DairyNZ: Newly minted doctors focus on facts

From left, university graduates Laura Rossi, Caleb Higham, Elena Minnée and Mallory Crookenden, who believe modern, science-led farming is the way forward for the dairy sector.

As well as discovering new ways to reduce dairy farming's greenhouse gasses and minimise impacts on waterways, DairyNZ's peer-reviewed research focuses on increasing the productivity of dairy cows, breeding improved animals, and more efficient farming systems.

DairyNZ carries out its own research programmes and collaborates with scientists at universities and crown research institutes including AgResearch and NIWA, and with international organisations.

Laura Rossi, who is a senior research technician at DairyNZ's Waikato research farms, holds a Doctor of Philosophy in Plant Science from Lincoln University.

Her doctoral research examined the interactions between perennial ryegrass and white clover, the dominant species in most Kiwi pastures. The study was part of the research supporting the development of the DairyNZ Forage Value Index that ranks perennial ryegrass cultivars based on their relative economic benefit to pasture-based systems.

"The results have important implications for the breeding industry and the pastoral sector, because they show that ryegrass evaluation systems based on monoculture swards under grazing are a good measure of expected relative cultivar performance," Rossi says.

"My research also quantified the important contribution of white clover to pasture production and pasture nutritive value, and emphasised the significant role that this legume plays in sustainable dairy systems."

Rossi is from Uruguay where her work included advising farmers about crops, pastures, beef, and dairy production. During this time, she developed an interest in organic production, and is keen to see the development of sustainable dairy systems in New Zealand with an emphasis on organics.

Caleb Higham, who is a catchment engagement leader at DairyNZ, holds a Doctor of Philosophy in Environmental Science from Massey University. His role is to ensure farmers are aware of environmental initiatives that support sustainable farming practices and look after the land and waterways. He works directly with farmers and alongside the DairyNZ team advising farmers, as well as with milk firms and regional councils.

Higham's doctoral research was into water usage on dairy farms in New Zealand versus in other countries where farming systems, and aspects such as climate and geography differ. "We now have a New Zealand benchmark to gauge improvements against.

I researched a range of farming regions, and irrigated and non-irrigated farms to develop a water accounting framework that allows accurate measurement of the water used."

Elena Minnée, who is a post-doctoral scientist at DairyNZ, holds a Doctor of Philosophy in Agricultural Science form Lincoln University.

Her research sought to understand how dairy cows digest the different pasture species, and how this could influence nutrient absorption. Data from experiments was used to predict nitrogen excretion from dairy cows fed different diets.

Minnée's work at DairyNZ focuses on exploring dietary options for improving the environmental impact of dairying, including measuring nitrogen excretion and methane emissions from cows fed different diets.

"We're now using models to scale up to the farm level so we can predict the impact on whole farm nitrogen leaching, and on profitability."

Mallory Crookenden, who is also a post-doctoral scientist at DairyNZ, holds a Doctor of Philosophy in Veterinary Science from Massey University. Her research was into immune changes in dairy cows during calving when they are particularly vulnerable to infection.

"My research investigated mechanisms that influence the cow's immune system at calving so we can work on reducing the risk of disease and improve animal health and well-being."

At DairyNZ Crookenden's role involves using molecular biology and immunology to answer questions relating to animal health and wellbeing, reproductive success, and breeding cows that produce less nitrogen.

Dairy farmers contribute $14 million annually to support DairyNZ's research programmes.