Using Grazing As A Management Strategy For Perennial Pastures

The profit and sustainability of livestock enterprises rely on pasture to provide feed of suitable quantity and quality to meet livestock production targets at acceptable costs.

Grazing management is a powerful and cost effective management tool. Use it routinely to achieve and maintain profitability. Grazing management,

  •  increases the quantity and quality of pasture;
  •  manipulates the time availability of feed;
  •  reduces weed problems;
  •  ensures persistence; and
  •  puts you in control of pastures and animal production.

Use grazing management to provide feed in appropriate quantity and quality, and at the right time so that animals achieve their growth potential. You need a good knowledge of pasture species as well as an understanding of the objectives of the enterprise when planning grazing strategies.

Management is needed because pasture species are not ideally matched to:

  •  the climatic variability between and within years;
  •  varying soil types between and within paddocks;
  •  weed competition (although many weeds provide valuable feed!);
  •  grazing habits of livestock, within and between species;
  •  grazing pressure; and
  •  soil fertility, waterlogging, salinity, acidity, insect damage and so on.

Conditions on different farms vary enormously, so it is impossible to outline a standard ‘recipe’ for grazing  management. But we do have a growing understanding of how to manipulate pastures through grazing management to provide for specific animal requirements.

Grazing management has an important role in achieving

the basic requirements of our pastures because:

  •  successful pastures need a persistent and productive legume base;
  •  spring and autumn are critical periods for many pasture species and mixes and summer is important for temperate perennial grasses. Mismanagement at these times affects production, composition and persistence;
  •  maintenance of a good ground cover of persistent and productive species is crucial for livestock performance.

It also reduces erosion and weed invasion; and

  •  high pasture growth rates throughout the growing season maximise water and nutrient use and minimise off site degradation.

Species, soil type, moisture, temperature, fertiliser practice and grazing management all affect pasture production and producers influence species, fertiliser inputs, and the way stock graze pastures. From a grazing perspective, pasture production is directly influenced by the intensity and frequency of its past grazing. This affects how quickly and how much the pasture can regrow at any time.

Manipulating species composition:

The botanical composition of a pasture affects the amount and quality of FOO (Food On Offer) which, in turn, is reflected in animal production. Botanical composition can be modified by grazing and a range of other farm practices (including the use of fertilisers, herbicides and insecticides).

Grazing practices:

The following grazing procedures affect the botanical composition of a pasture:

  •  stocking rate. High stocking encourages clover; low stocking encourages grasses;
  •  continuous grazing of either sheep or cattle encourages clover dominant pastures if soil nutrient levels support clover;
  •  rotational grazing with adequate rest periods at three to five week intervals and high grazing pressures benefit desirable species;
  •   strategic grazing based on the stage of growth of the plant benefits desirable species;
  •  grazing strategies in conjunction with herbicides or fertiliser, spray-grazing, use of nitrogen in autumn;
  •  hard grazing over the flowering period reduces seed production in erect seeding annuals such as, balansa, persian clovers and serradella; and
  •  heavy spring grazing pressure reduces seed set by annual grasses (such as annual ryegrass) and reduces the quantity of annual grasses in the pasture the following year. This is also a consequence of conserving hay and, to a lesser extent, silage, as animals are confined to a smaller area. Other farm practices that affect composition by altering the balance of plant competition include:

Herbicides:

  •  Use of selective herbicides to control broad-leafed weeds in autumn and winter;
  •  herbicide plus grazing pressure (spray-graze technique), to remove broad-leafed weeds by a combination of sub-lethal rates of phenoxy herbicides and increased stocking pressure;
  •  use of grass killing herbicides in winter, such as the removal of vulpia (silver grass) with simazine;
  •  reducing seed set by annual grasses and broadleafed weeds using paraquat or glyphosate (spray topping) in spring. It’s a good preparation for reseeding next year. But watch out! This  technique also reduces clover seed set.

Insecticides:

Redlegged earth mite is a major pest of Australian pastures. Control it with insecticides as well as by grazing. The CSIRO has developed the Timerite® technique to control redlegged earth mite with one insecticide spray in spring, increasing clover seed yield by 37 per cent.

 

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