Feed Cost per Unit of Gain

Cost of gain is the feed bill divided by the weight it produced, and it is the number that answers the question every feeder faces daily: sell this animal now, or feed it another month? The comparison is simple once the figure exists. If the next kilogram of gain costs $2.20 in feed and the market pays $2.60 for a kilogram of liveweight, feeding continues to pay. When those two cross, it stops — regardless of how much room the animal has left to grow.

What this page calculates is the FEED cost of gain, which is not the cost of gain. Yardage, labour, bedding, veterinary and medicine, interest on the money tied up in the animal, death loss and depreciation on the facility are all real and all absent from this division. Together they commonly add a third again to the feed figure, and they are dominated by time rather than by weight — which is why a ration that gains faster can be cheaper overall even at a higher feed cost per kilogram, since it spreads fewer days of fixed cost over the same gain. Compare a feed cost of gain only against another feed cost of gain, and never against a full cost of gain from somebody else's spreadsheet.

Cost of gain rises as an animal finishes, for the same reason conversion worsens: late gain is fat, fat is energetically expensive, and maintenance takes a larger fixed bite as body weight climbs. The marginal cost of the last twenty kilograms can be well above the average across the whole feeding period, and averages are what hide the moment the animal stopped paying its way. Anyone making a sell-or-feed decision wants the marginal figure, computed over the last weighing interval, not the figure for the pen since arrival.

Two errors recur in the inputs. Feed valued at book price rather than what it would actually fetch understates the cost of home-grown feed — grain fed to cattle has an opportunity cost equal to what it could have been sold for, and ignoring that quietly transfers profit from the cropping enterprise to the feeding one. And the gain has to be liveweight against liveweight or carcass against carcass; a cost per kilogram of carcass gain looks about 40% worse than the same performance measured live, and the two are quoted interchangeably far more often than they should be.