This calculator helps estimate daily feed requirements based on horse weight, activity level, and forage quality. It's a guide and should be used in conjunction with professional veterinary advice.
Maintenance (Light work, pasture)
Moderate Work (Riding 3-5 times/week)
Heavy Work (Intense training, competition)
Very Heavy Work (Endurance, racing)
Typical values range from 45% (poor) to 60% (excellent). Consult hay analysis for accuracy.
Your results will appear here.
Understanding Equine Nutrition Calculations
Proper nutrition is the cornerstone of equine health, performance, and longevity. The daily dietary needs of a horse are influenced by several factors, including its body weight, workload, and the nutritional content of its feed, especially forage. This calculator provides an estimate for a horse's daily feed requirement in kilograms, focusing on total digestible nutrients (TDN) and energy needs.
The Math Behind the Calculator:
The calculation is based on established equine nutrition principles:
Digestible Energy (DE) Requirement: A horse's basic energy requirement for maintenance (at rest) is approximately 16.7 Mcal/day per 1000 lbs of body weight (or ~33 Mcal/kg). This value is then adjusted for activity level. The formula used here simplifies this by directly multiplying the horse's weight in kg by a factor representing energy needs per kg of body weight. A typical starting point for maintenance might be around 20-25 Mcal/day for a 500kg horse, and this increases with work.
Forage as a Primary Source: Forages (hay, pasture) are the most natural and economical source of nutrients for horses. The calculator estimates the amount of TDN provided by forage based on its quality. A common guideline is that a horse should consume 1.5% to 2.5% of its body weight in dry matter forage daily.
TDN from Forage: The digestible energy content of forage is often expressed as a percentage of Total Digestible Nutrients (TDN). A higher percentage of TDN in forage means it's more energy-dense. For example, if forage is 50% TDN, then 1 kg of that forage provides 0.5 kg of TDN.
Calculation Logic:
Calculate Base Energy Needs: The calculator uses a simplified multiplier for activity level applied to body weight to estimate total daily energy needs in Mcal. (Note: For simplicity in this calculator, we are not explicitly calculating Mcal but rather estimating TDN needs as a proxy, which is common in practical feeding recommendations.) A more accurate method would involve specific Mcal requirements.
Estimate TDN Requirement: Often, DE requirements are directly related to TDN. A common guideline is that a horse needs approximately 0.8 to 1.0 kg of TDN per 100 kg of body weight for maintenance, increasing with work. This calculator uses a similar approach, estimating TDN requirements based on weight and activity.
Calculate TDN from Forage: The amount of TDN supplied by forage is calculated as: (Forage Intake in kg) * (Forage Quality % TDN / 100)
Estimate Total Feed (Dry Matter): The calculator aims to provide an estimated total dry matter intake. A common starting point is that a horse consumes 1.5% to 2.5% of its body weight in dry matter per day. The calculator uses the activity level multiplier to influence this percentage range.
How to Use This Calculator:
Horse Weight: Enter your horse's weight in kilograms. If you don't know the exact weight, use a weight tape or estimate based on breed and condition.
Activity Level: Select the option that best describes your horse's typical daily workload.
Forage Quality: Enter the percentage of digestible energy (TDN) in your horse's primary forage (hay or pasture). If unsure, use an average of 50% and adjust based on your horse's condition and energy levels. For precise feeding, a hay analysis is recommended.
Calculate: Click the button to get an estimated daily feed requirement in kilograms of dry matter.
Important Considerations:
This is an estimate: Individual horses have unique metabolic rates and needs. Monitor your horse's body condition, energy level, and overall health.
Concentrates: This calculator focuses on the total dry matter intake, often met by forage. If your horse requires additional energy or nutrients beyond forage, concentrates (grains, supplements) will be needed. The amount and type of concentrate should be determined based on the forage analysis and the horse's specific needs.
Water: Always ensure free access to clean, fresh water.
Veterinary & Nutritionist Advice: Always consult with a veterinarian or a qualified equine nutritionist for personalized feeding plans, especially for horses with health issues, breeding stock, or elite athletes.
function calculateFeed() {
var horseWeightKg = parseFloat(document.getElementById("horseWeightKg").value);
var activityLevel = parseFloat(document.getElementById("activityLevel").value);
var forageQuality = parseFloat(document.getElementById("forageQuality").value);
var resultDiv = document.getElementById("result");
// Clear previous results and error messages
resultDiv.innerHTML = 'Your results will appear here.';
// Input validation
if (isNaN(horseWeightKg) || horseWeightKg <= 0) {
resultDiv.innerHTML = 'Please enter a valid horse weight in kg.';
return;
}
if (isNaN(forageQuality) || forageQuality 100) {
resultDiv.innerHTML = 'Please enter a valid forage quality percentage (1-100).';
return;
}
// — Calculation Logic —
// Simplified model: Estimate Dry Matter Intake (DMI) as a percentage of body weight, adjusted by activity level.
// Typical DMI is 1.5-2.5% of body weight for maintenance. We'll use the activity level to adjust this range.
var minDMI_percentage = 1.5;
var maxDMI_percentage = 2.5;
// Adjust DMI percentage based on activity level
var adjustedMaxDMI_percentage = maxDMI_percentage * activityLevel;
// Cap the adjusted percentage to avoid unrealistic values (e.g., > 3.5%)
if (adjustedMaxDMI_percentage > 3.5) adjustedMaxDMI_percentage = 3.5;
var estimatedMaxDMI_kg = horseWeightKg * (adjustedMaxDMI_percentage / 100);
var estimatedMinDMI_kg = horseWeightKg * (minDMI_percentage / 100); // Using a base min for comparison
// Further refinement to estimate if forage alone can meet needs or if concentrates are likely required.
// A common heuristic: a horse needs roughly 0.8-1.0 kg TDN per 100 kg body weight for maintenance.
// This increases with work. Let's use a simplified TDN target.
var baseTDN_per_kg_BW = 0.008; // kg TDN per kg body weight for maintenance
var targetTDN_kg = horseWeightKg * baseTDN_per_kg_BW * activityLevel;
// Estimate TDN provided by the maximum estimated forage intake
var estimatedTDN_from_max_forage = estimatedMaxDMI_kg * (forageQuality / 100);
var resultMessage = "";
if (estimatedTDN_from_max_forage >= targetTDN_kg) {
// Forage alone *might* be sufficient, but need to check minimum intake
if (estimatedMaxDMI_kg >= (horseWeightKg * 0.015)) { // Ensure at least 1.5% DMI
resultMessage = "Estimated Daily Dry Matter Intake: " + estimatedMinDMI_kg.toFixed(2) + " – " + estimatedMaxDMI_kg.toFixed(2) + " kg. ";
resultMessage += "Forage quality may be sufficient, but monitor condition.";
} else {
resultMessage = "Estimated Daily Dry Matter Intake: " + (horseWeightKg * 0.015).toFixed(2) + " – " + estimatedMaxDMI_kg.toFixed(2) + " kg. ";
resultMessage += "Forage alone may not meet minimum intake requirements. Consider concentrates.";
}
} else {
// Forage is likely insufficient, concentrates are needed
var shortfall_kg_TDN = targetTDN_kg – estimatedTDN_from_max_forage;
resultMessage = "Estimated Daily Dry Matter Intake: " + estimatedMinDMI_kg.toFixed(2) + " – " + estimatedMaxDMI_kg.toFixed(2) + " kg. ";
resultMessage += "Forage alone is likely insufficient. ";
resultMessage += "Consider adding concentrates to meet approximately " + shortfall_kg_TDN.toFixed(2) + " kg TDN deficit.";
}
resultDiv.innerHTML = " + resultMessage + ";
}