farmers postcard weeds and livestock...pyrrolizidine alkaloids toxins damage the liver +/- lungs and...

Lou Baskind BVScDistrict Veterinarian Local Land Services(02) 4842 2594lou.baskind@lls.nsw.gov.au

Farmers Postcard

Weeds and Livestock

© State of New South Wales through Department of Industry 2019. You may copy, distribute, display, download and otherwise freely deal with this publication for any purpose, provided that you attribute the Department of Industry as the owner. However, you must obtain permission if you wish to charge others for access to the publication (other than at cost); include the publication in advertising or a product for sale; modify the publication; or republish the publication on a website. You may freely link to the publication on a departmental website.

• Physical impediments or injuries

• Malnutrition

• Poisonings

What problems can common weeds cause in livestock?

• Impediments• Restricts access to water points

• Restricts access to feeding areas

• Limits movement and mustering

• Spines can cause injury

• Livestock can get stuck

• Injury• Physical damage to eyes, ears, feet

and mouth

• Wool contamination

Physical impediments or injuries

Physical impediments or injuries examples

BlackberryRubusfruticosusspecies aggregate

GorseUlex europaeus

Sweet BriarRosa rubiginosa

Physical impediments or injuries examples

ThistlesE.g. Illyrian Onopordum illyricum; Scotch Onopordum acanthiumSaffron Carthamus lanatus

NoogooraburrXanthium strumariumsyn. Xanthium occidentale

Cathead / CaltropsTribulusterrestris

• Tangled prickly stems

• Dense thickets

• Sharp spines

• Palatability problems

Image 2

Physical impediments or injuries

Wool contamination

• Reduces price (extra processing)

• Injuries / uncomfortable to handle

• Damages equipment

Wool contamination

Saffron Thistle Carthamus lanatus

Bathurst BurrXanthium spinosum

Noogoora burrXanthium strumarium

Cathead / CaltropsTribulus terrestris

• Reduces price (extra processing)

• Injuries / uncomfortable to handle contaminated wool

• Damages equipment

• Eyes, ears, feet and mouth

• More susceptible to other health problems

• Scabby mouth

• Pinkeye

Physical damage

Scabby mouth in sheep Pinkeye in cattle Pinkeye

Thistles Burrs

Physical damage examples

Malnutrition

• Competes with better quality pasture

• Unpalatable

• Poor nutritional content

• If too fibrous: limits intake

Malnutrition examples

Serrated tussockNassella trichotoma

African lovegrassEragrostis curvula

An introduction to pasture quality• Digestibility

• How much of the plant can be utilised

• Related to energy content• See table

Example: Adult angus cow 550kg body weight

Late vegetative to early flowering Cocksfoot (Dactylis glomerata)

Versus

Late vegetative to early flowering African Lovegrass (Eragrostis Curvula)

An introduction to pasture quality

Cocksfoot (Dactylis glomerata)

Digestibility is 70% Energy 9.9 MJ ME/kg DM (see table)

An introduction to pasture quality

Fibre (NDF) is 60% calculated maximum daily intake is 2% bodyweight = 11 kg DM / day

African Lovegrass (Eragrostis curvula)

Digestibility is 50% Energy 6.5 MJ ME/kg DM (see table)

An introduction to pasture quality

Fibre (NDF) is 73% calculated maximum daily intake is 1.65% bodyweight = 9 kg DM / day

Calculating maintenance energy

For more information see NSW Department of Primary Industries’ Managing and Preparing for Drought Guide 2018, and many other useful feeding guides on the NSW DPI website https://www.dpi.nsw.gov.au/ animals-and-livestock/nutrition

Weight of cattle 

Energy of feed

Kg per day

“Dry” (Maintenance)6.25kg / day

6 months pregnant (add 20%)7.5kg / day

8 months pregnant (add 40%)8.75kg / day

With a calf (add 60%)10kg / day

In the cold (add 20%) with calf11.25kg / dayWeight loss(cannot eat enough)

Cocksfoot (Dactylis glomerata)

African Lovegrass (Eragrostis curvula) “Dry” (Maintenance)

10.3kg / dayWeight loss(cannot eat enough for maintenance)

6 months pregnant (add 20%)12.36kg / day

8 months pregnant (add 40%)14.4kg / day

With a calf (add 60%)16.5 kg / day

In the cold (add 20%) with calf18.6 kg / day

Malnutrition

• Quality too low to maintain stock body weight

• Animals may not graze it by choice

• Indigestible balls in rumen

Animal health and welfare

Malnutrition example

Serrated tussockNassella trichotoma

• Digestibility 30 – 50%• Energy 4 – 7 MJ ME kg/DM• NDF 85%

Malnutrition example

Serrated tussock (Nassella trichotoma)

Poisonings

• What makes plants poisonous?

• Some plant poisoning syndromes

• Plant poisoning “first aid”

What makes plants poisonous?

• Multifactorial

• Plant factors

• Environmental factors

• Animal factors

There are over 200 plant species in Australia that are potentially toxic to ruminants!

Plant factors• Toxic chemicals (defence mechanisms)

• Palatability

• Stage of growth

• Part of the plant (stems, leaves or flowers)

• Disturbance or stress (see environmental factors)

Environmental factors• Rainfall moisture stress

• High temperatures wilting

• Cold or overcast conditions

• Soil minerals and nutrients (including urine and manure)

• Insects or pathogens

• Fertiliser use

• Herbicide use

Animal factors• Species (ruminant vs non-ruminant)

• Age (detoxification systems, body size)

• Prior learning / novel foods

• Hunger

• Malnutrition

• Confinement / lack of choice

• Tolerance

Drought!

Nitrate toxicity on fodder oats (avena sativa)

Case study

Avena sativaLake George area, 2019

Basic overview of nitrate toxicity

“The perfect storm”

• Sudden death (+/- collapse, breathing problems)

• “Staggers”

• Gastrointestinal (bloat, diarrhoea etc.)

• Photosensitisation

• Chronic and cumulative poisonings

• Bracken poisoning

Some plant poisoning syndromes

Sudden death: Nitrate toxicity

Ruminants

• Organs starved of oxygen

• Rapid breathing

• Weakness

• Lethargy

• Abortions

Sudden death: Nitrate toxicity examples

Cathead / CaltropsTribulusterrestris• Relatively

un-palatable

Wild Radish (Raphanusrapha-nistrum)• palatable

Mintweed(Salvia reflexa)• Relatively

unpalatable• More

palatable as it dies in late autumn / early winter

ThistlesPatersonsCurseEchiumPlantagineum• Relatively

palatable, more after herbicides

• Sudden death (+/- collapse, breathing problems)

• “Staggers”

• Gastrointestinal (bloat, diarrhoea etc.)

• Photosensitisation

• Chronic and cumulative poisonings

• Bracken poisoning

Some plant poisoning syndromes

• Falling with tremors syndrome

• Other neurological or neuromuscular conditions

“Staggers”

Staggers example: “Phalaris staggers”

Phalaris (Phalaris aquatica)

• Multifactorial• Lush new growth• In the morning• High soil nitrogen• High temperatures• Foggy or cloudy weather /

shade• Frost

• Tremors and

weakness

• Worse when forced

to exercise

• Excitable

• Head tremors,

twitching, nodding

• Kneeling,

knuckling

• Falling over

• Problems eating

• (Sudden death)

• Cattle and sheep

• Alpacas (sudden death syndrome)

Staggers example:“Coonabarabran staggers”

Cathead / Caltrops(tribulus terrestris)

• Progressive muscle weakness

• Lean to one side

• Walk on diagonal

• Eventual deathSheep• Eating large

amounts

Staggers example: Sulphur poisoning

Wild radish (Raphanusraphanistrum)

• Stop eating

• Lethargic

• Breathing problems

• Depression / aggression

• Apparent blindness

• Head pressing

• Aimless circling

• Confusion

• (Sudden death)

Ruminants

• Sudden death (+/- collapse, breathing problems)• “Staggers”

• Gastrointestinal

• Photosensitisation• Chronic and cumulative poisonings• Bracken poisoning

Some plant poisoning syndromes

Gastrointestinal example: Steroidal glycoalkaloids

Solanum species• Unripe fruits• Green parts

Herbivores• Hungry

• Severe diarrhoea and colic

• +/- vomiting

• Rarely breathing problems and depressed brain function

• Sudden death (+/- collapse, breathing problems)• “Staggers”• Gastrointestinal

• Photosensitisation

• Chronic and cumulative poisonings• Bracken poisoning

Some plant poisoning syndromes

Photosensitisation

• Primary or secondary• Sensitiser molecules lodge in skin• Activated by sunlight• React and cause inflammation• Unpigmented and unprotected skin affected

• PrimaryPlant pigments

• SecondaryLiver-damaging plant toxins Liver can’t excrete chlorophyll breakdown productsThese lodge in skin as sensitiser molecules

Photosensitisation: Reddened and swollen skin

• Sheep: Ears, eyelids, face, lips, coronets

• Cattle: Teats, udder, escutcheon, muzzle, underside of tongue • +/- Drooping ears, weeping eyes, high temperatures, restlessness and

confusion, incoordination, lameness, abortion

Photosensitisation examples

St Johns WortHypericum perforatum

Primary photosensitisation

Horses > Sheep > Cattle > Goats

• Worst in summer during flowering• Sheep only need ~60g in summer

(versus ~3kg in winter for toxic effect)

• Can use strategic grazing • Use adult Merinos, fine or super-fine, not

pregnant, not lactating, with 4 months of wool growth

Photosensitisation examples

Caltrop / CatheadTribulus terrestris

Mostly ruminants

• Stressed plants more toxic

• Chronic exposure

• Young animals more susceptible Secondary photosensitisation

• Sudden death (+/- collapse, breathing problems)• “Staggers”• Gastrointestinal • Photosensitisation

• Chronic and cumulative poisonings

• Bracken poisoning

Some plant poisoning syndromes

Pyrrolizidine Alkaloids

Toxins damage the liver +/- lungs and kidneys

Pigs > Poultry > Cattle and Horses > Sheep and Goats

Damage builds up over time

Once illness is observed it is permanent and usually fatal

Weeks to months until symptoms appear

Pyrrolizidine Alkaloids symptoms

EmaciationDiarrhoeaYawningCompulsive walkingBlindnessInjury from collisionsHead pressingMsucle tremorsDangerous behaviour

Weight lossDiarrhoeaDangerous behaviourBreathing difficulties

Weight lossDiarrhoeaBehaviour changeBreathing difficulties

“Toxaemic jaundice”Sudden death when stressed • Mustering

Pyrrolizidine alkaloids examples

Paterson’s curse(Salvation Jane)Echium plantagineum

FireweedSeneciomadagascariensis

• Sudden death (+/- collapse, breathing problems)• “Staggers”• Gastrointestinal • Photosensitisation• Chronic and cumulative poisoning

• Bracken poisoning

Some plant poisoning syndromes

Bracken Poisoning

• Extensive bleeding (“bracken poisoning”)

• Eating large amounts over 2 – 4 weeks

• Pale gums and whites of eyes +/- with pinpoint bleeding

• Blood in urine, manure, nasal discharge

• Infections and fever

• Tumours of the urinary bladder

• Eating small amounts over years

• Red urine +/- blood clots

• Progresses to anaemia, weakness, wasting, death

Bracken Poisoning

BrackenPteridium esculentum

• All parts of plant are toxic including underground parts

• Greatest concentration of toxin in young unfurling fronds

• 2 -4 weeks of intake

• Young animals, novel feed, palatable part of plant

• Move livestock slowly and carefully to an area with a different plant species composition

• Minimal stress

• Good quality non-green hay

• Good quality clean water

• Contact your vet or district vet

• Get the diagnosis confirmed

Plant poisoning “first aid”

• Photosensitisation

• Reduce exposure to sunlight• Shed / shade +/- animal sunscreens

• Good quality non-green hay

• Good quality clean water

• Contact your vet or district vet

• Get the diagnosis confirmed

• Vet to determine use of anti-inflammatory or antibiotic treatments

Plant poisoning “first aid”

• Weed seeds and stock• Different diets will affect the passage of seeds

through the gut• Generally will take 3- 4 days but up to 7 days• 10 day quarantine is best practice

• Adherence to sheep wool• Seeds can stay attached to wool for months• Shear before release from quarantine

• Care with bought in feed• Poisonings• New weeds establishing

Biosecurity

Resources and contacts

https://www.dpi.nsw.gov.au/biosecurity/weeds

https://www.olg.nsw.gov.au/local-government-directory

NSW Invasive Plants and Animals Enquiry LineP: 1800 680 244E: weeds@dpi.nsw.gov.au

Thank you!

Farmers Postcard

Weeds and LivestockLou Baskind BVScDistrict Veterinarian Local Land Services(02) 4842 2594lou.baskind@lls.nsw.gov.au

Images courtesy of

• Australian Wool Testing Authority Ltd. Vegetable Matter in Australian Wool. 2019. https://www.woolwise.com/wp-content/uploads/2017/06/Vegetable-Matter-in-Australian-Wool.pdf

• McKenzie R. Australia's poisonous plants, fungi and cyanobacteria. CSIRO Publishing, Collingwood, Vic., 2012

• Moore J. Furze or Gorse. 2019. http://www.herbiguide.com.au/Photos/Ulexeuro.pdf

• NSW Department of Industry. Managing and Preparing for Drought 2018. Department of Primary Industries, Skills and Regional Development, New South Wales, 2018

• NSW Department of Primary Industries. Prograze Manual Ninth Edition. Department of Primary Industries, Skills and Regional Development, 2017

• NSW Department of Primary Industries. Pinkeye in Cattle https://www.dpi.nsw.gov.au/__data/assets/pdf_file/0017/103904/pinkeye-in-cattle.pdf

• NSW Department of Primary Industries WeedWise. https://weeds.dpi.nsw.gov.au/

• WA Department of Primary Industries and Regional Development. Scabby Mouth in Sheep. https://www.agric.wa.gov.au/livestock-biosecurity/scabby-mouth-sheep

• Walker E. A Case of Photosensitisation Caused by St Johns Wort. Flock & Herd Case Studies 2012. http://www.flockandherd.net.au/sheep/reader/photosensitisation-stjohns-wort.html