Calculating Your Hay Needs: How Much Hay Do Your Animals Really Need?

Determining your exact hay requirements prevents costly overstocking or dangerous shortages. This comprehensive guide provides precise calculation methods for all livestock types, complete with real-world examples and adjustment factors. calculating hay needs

Daily Hay Consumption Formulas. calculating hay needs.

Basic Calculation Method

(Animal Weight × Percentage of Body Weight) ÷ Dry Matter Content = Daily Hay Need

Variables:

• Percentage of Body Weight: 1.5-3% (average 2%)
• Dry Matter Content: 85-90% for properly cured hay

Species-Specific Intake Guidelines

Animal Type	% Body Weight (Daily)	Dry Matter Intake	Notes
Mature Horses	1.5-2.5%	15-20 lbs	More for hard keepers
Dairy Cows	2.5-3.5%	25-35 lbs	High lactation increases
Beef Cattle	2-3%	20-30 lbs	Winter feeding higher
Sheep/Goats	2-3%	4-6 lbs	Adjust for pregnancy
Alpacas/Llamas	1.5-2.5%	3-5 lbs	Finicky eaters

Source: National Research Council Nutrient Requirements

Step-by-Step Calculation Process. Calculating hay needs

1. Determine Animal Units

Convert all livestock to Animal Unit Equivalents (AUE):

• 1 AUE = 1,000 lb cow
• Horse = 1.2 AUE
• Sheep/Goat = 0.2 AUE
• Alpaca = 0.15 AUE

2. Calculate Daily Needs

Example: 1,200 lb horse at 2% intake
(1,200 × 0.02) ÷ 0.9 = 26.7 lbs/day DM

3. Adjust for Storage Loss

Multiply by 1.1-1.4 depending on storage method:

• Barn stored: 10% loss factor
• Covered outside: 25%
• Unprotected: 40%

4. Annual Requirement

(Daily Need × Days Fed) × Loss Factor = Annual Hay Needed

Feeding Scenario Examples. calculation Hay needs

Small Horse Farm (3 Horses)

• 1,200 lb horses
• 180 feeding days/year
• Barn storage

(26.7 lbs × 180) × 1.1 = 5,286 lbs/horse
Total: ~8 tons (16 standard small squares)

50-Head Beef Herd

• 1,400 lb cows
• 120 winter feeding days
• Covered outside storage

(28 lbs × 120) × 1.25 = 4,200 lbs/cow
Total: ~105 tons (210 large round bales)

Special Considerations

Life Stage Adjustments

Condition	Intake Increase	Duration
Late Gestation	+15-20%	Last 3 months
Lactation	+25-40%	Until weaning
Growth	+20-30%	First 2 years
Cold Stress	+1%/°F below 30°F	Winter months

Hay Quality Factors

• RFV >130: Reduce amount 10-15%
• RFV <90: Increase 20-25%
• Moldy Hay: Increase waste factor 50%

Tools for Precise Calculations

1. Digital Hay Calculators

• University of Minnesota Hay Calculator
• NRCS Feed Needs Calculator

2. Mobile Apps

• HayNow (iOS/Android)
• FeedCost by Auburn University

3. Spreadsheet Templates

• Penn State Dairy Spreadsheets
• Beef Cattle Research Council Tools

Common Calculation Mistakes. Calculating Hay Needs

1. Ignoring moisture content (always use dry matter basis)
2. Underestimating storage losses
3. Forgetting weather impacts (cold increases needs)
4. Overlooking body condition changes
5. Assuming consistent bale weights

Hay Budgeting Worksheet

Step 1: List all animals with weights
Step 2: Calculate daily DM needs
Step 3: Determine feeding period
Step 4: Add loss factors
Step 5: Convert to bale counts

Regional Considerations

Northern Climates

• 210+ feeding days
• Add 30% for snow cover
• Consider heated waterers

Southern Climates

• 90-120 feeding days
• Watch for rain damage
• Higher spoilage risk

When to Recalculate Needs

1. Herd size changes ±10%
2. New hay test results
3. Extreme weather events
4. Change in animal condition
5. Storage method changes

Emergency Planning

Minimum Safe Stockpile:

• 30 days extra for small farms
• 15 days extra for large operations
• 5% contingency for disasters

“Better to have hay left over than animals going hungry.” – Old Rancher’s Adage

Need personalized help? Contact our nutritionists at Contact Us for a free hay needs assessment.