1. What is Relative Feed Value?

The Relative Feed Value (RFV) is an index used to compare the quality of forages for horses. It combines measures of digestibility (DDM) and intake potential (DMI) into a single value that predicts how well an animal will perform on a particular forage.

2. How Does the Calculator Work?

The calculator uses the RFV equation:

Where:

• \( DDM \) — Digestible dry matter (%)
• \( DMI \) — Dry matter intake (% of body weight)
• 1.29 — Adjustment factor based on standard values

Explanation: Higher RFV values indicate higher quality forage that will support better animal performance.

3. Importance of RFV Calculation

Details: RFV helps horse owners and nutritionists select appropriate forages, balance rations, and predict animal performance. It's particularly useful when comparing different hay types or cuttings.

4. Using the Calculator

Tips: Enter DDM as a percentage (typically 40-80%) and DMI as percentage of body weight (typically 1-3% for horses). Both values must be greater than zero.

5. Frequently Asked Questions (FAQ)

Q1: What is a good RFV for horses?
A: For mature horses at maintenance, RFV >100 is good. Performance horses may need RFV >120. Values below 80 indicate poor quality forage.

Q2: How is DDM determined?
A: DDM is typically measured in a lab through digestibility trials or estimated from fiber analysis (ADF content).

Q3: Does RFV account for protein content?
A: No, RFV only considers energy availability. Crude protein should be evaluated separately when balancing rations.

Q4: Can RFV be used for all forages?
A: RFV works best for legume and grass hays. It's less accurate for silages or very immature forages.

Q5: How often should forage be tested?
A: Test each new cutting or batch of hay, as quality can vary significantly between fields and harvest times.