From next year, organic nitrogen excretion rates on dairy farms will change. The new regime, called banding, will come into use from January 2023 and will replace the existing one-size-fits-all approach.

The new measure categorises dairy cows into one of three bands based on average milk yield per cow.

  • Band 1: cows producing less than 4,500kg milk annually will be assigned an organic nitrogen of 80kgN/ha/year.
  • Band 2: cows producing between 4,500kg and 6,500kg milk annually will be assigned an organic nitrogen of 92kgN/ha/year.
  • Band 3: cows producing over 6,500kg milk annually will be assigned an organic nitrogen of 106kgN/ha/year.

    • There is 1.03kg of milk in every litre of milk, so herds milking more than 4,370l and less than 6,310l annually will be banded in the 92kg category, while those milking more than 6,310l annually will be under the higher category of 106kgN/ha.

    The amount of organic nitrogen permitted per hectare is 170kg/ha, with a derogation required to go above this up to a maximum of 250kg organic nitrogen per hectare.

    With these new changes, those in the higher producing bands will hit the limit with a lower stocking rate compared to those in the lower yielding bands.

    High-yielding and highly stocked herds are the ones most affected by this measure. If producing more than 6,500kg/cow, the maximum stocking rate with a derogation will be 2.36 cows/ha, down from 2.8 cows/ha currently.

    This means that these farms will need to reduce stock or get extra land in order to maintain existing cow numbers if they breach 2.36 cows/ha.