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Poisonous plants – A brief introduction
Robert Mc Kinnon SDV Central North LHPA
Plant factorsspeciescultivarstage of growthpest/fungusmono/polyculture
Animal factorsspeciesprevious exposureagenutritional status
Environmental factors
management
RainfallTemperatureSoil typeSolar radiation
Why do animals eat poisonous plants
• Problem with introduced animals
• The way we manage stock and pastures
• At certain times in their life cycle they are palatable to stock
– Sugars they produce
– Higher energy density then surrounding feed
– They are used as a fibre source
Arrowleaf Clover* Balansa Clover* Berseem Clover* Biserrula* Barrel Medic*
Burr Medic* Crimson Clover* Gama Medic* Gland Clover* Hybrid Medic*
Murex Medic* Snail Medic* Sphere Medic* Strand Medic* Persian Clover*
Rose Clover* Serradella Subterranean
Clover*
Wooly Pod
Vetch*
Strawberry
Clover*
Birdsfoot Trefoil* Caucasian Clover* Lotus* Lucerne* Red Clover*
White Clover* Grazing Brome Kangaroo Grass Pasture Brome Perennial Veldt
Grass
Cocksfoot Prairie Grass* Puccinellia Ryegrass* Ryegrass-Annual*
Phalaris* Tall Wheatgrass Timothy Wallaby Grass* Weeping Grass
Tall Fescue* Atro Axillaris Creeping Vigna Forage Peanut
Glycine Greenleaf
Desmodium
Roundleaf Cassia Bahia Grass Bambatsi Panic*
Bermuda Couch
Grass*
Bluegrass Buffel Grass* Creeping
Bluegrass
Digit Grass
Forest Bluegrass Gatton or Green
Panic*
Indian Bluegrass Kikuyu* Lovegrass
Mitchell Grass* Molasses Grass Paspalum* Purple Pigeon
Grass*
Rhodes Grass*
Setaria* Chicory Plantain Couch grass* Liverseed *
Oats* Winter Wheat* Fodder sorghum* Forage brassicas* Canola *
Table 1: pasture species and toxicity
Early vegetative Vegetative Mature Senescence
Nitrate/Cyanide
Bloat
Hypocalcaemia
Hypomagnesaemia
Photosensitisation
Fog fever
Ergot derivatives
Lactic acidosis
Thiaminase (pem)
Management poisonings#
Enterotoxaemia
Mesenteric torsions
Woody tongue
Grass seed
# Management poisonings refer to npn poisoning, grain poisoning , mycotoxicosis, bloat, induced calcium deficiency from supplementation
Syndromes
• Sudden death
• Recumbency and death
• Neural type
• Ataxia type
• Dermatosis
• Illthrift
• Haemorrhage
Sudden death
• Plants that cause bloat• Nitrate poisoning• Cyanide poisoning• Oxalate poisoning via hypocalacaemia• Peracute liver damage – green cestrum• Peracute Crown beard• Peracute oleander• Acute Phalaris poisoning• Noogoora burr• Blue green algae
Plants the cause recumbency and death
• Mother of millions
• Rock fern (cattle)
• Single leafed cape tulip
• Oleander
• Crown beard
Neural type lesions
• Thiaminase containing plants (rock fern, nardoo fern, pastures, wild turnip) cause PEM
• Patersons curse
• Blue heliotrope
Group 1 limb paresis syndromes
Ixiolaena brevicompta Billy buttons
Malva parviflora Marshmallow
Trachymene ochracea Wild parsnip
Tribulus terrestris Cathead, caltrops
Xanthorrhoea spp Grasstrees ,yucca
Lathyrus spp peas
Humpy back syndrome (malva, malvastrum, solanum, sida)
Acute soluble oxalate hypocalcaemic staggers Oxalate plants
Group 2 Limb paresis with knuckling syndromes
Romulea rosea Onion grass
Trigonella foenumgraecum Fenugreek
Stachys arvensis Stagger weed
Trachyandra divaricate Branched onion weed
Tribulus micrococcus Yellow vine (reversible)
Macrozamia spp Cycad leaves
Stypandra glauca Nodding blue lily
ipomoea Convolvulus weir vine
Group 3 Falling syndromes
Swainsona sp Darling pea
Solanum cinereum Narrawa bur
Group 4 Falling with tremors syndrome
Phalaris sp phalaris
Lolium perenne Perennial ryegrass
paspalum Paspalum infected with Claviceps paspali
Sorghum spp
Aspergillus clavatus infected grain sprouts
Chamaecytisus proliferus var palmensis Tagasaste
Lupinus albus Braod leaf lupin bitter types
Group 5 Convulsive syndromes
Thiaminase group of syndromes Ferns- rock, nardoo, bracken
Tunicamycin like group of syndromes Blow away and beard grass and annual ryegrass
affected by Rathayibacter toxicus
Terminal convulsions Phalaris acute ammonia toxicity
Ataxia syndromes (mainly relate to sheep)
Dermatosis syndromes
• Photosensitisation
- Pasture
- Medic
- Tribulus
- St johns wort
- anything damages liver
• Ergot – vascular lesions
• Vetch – eosinophilic granulomas
Illthrift syndromes
• Liver damaging plants - eg blue heliotrope
• Endophytes (ergovaline)- hyperthermia
• Vetch
Haemorrhage syndromes
• Rock fern cattle
• Bracken fern young cattle
The big 4 poisonings seen in the area
• Bloat
• Nitrate/nitrite
• Rock fern
• Polioencephalomalacia (thiaminase related)
Bloat
• Gaseous bloat - phytogenous cardiac glycosides
• Frothy bloat – stable foam from soluble proteins and carbohydrates
• Mechanical blockage
Nitrate/nitrite
• Many plants can contain large amounts of nitrate including
– Quick growing immature
– Frosting
– Water stressed
– Cloudy weather and heavily fertilised country
– Certain plants – variegated thistle
Nitrate/nitrite continued
• In this area we had a number of poisonings from hay. This is usually due to not the fodder crop but the water stressed contaminant
• Symptoms
– Occur quickly or after several days
– Weakness
– Trembling
– Staggering
– Rapid breathing
– Collapsing
– Brownish-blue membranes (mouth and nostrils)
Rock fern
Introduced animals
Usually winter spring months
Sheep develop PEM
Cattle display a haemorrhagic syndrome
Can continue to kill cattle up to three weeks after removal of the source
POLIOENCEPHALOMALACIA
• Due to deficiency in Vitamin B1
• This can be due to a frank deficiency
• Thiaminases in plants or from bacteria in the bowel.
• Sheep appear blind to start off with followed by star gazing and opithotonus
• Cattle have a tendency to be recumbent and not alert to the environment
• Or throw fits and die
• Number of species involved
– Rock fern
– Nardoo fern
– Wild turnip
– Pastures
Treatment
• We look at the herd rather then individual animal treatments
• It is amazing how the problem dissipates with a paddock change
• Prevention is the key
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