FCR in pig farming: how to calculate feed conversion and where the losses hide
What feed conversion ratio (FCR) is, the formula, typical values for nursery and finishing pigs, and five places where a pig complex loses feed without noticing.
FriendFarms team2 min read
Feed conversion ratio (FCR) is the kilograms of feed a pig eats to gain one kilogram of live weight. An FCR of 2.6 means 2.6 kg of compound feed for every kilogram of gain. Lower is better, and because feed is 60–70% of the cost of producing a pig, every 0.1 of FCR is real money.
The formula
FCR = feed consumed (kg) ÷ live-weight gain (kg)
Live-weight gain is the closing weight minus the opening weight of the group, plus the weight of animals that died or were culled during the period. Leaving out dead and culled pigs shrinks the gain while the feed they ate stays in, so the report shows a worse FCR than the farm really achieves — and hides where the feed actually went.
Typical values
| Stage | Weight range | Typical FCR |
|---|---|---|
| Nursery | 7–30 kg | 1.4–1.7 |
| Growing | 30–60 kg | 2.2–2.5 |
| Finishing | 60–115 kg | 2.7–3.1 |
| Whole-herd (sow + progeny) | — | 2.8–3.2 |
The numbers depend on genetics, diet and climate; use them as a sanity check, not as a target.
Where feed disappears
- Silo and bin reconciliation. Deliveries are logged in tonnes from the mill, consumption is estimated per barn. If nobody reconciles the two weekly, a 3–4% drift lives unnoticed for a month.
- Feeder adjustment. Feeders opened too wide spill feed into the slats. It shows up as worse FCR in one pen while the neighbours look fine.
- Wrong diet phase. Keeping pigs on the grower diet a week too long, or switching too early, costs both feed and gain.
- Unrecorded mortality. A dead pig that is not in the system still “ate” the feed — the gain disappears from the denominator.
- Monthly instead of daily data. A monthly report tells you about a problem four weeks after it started.
How FriendFarms calculates it
FriendFarms records feed write-offs and every batch weighing, including from the offline barn terminal. Average daily gain is stored with each weighing, FCR is calculated per batch on the performance page and exported in the monthly FCR report, and batches whose feed phase lags behind their age and weight are flagged on the feeding screen.
Key takeaway: measure FCR per pen, include dead and culled animals in the gain, and reconcile silos weekly. The biggest saving usually comes not from a new diet but from noticing a drift in days instead of months.