Making More from Sheep Australian Wool Innovation Limited Meat & Livestock Australia
MODULE 7: Grow More Pasture
Tool 7.5
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Individual pasture and forage species have specific grazing requirements. You can use these requirements to increase or maintain that species in the pasture or to decrease a species, eg, to increase the relative contribution of other species in the mixture. The table in this tool contains species specific information and the following are some general rules for grazing management:

Grazing frequency

Plants that can cope with heavy, continuous grazing during their growing season are those with a prostrate (flat) growth habit (sub clover, annual medics and many broadleaf weeds such as capeweed, erodium and thistles), or those with rhizomes or stolons (bent grass, couch grass, kikuyu). These plants are able to maintain some leaf for photosynthesis even when kept grazed very short, and hence are able to survive. Plants that have a more upright or erect growth habit, such as many introduced and native perennial grasses, and most annual grasses, are less resilient to heavy, continuous grazing, because most leaf (and stem) material is easily removed by stock, leaving little capacity for regrowth.

Grazing tactics

If you want to modify your current grazing system or methods, be clear about the benefits you are trying to achieve, for example:

  • Use rotational grazing to increase autumn/winter growth rates of desirable perennial and annual grasses. This will improve the size and persistence of perennial grasses and also help suppress broadleaf weeds
  • Use crash-grazing or set stocking (with a high stock density) in spring to prevent annual or perennial grass weeds dominating in problem paddocks and also to increase the annual clover content
  • Remove stock from paddocks when groundcover falls below the acceptable limit in your district to protect the pasture and the soil (see procedure 6.2 in Healthy Soils). Maintain groundcover and litter at the time of the season break to reduce germination of annual broadleaf weeds such as capeweed. However, leaving more than 1,000 kg DM/ha (litter/dead pasture) in the paddock at time of the autumn break will reduce germination of annual clovers
  • Maintain a flexible approach. Varying seasonal conditions from year to year will affect pasture composition so you need to be able to adapt your grazing system accordingly. Because you can’t manage all paddocks correctly in all years ensure poor management is not repeated in the same paddock in successive years.
  • When applying your grazing strategy or tactic, refer to the seasonal targets you have set for the class of livestock grazing the paddock/s (see tools 10.4 and 10.5 in Wean More Lambs). Pasture and animal production objectives are not always compatible and compromises (economic, environmental and social) have to be made.
  • Rest periods (for rotational grazing systems) should be based on allowing the grass you want to be most dominant in the pasture to grow back a target number of leaves. Only when this target number of leaves has regrown on a tiller has the plant fully restored its reserves in readiness for the next grazing and re-growth cycle. This may require lowering your stock numbers or deferment of grazing. The following table lists these targets for species where clear rules are available.
Pasture type Increase or maintain Decrease/remove
Temperate native grasses
  • Use strategic, tactical or rotational grazing
  • Maintain groundcover at 70% (high rainfall) or 40% (semi-arid areas)
  • Allow flowering and seed set of desirable grasses
  • Use low rates of phosphorus and sulphur and manage grazing to ensure grasses are not killed
  • Continuously graze even at low and moderate stocking rates
  • Overgraze, especially in dry conditions
  • Regularly burn pastures
  • Allow shrub and weed invasion

[Note – many states/catchments restrict native pasture management interventions– see procedure 5.3 signposts in Protect Your Farm’s Natural Assets]

Tropical grasses
  • Allow flowering and seed set once a year
  • Rotationally graze and supplement stock when green herbage mass is low
  • Control growth of temperate species (eg, clover, barley grass, ryegrass) in early spring
  • Control growth of competitive, summer growing annual grasses
  • Provide adequate nitrogen
  • Do not overgraze when dry or N is low
  • Maintain groundcover
  • Reduce fertiliser and nitrogen inputs
  • Graze heavily during flowering
  • Graze rhodes grass to ground level

[Note - Purple pigeon, Rhodes grass and green panic are susceptible to overgrazing particularly when dry and nitrogen is low]

Phalaris
  • Increase phosphorus applications
  • In northern environments with more summer rainfall, rest in spring/summer, remove excess trash late in summer then rest until 3-4 weeks after autumn break
  • In southern environments, lenient rotational grazing over autumn/winter to allow more tillering of the existing plants
  • Graze after the plants reach 4-leaves/tiller
  • Allow soil fertility to decline
  • Graze heavily during spring/summer or repeatedly cut so it is not allowed to run to head
  • Graze heavily any new green shoots in summer and autumn, but monitor stock for any signs of phalaris poisoning such as phalaris staggers and sudden death syndrome
Cocksfoot
  • Graze to maintain above 1000-1500 kg DM/ha
  • Apply high rates of phosphorus fertiliser
  • Avoid continuous grazing of green shoots during summer and autumn
  • Graze plants when they reach 4-leaves/tiller to maximise feed quality
  • To avoid cocksfoot dominance, graze all summer growth including individual tussocks down to 10cm tall at the autumn break
  • Graze heavily during autumn to physically pull plants from the ground
  • Graze hard down to 2.5cm or less during late spring or summer
  • Allow soil fertility to decline
Perennial ryegrass
  • Rotationally graze during summer, ideally after plants reach 3-leaves/tiller
  • Apply high rates of phosphorus fertilisers
  • Allow soil fertility to decline
  • Do not allow to run to head
  • Graze continuously and heavily during summer
Tall fescue
  • Graze frequently (every 14-21 days) for short periods (2-3 days) during periods of active growth, once the plants reaches 4-leaves/tiller
  • Do not graze until 3 weeks of good active growth and/or 12-15cm of grass growth
  • Set stock or rotationally graze from autumn to spring to maintain 1,000-2,500kg green DM/ha (or 5‑15cm) of pasture
  • Continuously graze in hot dry conditions
  • Graze heavily during dry summers or early autumn
Sub clover
  • Avoid grazing until seedlings have 3-5 true leaves, usually 3-6 weeks after the autumn break
  • Keep grass/weed cover below 1,000kg green DM/ha during summer/early autumn
  • Maintain a sward height of 5cm or less until flowering
  • Increase phosphorus applications
  • Maintain grass and weed cover above 1,000kg green DM/ha
  • Do not control earth mites
  • Cut hay or graze heavily during seedset
  • Apply herbicides during flowering
  • Allow soil fertility to decline, including molybdenum and boron
White clover
  • Keep grass/weed cover low at break and graze continuously to keep the grasses short
  • Over winter and early spring, graze pasture to 750kg green DM/ha (or 3cm)
  • Heavily rotationally graze in spring to control grasses, maintaining pasture between 1,000‑3,000kg green DM/ha (or 10-25cm)
  • Increase phosphorus applications
  • Graze heavily during flowering
  • Graze to less than 1,200kg green DM/ha while under moisture stress during summer
  • Allow soil fertility to decline, including molybdenum and boron
Lucerne
  • Allow to achieve well in excess of 10% flowering prior to grazing. This must be achieved at least once per year, preferably in the autumn
  • Rotationally graze for most areas:
    - Summer: 2 weeks grazing and 5 weeks rest
    - Winter: 2 weeks grazing and 7-8 weeks rest
  • Set stock paddocks at heavy stocking rates
  • Allow soil fertility to decline, including molybdenum and boron
  • Potassium can run down when used intensively for hay production, zinc can be a problem on alkaline soils.
Grazing cereals
  • Delay first grazing until plants are well anchored and starting to tiller (6–8 weeks post emergence)
  • For winter types, longer deferment can increase growth and winter feed supply
  • High stock density rotational grazing gives the most even utilisation and allows recovery
  • Heavy grazing during the first 6–8 weeks
  • Heavy grazing in spring once the seed heads begin to form
  • Late grazing of semi-dwarf types can make any grain harvesting difficult
Chicory
  • If sown as a specialist finishing pasture, rotational grazing is essential – a four paddock system works well. Aim to maintain height between 5 and 40 cm.
  • In late summer, allow stands to develop stems and set seed if regeneration is required
  • If sown as a component of a mixed pasture, rotational grazing is essential for persistence, but it is likely to decline anyway.
  • Easily removed by set stocking
  • Plants very susceptible to overgrazing and trampling when dormant (winter)
  • More erect varieties (eg, Grouse) have higher crowns and are more susceptible to overgrazing
Brassicas
  • Most brassicas are grown to maturity and grazed only once so strip grazing is needed to minimise trampling losses
  • Some forage Brassica hybrids are suited to multiple grazing – strip grazing minimises trampling losses and allows more rapid recovery
  • Not applicable