Why use this calculator
Average daily gain is the single number that decides whether a feeding program pays. It sets the turnoff date, the weight the mob will hit at sale and, through feed conversion, most of the cost. Producers usually track it loosely, by memory of the last weigh, which hides the two things that matter: how far behind budget the mob actually is, and what each extra kilogram is genuinely costing.
This tool puts the growth path and the cost build up side by side so you can see the point at which feeding another fortnight stops making money. It also converts feed conversion ratio into a daily intake and checks that intake against liveweight, which catches the most common error in a feed budget, an assumed conversion ratio that no animal could physically eat.
How to use it
- Enter the start weight from the scales, curfewing stock the same way you will at the finish weigh so the two numbers are comparable.
- Enter the finish weight, which should be the specification your buyer actually pays on rather than a round number.
- Put in the days between the two weighings, or the planned length of the feeding program if you are budgeting forward.
- Enter a feed conversion ratio from your own records if you have them, since published figures vary widely with ration and animal type.
- Enter the delivered ration price per tonne as fed, including freight and any mixing charge.
- Finally add your other running costs per head per day, covering yard, labour, health treatments, bedding and interest, so the cost of gain is the whole cost rather than just the grain.
What each result means
- Average daily gain
- Kilograms of liveweight added each day across the whole period. This is the number to benchmark a mob or a ration against.
- Total liveweight gain
- The whole gain per head across the period, which is what the feed bill is actually buying you.
- Feed required per head
- Kilograms of ration as fed to deliver that gain, useful for sizing a grain order or a silo.
- Daily feed intake per head
- How much ration each animal must eat every day to hit the target growth rate at your conversion ratio.
- Intake as a share of liveweight
- Daily intake divided by average liveweight. Above roughly three and a half per cent the budget is asking for more than an animal can eat.
- Feed cost per head
- The ration cost of the whole feeding period for one animal, before labour, yard and health costs.
- Other costs per head
- Yard, labour, health, bedding and interest accumulated over the days on feed at your daily rate.
- Total cost of gain per head
- Feed plus running costs for one animal across the program. This is the number to compare with the value added at sale.
- Cost per kilogram of gain
- What each extra kilogram of liveweight costs to put on. Feeding pays only while this sits below the price per kilogram at sale.
- Cost per head per day
- Feed plus other running costs for one animal for one day on the program, the figure to compare against agistment or the cost of selling and buying back.
The formula
Average daily gain, or ADG, equals (finish weight minus start weight) divided by days on feed, in kilograms per day. Total gain is finish weight minus start weight in kilograms. Feed required equals total gain multiplied by the feed conversion ratio, which is kilograms of ration as fed per kilogram of liveweight gain. Daily intake equals ADG multiplied by feed conversion ratio. Feed cost equals feed required divided by 1,000 and multiplied by the ration price per tonne. Total cost of gain equals feed cost plus daily running cost multiplied by days. Cost per kilogram of gain equals total cost divided by total gain.
How this number is used in practice
The decision this number drives is when to stop feeding. Every extra day adds feed and running costs at a known rate, while the value added depends on the liveweight price and on whether extra weight moves the mob into or out of a specification.
Once cost per kilogram of gain rises above the liveweight price you expect, the next kilogram destroys value even though the animal is still getting heavier. In practice this happens gradually, because feed conversion worsens as cattle get heavier and lay down more fat, so the last month of a long program is almost always the most expensive.
Weighing discipline matters more than the arithmetic. Gut fill can move a beast by twenty to thirty kilograms depending on how recently it drank and grazed, which on a hundred day program is the difference between a genuine 1.2 kilograms a day and an apparent 1.5.
Weigh at the same time of day, with the same curfew, and use the same scales. A mob weighed off green feed and then weighed again off a curfew will produce a growth figure nobody should budget on.
Typical ranges are worth carrying in your head. Grain finished cattle commonly run at 1.2 to 1.8 kilograms a day with a feed conversion between six and nine to one as fed. Cattle finishing on good spring pasture do 0.8 to 1.2. Store cattle on dry standing feed may only hold weight.
Lambs typically gain 0.15 to 0.35 kilograms a day at a conversion around four or five to one, and pigs sit at 0.6 to 0.9 kilograms a day at roughly 2.5 to 3.2 to one, which is why pork can be produced on far less grain than beef.
Worked examples
Steers from 280 kg to 520 kg over 200 days at 7:1 on a $420 ration
1.200 kg a day and 1,680 kg of feed per head.
Lambs from 32 kg to 52 kg over 70 days at 4.5:1 on a $480 ration
About 0.286 kg a day and 90 kg of feed per head.
Weaner pigs from 25 kg to 105 kg over 100 days at 2.8:1 on a $520 ration
0.800 kg a day and 224 kg of feed per head.
When people use it
- Setting a turnoff date that lands a mob on specification for a forward contract
- Deciding whether to keep feeding or sell as stores when grain prices move
- Comparing two rations on cost per kilogram of gain rather than on price per tonne
- Budgeting the grain and hay a feeding program will need before you buy it
- Checking a mob against budget at the fortnightly weigh and reacting early
- Benchmarking your own feed conversion against published ranges for the class of stock
Tips
- Weigh under the same curfew every time. Gut fill alone can shift a beast twenty to thirty kilograms and wreck a growth figure.
- Use your own feed conversion ratio wherever possible, because published figures assume rations and animals that may be nothing like yours.
- Expect conversion to worsen as animals get heavier and fatter, so a long program costs more per kilogram at the end than at the start.
- Compare cost per kilogram of gain against the liveweight price, not the carcase price, unless you have adjusted for dressing percentage.
- Check the intake share of liveweight. If the budget needs more than about three and a half per cent, the conversion ratio is wrong.
- Build the induction period into the days on feed. Cattle coming onto grain often lose weight in the first week or two.
- Weigh a consistent draft of the same animals rather than the whole mob if yard time is tight, and keep that draft for the season.
What it assumes, and where it stops being accurate
- Gain is assumed to be linear across the period. Real growth curves dip at induction and flatten as animals finish.
- Feed conversion is treated as constant, which understates the cost of the last few weeks of a long feeding program.
- Feed figures are on an as fed basis. If your ration is quoted as dry matter, adjust the price and the quantity for moisture first.
- Feed wastage, spoilage and refusals are not separated out. Add them to the conversion ratio or to the running cost per day.
- Deaths, pulls and treatments are not modelled, so the cost per head applies to animals that complete the program.
- Prices are whatever you enter. Ration and liveweight prices move through the year and should be re-entered rather than trusted.
Terms used on this page
- ADG
- Average daily gain, the kilograms of liveweight added per day across a period.
- Feed conversion ratio
- Kilograms of feed consumed per kilogram of liveweight gain. Lower is more efficient.
- As fed
- Feed measured at its delivered moisture content, rather than dried down to dry matter.
- Curfew
- A standard period off feed and water before weighing, so gut fill does not distort the result.
- Cost of gain
- Total feed and running cost divided by the kilograms of liveweight added.
Questions people ask
- How is average daily gain calculated?
- Average daily gain is simply the final liveweight minus the starting liveweight, divided by the number of days between the two weighings. A steer that goes from 280 to 520 kilograms in 200 days has gained 240 kilograms, which is 1.2 kilograms a day. The arithmetic is easy, but the weighing discipline behind the two numbers is where accuracy is won or lost.
- What is a realistic daily gain for cattle?
- Grain finished cattle commonly gain 1.2 to 1.8 kilograms a day. Cattle on good spring pasture do 0.8 to 1.2, and stock on dry standing feed may only hold weight. Breed, frame score, health, weather and ration all move the figure, so your own records beat any published average for budgeting.
- What does feed conversion ratio mean?
- Feed conversion ratio is the kilograms of feed needed for each kilogram of liveweight gain, so a lower number is more efficient. As fed, cattle typically sit between six and nine to one, lambs around four to six, and pigs between 2.5 and 3.2. It worsens as animals get heavier because late gain is mostly fat, which is energetically expensive.
- Why does my cost per kilogram of gain look so high?
- Usually because running costs are included and grain alone was being considered before. Feed is typically sixty to eighty per cent of the cost of gain, with yard, labour, health, interest and mortality making up the rest. The whole figure is the one to compare against liveweight price, because all of it is money you spend.
- When should I stop feeding and sell?
- When the cost of the next kilogram of gain exceeds the liveweight price you expect to be paid for it, or when extra weight pushes the mob outside a specification. Because conversion worsens with weight, the marginal cost rises through the program even while the average looks acceptable.
- Should I use dry matter or as fed figures?
- Be consistent. This tool works on an as fed basis, matching how rations are bought and delivered. If your conversion ratio comes from a dry matter trial, convert it by dividing by the dry matter percentage of your ration, otherwise you will underestimate both tonnage and cost.
Use this with
Livestock Weight Gain Calculator answers one part of the question. These pick up where it stops: Livestock Feed Calculator, Stocking Rate Calculator, Hay & Silage Feed Calculator, Cost Per Hectare Calculator and Livestock Gestation Calculator.
Where these figures come from
Figures and rules on this page follow Australian law and ATO guidance.
- Meat & Livestock Australia. Producer research on grazing management, DSE benchmarks and growth paths
- NSW Department of Primary Industries. Primefacts on stocking rates, soil acidity, livestock nutrition and breeding
- Agriculture and Horticulture Development Board, United Kingdom. UK crop and livestock benchmarking, nutrient management and growth data
- ABARES, Australian Bureau of Agricultural and Resource Economics and Sciences. National farm performance, commodity price and production data
Livestock Weight Gain Calculator produces an estimate for general information. It is not financial, tax, medical, legal or engineering advice. read the full disclaimer. Spotted a wrong number? Report it and it gets fixed. The form picks up this calculator and the inputs you used.