Article Summary: Every extra tonne of grass your herd actually eats can add about NZ$300 to net profit, so measure covers weekly, graze ryegrass at the 2½- to 3-leaf stage, match stocking rate to growth, conserve surpluses promptly, and use supplements only when they truly cut cost per kilogram of milk-solids turning more sunlight into margin instead of waste.
Pasture is more than background scenery; it is the primary fuel that keeps a grazing‑based dairy system turning. When you convert a larger share of home‑grown grass into milk, you protect your margin on both sides of the ledger lifting production while holding feed costs in check. This article unpacks why pasture utilisation matters and sets out practical steps you can take to turn more grass into profit.
Pasture as the Economic Engine
On a pasture‑centred farm, most of the milk in the vat starts as sunlight captured by ryegrass and clover. That free solar energy makes grass the lowest‑cost feed in the system, typically a fraction of the price of purchased concentrates or forages on a dry‑matter basis. Every kilogram of dry matter (DM) you harvest on‑farm therefore displaces a kilogram you would otherwise need to buy.
New Zealand data illustrate the point clearly: farms that consistently harvest high dry‑matter yields per hectare spend less on bought‑in feed and achieve healthier operating margins, season after season. Although milk payout and weather swing from year to year, the relative cost advantage of grass remains remarkably stable.
The Value of Each Extra Tonne of Grass
Modelling by DairyNZ, among others, suggests that each additional tonne of pasture DM consumed per hectare adds in the region of NZ $300 to net operating profit. The figure varies slightly with milk price, but the direction is consistent: more grass eaten equals more profit retained.
Why is the gain so large? First, the marginal cost of growing an extra tonne of pasture fertiliser, irrigation, or re‑seeding where required—is usually well below the cost of a tonne of purchased feed. Second, utilising that extra grass often raises milk yield without the overheads linked to handling, storing, and feeding supplements.
Measuring What You Grow and Use
You can only manage what you measure. Weekly farm walks, rising‑plate meters, and modern labour-free satellite‑supported tools (such as Pasture.io) all help you estimate cover and growth rate with great accuracy. Recording these data builds a feed budget that shows supply ahead of demand, giving you time to adjust rotation length or conserve surplus before quality declines.
Equally important is tracking what disappears into cows’ mouths or the silage pit. Many farmers now calculate an annual “pasture eaten per hectare” figure. Averages around 10–12 t DM/ha are common, yet top performers frequently exceed 14 t or more. That benchmark keeps the whole team focused on utilisation rather than production alone.
Grazing Management: Timing, Rotation, and Residuals
Hitting the pasture at the right stage is central to utilisation. A common rule of thumb for perennial ryegrass is to graze at the two‑and‑a‑half to three‑leaf stage. Earlier and you sacrifice yield; later and you compromise quality as dead material builds up. You can use the leaf stage predictor, or calculate your own within our Pasture.io app.
Rotation length should stretch or shrink with growth rate. In spring, rapid growth often allows rotations as short as 18–20 days, while cooler conditions might extend them to 30–35 days. Whatever the season, aim to leave a post‑grazing residual of roughly 1 500 kg DM/ha. That height keeps photosynthetic area intact for rapid regrowth without leaving so much that cows tread valuable grass into the soil.
Balancing Stocking Rate with Feed Supply
Cows cannot eat grass that is not there, and no amount of skill in the paddock can fully offset an imbalance between demand and supply. A practical starting point is to match the herd’s daily intake requirement (in kg DM) to the average daily pasture growth rate across the milking platform.
When growth persistently outstrips demand, the system is under‑stocked. You can lift milksolids per hectare either by adding cows within environmental limits or by harvesting the excess as silage or hay. Conversely, if the wedge shows repeated feed deficits, consider whether the herd is too large, soil fertility is limiting, or irrigation scheduling needs refinement.
Turning Surplus into Silage or Opportunity
Surplus grass is both a blessing and a threat. Left ungrazed, it soon goes rank, lowering metabolisable energy and shading new tillers. Timely conservation avoids that bottleneck. Cutting young grass for high‑quality silage keeps extra feed on the farm and preserves sward density.
Some farmers lock a “leader–follower” system into their plan: milkers graze first, followed by heifers or dry cows to tidy up the paddock. Others run a ‘flexi‑herd’ a small group that can be added or removed depending on growth. Whichever tactic you choose, the aim is to capture surplus before it becomes waste.
Minimising Wastage
Even well‑timed grazing can slip if wet weather turns gateways into mud or if mobs linger too long on a break. Practices that protect the soil surface—back‑fencing, on‑off grazing, wood‑chip stand‑off pads—help keep treading losses low. Weed control, annual over‑sowing of thin patches, and maintaining soil nutrient status are equally important; they convert marginal areas into productive ones rather than costly voids.
Remember, grass that is trampled, shaded out, or unharvested is not neutral—it represents fertiliser, seed, and labour that earned no return. Small gains in efficiency here often exceed the impact of cutting other farm costs.
Complementary Feeds: Buying with Discipline
Supplements have a place, particularly during short feed gaps or to balance a ration nutritionally. The key is discipline: weigh the cost of the feed (delivered and fed out) against the likely milk response. If adding a kilogram of maize silage costs more per megajoule than home‑grown grass and the cows’ yield bump is modest it may erode rather than boost profit.
Running partial‑budget scenarios before each purchase keeps decisions objective. Ask: Will this feed lower whole‑farm cost per kilogram of milk‑solids once extra labour, fuel, and shrinkage are counted? If the answer is no, redirect effort to growing or utilising more grass instead.
Building a Resilient Pasture‑First System
Focusing on pasture utilisation creates a farm that is naturally resilient. When milk prices sag, low feed costs protect cash flow. When prices rise, the same cost base converts quickly into stronger margins. Environmental metrics also tend to improve: fewer truckloads of imported feed mean a smaller carbon footprint and less nutrient import.
Cultivating such a system is iterative rather than revolutionary routine measurement, timely decision‑making, and attention to detail add up over seasons. The reward is a business that turns sunshine and rainfall into milk efficiently, year after year.
Key Takeaways
-
Measure consistently. Weekly cover estimates and accurate records underpin every grazing decision.
-
Grail residuals. Leave around 1,500 kg DM/ha to maximise regrowth without wasting feed.
-
Match demand and supply. Adjust herd size, rotation length, or conservation strategy so grass grown is grass used.
-
Control wastage. Minimise pugging, weeds, and shading to convert inputs into saleable milk.
-
Buy feed carefully. Only bring in supplements that clearly lower the cost per kilogram of milk‑solids.
By treating pasture as the cornerstone of your feeding programme, you position your dairy to thrive—whatever the season or payout brings.
Until we meet again, Happy Grazing!
- The Dedicated Team of Pasture.io, 2025-08-07