Average daily gain — ADG — is the single most useful number on a fattening farm. It tells you whether an animal, a pen or a ration is doing its job, long before sale day.
The formula
ADG is the weight gained between two weighings, divided by the number of days between them:
ADG (kg/day) = (later weight − earlier weight) ÷ days between the weighings
Worked example
A steer weighed 335 kg when it arrived on 5 July and 412 kg on 2 October.
| Weight gained | 412 − 335 = 77 kg |
|---|---|
| Days between | 89 days |
| ADG since arrival | 77 ÷ 89 = 0.87 kg/day |
Since arrival vs recent gain
Both numbers matter, and they answer different questions:
- ADG since arrival shows how the animal has done overall — useful for judging a purchase or a lot.
- Recent ADG (between the last two weighings) shows how it is doing now. A drop here is the early warning you want: illness, a ration change, bullying in the pen or heat stress.
Weigh consistently
Gut fill can change an animal's weight by several percent within a day, which can swamp a week's real gain. To keep ADG honest:
- Weigh at the same time of day, ideally before the morning feed.
- Leave at least two to four weeks between weighings — short gaps exaggerate noise.
- Expect the first weeks after purchase to look odd: animals often lose weight in transport and then regain it quickly.
- Use the same method each time. If you sometimes use a tape, see estimating weight with a tape.
Set a minimum-gain line
Rather than eyeballing a list of numbers, draw a line: the weight an animal should have reached if it gained at least your minimum each day.
Minimum-gain line on a date = arrival weight + (minimum daily gain × days since arrival)
Any animal whose latest weight sits below its line deserves a closer look. The right minimum depends on species, breed, age, sex and ration — set it from your own records, and ask your vet or nutritionist for local guidance.
In FarmoraX
Each animal's growth chart shows its weights, its minimum-gain line and its target weight. Minimums can be set per animal, group, label or animal type, and animals whose latest weight falls below the line (after their first two weeks) are flagged as Below threshold.
Turn gain into money
ADG on its own doesn't say whether gain was profitable. Pair it with feed cost:
Feed cost per kg gained = feed cost over the period ÷ kg gained over the period
A pen gaining a little less on a much cheaper ration can be the better business. See costing a fattening animal for the full picture.