Contents
Industry Background
Management
Nutrition
Animal Health
Breeding
Fibre Production
Fibre Marketing
Meat Production and Marketing
Pasture and Weed Control
Economic Analysis
Tanning Skins

J1

Weed Control Using Goats

  • Peter Holst, NSW Dept. of Agriculture, Cowra, NSW
  • Helen Simmonds, "Rowan Park", NSW

Weeds in pasture greatly reduce the short and long term profitability of the pasture. The traditional methods of weed control in pastures are cultural, biological, chemical, mechanical or grazing. Not all are necessarily effective or desirable.

Preferential selection (palatability) of plants by animals is affected by plant and animal based factors.

Animal-based factors may be categorised into five classes:

  • the senses
  • species and breeds
  • individual variation
  • previous experience
  • physiological condition

The actual ability of goats to utilise a variety of vegetation types is attributed to their dexterity, narrower mouth, mobile upper lip, prehensile tongue and a propensity to stretch upward on the hind legs to reach forage.

Plant-based factors include:

  • species
  • intra specific variation
  • chemical composition
  • morphology or physical traits
  • succulence or maturation

All animals have dietary preferences. This can be observed in horse paddocks, or on adjacent sheep or cattle properties, where the weed problems are different to where goats are run. Goats eat a variety of undesirable plants and shrubs that sheep and cattle avoid, and often the nutritive value of these species is quite high.

Goats are efficient browsers and grazers of uncontrolled plants in rocky outcrops. They will also eat any weeds that germinated too early or too late to be affected by herbicides. Similarly, degraded non-arable country with woody and other weeds may be reclaimed by goat grazing.

The major control process is ecological, as the weed is placed at a comparative disadvantage in the presence of vigorous clover. This is because clover is not highly sought by goats.

In Australia we have both fibre and meat type goats that are suitable for weed control. In general the bush goat (derived from ferals), cashmeres (not off-shears), and boer X goats can be used.

The principle roll of the goat as a weed controller is to place the weed at a competitive disadvantage to the surrounding pasture. They preferentially graze the weed, preventing it from flowering and setting seed, reduce the plants stored energy reserves, and finally, ringbark and trample small bushes.

Advantages of using goats include the savings in the cost of chemicals, time, labour and machinery, also a sustained and efficient level of control. The returns from the "spin-off" profits make utilising goats plain common sense.

Assessing Pasture and Weeds

Before you can devise a stocking strategy you need to assess pasture quality and quantity and the degree of weed infestation. This is best judged in the weed"s late vegetative stage, before flowering. Simply estimate the percentage ground cover of the weed in a square (0.5m x 0.5m). Walk over the entire paddock and repeat the assessment in about 30 random positions.

For larger woody weeds (blackberry, broom, gorse) estimate the proportion of the paddock taken up by the weed.

From these assessments, and with the knowledge of weed palatability (see Table 1), you can devise a stocking strategy.

Preparation

Any necessary improvements must be made before goats arrive on a property. These include fences, water points, and yards.

Goats test the lower portion of fences: any drains, low areas and diagonal stays etc. will need to be attended to, to ensure there are no escapees. Electric fencing is a reliable and inexpensive method of upgrading existing fences. As a general rule, any fence that will contain crossbred ewes will contain goats.

For localised woody weed infestations, it may be best to isolate the infestation with fencing. This has two benefits. It confines your goats to the infested area, so that fewer goats may be required for the job of controlling the weed; and it preserves the remaining pasture for your sheep or cattle.

In dense infestations of woody weeds such as blackberry, scotch broom or gorse, slash paths through the infestation to allow greater access for goats.

Goats will ringbark some mature trees, particularly over the late winter/spring period. Soft-barked gums are most at risk and so may require protection from goats. You may need to take protective action if your goats begin to chew the tree bark. Even within the same species, individual trees will have a different attractiveness to goats. A trace element salt lick is always useful and often negates the need to attack trees.

Wire mesh wrapped twice around the trunk to a height of 2 metres will prevent damage. Exposed roots may also need covering.

Control or Eradicate

Control is achieved by stopping the annual replenishment of seed reserves in the soil, and eradication is achieved after the exhaustion or effective suppression of these seed reserves. Therefore, eradication of a weed depends on several years of continuous control.

Efficient control is achieved by goat grazing, even though the goats are consuming seedheads of weeds. Research has shown that very few of the seeds ingested by goats remain viable.

"Set" or "Strategic" Stocking?

Knowing how palatability varies at each stage of plant growth allows you the flexibility of either set stocking or strategic stocking.

Set stocking with goats can be an advantage in the first year of a weed control program. It allows you to "quarantine" the new animals, a good management strategy in case the animals are affected by lice or other health problems. It also reduces the cost of upgrading fences, as only one paddock will require upgrading.

However, after the quarantine period, it is advisable to integrate other livestock. This ensures peak production from the herbage in the paddock.

The strategic grazing option requires goats to graze alongside other stock at the "strategic" time - for example when the weeds are most palatable to the goats (as when thistles are flowering) so that competition with other livestock for feed is greatly reduced. Because strategic grazing, by definition, is only used at particular times there must be alternate grazing and holding areas for the goats. This means you will have to fence both the weedy paddock and the other holding paddocks.

Conclusion

The integration of goats on a farm can be ecologically and economically significant. These comments on management are intended to be positive and allow sound management of the animals. The few hours per month involved in sound management are negligible to that involved in traditional weed control.

Table 1. The potential toxicity, and palatability, of some Australian plants to goats.

Botanical nameCommon namepalatability*
Acacia aneura mulgaHigh
Acacia escelsaironwood Medium
Acacia farnesianamimosa bush Medium
Acacia glaucescens coastal myall, sally wattle Toxic
Acacia karoo karoo thorn Low
Acacia mearnsii black wattle High Flower
Acacia nilotica prickly acacia Medium
Acacia homalophylla yarran Medium
Acacia paradoxa kangaroo thorn Medium
Acaena ovina sheeps burr Medium
Acetosa sagittata turkey rhubarbHigh
Aconitum napellus monkshood Toxic
Acroptilon repens creeping knapweed Medium
Aesculus horse chestnut Medium
Agapanthus spp Low
Agave spp century plant Low
Ageratina adenophora crofton weed Medium
Ageratum houstonianum blue billygoat weed Medium
Ageratum riparia mistflower Medium
Ailanthus altissima tree of heaves Low
Alhagi pseudalhagi camel thorn Medium
Allium triquetrum three corner garlicLow
Allium vineale wild garlic Low
Alternanthera pungens khaki weed Low
Amaranthus spp boggabriMedium
Ambrosia artemisifolia annual ragweed Medium
Ambrosia confertiflora burr ragweed Medium
Ambrosia psilostachya perennial ragweed Medium
Ambrosia tenuifolia lacy ragweed Medium
Ammi majus bishops weedMedium
Amsinckia spp amsinckia Nil
Andropogon virginicus whiskey grass Medium Regrowth
Angophora spp appleMedium High
Anredera cordifolia madeira vineLow
Apophyllum anomalum warrior bush High
Araujia hortorum mothplant Medium
Arctotheca calendula capeweed High
Argemone mexicanamexican poppy Nil
Aristida sppwire grassMedium
Asclepias sppredhead cotton bushNil
Asclepias curassavica cotton bush Nil
Asphodelus fistulosus onion weed Nil
Atalaya hemiglauca whitewoodHigh
Atriplex sppsaltbush Medium
Atropa belladonnadeadly nightshade Toxic
Avena spp wild oats High
Baccharis halimifolia groundsel bush High
Bambusa sppbambooHigh Regrowth
Bidens pilosacobblers pegHigh
Brachychiton populneum kurrajong High
Brassica tournefortii wild turnip High
Bromus diandrusgreat brome High Regrowth
Brugmansia candidaangels trumpet Toxic
Bursaria spinosajimmy burnHigh
Buxus spp box hedgeMedium
Caesalpina sppmysore thornNil
Calicotome spinosaspiny broom Medium
Callitris columellaris cyprus pine High
Callitris endlicheri black cyprus pine Nil
Calotropis procerarubber treeHigh
Caninia quinquefariaHigh
Cannabis sativaindian hempHigh
Capparis mitchelliiwhite orange Medium
Capsella bursa-pastoris shepherds purseNil
Cardiospermum sppballoon vine Medium Flower
Carduus nutansnodding thistle Medium Flower
Carduus pycnocephalus slender thistleMedium Flower
Carex spp sedgeMedium Flower
Carthamus lanatussaffron thistle Medium Flower
Carthamus leucocaulos glaucus star thistle Medium Flower
Cassia artemisioides silver cassia Low
Cassia eremophiladesert cassia Nil
Cassia floribundaarsenic bush, smooth cassia Medium
Cassia obtusifoliasickle pod High
Cassinia arcuatasifton bushLow
Casuarina cristatabelah High
Cenchrus echinatusmossman river grass Medium Regrowth
Cenchrus sppspiny burrgrass Medium Regrowth
Centaurea melitensis cockspur Low
Centaurea nigrablack knapweed Medium
Centaurea solstitialis st barnabys thistle Medium Flower
Cestrum parquicestrum Toxic
Chamaecytisus proliferus lucerne tree High
Chenopodium albumfat hen High
Chenopodium nitrariacem nitre goosefootHigh
Chloris spp windmill grass Medium Regrowth
Chondrilla junceaskeleton weed Medium Regrowth
Chrysanthemoides monilifera bitou bush High
Cichorium intybuschicory Medium
Cineraria lyratacinerariaMedium
Cinnamomum camphoracamphor laurel High
Cirsium arvenseperennial thistle Medium Flower
Cirsium vulgareblack thistle Medium Flower
Citrullus colocynthis bitter appleMedium
Citrullus lanatusbitter melonLow
Codonocarpus spphorse radish tree Low
Conium maculatumhemlock Medium
Consolida ambigualarkspurToxic
Convallaria majalislily of the valleyToxic
Convolvulus arvensisbindweedHigh
Conyza albidatall fleabaneHigh
Coreopsis lanceolata coreopsis Medium
Cortaderia spppampas grass High Regrowth
Cotoneaster spp Medium
Cotula australiscarrot weed Medium
Craspedia sppround billy buttons Medium Flower
Crataegus spphawthornMedium
Cryptostegia grandiflora rubber vineLow
Cucumis myriocarpuspaddy melon Medium
Cuscuta spp dodder High
Cycas spp zamia Low
Cynara cardunculusartichoke thistle High Flower
Cynodon dactyloncouch Medium
Cyperus aromaticusnavua sedge Medium Flower
Cyperus rotundusnut grassLow Flower
Cytisus scopariusbroom High
Danthonia sppwallaby grass High
Daphne odora Toxic
Datura stramoniumthorn apple, jimson weedNil
Delphinium spp Nil
Dieffenbachia sppdumbcaneToxic
Digitalis purpureafoxglove Toxic
Diplotaxis tenuifolia sand rocketMedium Flower
Dittrichia graveolens stinkwortMedium Regrowth
Dodonaea attenuatanarrow leaf hop bush High
Dodonaea viscosabroad leaf hop bush Medium Flower
Duboisia hopwoodiipituri Nil
Duranta repensToxic
Ecballium elateriumsquirting cucumber Nil
Echium plantagineumpatersons curse Medium Flower
Echium vulgarevipers bugloss High Flower
Emex australisemexMedium
Eragrostis australasica cane grassMedium
Eragrostis curvulaafrican love grassHigh Regrowth
Eremophila longifolia emu bush High
Eremophila mitchellii budda Low
Eremophila sturtiiturpentine bushNil
Erodium spp crowfoot Medium Flower
Erythrina sppcoraltreeHigh
Erythroxylum cocacoco leaf Medium
Eucalyptus albenswhite box Medium Flower
Eucalyptus cladocalyx sugar gum Toxic
Eucalyptus melliodora yellow box Medium Regrowth
Eucalyptus polyanthemos red box Medium Flower
Eucalyptus populneabimble box Low
Euphorbia helioscopia spurge Nil
Euphorbia heterophylla milkweed Nil
Euphorbia lathyruscaper spurge Nil
Euphorbia pulcherrima poinsettia Toxic
Euphorbia terracinageraldton carnation Toxic
Foeniculum vulgarefennel Medium
Froelichia floridana cottontails Medium
Galenia pubescensgaleniaMedium
Gastrolobium grandiflorum desert poison bush Toxic
Gaura parvifloraclockweed Medium
Geijera parviflorawilga Low
Gelsemium sempervirens yellow jasmine Toxic
Genista linifoliaflax-leaved broom High
Genista monspessulana canary broom High
Gleditisia triacanthos honey locust tree High
Gloriosa superbaglory lily Toxic
Gnaphalium sppcudweed Low
Gomphocarpus fruticosa narrow-leaf cotton bush Nil
Gomphocarpus physocarpus balloon cotton bushNil
Gorteria personataHigh
Haloragis asperaHigh
Heliotropium amplexicaule blue heliotrope Toxic
Heliotropium europaeum common heliotrope Low
Helleborus nigerchristmas rose Toxic
Heterodendrum oleifolium rosewood High
Hibiscus trionumbladder ketmia Medium
Hirschfeldia incanabuchan weed Medium Regrowth
Homeria spp cape tulips Low
Hordeum leporinumbarley grass Medium
Hydrangea sppLow
Botanical nameCommon namepalatability*
Hyparrhenia hirtacoolatai grass High
Hypericum androsaemum tutsanLow
Hypericum perforatum st johns sortLow Toxic
Hypericum tetrapterum st peters wort Medium
Hypericum triquetrifolium tangled hypericum Medium
Hypochaeris radicata cats earFlower
Ibicella luteadevils claw Nil
Ilex spphollyLow
Imperata cylindricablady grass High Regrowth
Ipomoea lonchophylla cow vine Medium
Ipomoea plebeiabell vine Medium
Ipomoea purpureamorning glory High
Ipomoea sppweir vine Medium
Iva axillarispoverty weed Medium
Jatropha curcasphysic nut Toxic
Juncus acutusspiny rush Flower
Juncus spprushes Meium Flower
Kalanchoe tubifloramother of millions Toxic
Laburnum spp Low
Lactuca serriolaprickly lettuce High
Lantana camara sppHigh
Lathyrus odoratussweet pea Toxic
Laurel spp M
Lavandula stoechaslavenderMedium
Lepidium spppeppercress Medium Flower
Leucanthemum vulgare ox-eye daisyMedium
Ligustrum lucidumbroad-leaf privetHigh
Ligustrum sinensesmall-leaf privet High
Linaria dalmaticadalmation toad-flaxToxic
Lolium spp rye grassHigh
Lomandra longifoliamat rush Low
Lonicera japonicahoneysuckle High
Lycium ferocissimumafrican box-thorn Medium
Macfadyena unguis-cati cats-claw creeper Nil
Macrozamia sppburrawang Nil
Maireana sppblue bush Medium
Malva parvifloramarshmallow Low
Malvella leprosaivy-leaf sidaMedium
Marrubium vulgarehorehound High Flower
Medicago falcatayellow-flowered lucerne High
Medicago sativalucerne High
Melia azedarachwhite cedar Medium
Melianthus comosustufted honerflower Nil
Melilotus albusbokhara clover Medium
Muehlenbeckia Cunninghamii lignumHigh
Myagrum perfoliatummitre cress High
Nassella neesianachilean needle gress Medium
Nassella trichotomaserrated tussock Medium Regrowth
Nerium oleanderoleander Toxic
Nicandra physalodesapple of peru Medium Flower
Nicotiana glaucatree tobacco Medium
Olea europaeaolive Medium
Olearia ellipticaaustralian daisy Medium
Onopordum acanthiumscotch thistle Medium
Onopordum acaulonstemless thistle Medium Flower
Onopordum illyricumillyrian thistleMedium Flower
Opuntia inermisprickly pear Low
Opuntia strictacommon prickly pear Low
Owenia acidulagruieHigh
Oxalis latifoliaoxalis Low
Oxalis pes-capraesoursob Medium
Papaver somniferumopium poppy Low
Parthenium hysterophorus parthenium weed Medium
Peganum harmalaafrican rue Nil
Pennisetum macrourum african feather grass Medium Regrowth
Pennisetum villosumlong-style feather grass Medium Regrowth
Pentzia suffruticosa calomba daisy Low
Persicaria sppsmart weed Medium
Phalaris minorlesser canary grass High
Phragmites australis common reed Medium Flower
Phyla canescenslippia Low
Physalis virginianaperennial ground cherry Low
Physalis viscosaprarie ground cherry Medium Flower
Phytolacca octandrainkweed Medium
Pimelea curviflorapimelia, desert rice bush Nil
Pinus radiataradiata pine High
Poa labillardieripoa tussock Medium
Polygonum avicularewire weed Medium
Portulaca oleraceapurslane Low
Proboscidea louisianica devils claw Low
Prosopis julifloramesquite High
Prunus persicapeach, plum High
Pteridium esculentum bracken L Pd
Pyracantha sppindian hawthorn High
Raphanus raphanistrum wild radish Medium
Rapistrum rugosumturnip weedHigh
Rhododendron spp Low
Ricinus communiscaster oil plant Medium
Robinia pseudoacacia black locust Medium
Romulea roseaguildford grassMedium
Rosa canina dog rose High
Rosa rubiginosa sweet briar High
Rubus fruiticosusblackberry High
Rumex acetosellasorrel Medium
Rumex browniiswamp dock Low
Rumex conglomeratusclustered dock Low
Rumex crispuscurled dock Medium
Rumex obtusifoliusbroad-leaf dockLow
Rhododendron sppLow
Ricinus communiscaster oil plantMedium
Robinia pseudoacacia black locust Medium
Romulea roseaguildford grassMedium
Rosa canina dog rose High
Rosa rubiginosasweet briar High
Rubus fruiticosusblackberry High
Rumex acetosellasorrel Medium
Rumex browniiswamp dock Low
Rumex conglomeratusclustered dock Low
Rumex crispuscurled dock Medium
Rumex obtusifoliusbroad-leaf dock Low
Rumex pulcherfiddle dock Medium Regrowth
Salsola kali soft roly poly Medium
Salvia reflexamint weed Medium
Schinus spppepper tree High
Sclerolaena birchiigalvanised burr Medium
Sclerolaena muricata black roly poly Medium Regrowth
Scolymus hispanicusgolden thistle Medium Flower
Senecio jacobaearagwort Low
Senecio madagascariensis fireweed High Flower
Senecio pterophorusafrican daisy Low
Senecio quadridentatus cotton fireweed High
Senecio vulgariscommon groundselHigh
Senna artemisioidessilver cassiaLow
Senna barclayanapepper-leaved sennaMedium
Sida acuta spiny-head sidaMedium Regrowth
Sida cordifoliaflannel weed Medium
Sida rhombifoliapaddys lucerne High
Silene vulgarisbladder campion Nil
Silybum marianumvariegated thistleHigh
Sisymbrium officinale hedge mustard High Flower
Solanum carolinensecarolina horse nettleLow
Solanum cinereumnarrawa burr Nil
Solanum elaeagnifolium silverleaf nightshade Medium
Solanum hermanniiapple of sodom Nil
Solanum laciniatumkangaroo apple Nil
Solanum marginatumwhite-edge nightshade Nil
Solanum mauritianumwild tobacco tree Medium
Solanum nigrumblackberry nightshade Nil
Solanum rostratumbuffalo burr Nil
Soliva pterospermajo-joLow
Sonchus sppmilk thistle High
Sorghum halepensejohnson grassHigh
Sorghum sppsilk forage sorghum High
Sorghum x almumcolumbus grass High Regrowth
Sporobolus carolifairy grass Medium Flower
Sporobolus indicusgiant parramatta grass Medium Regrowth
Sporobolus pyramidalis giant rats tail grass Medium Regrowth
Stachys arvensisstagger weed Medium
Stevia eupatoriastevia Low
Stipa caudataespartilloMedium Regrowth
Stipa sppspear grass Medium Regrowth
Swainsona sppdarling peaToxic
Tagetes minutastinking roger Medium
Taxus baccataenglish yew Toxic
Thevetia peruvianayellow oleander Toxic
Thunbergia grandiflora blue trumpet vine Medium
Toxicodendron radicans poison ivy Low
Toxicodendron succedaneum rhus tree Medium
Trema asperapeach leaf poison bush Toxic
Tribulus terrestriscaltrop Medium
Trifolium sppcloversMedium Flower
Typha sppcumbungiMedium
Ulex europaeusgorse High
Urochloa panicoidesliverseed grass High
Urtica incisascrub nettle Low
Urtica sppstinging nettle Low
Ventilago viminalissupplejack High
Verbascum thapsusaarons rod, great mullein High Flower
Verbena sppverbena High Flower
Verbena tenuisectamaynes pest High
Watsonia bulbillifera watsonia Medium Regrowth
Xanthium occidentale noogoora burr Toxic
Xanthium orientalecalifornian burr Toxic
Xanthium spinosumbathurst burr Low
Zantedeschia aethiopica arum lilyNil

palatability* where:
Flower = Eaten at flowering
High = High palatability
Low = Low palatability
Medium = Moderate palatability
Nil = Not eaten
Physical = Physical damage caused by goats
Recent = Recent growth, regrowth
Toxic = Toxic

Grazing impact is a result of plant selection (palatability or aversion) rather than plant availability so that Table 1 directly assists grazing management while the genera listing helps our understanding of palatability, toxicity, and the theory of aversion (Provenza, 1996).

These are indications of potential toxicity only, and not all of these are applicable to goats,who have a remarkable digestive system. Many plants are found as garden refuse, and fed to livestock as a "treat", while others are found naturally in grazing areas.

For further information see: "The Potential Palatability and Toxicity of Australian Weeds to Goats". Simmonds, Holst and Bourke. This also includes new information on palatability to goats of many more weeds.

© 2000 ACGA