Farm Feed Budget Calculator NZ
A feed budget puts what the farm will grow against what the stock will eat over the same period, and tells you which way the gap runs and how big it is. This does that in kilograms of dry matter, adds whatever is in the stack or the shed, and prices the shortfall if there is one. The whole value of the exercise is lead time. A budget run in autumn for the coming winter leaves room to buy feed while it is available, to sell stock while the market is still there, or to book grazing before everyone else does. The same budget run in the middle of a deficit tells you exactly how bad things are and gives you almost no options, which is why the period is something you set rather than something fixed. No pasture growth rate is supplied here, and that is not an omission. Growth varies enormously with region, soil, season and fertility, and a national average would be wrong nearly everywhere it was used. Your own figure from the same time last year is worth far more than any published one, and if you have no measurement at all, running the budget two or three times across a range of plausible growth rates will tell you more than a single confident guess.
At 80 percent utilisation, 58,320 kg DM of what this farm grows over the period never reaches an animal. Pasture grown and pasture eaten are different numbers. Utilisation is applied here, because the feed trampled or fouled was grown and not eaten.
How it works
Pasture grown is the effective area multiplied by the daily growth rate and the days. Applying utilisation converts that into pasture actually eaten, which is the figure that matters, since feed trampled, fouled or left behind was grown but never fed anything. Demand is the stock units multiplied by their daily intake and the days. Feed in store is added to the supply side. The balance is supply less demand, and the days covered figure divides the total supply by the daily demand, which answers the more practical question of how far the feed goes rather than how much is missing.
Utilisation is where budgets quietly go wrong
Growth rates are usually quoted as kilograms of dry matter grown, and stock eat a good deal less than that. The difference is trampling, fouling, and residual left behind, and at 80 percent utilisation a fifth of everything the farm grows never reaches an animal. A budget that compares grown pasture with eaten demand is therefore comparing two different things and will read about 20 percent more comfortable than the farm actually is, which is exactly the error you do not want in a winter budget. Applying utilisation on the supply side is what keeps both halves in the same units.
Worked example
A 180 hectare farm growing 18 kilograms of dry matter a hectare a day over 90 days grows 291,600 kilograms, and at 80 percent utilisation 233,280 kilograms of that is actually eaten. With 60,000 kilograms already in store the supply is 293,280 kilograms. Against 1,900 stock units eating 1.4 kilograms a day for 90 days, demand is 239,400 kilograms, so the farm is 53,880 kilograms of dry matter in surplus and the feed covers 110 days rather than the 90 budgeted. Had utilisation been 60 percent rather than 80, the same farm would be 4,440 kilograms short instead, which is the whole argument for getting that figure right.
Related calculators
- Stock Units: converting the mob into stock units first.
- Silage Stack Yield: what is actually in the stack.
- Winter Hay and Baleage: filling the gap in bales.
- Hay Bale Weight: what bought feed is really costing.