Low N Sires®



The Pathway, which is being investigated is:
LowN sires pathway


LowN Sires® > reduce Milk Urea Nitogren (MUN)  through breeding.

The LowN Sires® team have a lower breeding value for Milk Urea Nitrogen, compared to the average bull. CRV is participating in research to confirm the impact that this could have on Nitrogen excreted in Urine, with the aim of working to reduce Nitrogen leached (and therefore potentially assisting farmers to reduce their environmental footprint).

Agriculture’s impact on the environment is a major topic world-wide. In New Zealand degradation of waterways is the main concern.

Much of the contamination of waterways is caused by Nitrogen leached from urine patches of cows. Reduction of the concentration of Nitrogen excreted in urine is desirable to reduce this leaching.

CRV has several research and development programmes, both in New Zealand and internationally, aimed at improving farming sustainability.

Investigation into whether breeding can reduce Nitrogen concentration in urine is one of those programmes.










MUN is the concentration of Urea Nitrogen contained in milk.

The daughters of LowN Sires will have lower MUN than the daughters of the average bull

The steps in the pathway being investigated are:
1. Breeding with LowN Sires™ will reduce MUN concentration in their progeny.
2. International research indicates that if MUN is reduced, then the amount of Nitrogen excreted in Urine is reduced.  A recent study by Lincoln University in New Zealand suggests that low MUN cows urinate a lower concentration of urinary nitrogen, and CRV is participating in research to further establish the application of this hypothesis in New Zealand.

3. If the amount of Nitrogen excreted in urine is reduced then the amount of Nitrogen leached would be reduced.

Nitrogen leaching on dairy farms is a problem that predominantly stems from the cow’s urine.
• The amount of Nitrogen in the urine patch is the problem
• If we reduce the amount of Nitrogen hitting the ground by breeding cows that pee less nitrogen, then leaching will be reduced.

DairyNZ is leading a seven-year research programme that aims to breed cattle with a lower nitrate leaching footprint.

This programme aims to 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
  • CRV Ambreed is working with DairyNZ, AgResearch and Fonterra on this.
  • Phase 2 of the research into where the nitrogen goes will study groups of animals genetically different for MUN to understand more precisely the relationship between reducing MUN and reducing nitrogen in urine.
  • Read more about the DairyNZ led research

We’d love to talk. Contact your local field consultant to discuss how LowN Sires® will work for you.