Over summer, DairyNZ ran a range of on-farm trials exploring everything from cow behaviour to farm system performance. Lead scientists share a snapshot of what happened in the field, with photos capturing the work in action and showing how levy-funded research delivers practical value for farmers.
Inside Dairy
4 min read
DairyNZ senior research technician Eliza Hay, who has been involved in the trial work on Scott Farm.
A five-year research trial, established at Scott Farm in autumn 2025, is re-evaluating perennial ryegrass pasture management for summer-dry regions. The study is looking at how different pre-grazing and residual pasture masses affect plant growth above and below ground.
Using mini-rhizotrons (transparent tubes inserted into the ground that cameras are lowered into to take high-resolution images of roots), researchers are monitoring changes in root mass over time under each management approach. The goal is to provide practical insights to help farmers grow more resilient, persistent pastures in challenging conditions.
A rhizotron installed in the research plot
The transparent tube lets researchers lower a specialised camera into the soil to capture high-resolution images of plant roots.
Drone image
Drone image of replicated plot study.
DairyNZ recently completed the spring and summer phases of its Targeted Supplementary Feed Trial at Lye Farm, Waikato. The technical team is now processing and analysing samples, and we look forward to sharing the results soon.
The trial investigated how different types and amounts of starch- and fat-based supplements affect methane emissions in pasture-fed dairy cows, and how responses change as pasture quality shifts through the season.
DairyNZ senior research technician Eliza Hay, who has been involved in the trial work on Scott Farm.
The research also looked at cow productivity and wider farm system impacts, providing a clearer picture of the value of targeted supplementation as a greenhouse gas mitigation strategy. Sixty cows were monitored in individual feed stalls, allowing precise measurement of feed intake, feeding behaviour, and methane emissions. Freshly cut pasture was delivered twice daily using a cut-and-carry method, with supplements also offered after each milking. This setup aimed to mimic paddock grazing and in-shed feeding while capturing accurate data.
Researchers from DairyNZ, Lincoln University, the Bioeconomy Science Institute (formerly AgResearch), Fonterra and AbacusBio are in the third season of multi-year studies at the Lincoln University Research Dairy Farm. The Low N Farmlet Trial is testing how a combination of strategies can reduce nitrogen (N) leaching by more than 40% while keeping a viable dairy business.
So far, using lower N fertiliser, slightly reduced stocking rates and diverse pastures has reduced N leaching on the milking platform by around 45%. Greenhouse gas emissions are down 12% per hectare and emissions intensity by 5% per kgMS.
These reductions were linked to 11% lower profitability in the first two years, although the trade-off was moderated by selecting complementary mitigations suited to the farm’s soil and climate.
Switching the support block to a pasture-based wintering system also reduced N losses compared with kale wintering followed by an oats catch crop.
Work continues to assess the economics and land requirements under different scenarios, helping identify practical options to reduce N while maintaining a productive system.
Low N systems lead scientist: Dr Claire Phyn, DairyNZ principal scientist
In the 2025/26 season, DairyNZ collected around-the-clock physical activity and stress data from 45 farmers using Garmin Instinct 2 watches. The study linked this information to farm management, working hours, tasks and participants’ wellbeing, providing evidence of what drives fatigue and stress at different times of the year. These insights will help inform strategies to support farmers’ health, productivity and retention in the sector.
Our 2025/26 summer Heat Stress Mitigation Trial at DairyNZ Scott Farm, Waikato, has been developed with farmers.
It measures the behaviour, physiology and production of cows under different heat-stress mitigation strategies, with the goal of providing farmers with the information they need to make informed decisions to minimise the effect of heat stress. Strategies being compared include providing shade, using yard misters or sprinklers, and adjusting milking frequency.
At DairyNZ Scott Farm, researchers are comparing a 24-month calving interval with the usual 12 months under a typical Waikato pasture-based system. The farmlet trial began with Friesian cows in ‘23/’24, showing promise for production, management and profitability. In ‘25/’26, Jersey farmlets were added, helping assess likely crossbreed performance.
The extended lactation system calves half the herd each spring, spreading the on-farm workload more evenly across the year and hopefully improving labour productivity.
Fewer calvings and a lower replacement rate mean nearly 60% fewer non-replacement calves, making it easier to rear the remaining animals as dairy-beef.
A study at Scott Farm, which is part of the Cow Quality of Life project, will develop knowledge for assessing cows’ physical and thermal comfort in pasture based dairy systems. Groups of cows will be monitored across the season to understand how everyday conditions – heat, muddy paddocks, or a feed pinch – affect their behaviour.
On-animal sensors (wearables) will track their responses, while also recognising the benefits of grazing systems, such as freedom of movement and natural behaviours like grazing.
The aim is to create a method that can objectively measure and demonstrate the high standards of animal care on New Zealand farms.
At the same time, the tool will provide farmers with feedback to manage risks like heat stress and support cow wellbeing and milk production.
Farmers told us they want clear, independent guidance on how to get the most value from wearable technology.
The next phase of this work will use real farm data to show what typical cow behaviour patterns look like across different farm systems, and how they link to business benchmarks (such as production, reproduction, labour and profit).
The aim is to give farmers practical benchmarks and make it easier to spot opportunities that have the greatest impact.
This article was originally published in Inside Dairy May-July 2026.
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