Article Summary: Rotational grazing swaps continuous set-stocking for a planned circuit of paddocks, letting grass recover to its leafiest, most nutritious stage before cows return. By matching paddock size and rotation length to seasonal growth, measuring covers each week, and aiming for a 1,500 kg DM/ha residual, you lift feed utilisation towards 90 %, trim bought-in supplements, and keep pasture and animals in better health.
Rotational grazing sits at the heart of many successful New Zealand dairy operations. By moving stock through a series of paddocks in a planned sequence, you allow pasture to rest, recover and regrow before it is grazed again. The system is not complicated, yet it demands a bit of forethought and steady attention to detail. This guide walks you through the core ideas why rotation matters, how to lay out paddocks, and what to look for each day so you can lift pasture harvested per hectare and support a healthier, more productive herd, and essential become a pasture pro.
Why rotation beats set‑stocking
Under continuous or set‑stocking, cows graze the same area for long stretches. Plants never reach their ideal growth stage, and weaker species often take over. Rotational grazing breaks this cycle. Each paddock is grazed for a short period and then rested, giving ryegrass and clover time to replace leaf area, rebuild root reserves and restore sugars essential for rapid rebound. In practical terms, this means more leaf, less stem and higher pasture quality at the next grazing.
Research across temperate dairying regions shows utilisation—how much grown feed actually ends up inside the cow—can lift from 40–70 % under continuous grazing to 80–90 % with a well‑managed rotation. Because pasture remains the cheapest feed source on most Kiwi farms, every extra kilogram of dry matter consumed rather than wasted drops straight to the bottom line. You also reduce reliance on purchased supplements, trim feed costs and simplify feed budgeting.
Planning your paddocks
Paddock number and size
A good rule of thumb is enough paddocks to cover at least the length of your target rotation. For many spring‑calving herds, that means 20–30 separate areas, each grazed once every 20–30 days as growth surges. Smaller herds, or farms with varying soil types, can tweak sizes so that a single break lasts roughly one grazing interval often one milking in spring and 24 hours later in summer.
Shape, water and access
Square or slightly rectangular paddocks let stock spread out, nibbling more evenly and leaving a tidier residual. Where the layout is irregular, temporary electric fencing can square up corners or split long strips to reduce walking distance. Try to place water troughs near the centre of each paddock to avoid heavy treading around gateways. Good laneways matter too; if cows can reach the next break quickly, you waste less grazing time and reduce pugging around entrances.
Flexibility for the shoulder seasons
Rotation length rarely stays static. During autumn slow‑down or early spring flush, you may need to halve or extend the grazing window. Portable tapes allow on‑the‑go subdivision without major capital works, letting you fine‑tune paddock size to the prevailing growth rate while keeping the long‑term layout intact.
Finding the right rotation length
Pasture growth is driven by temperature, moisture and leaf area. Ryegrass typically reaches peak quality at the 2½–3‑leaf stage about 18–25 days in spring and 25–35 days in cooler months. Enter earlier and cows nip off emerging leaves that have not yet built energy reserves; enter later and plants push up stems, falling in feed value.
Aim for a rotation that matches average regrowth time but be ready to adjust weekly. Rising plate meters, satellite-backed readings by our Pasture.io, or simple pasture walks give you real‑time feedback. If pre‑grazing covers are creeping above target (say 3,000 kg DM/ha), speed up the round. If covers slide below (under 2,100 kg DM/ha), slow the herd or offer a supplementary break so grass can catch up. The secret is staying proactive rather than reacting once shortages bite.
Managing post‑grazing residuals
What is left behind after grazing sets the scene for the next cycle. For ryegrass/clover swards, aim to leave a short, even carpet about 3.5–4.5 cm tall roughly 1,500 kg DM/ha. Higher residuals shade tillers, prompting rank, stemmy regrowth. Scalp below 3 cm and plants dip into root reserves, delaying bounce‑back and exposing soil to weeds.
Reach the right residual by altering either the time cows spend in the paddock or the area allocated. Larger herds often split a paddock in half, grazing one section from morning milking until afternoon, then shifting to the back half overnight. Keep an eye on paddock edges; if cows loiter around gateways, they will over‑graze those spots first. Shifting back‑fences and providing water away from exits encourage more uniform utilisation.
Day‑to‑day routines that keep the wheel turning
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Regular monitoring: Walk the farm at least weekly, scoring covers by eye (not recommended), plate meter or app such as Pasture.io. Patterns over time are more useful than one‑off measures.
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Timely shifts: Move animals on as soon as residuals are reached rather than waiting for a set clock time. In spring this might be twice daily; in winter once every 36–48 hours.
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Pasture records: Note pre‑ and post‑grazing measurements. Over a season, these data reveal which paddocks are star performers, which struggle, and where capital fert or re‑sowing will pay.
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Stocking flexibility: When growth rockets, bring in young stock or dry cows to tidy heavier covers. During feed pinch‑points, draft lighter milkers or early calvers first so better‑conditioned cows clean up residues.
Daily discipline need not be onerous ten minutes with a plate meter and a mental map is often enough but it does compound. Small, consistent tweaks save you from large, urgent fixes later.
Benefits beyond the pasture
Rotational grazing delivers more than extra mouthfuls of grass. Short grazing bouts lower parasite pick‑up, particularly for calves, as infective larvae die off during the rest period. Hooves spend less time on any one patch, reducing soil pugging in wet spells and sparing clover stolons from trampling. Over time, pastures grow denser, root deeper and require fewer weed sprays.
Animal health lifts too. A steady supply of leafy material supports higher milk proteins and better body‑condition scores, which flow on to improved fertility. Farmers often report calmer herds; cows learn the routine and walk willingly from break to break, cutting milking delays.
Finally, the system fits well with environmental goals. Higher utilisation means less uneaten herbage that can oxidise or leach nutrients, and shorter grazing windows cut urine concentration in hot spots, lowering nitrate risk.
Quick‑start checklist
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Walk the farm and sketch a basic paddock map.
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Confirm water points and build or repair gateways before splitting more paddocks.
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Set an initial spring rotation of 20–25 days, adjusting each week as covers dictate.
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Measure pre‑grazing mass and aim for a 1,500 kg DM/ha post‑grazing residual.
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Keep simple records so trends and opportunities for improvement stand out.
Start small if you prefer: divide one or two larger paddocks first, learn the rhythm, then expand. Within a season you will see tighter pastures, more contented cows and a smoother feed curve. The process is incremental, but the rewards build quickly once the wheel is turning.
Until we meet again, Happy Grazing!
- The Dedicated Team of Pasture.io, 2025-07-15