MID dairy farms are now facing ever increasing fertiliser costs, with urea now over $3.00 per kg of element N. Whether synthetic N sources can be used profitably depends on both the nitrogen’s productivity, and on the productivity (as it is converted to milk) of the grass it might grow.
At the MDF, the report table of figures shows the Pasture growing spend and pasture price fluctuating between this year and the same time last year as the N price rises and the application rate decreases (100 kg last year to 80 kg this year). There are multiple factors feeding into the grass price (for example no irrigation water is in the cost of the grass this year) making it difficult to use these indicators to judge whether any change of nitrogen input is more profitable or not.
However, we can see a positive change in feed margin when comparing this year to last year in response to changes in a wide variety of input factors.
For MID farms, N sources such as urea are worryingly expensive, and a common question will be: do I cut down my application?
Some key factors to consider when making fertiliser decisions is the production response of the pasture to a unit of N, and the production response of the cow per unit of grass. This will be highly individual on a farm to farm basis.
-The productive response to N (additional grass due to the N alone) is very variable and dependent on all other grass growing inputs and grazing management. (e.g. N is lost if the soil is too wet, or too dry; if grazing occurs at 1.5 leaves; if grazed down to 2 cm; if weedy grasses are present; if not enough P and K is available, etc, etc).
It is not easy to know where any level of input is on the productive response curve, but a look in the paddock might help work it out for nitrogen. To work out pasture N response, if 1 kg of N applied per hectare per day resulted in a grass offer, after a 30-day grazing rest, of 1,400 kg DM per ha, compared to 950 kg DM per ha with no N, a 15 kg response to N has occurred.
Running the numbers on your grass response will help you determine whether a productive response is possible from fertiliser application- a 20 kg plus productivity response is possible, just as a zero response is.
-Once we know a rough kg grass response to kg N response, we can work out the extra cost of the grass. For example, at current prices (N at $3.48 per kg of element) and assuming a 15 kg DM grass per kg of N response, the cost of the extra grass is $232 per tonne. We expect grass to be only $50 per tonne so $232 seems unprofitable at this stage of the calculations.
– However, the productive response of milk to a tonne of feed is variable, and dependent on many management factors. It can range from zero to 160 kg milk solids per tonne of feed. Assuming a 110 kg milk response, and a milk price of $7.00 per kg MS, the $232 priced grass would result in $770 worth of milk, i.e. a profitable margin.
Grass based dairying is a complex game. It is best not to follow simple rules of thumb, but think about productive responses to inputs, then apply the input and output prices.
When input prices rise you may be able to cope by getting a productivity increase from that input, and maintain the margin, or maybe you are at peak productivity for that input and will need to make adjustments. It sll depends on your numbers.
| FEED MARGIN PERFORMANCE | MDF THIS TIME LAST YEAR | MDF TEN DAYS AGO | MDF THIS TEN DAYS | Units |
| Ten days to date: | 20-Nov-20 | 10-Nov-21 | 20-Nov-21 | |
| Milker graze area | 71 | 65 | 68 | Ha |
| Milkers | 295 | 295 | 295 | Head |
| Stocking rate | 4.2 | 4.5 | 4.3 | cows/ha |
| Average graze rest time | 30 | 30 | 30 | Days |
| Estm’d pasture consmp’n | 49 | 49 | 47 | kg DM/ha/day |
| Pasture consum’d per cow | 11.8 | 10.8 | 10.8 | kg DM/cow/day |
| Pasture growing spend | $3.85 | $3.02 | $3.02 | $/ha/day |
| Estm’d pasture price | $78 | $62 | $64 | $/T DM |
| Conc (incl additives)supp fed/cow | 6.3 | 5.9 | 5.9 | kg DM/cow/day |
| Conc (incl additives)supp avg price | $353 | $447 | $447 | $/T DM |
| Hay/silage supp fed/cow | 0.0 | 0.0 | 0.0 | kg DM/cow/day |
| Hay/silage supp price | $/T DM | |||
| Feed Conversion Efficiency | 112 | 111 | 114 | kg MS/tonne DM |
| Total feed intake/cow | 18.0 | 16.5 | 16.5 | kg DM/cow/day |
| NDF Fibre in diet | 32.9% | 31.4% | 31.4% | % NDF |
| Litres/cow | 27.3 | 25.8 | 25.6 | l/cow/day |
| Fat test | 4.21% | 3.83% | 4.03% | % |
| Protein test | 3.24% | 3.33% | 3.37% | % |
| Milk Solids per cow | 2.03 | 1.85 | 1.90 | kg/cow/day |
| Milk price (less levies)/kg MS | $5.80 | $6.55 | $6.53 | $/kg MS |
| Milk price (less levies)/litre | $0.43 | $0.47 | $0.48 | $ per litre |
| Milk income/cow | $11.77 | $12.09 | $12.39 | $/cow/day |
| All feed cost/cow | $3.15 | $3.28 | $3.31 | $/cow/day |
| Margin over all Feed/cow | $8.62 | $8.81 | $9.08 | $/cow/day |
| MOAF /ha /day | $35.82 | $40.00 | $39.37 | $/ha/day |
| Farm MOAF per DAY | $2,543 | $2,600 | $2,677 | $/day |