Feed Efficiency Monitor Calculator

This calculator distills a feeding trial down to the numbers that actually predict profitability: Feed Conversion Ratio (FCR), Residual Feed Intake (RFI), and cost per pound of gain. FCR is the simplest and most commonly quoted metric — total feed consumed divided by total weight gained — and for beef cattle it typically runs 5 to 8, with lower numbers meaning the animal converted feed to muscle more efficiently. RFI digs deeper: it estimates how much feed an animal should eat based on its metabolic body weight (body weight raised to the 0.75 power, an NRC approximation calculated through kilograms and converted back to pounds) and compares that expected intake to what the animal actually consumed. A negative RFI means the animal ate less than predicted for its size and growth — a genuinely more efficient animal, independent of frame size — while a positive RFI flags an animal eating more than its body weight alone would predict.

The calculator also converts feed cost per ton into a cost per pound of gain and rolls up a total feed bill across the whole group, plus reports average daily gain and daily intake for quick trend-spotting. Because RFI depends on body-weight scaling rather than a simple ratio, it's the more useful metric for comparing animals of different sizes within the same test, while FCR remains the industry-standard shorthand. Keep in mind this uses a population-level NRC approximation for expected intake — individual breed, sex, and environmental factors can shift the true expected-intake baseline, so RFI here is a solid estimate, not a lab-calibrated equation.