Earlier in 2024, DAFM announced proposed animal organic nitrogen excretion changes as outlined to the Agriculture Water Quality Working Group in December 2023. In light of these changes, ICBF has launched a new Nitrates Calculator that HerdPlus farmers and their agricultural advisers can use. The Calculator factors in the new animal excretion changes. It will assist all livestock farmers (both derogation and non-derogation) and their farm advisers in ensuring farm holdings are within organic nitrogen stocking limits (i.e. 170, 220, 250 organic N/hectare).

The proposed excretion changes are currently subject to the appropriate assessment process before the Minister for Housing, Local Government & Heritage. All farmers were alerted to these intended changes in a letter from DAFM earlier this year.
The latest Teagasc research proposes the following:


• Calves aged 0-3 months – 1 kg organic N excreted per animal
• Calves 4-12 months- 20kgs organic N excreted per animal
• Female (1-2 yr. olds)- 55 kgs organic N excreted per animal
• Male (1-2 yr. olds)- 61 kgs organic N excreted per animal
• Cattle 2yr + & Suckler Cows- 65 kgs organic N excreted per animal (no change)
• Dairy Cows – Animal excretion rate dependent on dairy cow banding & crude protein % selected and submitted to DAFM.


The ICBF Nitrates Calculator calculates the organic N per dairy cow based on the latest cow banding submitted via the ICBF banding screen.


The above animal excretion changes are now reflected in the new ICBF Nitrates Calculator, available on the desktop version of HerdPlus online. After logging in, this will be available under the “Applications” menu listed items. Using a laptop/PC or tablet device is preferable for using the new calculator.

How to Use the Calculator

The new calculator allows users to input their projected stock numbers on the farm from now until the end of the year. This will enable an end-of-year organic N & P total to be projected for farm holdings. The nitrates calculator can then project what a farmer’s overall organic N per hectare may be at the end of the year. Farmers and advisers should note livestock ages when entering projected stock numbers on the calculator, particularly when stock may go from one age category to another, i.e. going from 0-1 yr. old to 1-2 yr. old animals.

The calculator can also be changed to propose future stock numbers to ensure farmers are within the 170/220/250 organic N/ha limits by year’s end. If projections on the calculator indicate a farmer going over any of these farm limits, farmers are urged to discuss nitrates compliance options with their agricultural advisers to avoid any potential penalties from DAFM.

One of the new features for farmers is the ability to now add on other types of livestock (ovine or equines) they may have farm which can also now be factored into overall organic N produced on farm.


Farmers are advised to consult with their agricultural advisers as regards their overall requirements for nitrates compliance.

The ‘Farm N Calculator’ function allows users to input their total land hectares. This function will calculate the overall organic N/ha for your farm once stock values have been saved and projected ahead. Farmers and advisers should refer to their latest BISS application for their latest individual farm holding land areas.


Nitrates derogation farmers and advisers are reminded to refer to the published Water Quality Review Implementation Map regarding the area their farm holdings are in, i.e., 250 or 220 organic N/ha land designation, to use the Farm N calculator effectively.

Farmers who are borderline towards their 170/220/250 organic N/ha limits are advised to check their position with their advisers on the ICBF Nitrates Calculator monthly, to avoid any possible breaches of overall stocking limits.

We hope this new application tool will assist our HerdPlus farmers and their farm advisers in meeting nitrates compliance going forward. For queries on how to use the ICBF Nitrates Calculator, please contact the HerdPlus team at 023-8820242 or email [email protected]