Session One of the MD Small Ruminant Webinar Series

1. TOXIC PLANTS
SUSAN SCHOENIAN & JEFF SEMLER
UNIVERSITY OF MARYLAND EXTENSION

2. TOXIC PLANTS
 Many plants contain
toxic compounds but
that doesn’t mean
they are always toxic.
 Toxic plants can be in
the pasture or in the
landscape.

3. TOXIC PLANTS
• Landscape Plants
• Pasture Plants
• Weeds
• Forage
Japanese Yew

4. VEGETABLE GARDENS
Many members of the night shade family.
Irish Potatoes

5. LANDSCAPE PLANTS
• Japanese Yew
• Azalea & Rhododendron
• Ornamental Cherry
• Red Maple (Acer rubrum)
• Garden Vegetables Ornamental Cherry
Rhododendron
Red Maple

6. LANDSCAPE PLANTS
• Not feed
• Best place for them is the compost pile.
Lilies

7. POISONOUS PLANTS COMMONLY
FOUND IN PASTURES
• Nitrate & Oxalate Poisoning
• Liver Disease & Sunlight Sensitivity
• Organ Failure
• Cardiovascular Health
• Irritation
• Cyanide Poisoning
• Physical Injury
Buttercup

8. DO NOT PANIC
• Many plants are not always
toxic
• Some plants are mildly or
medicinally toxic
• Many toxic plants are not
palatable
• Some plants are lethal
Wild Black Cherry

9. NITRATE & OXALATE
POISONING
• Some plants absorb excess nitrates or oxalates from the
soil and store them in plant tissues.
• Toxicity problems can occur in animals which feed on
these plants.

10. LAMBSQUARTER,
CHENOPODIUM ALBUM
• Animals Affected: Sheep and pigs
• Toxin family: Nitrate and oxalate accumulator
• Other: Poisonous if eaten in large amounts, young leaves
palatable

11. DOCK, RUMEX SPP.
• Animals Affected: Sheep and horses, cattle less susceptible
• Toxin family: Oxalate accumulator: not a common source of
oxalate poisoning, but Rumex spp. will cause poisoning if
eaten in excess
• Other: May cause irritation to the skin and digestive tract.
• Dangerous levels are rare. Can cause hypocalcemia.
• Toxin is detoxified by the rumen except if eaten in large
quantities. Rumex spp. in silage is not a critical problem

12. LIVER DISEASE & SUNLIGHT
SENSITIVITY
• Plants causing liver disease and photosensitation (sensitivity to
sunlight) are often grouped together, as photosensitivity is
often a secondary symptom of liver disease cause by
poisonous plants.
Cocklebur

13. COCKLEBUR,
XANTHIUM STRUMARIUM
• Animals Affected: All livestock
• Toxin Family: Sulfated glycoside (Carboxyactractyloside)
causing liver necrosis.
• Other: Death occurs rapidly. Seedlings and seeds are very
toxic, but toxins are not present in mature plants.
• Seeds are rarely eaten as they are contained in a bur.
• Toxicity remains in hay and silage.
• Burs also cause economic damage to wool producers.

14. ORGAN FAILURE
• This group of plants contain pyrrolizidine
alkaloids which are the most common
cause of liver damage, but also can
cause kidney damage, heart failure,
cancer and photosensitization.
• Animals typically will not readily eat
plants with pyrrolizidine alkaloids, unless
no other forage is available.
Groundsel

15. RAGWORTS/GROUNDSEL,
SENECIO SPP.
• Animals Affected: All Livestock.
• Toxin Family: Pyrrolizidine alkaloids – amounts varying with
species and stage of growth, young plants being most toxic.
• Other: Causes acute liver necrosis and quick death or chronic
poisoning by ingesting small amounts over longer period of
time (generally within 3 weeks) causing chronic liver disease.
Wobbling, loss of appetite, lethargic, crusty eyes/nose,
prevents liver cell reproduction.
• Not palatable unless other forage not available. Young leaves
most toxic. Remains toxic in hay

16. JIMSONWEED, DATURA
STRAMONIUM L.
• All parts of Jimsonweed are
poisonous.
• Leaves and seeds are the
usual source of poisoning,
but are rarely eaten do to its
strong odor and unpleasant
taste.
• Poisoning can occur when
hungry animals are on
sparse pasture with
Jimsonweed infestation.
• Most animal poisoning
results from feed
contamination.

17. CARDIOVASCULAR HEALTH
• Cardiac glycosides are the most
common toxin affecting cardiovascular
health.
• Generally all parts of the plant are
highly toxic and lethal if eaten in small
quantities.
• However, animals typically will not
readily eat these unpalatable plants,
unless no other forage is available.
Horsenettle

18. NIGHTSHADES, SOLANUM
SSP.
• Animals Affected: Livestock and
humans
• Toxin Family: Steroidal
glycoalkaloids
• Other: Decreased heart and
respiratory rates, muscle
weakness, colic; can lead to
cardiac arrest. Rarely eaten
unless no other forage is
present. Bright berries of S.
dulcamara can be attractive to
children.

19. IRRITATION
• Plants in this group contain
compounds that may irritate an
animal's digestive tract, mouth or
skin if consumed.
• These plants are not generally
palatable and are typically avoided.
Leafy Spurge

20. BUTTERCUPS, RANUNCULUS
SPP.
• Animals Affected: sheep, cattle
• Toxin Family: Protoanemonin from
Ranunculin glycoside, released when plant is
chewed.
• Other: Protoanemonin irritates the mouth,
causes excessive salivation and intestinal
irritation which can result in diarrhea. Can be
fatal if eaten in excessive quantities. Causes
sharp drop in milk production, and blistered
lips. Creeping buttercup is toxic to cattle. Bur
Buttercup is highly toxic to sheep. Toxin lost
in dried forage. Plants not highly palatable:
generally avoided.
Buttercup

21. CYANIDE POISONING
• This group of plants contain
cyanogenic glycosides that
are converted to hydrogen
cyanide or prussic acid
when the plant cells are
damaged.
• Chronic poisoning over
time causes loss of nerve
function while acute
poisoning causes death.
Chokecherry

22. PRUNUS SEROTINE –
BLACK CHERRY
• Animals Affected: Ruminants
• Toxin Family: Cyanogenic glycosides
found in seed and leaves, bark and
shoots.
• Other: Causes cyanide poisoning.
Largest succulent leaves are most
toxic. Wilted leaves and new growth
are also highly toxic. Do not plant
near animal enclosures.

23. PRUSSIC ACID POISONING
• Sudangrass, forage sorghums and sorghum-sudangrass
crosses (all in the genus Sorghum) are often planted for
summer pasture and sometimes fed as green chop, silage or
hay.
• Under certain environmental conditions, livestock may develop
symptoms of prussic acid poisoning when these forages are
pastured or fed as green chop.
• Death can result from prussic acid poisoning, most commonly
when livestock have fed on plants that are either very young,
stunted by drought or frosted.
• Cattle and sheep are more susceptible than swine, since they
are more likely to consume large quantities of the poison.

24. PRUSSIC ACID POISONING
• Johnsongrass, shattercane and sorghum almum could contain
dangerous levels of prussic acid, and may be hazardous in
pure stands or as contaminants in sudangrass or sorghum-
sudan cross pastures.
• Fence rows contaminated with these weedy species might also
be hazardous.
Johnsongrass

25. PRUSSIC ACID POISONING
• Drought. Severe drought is probably the most common cause
of prussic acid poisoning. Drought-stricken plants are
hazardous to feed because they are mostly leaves. Sorghum
grazed or fed as green chop in the heart of a drought may
retain high levels of this poison.
• Freezing. Cold weather may kill only the tops of sorghum
plants, leaving the lower portion alive. The unbound prussic
acid in this forage does not decline until wilting begins. The
forage is usually considered safe to pasture or feed as green
chop 5-6 days after a killing frost. New shoots emerging from
unkilled portions of the plant are apt to be high in prussic acid.
Therefore, this forage should not be used until that new growth
reaches a height of 2 feet.

26. PHYSICAL INJURY
• Many plants have characteristic that can cause injury to
grazing animals.
• Some grasses can be palatable when young, but can
cause injury to the nose, eyes, mouth and ears of grazing
animals when plants mature with long awns.

27. CHEAT,
BROMUS SECALINUS
• Animals Affected: All livestock
• Toxin Family: Physical injury
• Other: Awns cause physical injury to nose and mouth of
grazing animals.

28. ERGOT ALKALOIDS - FESCUE
TOXICOSIS
Tall fescue is the primary cool season grass in the
Eastern US.
Kentucky 31 tall fescue contains an endophyte (fungus)
that produces ergot alkaloids (toxin).
Ergot alkaloids alter systems of the body that are
controlled by neurotransmitters (brain chemicals): heart,
blood, appetite, hormonal, gut motility, muscle
contractions, and body temperature.
Signs of fescue toxicosis vary by livestock species.
• Sheep seem to be less affected than cattle.
• Limited information is available on goats.
• Cost to small ruminant industry is unknown
• $500-$1 billion cost to beef industry.

29. SOME POTENTIAL EFFECTS OF
FESCUE TOXICOSIS SYNDROME
(some scientifically-proven*, some antidotal) -- mostly sub-clinical
HEALTH/WELFARE
Fescue foot
Fat necrosis*
Rough hair
coats
Heat stress*
GROWTH
Suppressed
appetite*
Lower intake*
Reduced
weight gain*
REPRODUCTION
Prolonged gestation
Thickened placentas
Reduced fetal growth*
Weak offspring
Poor mothering
Reduced milk*
production
Agalactia*

30. MINIMIZING THE EFFECTS OF
FESCUE TOXICOSIS
Dilute endophyte-infected tall fescue with other grasses or legumes.
Replace endophyte-infected tall fescue with another forage, e.g.
endophyte-free or novel tall fescue varieties (e.g. MaxQ™ tall fescue).
Increase stocking rates to prevent plant maturation and seed head
formation (fungus concentrates near seed head).
Avoid summer grazing and N fertilization.
Stockpile for fall and winter grazing, when effects of endophyte are less.
Alter nutritional management by providing supplemental feed to dilute
endophyte.
Don’t breed on endophyte-infected pastures.
Feed mineral mixes specifically formulated for sheep or goats.

31. RESOURCES
• http://poisonousplants.ansci.cornell.edu/index.html
• http://research.vet.upenn.edu/poisonousplants/Home/tabid/5034
/Default.aspx
• https://www.extension.purdue.edu/extmedia/ws/ws_37_toxicplan
ts08.pdf
• http://smallfarms.oregonstate.edu/poisonous-plants-commonly-
found-pastures
• http://www.extension.umn.edu/agriculture/forages/utilization/plan
ts-poisonous-to-livestock/
• https://www.agry.purdue.edu/ext/forages/publications/ay196.htm
Kiko x Boer

32. QUESTIONS?
THANK YOU FOR YOUR ATTENTION.
Kiko and crossbred bucks from 2012 test.