How much PKE per cow per day, and what FEI grading costs
By Dave Wilson. Published 3 October 2026. This is general information, not feeding advice for your herd. Talk to your vet or nutritionist about your own farm.
The short answer. The general rule is no more than 3 kg of PKE (palm kernel) per cow per day, and no more than 20% of what the cow eats. Feeding PKE pushes up Fonterra's FEI fat grade, and under the grades Fonterra announced in 2017, grade C brings a 10% deduction and grade D a 20% deduction for each collection day.
The 3 kg guideline
Anexa Vets puts it this way: aim to keep PKE at no more than 20% of total intake, which is no more than 3 kg in a 15 kg diet, and "the general rule is no more than 3kg PKE/cow/day regardless" (Anexa, 2021).
The share of the diet matters as much as the kilograms. DairyNZ's example: a cow eating 3 kg of PKE out of a 15 kg diet will have a higher FEI than one eating 3 kg out of 18 kg (DairyNZ). So the same 3 kg is a bigger share of the diet when cows are eating less.
Why PKE pushes up FEI
PKE has a high plant fat content, from about 3% to 10% depending on where it came from, the supplier and the shipment (DairyNZ, Anexa). That fat changes the milk fat in ways that make it harder to process.
Anexa lists other things that can raise FEI:
- feeding PKE alongside feeds high in starch (maize) or sugar (molasses)
- a rushed transition onto crops
- switching to once-a-day milking
- Jersey herds, which naturally produce milk with a higher fat content
How FEI grading works
Fonterra set up the Fat Evaluation Index (FEI) to encourage milk with fat that is better suited to making dairy products. Farmers get a grade from A to D, reported daily as a 6-day rolling average. Milk graded C or D three days in a row is retested, and demerits only apply if the retest confirms the grade (Anexa).
When Fonterra announced the grades, it set them out like this (Fonterra, December 2017):
| Grade | FEI result | What it means | Penalty |
|---|---|---|---|
| A | Under 7.50 | Meets requirements | None |
| B | 7.50 to 9.00 | Meets requirements, approaching the limit | Alert only |
| C | 9.01 to 11.00 | Over the limit | 2 demerits and a 10% deduction per collection day |
| D | Over 11.00 | Well over the limit | 4 demerits and a 20% deduction per collection day |
Demerits started in September 2018. Check the current figures in Fonterra's terms of supply on Farm Source, since they may have changed since 2017.
Work out your farm's own average
The sum is simple, and the PKE tonnes are the same ones you total for the Farm Dairy Record feed section:
kg PKE per cow per day = PKE tonnes delivered × 1,000 ÷ cows ÷ days
An example with made-up numbers: 36 t of PKE delivered in September, 30 days, 430 cows milking.
36 × 1,000 = 36,000 kg. Divided by 430 cows is 83.7 kg per cow. Divided by 30 days is 2.79 kg of PKE per cow per day.
Three things to watch:
- Count the PKE in blends. If some of your PKE comes in a PKE and DDG blend, only the PKE share counts.
- Delivered is not the same as fed. If the silo was fuller or emptier at the end of the month than at the start, adjust for it, or work over a longer period so it evens out.
- Count only the cows getting PKE. If dry cows get a share, work them out separately.
Getting the first number from FeedTally
The hard part of the sum is the PKE tonnes, because PKE arrives on dockets from more than one merchant and often inside blends. FeedTally reads each docket from a phone photo, splits blended loads into tonnes of each feed, and shows the month's PKE tonnes on the owner's dashboard, by shed and by merchant. Divide by your cows and days and you have the farm's average.
PKE prices
PKE prices change week to week, so we don't quote them here. For current prices see the Ruralco Grain Report, the markets coverage in Farmers Weekly, or ask your merchant.