Case Studies
Rob and Cherrie Chubb: Balancing productivity and environmental responsibility
Over the last 24 years, Rob and Cherrie Chubb have developed a simple, highly efficient pasture-based system in Golden Bay, guided by a commitment to improving their herd and reducing their environmental footprint a little more each year. The Chubbs milk 142 crossbred cows on a 52.9ha irrigated dairy platform, supported by a nearby 34ha run-off block used for young stock grazing, wintering and supplementary feed production.
In the season ending May 2025, the herd produced an impressive 482 kg of milksolids per cow, while consuming just 326 kg of imported supplement per cow.
Alongside their achievements in milk production, the Chubbs have made targeted changes to reduce nitrogen losses and improve environmental outcomes across the farm. Despite already operating at a relatively low nitrogen loss of 66 kg N/ha in the monitored baseline year (2017), they have since reduced whole-farm nitrogen loss by a further 8% to 61 kg N/ha. Impressively, this improvement sits alongside a 5% increase in milk production, rising from 65,396 kg of milksolids to 68,827 kg, and while maintaining the same irrigated footprint across the dairy platform.
Nitrogen surplus indicators have also declined substantially over the same period, reducing overall nitrogen pressure within the farming system. Overseer modelling showed a reduction in nitrogen surplus from 164 to 138 kg N/ha, while DairyNZ nitrogen surplus fell by 25% from 61 to 46 kg N/ha.
Several management changes have contributed to Rob and Cherrie’s progress. Historically, nitrogen fertiliser was applied at a higher rate using granular products contributing to a higher overall nitrogen input within the system. The Chubbs have since reduced application rates from 107 to 89 kg N/ha, they have shifted to liquid nitrogen and are applying smaller amounts more precisely to ease overall nitrogen pressure. Winter cropping has also been removed from the system entirely, with cows instead fed pasture, hay and baled silage during winter periods.
The Chubbs are also taking a closer look at nutrient cycling within their effluent system. Effluent is now being tested to better understand its nutrient value, and plans are underway to expand the effluent application area. By spreading nutrients over a larger area, they aim to further improve nutrient utilisation and reduce concentrated nitrogen losses.
Despite operating on a fully irrigated platform, where irrigation remains a key pathway for nitrogen movement through the soil profile, the farm has successfully reduced nitrogen losses through better management of nutrient inputs and improved system efficiency.
These environmental improvements have not come from dramatic system change, but from Rob and Cherrie’s practical decision-making that has strengthened both their farm’s performance and nitrogen footprint over time.
Together, Rob and Cherrie have built a highly efficient system that maximises feed and converts it into milk production. At the centre of this is a close alignment between pasture management and herd breeding, with each area reinforcing the other.
Rob takes a disciplined approach to pasture management, with daily attention to maintaining pasture quality and achieving optimal post-grazing residuals throughout the season. Cows are allocated generous quantities of high-quality pasture, while pre-mowing, topping and timely harvesting of surpluses ensure feed quality is maintained and grazing flexibility is maximised. The result is excellent pasture utilisation and a reduced reliance on imported feed inputs.
Complementing this, Cherrie is passionate about building a consistent, high-performing crossbred herd. Every mating decision is carefully considered and implemented using a selected team of CRV bulls, with emphasis on fertility, capacity, temperament and production. This long-term breeding focus supports the system by ensuring cows are well suited to converting high-quality pasture into sustained production.
Their story is a powerful example of farmers driving meaningful change through a genuine commitment to doing the best they can for both their business and the land they farm on.
