Ms Cook spoke about a research project she is part of at a field day at Steven and Hayley Clarke’s dairy farm in Brydone this month.
The joint project between Fonterra and DairyNZ, with support from LIC, analysed performance data from hundreds of dairy farms across New Zealand.
An aim of the project was to learn about the drivers of emissions performance and profitability on-farm.
Fonterra was targeting a 30% intensity reduction in on-farm emissions by 2030 from a 2018 baseline, Ms Cook said.
The fastest way to improve emissions intensity on-farm was by running an efficient farm system and producing more milksolids per cow.
"There will be less emissions per unit of milk product out the gate"
A focus of the project was the nitrogen brought in to a farm system and not transformed into a product, which put it at risk of leaching or entering the atmosphere as nitrous oxide.
The data shows if farmers source feed for their herd from wherever it was available, such as purchasing it or using a grazier, they generally had a nitrogen surplus.
"If you don’t care where your feed comes from, the higher your nitrogen purchase surplus will be, so there is a leaching risk"
Data comparing the amount of pasture and crops grown on a dairy platform, compared to the liveweight of the herd eating it, shows a reduction in "nitrogen purchase surplus’’.
A farm system featuring more feed grown on a milking platform than a system obtaining feed off the platform had a reduction in emissions intensity, she said.
Feeding cows on pasture and crops grown on farm was the best way to lower emissions.
"We are feeding cows better and we are doing it with our cheapest, most low emissions source of feed"
How dairy farmers choose to feed their herd would define their profitability and how they meet their sustainability targets.
The farms with the highest profit generally had cows eating more home-grown feed, had lower purchase nitrogen surplus, and produce more milk per cow, per hectare and per cow liveweight.
Farmers with the highest profits and lowest emissions used less supplementary feed.
High footprint feeds include any concentrate feed served on a trailer or an in-shed feeding system.
Any farm had the potential to reduce emissions by the efficient use of their inputs, Ms Cook said.
The data showed super efficient farms with low emissions were driving productivity and managing their inputs, she said.
"It is boring old farm efficiency that gets us there in the end and we know that is really good for profit"
Farmers should track how much home-grown feed they were producing and the herd was eating so they had data to make future decisions.
"So you know what you are going to to do next in your business to drive the next gain in profitability"
