Feed Conversion Ratio Explained
Feed conversion ratio tells you how many kilograms of feed an animal needs for each kilogram of live weight gained. It is one of the most useful efficiency numbers in a feedlot — and one of the first to suffer when ration quality, health or heat stress slips.
What is feed conversion ratio in a feedlot?
Feed conversion ratio (FCR) is total feed eaten divided by live weight gained. A steer that eats 1,400 kg and gains 280 kg has an FCR of 5.0 — lower is better. Typical finishing cattle on maize-based rations often land between 5.5 and 7.5. Model FCR in the feedlot calculator when planning batch margin.
What feed conversion ratio measures
Feed conversion ratio is total feed eaten divided by weight gained over the same period. If a steer eats 1 400 kg of feed and gains 280 kg, feed conversion ratio is 5.0 (1 400 ÷ 280).
A lower feed conversion ratio generally means better efficiency: less feed per kilogram of gain. A higher figure means more feed is required for the same growth — which pushes up cost per kilogram gained unless feed is very cheap.
Typical ranges for finishing cattle
There is no single correct number for every farm. Breed, starting weight, ration energy, pen conditions and health all play a role. Many South African finishing systems aim for feed conversion ratio somewhere between about 5.5 and 7.5 on as-fed basis for maize-based rations, with better numbers on well-managed batches and weaker numbers when animals are sick, heat-stressed or on very roughage-heavy diets.
Use your own past close-out records where possible. A neighbour’s average on a different ration is only a rough guide.
How it links to profit
Feed is usually the largest variable cost in a feedlot. When maize or concentrate price rises, a poor feed conversion ratio hurts twice: you buy more tons and you pay more per ton. Improving average daily gain without blowing out feed conversion ratio is the balance good feedlot managers work on with their nutritionist.
When planning a batch, estimate feed conversion ratio conservatively. If actual performance beats the plan, margin improves. If you plan too optimistically, the batch can still lose money at a decent selling price.
What can improve feed conversion ratio
- Consistent ration mixing and adequate trough space
- Good water supply and shade in hot months
- Timely treatment of sick animals and solid vaccination programmes
- Matching ration energy to animal weight and avoiding sudden ration changes
- Buying healthy weaners with known starting weights
Quick comparison
Two batches gain 250 kg per animal. Batch X uses feed conversion ratio 6.0 (1 500 kg feed). Batch Y uses 7.2 (1 800 kg feed). At R4 800 per ton feed, Batch Y spends about R1 440 more on feed per animal before any other costs. That difference alone can decide whether the batch is worth doing.
Frequently asked questions
How do you calculate feed conversion ratio?
Divide total feed eaten by weight gained over the same period. If an animal eats 1,500 kg and gains 250 kg, feed conversion ratio is 6.0.
What is a good feed conversion ratio for finishing cattle?
There is no single target — breed, ration and health all matter. Many South African finishing systems see 5.5 to 7.5 on an as-fed basis; use your own close-out records as the best guide.
Does a lower feed conversion ratio always mean more profit?
Usually, because less feed is needed per kilogram gained. But if cheap feed produces poor carcass grade or slow average daily gain, margin can still suffer.
What causes poor feed conversion ratio in feedlots?
Heat stress, respiratory disease, inconsistent ration mixing, sudden ration changes, overcrowding and starting with sick or lightweight weaners are common causes.
These guides and calculators are planning tools only. Check results against your farm records, feed labels, supplier prices and professional advice from your nutritionist, veterinarian or financial adviser where needed.