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Supplementary feeding

Supplementary feeding is often used in grazing systems to help meet production requirements. This may be a regular part of the production cycle to help match feed demand to feed supply or reserved for times of drought. The extent to which supplementary feeding is used depends on the business objective and seasonal conditions.

Important considerations in supplementary feeding include:

Animal health

Animal health must be considered foremost. In a drought feeding situation, if supplementary feeding is determined to be necessary through feed budgeting, but is not possible due to financial or labour constraints, livestock should be sold or agistment options sought when stock begin to fall below a condition score of 2.

Where supplementary feeding is being undertaken to achieve a particular production objective, the nutritional requirements of the animal as a ruminant must be considered and an appropriate ration devised accordingly.

Feed budgeting

Feed budgeting is the method of predicting whether the feed available to the herd or flock is sufficient to meet requirements. This requires an understanding of pasture growth rates throughout the year for a particular location and can be accessed via farm planning tools such as the feed demand calculator if on-farm records are not available.

The feed budgeting process

  • Predicting pasture availability and comparing it with stock requirements:
    • Estimate or measure the amount and quality of pasture currently available.
    • Estimate the number of days that pasture is required for current livestock classes, numbers and the targets set for their production performance.
    • Compare the number of days that pasture is required with the number of predicted days available for various weather patterns. Choose the pattern that is most suitable for the predicted circumstances.
  • Taking corrective action based on an assessment of the benefits and costs:
    • If the number of days of available feed exceeds that required, options for utilising the extra feed include increasing stock numbers on pasture or conserving the excess pasture by making silage or hay.
    • If the number of days of available feed is less than required to meet targets, decrease stock numbers on pasture or be prepared to supplementary feed.

Feed budgeting is a useful tool in avoiding over and undergrazing and optimising the conversion of quality feed into product. Overgrazing reduces plant leaf area and carbohydrate stores in the roots, thereby reducing production. Undergrazing reduces pasture quality and quantity and misses production and profit opportunities.

Production objectives

It is important to consider the enterprise's production objectives eg if the enterprise's production objective is to maximise weight gain, then a high energy supplement may be appropriate, such as grain. If the production objective is to wean more animals and supplementary feeding is required to minimise disease associated with nutritional deficiencies during late pregnancy, such as grass tetany or pregnancy toxaemia, hay may be a better option.

Both approaches will require an increased labour commitment and the economic and social impact of this will also have to be considered.

By identifying the need for supplementary feeding and aligning feed requirements with production objectives, the most suitable feed source can be identified and the impact of supplementation on the operating margin minimised.

The ultimate supplementation strategy adopted will depend on class of animal being fed, the timing of the intended market and the impact of compensatory gain eg  benefits of supplementary feed  growing cattle over the dry season can be almost completely eroded by compensatory gain if they are not sold until the following year.


To maintain good rumen function and assist good animal health, supplementary feeding should satisfy the animals need for protein, energy, roughage and minerals. Where supplementary feeding is being used to achieve particular production objectives, such as extra weight gain, care must be taken to ensure the provision of a balanced diet that is economically feasible. A high energy diet based on grain may require the addition of roughage, such as hay, to ensure good rumen function.

Common feed stuffs used in supplementary feeding to meet particular requirements include:

  • Energy - grain, molasses, silage.
  • Protein - meals such as cotton seed meal, lupins, silage.
  • Roughage - hay, silage.
  • Minerals - lime fed as calcium carbonate (CaCO3), phosphorus (minerals are best fed as pre-prepared licks to ensure that livestock do not exceed recommended intakes).

Seeking professional advice and analysis of suspected deficiencies is strongly recommended as this is a highly specialised area.