Mob Grazing: Density, Duration, and Recovery
Mob grazing compresses many animals into a small area for a short period, then moves them on. The concentration mimics wild herbivore herd behaviour. The mechanics are three variables held in tension: stocking density high enough to produce animal impact, graze duration short enough to prevent overuse, and recovery long enough for root reserves to fully restore before the next graze event.
What Exactly Is Mob Grazing and How Does It Differ from Simple Rotation?
Mob grazing is a high-density, short-duration grazing method where a large group of animals is concentrated on a small paddock area for a period ranging from a few hours to three days, then moved to the next paddock. The term mob comes from the Australian word for a group of livestock. In North America the same technique is often called ultra-high density (UHD) grazing or, when integrated with full recovery periods, Adaptive Multi-Paddock (AMP) grazing. The distinctions matter: mob grazing describes the density event; AMP describes the system within which that event operates.
The difference from simple paddock rotation is stocking density and monitoring. A set-stocked rotation divides pasture into, say, four paddocks and rotates animals through them on a fixed 30-day cycle at normal stocking rates. Mob grazing compresses the same or a larger herd into a single small paddock, or a series of temporary paddocks within a larger paddock, at stocking densities 10-50 times higher than normal. The high density produces animal impact: intensive hoof impact effects on hyphal network integrity in grazed soils, converting concentrated mob-grazing dung into stable compost carbon. The short duration prevents that impact from crossing into overgrazing. Then the mob moves, and the biochar amendment during the rest period that accelerates microbial recovery depending on climate and plant recovery rate.
The monitoring element separates mob grazing within an AMP system from calendar-based rotation. Entry and exit decisions are based on forage height and plant recovery indicators, not a fixed schedule. In fast spring growth, a paddock may be ready for re-entry in 45 days. In dry summer conditions, the same paddock may need 120 days. The monitoring makes the system self-correcting: if paddocks are consistently underperforming on recovery, it is a signal to reduce total stocking or add paddock count. For the decision framework underlying this monitoring approach, see the guide on Holistic Management: the Allan Savory framework.
Density, Duration, and the Biology of Animal Impact
The mechanism of mob grazing is not primarily about preventing overgrazing. It is about producing four specific biological effects that do not occur at low stocking density. First, hoof action at very high density (250,000 to 1,000,000 kg of liveweight per hectare) breaks the surface capping that forms on bare soil between rain events, increasing water infiltration. Studies in degraded semi-arid rangeland show infiltration rates increasing from 2-5 mm per hour under continuous grazing to 20-40 mm per hour after three years of managed mob impact, which is the difference between most rainfall becoming runoff and most rainfall entering the soil profile.
Second, concentrated dung and urine deposits create localised fertility hotspots that then disperse across the paddock through the soil food web during the recovery period. At low stocking density, animals distribute dung more evenly but at lower concentration per square metre, reducing the microbial activation effect. At mob density, the urine volume per unit area triggers a measurable microbial pulse within 24-48 hours of the mob moving on, detectable as elevated CO2 respiration and nitrate production in the top 5 cm of soil.
Third, saliva deposited by grazing animals contains growth-promoting compounds including cytokinins that stimulate plant regrowth. Research on wild herbivore grazing indicates that plants grazed by high-density herds recover faster per unit of remaining leaf area than ungrazed plants or lightly grazed plants. The saliva inoculation effect is not fully understood mechanistically but is consistently observed in practice: mob-grazed paddocks show faster initial regrowth than expected from the remaining leaf area alone.
Fourth, the cover crop mulch layer that parallels mob-grazing litter in weed suppression effect that reduces soil surface temperature, retains moisture, and provides a carbon substrate for soil microorganisms. In brittle semi-arid environments this trampled residue is the primary mechanism of organic matter incorporation into the soil, since biological decomposition is slow in the dry season. The residue left after the mob moves on feeds the fungal and bacterial community throughout the recovery period.
The graze duration limit is the constraint that makes mob grazing functionally different from overgrazing. The exit trigger is forage height, not time. When the sward drops to approximately 50 percent of entry height, the mob moves. This preserves the photosynthetically active leaf area that drives recovery and prevents animals from grazing into the root crown, which would force the plant to draw on root carbohydrate reserves for a second time in the same cycle.
The Numbers: Density Targets, Forage Heights, and Paddock Counts
Teague et al. (2016) provides the best large-scale dataset for AMP grazing outcomes in North American conditions. Across 13 sites in the Northern Great Plains over 10-year horizons, AMP grazing sites averaged soil organic carbon gains of 0.2-0.7 tonnes of carbon per hectare per year. The corresponding figure for continuously grazed sites at moderate stocking was zero to slightly negative SOC change. The mechanism driving the AMP advantage was consistent across sites: higher organic matter inputs from trampled residue and concentrated manure, combined with reduced soil disturbance from hoof action concentrated into short events followed by extended recovery.
Typical mob density targets for temperate grassland operations are 250,000-500,000 kg of liveweight per hectare for the graze event. To calculate the practical paddock size for a given mob: if you run 300 cattle averaging 550 kg liveweight, your mob is 165,000 kg. At a target density of 300,000 kg per hectare, your paddock area per move is 0.55 hectares. If your total grazing area is 300 hectares and you target a 90-day recovery period with 1-day graze events, you need a minimum of 90 paddocks of roughly 3.3 hectares each. In practice, most producers implement 30-60 paddocks and use temporary electric fencing within permanent paddocks to subdivide for mob events.
Forage height targets: enter at 30-50 cm for mixed temperate perennial pasture, exit at 10-15 cm. Enter at 20-35 cm for native semi-arid prairie, exit at 8-12 cm. These are not universal; they must be calibrated to the dominant species on the property and adjusted seasonally. In spring when growth is rapid, entry heights can be pushed higher to slow the rotation and prevent individual paddocks from becoming stemmy and unpalatable before the mob arrives.
The input cost arithmetic follows from the density numbers. AMP grass-finished beef variable costs run 200-450 USD per head across a 24-30 month production cycle, with zero purchased grain (SARE grass-fed beef enterprise budgets; Greener Pastures 2018, vault_atom_TBD). The primary capital expense is paddock infrastructure: permanent fencing, water points, and temporary subdivision equipment. Once infrastructure is in place, the system runs on labour for monitoring and moving rather than recurring inputs. Compare this to feedlot finishing at 900-1,400 USD per head variable cost (USDA ERS 2023), and the margin math resolves clearly in favour of the AMP operation, even after accounting for the longer 24-30 month finishing timeline versus 14-18 months in the feedlot.
Mob Grazing in Practice: Polyface and Northern Great Plains Data
Joel Salatin's Polyface Farm in Virginia's Shenandoah Valley is the most widely documented small-scale example of mob grazing integration. Salatin developed the Eggmobile and Pigaerator Pork systems, which follow cattle through paddocks on a three-day lag: cattle are mob-grazed through a paddock, then the chickens follow three to four days later to scratch through the manure and capture the fly larvae cycle before it completes, depositing their own fertility. The sequence mimics the cattle-bird mutualism that occurs in wild grassland systems. Salatin reports forage productivity increases of 50-200 percent over the first decade of the system on formerly degraded Virginia hillside pasture. The per-acre gross margins from his multi-species stacking system consistently exceed regional monoculture livestock benchmarks.
The Northern Great Plains operator data from Teague et al. (2016) shows a different context: large-scale semi-arid rangeland where mob densities are lower and recovery periods longer than in the humid Shenandoah Valley. Across 13 producer sites ranging from South Dakota to Texas, operators implementing AMP grazing with paddock counts of 8-24 (significantly fewer than the theoretical ideal) still documented measurable SOC gains within 10 years. This is significant because it demonstrates that the beneficial effects of managed mob grazing are observable even at paddock counts well below what full AMP theory specifies, making the method accessible to producers who cannot immediately achieve the infrastructure investment of a high-paddock-count system.
The practical error most producers make in transitioning to mob grazing is underestimating the paddock count required for adequate recovery in their climate. A producer transitioning from a 4-paddock rotation in semi-arid country to mob grazing with 6-8 paddocks will see improvement over continuous grazing but will not achieve the full recovery benefits because 6-8 paddocks at 1-2 day graze events provides only 6-16 days of rest per paddock. The minimum for semi-arid conditions is 90 days. Achieving 90 days with 1-day graze events requires 90 paddocks. The workaround is to use temporary electric fencing to create subdivisions within permanent paddocks, effectively multiplying the paddock count without the fencing capital cost.
Mob Grazing Within the AMP System and the Broader Stack
Mob grazing is the tactical event within the strategic framework of AMP grazing as the animal engine of regenerative agriculture. The density event produces the soil-building effects; the recovery period allows those effects to compound. Neither works without the other. The system that makes both possible is the multi-paddock infrastructure described in the AMP systems guide.
Water point placement is the dominant constraint on mob grazing implementation. Animals will not move more than approximately 800 metres to 1 kilometre from a water point in most conditions, and this maximum grazing radius determines the effective paddock size that can be uniformly grazed. In terrain where water is difficult to distribute, paddock size is limited by water access rather than by fencing, which is why paddock design and on-farm water infrastructure are inseparable from mob grazing planning.
Virtual fencing systems such as Nofence, Halter, and Vence remove the physical fencing constraint from mob grazing implementation, enabling AMP patterns on country where conventional fencing is economically prohibitive. The cost shift is significant: physical fencing for a 100-paddock AMP system on 500 hectares can exceed 500,000 USD in materials and labour. Virtual fencing hardware costs approach 200-300 USD per animal unit with ongoing subscription costs, making the economics attractive for operations where conventional paddock counts are below the AMP optimum. Water point infrastructure remains necessary regardless of fencing method.
The manure and urine deposited during mob grazing events feeds directly into the on-farm composting cycle when poultry are run in sequence behind cattle in the Polyface model. Silvopasture is the bridge between rotational grazing and agroforestry: tree rows integrated with pasture modify the microclimate, provide supplemental browse in dry periods, and add a timber income layer to the grazing enterprise. The integration of trees with mob grazing requires adjustments to paddock geometry and recovery period because tree shading affects grass growth rates and therefore the entry-height timing.
Frequently Asked About Mob Grazing
What is the correct stocking density for mob grazing?
Mob grazing stocking densities range from 250,000 to over 1,000,000 kg of liveweight per hectare for the duration of the graze event, which typically lasts 12-48 hours per paddock. The correct density for a specific operation depends on forage availability, paddock size, and paddock count. Starting mob grazing practitioners typically begin at 50,000-100,000 kg per hectare and increase density as the paddock system matures. The key constraint is that the graze event must end before the herd removes more than 50 percent of forage height.
How is mob grazing different from strip grazing?
Strip grazing uses a temporary electric fence to allocate a strip of pasture to animals for 12-48 hours, then advances the front fence while leaving a back fence to prevent re-grazing. Mob grazing operates on the same principle but at much higher density and within a multi-paddock rotation system where paddocks receive full recovery between visits. Strip grazing is a tactical tool; mob grazing within an AMP system is the strategic framework. Both use density to concentrate impact; the AMP system adds the long recovery period that drives soil improvement.
What happens if the recovery period is too short in mob grazing?
Re-grazing before root carbohydrate reserves are fully restored progressively weakens the sward. By the third or fourth cycle, preferred grasses show shorter regrowth, thinner stands, and reduced root depth. After several seasons of insufficient recovery, the pasture shifts toward less palatable, more stress-tolerant species and bare soil increases. This is the same degradation pattern as continuous grazing, just on a slightly delayed cycle. The diagnostic: if preferred grasses are getting shorter each rotation, recovery period is insufficient.
From Mob Events to AMP System Design
Mob grazing mechanics make sense in isolation. The infrastructure that enables them at scale is the AMP multi-paddock system: how many paddocks, how large, where water sits, and how virtual fencing changes the math. The AMP systems guide covers the engineering specifics with cost and paddock-count calculations.