A milk price of around $5.05/kg is regarded as the break-even point and the past two seasons have prompted many farmers to borrow heavily.
"The milk price has picked up but it has not really picked up at the farm level yet," she said. "Farm overdrafts are still incredibly high.
"It's going to be take at least until the end of this season for them to make up any ground."
Analysts do not expect to see demand pick up for PKE, although Kilsby said farmers use it "to fill the gaps where it makes sense".
PKE and other supplements have in the past been used to extend the end of the season, when prices were favourable.
Kilsby said PKE in particular has been popular as a cheap source of feed.
"Every farmer has a different view on PKE," Kilsby said. "But the drop in demand is driven by farmers pulling costs back."
New Zealand's biggest farming company, the state-owned Landcorp, has signalled its intention to stop PKE by the end of its financial year in June, after which time Landcorp farms would transition to alternative feed supplements.
New Zealand dairy production this season is falling, but not as quickly as some had expected.
Data from the Dairy Companies Association of NZ, which collects data from all the major dairy companies, shows production fell by 3.6 per cent in terms of milksolids in the season to date up to December.
Over the same period, Fonterra has reported a 5.5 per cent decline, indicating the co-op has lost suppliers to its competitors, Kilsby said.