Feed budgeting at its most complex takes into account all of the factors that influence pasture intake and use. Feed budgeting is the process of matching feed supply with the demand of the grazing animal.
In practice, estimates of feed on- offer, pasture growth rates and dry matter digestibility provide the information required to calculate stocking rate and the length of the grazing period.
This information needs to be adjusted to take account of the required pasture cover at the end of grazing and the proportion of pasture that is used.
Pasture utilisation is never 100% due to losses from trampling, selective grazing and natural decay. Feed budgeting can be used tactically to improve pasture utilisation and meet livestock production targets in the shortterm (e.g. strip grazing) or strategically to assess the ability of the feed base to meet livestock requirements over a full year.
There is now a range of tools and options available to improve the efficiency of production from grazing systems. Extension programs such as PROGRAZE focus on tactical grazing management to meet livestock targets.
Satellite images can be used to provide real time information on feed-on-offer and pasture growth rates at the paddock scale.
Computer programs such as GrassGro can be used for longer term strategic planning to simulate pasture and livestock production under different grazing regimes, while optimisation models such as MIDAS can be used to evaluate options for changes in whole-farm enterprise structures.
Opportunities offered by perennial plants in extensive grazing systems:
Significant opportunities exist to improve the profitability of extensive animal production systems through strategic use of perennial plants within a farming system. In this context the perennial plants may have a higher value when considered as a contribution to total farm feed resources than when considered on their own.
Opportunities for perennial plants include:
- Summer-active perennial plants have the capacity to fill the autumn feed gap by producing biomass and responding to summer rainfall when annual plants have died. The biomass produced usually has higher ME and CP than dry crop and pasture residues. Increased feed availability outside of the winter/spring growing season provides the opportunity to develop novel animal production systems that reduce the impact of seasonality of annual pastures on meat and wool production and quality.
- Perennial plants could also provide components of the diet that are lacking in dry autumn feed, such as crude protein and vitamin E.
- Tannins and other secondary compounds could help to reduce parasite burdens and reliance on chemicals.
- Small amounts of high quality feed in summer and autumn could improve the use of dry crop and pasture stubbles. For example, the high crude protein and low fibre in saltbush complements the high fibre and low protein content of crop stubbles, which can improve the use of the total feed resource.
- Selective plantings of perennials could be used to meet special animal nutrition needs such as high energy for colostrum production to improve lamb survival or to increase ovulation rate in breeding ewes.
- At lambing time the tussock growth habit of some perennial grasses (e.g. tall wheat grass) or the hedge formation of some shrubs will provide shelter and nutrition. This will protect the newborn lambs from wind and rain. At the same time, a close supply of feed allows the mother to graze close by and decreases the likelihood of mis-mothering.
- Mixed annual and perennial pastures provide animals with the capacity to manage their diet, offering both increases in profitability and environmental sustainability.
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