Calculate Livestock Units (LU) and Organic Nitrogen per Hectare
Total Livestock Units (LU):0.00 LU
Stocking Rate (LU / ha):0.00 LU/ha
Total Organic Nitrogen:0 kg N
Organic Nitrogen per Hectare:0 kg N/ha
How to Calculate Stocking Rate (Teagasc Guidelines)
Understanding your farm's stocking rate is critical for managing grass demand, ensuring animal performance, and maintaining compliance with the Nitrates Directive in Ireland. The Stocking Rate is defined as the number of livestock units (LU) per hectare of land area used for farming.
What is a Livestock Unit (LU)?
A Livestock Unit is a reference unit used to aggregate livestock of different ages and species. Teagasc and the Department of Agriculture, Food and the Marine (DAFM) use specific coefficients to convert animal numbers into LUs. This standardisation allows farmers to calculate the density of stocking regardless of the mix of animals on the farm.
Common Coefficients Used in Calculation
Below are the standard coefficients for Livestock Units and Organic Nitrogen production used in this calculator, based on general DAFM/Teagasc figures:
Animal Type
Livestock Unit (LU)
Organic N (kg/year)
Dairy Cow
1.00
89*
Suckler Cow
0.80
65
Cattle (0-1 yr)
0.40
24
Cattle (1-2 yrs)
0.60
57
Cattle (>2 yrs)
1.00
65
Sheep (Ewe)
0.15
7
*Note: Since 2023, Dairy Cow Nitrogen excretion rates are banded based on milk yield (Band 1: 80kg, Band 2: 92kg, Band 3: 106kg). This calculator uses a standard reference of 89kg for estimation purposes.
The 170kg N/ha Limit
Under the Nitrates Regulations, the general limit for organic nitrogen on a holding is 170 kg N per hectare. If your calculation exceeds this number, you may need to:
Apply for a Nitrates Derogation (allowing up to 220kg or 250kg N/ha depending on location and year).
Export slurry to another holding with lower stocking density.
Rent additional land to increase your farm area divisor.
Reduce livestock numbers.
How the Calculation Works
The calculation involves two main steps:
Calculate Total LU or N: Multiply the number of animals in each category by their respective coefficient.
Divide by Area: Take the total result and divide by the Net Farm Area (hectares).
For example, if you have 40 Hectares and 50 Dairy Cows:
Total N: 50 cows × 89 kg N = 4,450 kg N
N per Hectare: 4,450 / 40 = 111.25 kg N/ha
This farm would be well within the 170kg limit.
function calculateStockingRate() {
// 1. Get Input Values
var area = parseFloat(document.getElementById('farmArea').value);
var dairyCows = parseFloat(document.getElementById('dairyCows').value) || 0;
var sucklerCows = parseFloat(document.getElementById('sucklerCows').value) || 0;
var cattle01 = parseFloat(document.getElementById('cattle01').value) || 0;
var cattle12 = parseFloat(document.getElementById('cattle12').value) || 0;
var cattle2plus = parseFloat(document.getElementById('cattle2plus').value) || 0;
var sheep = parseFloat(document.getElementById('sheep').value) || 0;
// 2. Validation
if (!area || area <= 0) {
alert("Please enter a valid Farm Area greater than 0.");
return;
}
// 3. Define Coefficients (Teagasc/DAFM standards)
// LU Coefficients
var lu_dairy = 1.0;
var lu_suckler = 0.8;
var lu_c01 = 0.4;
var lu_c12 = 0.6;
var lu_c2plus = 1.0;
var lu_sheep = 0.15;
// Organic N Coefficients (kg N per head per year)
var n_dairy = 89; // Using standard average, acknowledging banding exists
var n_suckler = 65;
var n_c01 = 24;
var n_c12 = 57;
var n_c2plus = 65;
var n_sheep = 7;
// 4. Calculate Totals
// Total Livestock Units
var totalLU = (dairyCows * lu_dairy) +
(sucklerCows * lu_suckler) +
(cattle01 * lu_c01) +
(cattle12 * lu_c12) +
(cattle2plus * lu_c2plus) +
(sheep * lu_sheep);
// Total Organic Nitrogen
var totalN = (dairyCows * n_dairy) +
(sucklerCows * n_suckler) +
(cattle01 * n_c01) +
(cattle12 * n_c12) +
(cattle2plus * n_c2plus) +
(sheep * n_sheep);
// 5. Calculate Rates per Hectare
var stockingRateLU = totalLU / area;
var nPerHa = totalN / area;
// 6. Display Results
document.getElementById('results').style.display = 'block';
document.getElementById('totalLU').innerHTML = totalLU.toFixed(2) + " LU";
document.getElementById('stockingRateLU').innerHTML = stockingRateLU.toFixed(2) + " LU/ha";
document.getElementById('totalN').innerHTML = Math.round(totalN).toLocaleString() + " kg N";
document.getElementById('nPerHa').innerHTML = Math.round(nPerHa) + " kg N/ha";
// 7. Compliance Logic
var statusDiv = document.getElementById('complianceStatus');
var limit = 170;
if (nPerHa <= limit) {
statusDiv.className = "status-alert status-safe";
statusDiv.innerHTML = "Compliant: You are below the 170 kg N/ha limit.";
} else {
statusDiv.className = "status-alert status-danger";
statusDiv.innerHTML = "Warning: You exceed the 170 kg N/ha limit. Derogation or action required.";
}
}