FSTY 3016

FOREST PRODUCTS

Trees and Shrubs for Livestock Fodder

Introduction

Assessing the Value of Browse Plants

Detrimental Factors of Tree Fodders

Conclusion

References

Links

Introduction

Trees and shrubs have long been considered as important sources of nutrition for grazing animals, especially in those areas with a pronounced dry season. Often called browse or top-feed, they are an effective insurance against seasonal feed shortages, supplementing the quantity and quality of pastures compounds (Lefroy et al. 1992). Fodder trees are less affected by seasonal dry conditions because of their more extensive root systems and longer life-spans (Abel et al. 1997)

Torres 1983 defined browse as the "shoots or sprouts, especially tender twigs and stems of woody plants with their leaves. However the term can be broadened to include the flowers, fruits or pods, which can be more valuable than foliage, especially if the species is deciduous "(Torres 1989).

The type of fodder agroforestry system established will depend on the needs and objectives of the individual. Does the fodder shortage occur at a certain time of the year? How long does the period last? Is the problem associated with annual periods or seasonal drought, or is the shortage due to the quantity or quality of feed available? (Abel et al. 1997). A separation of the main objectives can be shown as follows.

[Return to main menu ]

Assessing the Value of Browse Plants

Within Australia there exists hundreds of native species well adapted to drought, which may provide useful fodder for introduced agricultural stock (Reid and Wilson 1985). There are also many exotic species that may also suit the purpose equally, or better, for individual site conditions.

The aim of planting fodder trees is to overcome the effects of troughs in fodder supply, or to insure against the risk of drought or fire (Abel et al. 1997). The following diagram illustrates the advantage of such trees in evening-out feed supplies throughout the year.

(Reid and Wilson 1985).

The forage value of any feed depends on the combination of its palatability, nutrition value and digestibility (Lefroy et al. 1992). Most feed types are not sufficiently digestible or nutritious to meet all of an animals' needs in isolation. During the dry season or southern summer, paddock feed usually has poor digestibility because dry grass is rich in fibre (cellulose and lignin) and poor in sugar and protein. Fodder trees and shrubs can provide protein and energy to keep rumin microbes active, increasing their ability to digest fibre, and thus enable livestock to make use of dry season pastures (Abel et al. 1997).

Good fodder trees should produce large crowns above livestock reach, that are capable of severe lopping during periods of high environmental stress. Alternatively, in intensively managed agricultural areas, trees can be grown totally protected and their leaves, etc. harvested and fed to livestock (Boland 1986).

(Tree Care Extension Officers 1996)

The selection of the appropriate species requires careful consideration. The many different aspects associated with purpose selected trees must be combined to ascertain the species most suited for the landowner and the local conditions.

Table 1. Considerations in the selection of species

(Abel et al. 1997)

Dr Brian Lowry, principle research scientist with CSIRO Tropical Agriculture, has identified a number of Australian and exotic tree species whose leaves, pods and flowers could provide fodder to sustain livestock through the dry season and extended droughts experienced in northern Australia. Most of the trees are legumes and several are known to promote pasture growth when grown in paddocks. All are also considered to be good timber trees, providing an alternative source of income for graziers. The trees which Lowry has identified with potential for this dual purpose agroforestry system include Siris (Albizia lebbeck), Forest siris (Albizia procera), Tipuana (Tipuana tipu), Yemane (Gmelina arborea), Dead finish (Albizia basaltica), White cedar (Melia azederach) and Rain tree or Monkey pod (Samanea saman syn. Albizia saman) (Lake 1997). Lowry believes that with the right tree species, it may be possible to have an agroforestry system where the trees provide a significant contribution to grazing animal nutrition at the time of greatest need, while still growing timber (Lake 1997).

Typical feed problems can be managed with fodder agroforestry systems by using the appropriate species for the particular feed shortage and the agroecological zone.

Table 2. List of some fodder tree and shrub species

S = Seasonal D = Drought Q = Quality

(Abel et al. 1997)

[Return to main menu]

Detrimental Factors of Tree Fodders

Trees and shrubs have several disadvantages as sources of feed.

[Return to main menu]

Conclusion

Trees have often been included in farm planning for amenity purposes, particularly around farm houses and buildings but also to provide shelter and shade for animals, crops and pastures or to reduce the harmful effects of rising watertables. A large number of tree and shrub species have also been documented as useful livestock fodder. The importance of trees and shrubs as animal fodder is accentuated in harsh environments, where limitations are imposed on both the quantity and quality of the natural pastures. Under these circumstances the value of trees and shrubs is considerable in meeting nutrient requirements and sustaining populations of ruminant livestock.

In recent years, this traditional use has been complemented by their exploitation in wetter areas for protein-rich browse and the nitrogen fixing abilities of many shrub and tree legumes.

The advantages and disadvantages offered by fodder trees and shrubs can be summed up as :

Advantages

• Plants last for many years, and are difficult to graze out.
• The foliage is high quality livestock feed
• Foliage is available during times of minor drought.
• Their deep-rooted habit can be used to stabilise land against erosion.
• They can be used to revegetate or colonise adverse landscapes.
• Root systems and high-N litter can help improve soil structure and fertility
• They can provide shade and shelter for stock.
• Some fodder species also have timber potential.

Disadvantages

• Many species may become environmental weeds
• Some contain toxic substances or thorns that make management difficult.
• Many contain tannins and other astringent compounds, which adversely affect digestibility of dry matter.
• Many require intermittent periods of heavy grazing followed by no grazing, requiring fencing.
• Tall growth forms may require more labour intensive management.

Clearly, though a highly valuable resource as supplementary feed supply for times of environmental stress, careful species selection is essential for successful fodder production.

[Return to main menu]

References

Abel, N., Baxter, J., Campbell, A., Cleugh, H., Fargher, J., Lambeck, R., Prinsley, R., Prosser, M., Reid, R., Revell, G., Schmidt, C., Stirzaker, R. and Thorburn, P. (1997). Design principles for farm forestry : a guide to assist farmers to decide where to place trees and farm plantations on farms. Barton, ACT, Rural Industries Research and Development Corp.

Boland, D.J. (1986). Selection of species and provenances for tree introduction. In Multipurpose Australian trees and shrubs : lesser-known species for fuelwood and agroforestry. Turnbull, J.W. ed. Canberra, ACIAR.

Lake, J. (1997). Dual purpose trees for agroforestry. Rural research 175, 8-11.

Lefroy, E.C., Dann, P.R., Wildin, J.H., Wesley-Smith, R.N. and McGowan, A.A. (1992). Trees and shrubs as sources of fodder in Australia. Agroforestry systems 20, 117-139.

Negi, S.S. (1986). Foliage from forest trees : a potential feed resource. In Agroforestry Systems : a new challenge. Khosla, P.K., Puri, S. and Khurana, D.K., eds. Nauni, Indian Society of Tree Scientists.

Reid, R. and Wilson, G. (1985). Agroforestry in Australia and New Zealand. Box Hill, Vic, Goddard and Dobson.

Torres, F. (1983). The role of woody perennials in animal agroforestry. Agroforestry Systems 2, 131-163.

Torres, F. (1989). Tree-fodder and silvopastoral systems. In Agroforestry systems in the tropics. Nair, P.K.R. ed. Dordrecht, Kluwer Academic Publishers.

Tree Care Extension Officers (1996). Managing native fodder trees. Qld. Community Education & Extension Support. http://www.dnr.qld.gov.au/resourcenet/fact_sheets/pdf_files/T37.pdf

[Return to main menu]

Links

Managing native fodder trees Qld DNR fact sheet

http://www.dnr.qld.gov.au/resourcenet/fact_sheets/pdf_files/T37.pdf

Exotic fodder trees - Qld DNR fact sheet

http://www.dnr.qld.gov.au/resourcenet/fact_sheets/pdf_files/T30.pdf

Fodder for thought - ACTANC 95. 6th Conference of the Australasian Council on Tree and Nut Crops Inc. Lismore, NSW, Australia. 11-15 Sept 1995

http://www.uq.edu.au/~gagkrego/acotanc/papers/champion.htm

[ANU Forest Products][Non-Wood Forest Products][Minor or Unusual Forest Products]

Copyright 1999 The Australian National University
Author: Forestry Web People
Comment and Feedback
Date Last Modified: 22.10.99

URL:http://www.anu.edu.au/Forestry/wood/nwfp/fodder/fodder.html