This programme will help farmers meet environmental targets by

• Identifying dairy cows with urinary N excretion characteristics that reduce the risk of nitrate leaching
• Determining the genetic basis of those characteristics and the scope for selecting sires that produce 'low N' daughters and
• Developing the breeding and management strategies required to implement 'low N' cows in farm systems

The programme is using high-tech urinary sensors, developed by AgResearch, to directly measure the timing, nitrogen content and volume of every urination event of individual cows over four-day trials.

At the same time, researchers are genotyping (DNA fingerprint) the cows and measuring the nitrogen content of their milk and blood, how much feed they consume, and the nitrogen content of that feed. The relationships between all these factors are being explored to find the best trait for breeders to select. Ideally this trait will be

• easy to measure
• under strong genetic control
• directly linked to farm level leaching and
• have no negative effects on milk production or other environmentally important traits

The first round of measurement occurred in Autumn 2019 on 354 cows across 5 research herds. This produced some interesting results, but numbers were too low to form any conclusions. A second round has taken place on 150 cows at the Ashley Dene Research and Demonstration Station in Lincoln, with results expected to be available in early 2021.

The project is also conducting an experiment using the metabolism stall facilities at DairyNZ’s Lye Farm to understand the mechanisms behind cows that excrete different amounts of urinary nitrogen. This experiment is underway in Autumn 2020, with results available later in the year.

How the project is funded

• DairyNZ is leading this seven-year, $21 million research partnership
• The government, via MBIE, has allocated $8.4 million to the project; $11.5 million will come from the farmer levy via DairyNZ, and the balance will come from CRV and Fonterra
• Participating scientists come from DairyNZ, AbacusBio, A.L. Rae Centre for Genetics and Animal Breeding (Massey University), AgResearch and Lincoln University

Inside Dairy and Technical Series articles

• Can genetics help reduce nitrogen leaching? (Inside Dairy February 2019)
• Economic values and why they matter (Inside Dairy February 2019)
• Low nitrogen cow research underway (Inside Dairy July 2018)
• Solutions to reduce nitrogen leaching and maintain profit (Inside Dairy July 2018)

Project funded by:

Research partners:

Low N Livestock is a DairyNZ-led collaborative research programme delivering science for better farming and environmental outcomes. The aim is to develop the knowledge and tools required to breed cows with urinary nitrogen excretion characteristics that reduce the risk of nitrogen leaching and to implement genetic and management strategies that reduce nitrogen losses to the environment. The main funders are DairyNZ and the Ministry of Business, Innovation and Employment, with co-funding from CRV-Ambreed and Fonterra.