued to sell the products at a wholesale and retail level until August 2015.