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