Things That Are Toxic To Sheep

Photo by Avi Werde on Unsplash

Updated May 25, 2021

It can be a challenge to ensure sheep residents have healthy, happy lives after coming to a sanctuary, and there are many different aspects of care to consider each day. Unfortunately, toxic and poisonous hazards are sometimes overlooked in the hustle and bustle of operating a sanctuary. While minor exposure to many of these toxins are unlikely to cause serious problems, large amounts can cause severe health issues and sadly, even death. There are also some toxins that are highly dangerous even in small amounts.

In order to help ensure you never run into this problem, we have compiled this resource of common plants and other potentially toxic things that have been known to be a problem for sheep.

Toxic Plants

This is not an exhaustive list. There may be particular plants that grow in your region that are not included on the list. Check with your region’s agricultural department to ensure you have a full picture of what could be problematic for sheep in your area!

Ask About Activated Charcoal

While prevention is imperative when it comes to protecting your residents from toxins, in the event that they accidentally ingest something toxic, the administration of an activated charcoal product may help absorb the toxins. This is not a magic cure and may not be appropriate in all situations, but it can be helpful to have on hand. We suggest asking your veterinarian if there are specific products they recommend for the various species in your care so you can have them ready should you need them. In addition to seeking urgent medical care, if a resident ingests a toxin, ask your veterinarian if administration of activated charcoal is advised.

Plants That Are Toxic To Sheep

We have built a list below of a number of plants known to be toxic in some way to sheep. If you’d like more information, Check out The Open Sanctuary Project’s Global Toxic Plant Database and filter Species Afflicted by sheep in order to see a list of plants across the world that are toxic to sheep. Please note that, while comprehensive, this list may not contain every single plant toxic to sheep!

Adonis, Pheasant's Eye
  • vomiting
  • abdominal pain
  • diarrhea
  • cardiac arrhythmias

Azalea
  • anorexiaPhoto by Jeffrey Hamilton on Unsplash
  • excessive salivation
  • vomiting
  • colic
  • frequent defecation
  • in severe cases, muscle weakness
  • bradycardia
  • cardiac arrhythmia
  • weakness
  • paralysis
  • coma may precede death

Bitterweed, Rubberweed
  • If ingested in lesser quantities over a period of weeks exhibit the following symptoms:
  • depressed
  • off-feed
  • teeth grinding
  • hunched-up appearance
  • muscle tremors
  • weakness
  • recumbency
  • regurgitation
  • lung congestion
  • coughing
  • pneumonia
  • death

Black Henbane, Hogs Bean
  • decreased salivation (dry mouth)H. Zell
  • bloat
  • intestinal stasis
  • colic
  • diarrhea may result
  • ataxia due to muscle weakness
  • dilated pupils are common and animals may have difficulty seeing normally.
  • excitement and convulsions may occur when large amounts of plant are eaten

Black Locust
  • diarrhea
  • weakness
  • depression
  • cold extremities
  • weak pulse
  • irregular heartbeat

Bouncing Bet, Soapweed
  • anorexia
  • decreased rumen activityInAweofGod'sCreation
  • excessive salivation
  • colic
  • diarrhea
  • acute liver toxicity and death are possible

Brackenfern
  • weaknessPhoto by Mike Erskine on Unsplash
  • weight loss
  • pronounced bleeding
  • most often fatal after diagnosis
  • lower cumulative doses are carcinogenic

Buckwheat
  • Animals with white skin are most severely affected.Image by Hans Braxmeier from Pixabay
  • Black skinned animals are not affected except for showing photophobia if the eyes are not pigmented. Initially the non pigmented skin becomes reddened, severely pruritic, swollen and painful.
  • Severe photosensitization results in serum exidation and necrosis of the skin, causing the skin to become dry, parchment-like and eventually sloughing.
  • Affected animals become very agitated when exposed to sunlight often desperately seeking shade under vehicles, buildings, trees etc. to avoid exposure to sunlight light.
  • Photophobia and tearing may be evident.

Buffalo Bur, Kansas Thistle
  • bloatingAndrey Zharkikh
  • diarrhea may result from eating the young green plants.

Castor Bean
  • vomiting
  • diarrhea
  • increased thirst
  • convulsions
  • prostration
  • circulatory collapse

Cocklebur
  • symptoms appear within a few hours
  • weakness
  • unsteady gait
  • twisting of neck muscles
  • depression
  • nausea
  • vomiting
  • labored breathing
  • rapid, weak pulse
  • death

Colorado Rubberweed
  • salivation
  • coughingMatt Lavin from Bozeman, Montana, USA [CC BY-SA 2.0 (https://creativecommons.org/licenses/by-sa/2.0)]
  • vomiting rumen contents
  • rumen stasis
  • bloat
  • weakness
  • recumbency
  • death
  • Poisoning is infrequent when other forages are available.

Cow Cockle, Spring Cockle, Dairy Pink
  • diarrhea
  • acute liver failure

Crotolaria, Rattlepod
  • Yellow coloration to the mucous membranes (jaundice), weight loss, diarrhea, rectal prolapse, edema of the legs, red urine (hemoglobinurea) are signs of severe liver disease. Dinesh Valke
  • Abnormal neurologic behavior develops (depression, aimless wandering, head pressing) once sever liver degeneration is present.
  • Secondary photosensitization develops as a result of severe liver disease.Vengolis [CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0)]
  • White skinned (non pigmented) areas become red, swollen, and painful before the skin dies and sloughs-off as is if severely sun-burned.

Curly Leafed Dock, Sorrel
  • Within a few hours of consuming toxic levels of oxalates, the following symptoms may occur:
  • muscle tremors
  • tetany
  • weakness
  • reluctance to move
  • depression
  • recumbency
  • Coma and death may result within 12 hours.
  • Animals that survive the acute effects of oxalate poisoning frequently develop kidney failure. If animals do not die from the acute effects of the low blood calcium levels, death results from kidney failure.

Day Blooming Jasmine, Night Blooming Jasmine, Cestrum
  • Animals that have consumed the calcinogenic Cestrum diurnum over a period of weeks, develop a syndrome of:
  • chronic weight loss
  • stiffness
  • reluctance to move
  • lameness
  • eventually recumbency
  • Affected animals have elevated blood calcium levels. Death results from progressive calcification of the soft tissues of the body.
  • Animals consuming the non-calcinogenic Cestrum species (all Cestrum species except Cestrum diurnum) develop signs of:
  • liver failure
  • including weight loss
  • depression
  • jaundice
  • hepatic encephalopathy

Death Camus
  • excessive, foamy salivation
  • vomiting
  • frequent urination/defecation
  • diarrhea
  • convulsions
  • muscle weakness
  • staggering
  • rapid/weak pulse and respiration
  • Death can occur within days after ingestion of 0.5-2% of body weight.

Desert Baileye
  • loss of appetiteDick Culbert from Gibsons, B.C., Canada [CC BY 2.0 (https://creativecommons.org/licenses/by/2.0)]
  • vomiting rumen contents
  • green staining around the lips and nose.
  • reluctance to move
  • muscle tremors
  • incoordination
  • prostration
  • rapid, pounding heart rate.
  • coughing may indicate the presence of an inhalation pneumonia resulting from the regurgitation of rumen contents

Dogbane, Indian Hemp
  • Dogbane is rarely eaten by livestock unless they are starving.Aphidoidea (Emily S. Kloosterman) at en.wikipedia [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)] Fritzflohrreynolds [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)]
  • abdominal pain due to hemorrhagic gastroenteritis
  • irregular heart rate
  • decreased cardiac output
  • death

Elderberry
  • increased heart rateImage by Mabel Amber, still incognito... from Pixabay
  • venous blood is bright cherry-red in color
  • increased respiratory rate
  • panting
  • open-mouthed breathing
  • extreme difficulty breathing
  • bright red mucous membranes
  • death results rapidly from asphyxiation.https://www.maxpixel.net/Elder-Elderberries-Black-Elderberry-Sambucus-Nigra-1595360
  • Cyanide poisoned animals become very excited when unable to breath.
  • Abortions may occur several days later if the mother survives the acute effects of cyanide poisoning.

English Ivy
  • local irritationPhoto by Jerry Wang on Unsplash
  • excessive salivation
  • nausea
  • excitement
  • difficult breathing
  • severe diarrhea
  • thirst
  • coma

Foxglove
  • gastrointestinal irritationPhoto by Lai Man Nung on Unsplash
  • diarrhea
  • anorexia
  • nausea
  • slow but strong pulse
  • contracted pupils

Flax Plant
  • difficulty breathing
  • open mouth breathing
  • excessive salivation
  • nervousness
  • weakness
  • mucous membranes appear pink and redder than normal
  • venous blood is cherry red in color
  • collapse
  • death

Goats Rue, Professor Weed, French Lilac
  • difficulty in breathinghttps://commons.wikimedia.org/wiki/File:Galegaofficinalis03.jpg
  • coughing due to the pulmonary congestion and edema
  • Animals rarely eat the plant unless forced into doing so when other forages are not available.

Greasewood
  • muscle tremorsCory Maylett [CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0)]
  • tetany
  • weakness
  • reluctance to move
  • depression
  • recumbency
  • Coma and death may result within 12 hours.
  • Animals that survive the acute effects of oxalate poisoning frequently develop kidney failure.
  • Animals die from renal failure.

Halogeton
  • muscle tremorsMatt Lavin from Bozeman, Montana, USA [CC BY-SA 2.0 (https://creativecommons.org/licenses/by-sa/2.0)]
  • tetany
  • weakness
  • reluctance to move
  • depression
  • Coma and death may result within 12 hours.
  • Animals that survive the acute effects of oxalate poisoning frequently Matt Lavin from Bozeman, Montana, USA [CC BY-SA 2.0 (https://creativecommons.org/licenses/by-sa/2.0)]develop kidney failure.

Holly
  • vomiting
  • diarrhea
  • stupor in animals if ingested in large amounts

Horsebrush
  • photosensitization occurs secondarily to the liver disease.
  • redness and edematous swelling of the tissues around the head
  • severe anorexiaDcrjsr [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)]
  • depression
  • dyspnea
  • prostration
  • death from acute liver failure.
  • Sheep seldom eat horsebrush when other forages are available.

Horse Nettle, Bull Nettle
  • salivation
  • colic
  • intestinal stasis
  • diarrhea
  • muscle tremors
  • weakness
  • rapid heart rate
  • weak pulse
  • Hemolysis and anemia may be present in severe cases.
  • labored breathing
  • nasal discharge
  • depression
  • drowsiness
  • incoordination
  • paralysis of rear legs
  • coma
  • death

Horsetail
  • symptoms are slow to developPhoto by Alesah Villalon on Unsplash
  • jaundice
  • loss of appetite
  • weakness
  • staggering gait
  • excitability
  • paralysis

Houndstongue
  • weight lossNPS / Jacob W. Frank
  • photosensitivity
  • jaundice of mucous membranes
  • poor condition
  • diarrhea
  • abdominal discomfort
  • head pressing
  • walking aimlessly
  • convulsions
  • coma
  • effects are cumulative, so even small amounts over time may result in a toxic dose
  • prolonged ingestion leads to liver failure
  • Ingestion of 5% of a sheep’s body weight in plant matter can be fatal.

Japanese Pieris
  • excessive salivation, vomiting, and abdominal pain usually develops 6-8 hours after the plant is eaten.
  • weaknessPhoto by David J. Stang [CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0)]
  • recumbency
  • increased heart rate
  • increased respiratory rate
  • Inhalation pneumonia is frequently the cause of death.
  • Seizures and convulsions occur in severely poisoned animals.

Jimmy Weed, Burrow Weed, Rayless Goldenrod
  • acetone odor to the breath
  • hindlimb weakness
  • knuckling at the fetlocks
  • posterior paralysis
  • severe muscle tremors
  • weakness
  • recumbency
  • respiratory paralysis
  • coma
  • death

Jimsonweed
  • dilation of the pupils
  • impaired vision
  • fast, weak pulse
  • nausea
  • loss of muscular coordination
  • violent, confrontational behaviors
  • trembling
  • milk is tainted

Johnson Grass
  • excessive salivation John Tann Johnsonn Grass, Sorghum halepense, a widspread weed of crops. Narrabri-Bingara Rd, near Paleroo, NSW Australia. January 2009.
  • difficulty in breathing
  • open mouth breathing
  • nervousness
  • weakness
  • urinary incontinence
  • cherry-red mucous membranes appear
  • cherry-red venous blood
  • Stressing the animal rapidly leads to collapse and death.

Kentucky Coffee Tree
  • excessive salivationMONGO [Public domain]
  • colic
  • diarrhea
  • depression

Kochia
  • photosensitization (appears as sunburn or white patches)
  • increased water consumption
  • weight loss and poor condition
  • poor vision or star gazing
  • lethargy
  • rough hair
  • stiff gait
  • jaundice
  • progressive liver disease and failure
  • kidney failure due to calcium oxalate crystals
  • hypocalcemia
  • spontaneous abortion
  • bloat

Lambs Quarter
  • Sudden deaths may occur as a result of acute respiratory failure.6th Happiness [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)]
  • Pregnant animals may abort at any stage of pregnancy.

Lantana
  • rapid heart rateImage by Grace Shih from Pixabay
  • difficulty in breathing
  • photosensitization, especially of the white skinned areas
  • conjunctivitis
  • Acute cases develop hemorrhagic diarrhea. Chronic poisoning results in constipation
  • jaundice
  • Death results after animals become severely emaciated.

Laurel
  • drooling
  • watery eyes
  • runny nose
  • vomiting
  • complete or partial blindness
  • drowsiness
  • convulsions
  • paralysis

Leafy Spurge
  • unlikely to eat unless starving
  • excessive salivation
  • vomiting
  • colic
  • diarrhea
  • sap can cause eye irritation

Leucana, Whiteland Tree, Guaje, Huaxin, Koa Haole
  • decreased feed consumption, excessive salivation
  • musculoskeletal degeneration
  • poor weight gain
  • congenital defects
  • enlarged thyroid glands (Goitre) in the fetus and mother
  • hair loss

Locoweed
  • depression
  • weakness
  • weight loss
  • incoordination

Lupine
  • teratogenic (fetal damage, abortion)
  • muscle tremors/spasms
  • labored breathing
  • incoordination
  • staggers
  • difficulty moving
  • agitation
  • loss of vision
  • head pressing
  • convulsion
  • coma

Marsh Arrow-Grass
  • symptoms appear rapidly
  • rapid, difficult breathing
  • almond odor to breath
  • sheep go down with head turned to one side

Milk Thistle
  • collapse and death may be the first symptoms of acute toxicity
  • frequent urination
  • mucous membranes (and blood) are brownish in color
  • frothing at the mouth
  • diarrhea
  • unthriftiness
  • trembling
  • staggering
  • abortions

Milkweed
  • loss of appetite
  • constipation
  • drooling
  • excitable
  • difficult breathing
  • rapid, weak pulse
  • convulsions
  • death

Monkshood, Aconite
  • salivation
  • bloating
  • muscle weakness
  • staggering gait
  • recumbency with inability to stand due to muscle paralysis.
  • increased respiratory rate
  • difficulty breathing
  • Sudden death due to severe cardiac arrhythmias is common.

Mustards
  • diarrhea
  • abdominal pain
  • vomiting
  • Salivation
  • mouth ulcers
  • photosensitization 
  • blindness
  • goiter
  • nitrate toxicosis
  • head shaking
  • aimless wandering

Nightshade
  • abdominal pain
  • stupidity
  • dilation of pupils
  • loss of appetite
  • diarrhea
  • loss of muscular coordinationPhoto by Daura Noble Martínez on Unsplash
  • unconscious
  • death

Nolina, Bear Grass, Bunch Grass
  • weight loss
  • photosensitization
  • swollen, reddened skin, especially of white skinned areas, or areas with little hair covering. The skin in these areas dies eventually, becoming parchment-like and peels off.
  • severe jaundice
  • cholecystitis
  • Animals will generally not eat this course plant unless there are no other forages available.

Oak
  • Acorns and young shoots can cause severe poisoning. Photo by Denny Müller on Unsplash
  • anorexia
  • constipation that develops into diarrhea
  • gastroenteritis
  • thirst
  • excessive urination

Onions
  • distinct odor of onion on the breath, feces, urine and milk of poisoned animals.Laura Hubers / USFWS
  • weakness and recumbency due to severe anemia.
  • pale mucous membranes
  • fast, weak pulse
  • dark red-brown colored urine
  • increased respiratory rate
  • staggering and collapse as a result of anemia
  • In severely anemic animals, stress and heavy parasite infestations may be sufficient to cause death.

Oleander
  • severe vomitingPhoto by Anna Hliamshyna on Unsplash
  • diarrhea
  • swollen and inflamed oral tissues
  • cold extremities
  • dilated pupils
  • increased heart rate
  • weakness
  • death

Orange Sneezeweed
  • decreased appetite
  • bloating
  • teeth grinding
  • rumen stasis
  • projectile vomiting of rumen contents leading to dehydration, weight loss, weakness and inhalation pneumonia.
  • A common name for the disease is ‘Spewing sickness’
  • muscle weakness
  • ataxia, especially in lambs causing them to lag behind the flock.
  • inhalation pneumonia

Perilla Mint
  • acute respiratory difficultyVengolis [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)]
  • rapid open mouth breathing (often referred to as cow asthma)
  • death

Pigweed
  • edema
  • nasal discharge
  • increased heart rate and respiration
  • bloat
  • kidney damage/failure; diarrhea, sometimes bloody
  • lack of appetite
  • weight loss
  • depression
  • weakness
  • muscle tremors
  • incoordination, staggering, or difficulty walking
  • lethargy
  • facial twitches

Poison Hemlock
  • death may occur within 15 minutes
  • frothing at the mouth
  • uneasiness
  • pain
  • dilated pupils
  • clamping of jaws
  • grating of teeth
  • vomiting
  • weak, rapid pulse
  • diarrhea
  • bloating
  • convulsions
  • respiratory failure

Ponderosa Pine
  • renal failurehttps://www.flickr.com/photos/jsjgeology/25571166908
  • abortion
  • Cows develop edematous swelling of the vulva and udder prior to abortion.

Princes Plume
  • cracked hooves and lamenessPhoto by Kip E. Panter

Purple Locoweed
  • decreased appetite and weight loss
  • malabsorption of essential minerals and vitamins
  • decreased growth rates
  • lambs may be born with deformed legs.
  • abortions and fetal death are common
  • abnormal behavior including sudden changes in temperament
  • aggressiveness
  • ataxia
  • falling over unexpectedly
  • violent reaction to routine management practices such as putting a halter on

Purslane
  • muscle tremorsDavid E Mead [CC0]
  • tetany
  • weakness
  • reluctance to move
  • depression
  • recumbency
  • possible kidney failure
  • coma and death may result within 12 hours.

Rhododendrons
  • anorexia
  • coughing
  • choking
  • retching
  • foaming at the mouth
  • vomiting
  • colic
  • paralysis
  • depression
  • groaning
  • muscle twitching
  • death

Salt Bush
  • lameness due to hoof wall deformity and horizontal cracks in the https://www.flickr.com/photos/carolannie/37490762214/hoof walls

Scotch Broom
  • excessive salivationImage by Etienne GONTIER from Pixabay
  • anorexia
  • colic
  • muscle tremors and incoordination
  • possible muscle degeneration

Serviceberry, Saskatooh Berry, June Berry
  • excessive salivationhttps://www.flickr.com/photos/mricon/4825749576 Image by lqlqlqlq75 from Pixabay
  • difficulty in breathing
  • open mouth breathing
  • excitement
  • nervousness
  • pink or red mucous membranes (more than normal)
  • cherry-red venous blood
  • Stressing the animal rapidly leads to collapse and death.
  • Pregnant animals may abort if they survive the cyanide poisoning themselves.

Snakeweed, Broomweed, Turpentine Weed
  • diarrhea followed by constipationMokkie [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)]https://www.flickr.com/photos/zharkikh/44084830381
  • loss of weight
  • abortions
  • retained fetal membranes.

Sneezeweed
  • symptoms are slow to develop
  • loss of vigor
  • loss of flesh
  • rapid pulse
  • labored breathing
  • loss of muscular control
  • drooling
  • high temperature
  • dizziness
  • spasms
  • convulsions

Sophora, Texas Mountain Laurel, Mescal Bean, Coral Bean, Frijollito
  • After consuming, stress or exercise often induces:
  • tremblingStan Shebs [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)] https://www.flickr.com/photos/kretyen/2692744968
  • stiff gait
  • falling
  • difficulty in rising

Spiny Plants (burs, thistles, needle grass)
  • drooling
  • lack of appetite
  • lameness
  • bloody saliva
  • head-shaking
  • weeping eyes
  • excessive thirst
  • lesions/ulcerations/blisters in mouth
  • rubbing; licking
  • mouth open, tongue hanging, or yawning
  • snorting or blowing
  • anxiety
  • weight loss
  • dehydration
  • decline in temperament
  • coughing
  • vomiting
  • occasionally colic and/or impaction

Spotted Or Blue Locoweed
  • weight loss
  • poor growth rates possibly due to poor absorption of nutrients from the intestinal tract.
  • Calves, lambs, and foals may be born with deformed crooked legs.
  • Abortions and fetal death are common.https://www.flickr.com/photos/ken-ichi/4528534113
  • depression
  • incoordination
  • staggering gait
  • unpredictable behavior
  • poor vision

Spurge
  • Contact with sap causes:
    • inflammation of skin
  • Eating causes:
    • diarrhea
    • vomiting
    • swelling around mouth and eyes
    • abdominal pains
    • muscle tremors
    • sweating
    • tainted milk has reddish color

St Johns Wort
  • photosensitization
  • photodermatitis
  • skin blisters
  • lesions on udders causing pain and refusal to nurse
  • skin may peel or slough, sometimes in sheets
  • redness and swelling of eyes
  • avoidance of sunlight
  • higher pulse rate and temperature
  • seeking out of water
  • head rubbing
  • anxiety
  • occasionally convulsions and/or death.
  • There may be a delay of up to three weeks after ingestion before symptoms appear.

Suckleya
  • excessive salivationUSDA ARS [Public domain]
  • sudden death
  • mucous membranes appear pink and redder than normal
  • venous blood is cherry-red
  • Stressing the animal rapidly leads to collapse and death.
  • difficulty in breathing
  • open mouth breathing
  • nervousness
  • weakness
  • death
  • excitement
  • nervousness
  • abortion

Sudan Grass
  • difficulty breathing
  • brownish “chocolate” blood
  • collapse
  • death

Sweetclover
  • lameness
  • bruises
  • hematomas
  • excessive bleeding
  • animals may have bloody noses
  • bloody feces
  • excessive bleeding from wounds or incisions

Tall Buttercup
  • inflammation and blisters where plant juice touches skin
  • mouth blisters cause drooling and loss of appetite
  • other symptoms similar to those for marsh marigold

Tansy Ragwort
  • nervousness
  • chills
  • pale mucous membranes
  • loss of coat luster
  • strong, rapid pulse
  • high temperature
  • staggering gait
  • weakness
  • death

Two-Grooved Milk-Vetch
  • cracking of hoof wallsDave Powell [Public domain]
  • lameness
  • deformed bones of the legs (crooked legs).
  • abnormal behavior including sudden changes in temperament
  • aggressiveness
  • ataxia
  • falling over unexpectedly
  • violent reaction to routine management practices such as putting a halter on
  • abortions
  • breaking off of long hairs
  • rarely if ever eat two-grooved milk vetch because it is unpalatable due to the high levels of selenium it accumulates
  • Its presence in a pasture however indicates that the soil is high in selenium, and therefore other forages in the area will accumulate selenium and pose a risk to residents.

Water Hemlock
  • death may occur within 15 minutes
  • frothing at the mouth
  • uneasiness
  • pain
  • dilated pupils
  • clamping of jaws
  • grating of teeth
  • vomiting
  • weak, rapid pulse
  • diarrhea
  • bloating
  • convulsions
  • respiratory failure

White Snakeroot
  • depression
  • inactivity
  • arched body
  • hind feet placed close together
  • excessive salivation
  • nasal discharge
  • nausea
  • rapid, labored breathing

Wild Cherry
  • Wilted cherry tree leaves cause anxiety
  • staggering
  • falling down
  • convulsions
  • rolling of the eyes
  • tongue hanging out
  • loss of sensation
  • dilated pupils
  • The sheep can then become quiet, bloat and die within a few hours of ingestion.

Yew
  • gastric distress
  • diarrhea
  • vomiting
  • tremors
  • dilated pupils
  • respiratory difficulty
  • weakness
  • fatigue
  • collapse
  • coma
  • convulsions
  • circulatory failure
  • death
  • Survival after yew poisoning is rare.

Other Potential Sheep Toxins

Algae

Blue-green algae, which is most often found in stagnant, slow-moving water when temperatures are high, can poison sheep. Symptoms generally develop quite rapidly and may resemble an allergic reaction. Convulsions may occur, but more frequently the sheep sinks to the ground and dies without struggling. Smaller amounts of poison cause weakness and staggering, followed by recovery. In some instances, apparent recovery from an attack is followed in a few days or weeks by evidence of photosensitization. There may be inflammation of the muzzle, the skin of the ear, the udder, or other parts of the body. Jaundice is often seen, and constipation is a common symptom. Such cases usually recover under good care.

Cantharidiasis (Blister Beetle Poisoning)

Blister beetles contain cantharidin, a toxic substance that is used as a defense mechanism against predators. There are more than 200 different species, and they can be found from Mexico to Southern Canada, and from the east coast of the United States as far west as New Mexico. Cantharidin can severely injure or kill sheep when even a small amount is ingested. Sheep come into contact with cantharidin by ingesting alfalfa hay that has been infested by blister beetles. The oily substance can contaminate the hay even if the beetles were crushed into the feedstuff. Crushing or chemically eradicating the beetles does not diminish the toxin potency.

Inspecting individual flakes of alfalfa hay before providing them to residents can help reduce the likelihood of poisoning. Dispose of any contaminated flakes, even if you have removed the beetle, as the toxin can still be left behind.  First-cutting hay is less likely to be contaminated than hay harvested later in the year, as the insects likely haven’t yet swarmed by then. Harvest alfalfa before it fully blooms to reduce the chances of beetle contamination. Hay is less likely to be contaminated by crushed beetles when harvested with a self-propelled mower or windrower. Crimping hay crushes the beetles into the hay.

Sheep that ingest a massive amount of toxin may show signs of severe shock, and unfortunately, die within hours. Symptoms of sublethal poisoning include depression, diarrhea, elevated temperatures, increased pulse and breathing rates, and dehydration. There is also frequent urination, especially after the first 24 hours.

If you suspect Blister Beetle Poisoning, contact your veterinarian immediately. If early veterinary care is provided, afflicted sheep have a chance of recovery.

Copper

Copper toxicity is especially dangerous in sheep because their liver accumulates copper much more readily than in other animals. Although copper is essential for sheep, too much copper can cause anemia, lack of appetite, fragile bones, lethargy, teeth grinding, jaundice, bloody urine, hair loss, and poor wool coverage. Sheep are ten times more susceptible to this condition than goats. Copper can accumulate in a sheep’s liver for a up to a year without any symptoms until the liver releases a large amount at once, causing damage to their red blood cells. Copper toxicity can also be a result of a lack of dietary molybdenum, sulfur, zinc, calcium, or liver damage. Left untreated, copper toxicity can be fatal in only a few days after presenting symptoms. If you suspect copper toxicity in sheep, contact a veterinarian immediately. Veterinary treatment includes a daily drench  of ammonium molybdate and sodium sulfate in specific quantities (too much can cause serious health repercussions). The best prevention includes ensuring that the sheep are not eating too much copper in their diet. Make sure that sheep are not given access to minerals not explicitly approved for sheep, as even goat minerals have too much copper for a sheep’s body. 

Grain Overload (Acidosis, Grain Poisoning)

Grain overload occurs when sheep eat large amounts of grain, causing carbohydrates to be released in the rumen and ferment instead of being normally digested. Lactic acid is produced resulting in slowing of the gut, dehydrations and sometimes death. While wheat and barley are the most common causes of grain overload, lupins and oats can also be the culprit.

Grain overload is most commonly seen where sheep may be in a newly harvested pasture and spilled and unharvested grains remain, and when sheep gain access to bags or cans of grains and pellets. If a sheep isn’t accustomed to eating grain, a sudden switch to grains can cause grain overload as well.

Signs of grain overload include:

  • depressed appearance
  • lying down
  • diarrhea
  • dehydration and thirst
  • bloating (of the left side of the abdomen)
  • staggery or tender gait and ‘sawhorse’ stance
  • death

If you suspect a sheep has grain overload, contact your veterinarian immediately. Treatment depends on the severity of the condition. Following grain overload, the rumen lining takes up to six weeks to repair, and some animals may develop secondary infections that will require veterinary treatment.

Hardware Disease

Hardware Disease refers to the injuries that can result from any animal resident eating something they shouldn’t, especially pieces of human-made hardware like nails, screws, and staples. Hardware disease can have devastating effects on any resident. Check out our resource on Hardware Disease prevention here.

Lead Toxicity

Lead was once used in paints and pesticides, and can also be found from natural environmental sources. Even if you have never used any products containing lead, it may still be present in old barn or fence paint, or in the soil. Places where old machinery and leaded gas have been stored may also have caused contamination, as would old treated lumber and railroad ties. Sheep may ingest the lead in the environment through the consumption of grass, clover, and dandelion or from chewing or licking on tainted surfaces.

Having the soil tested at your sanctuary is an easy way to learn if the environment is safe for residents. You can check with a local environmental conservation service, or agricultural extension office to inquire about testing. It is usually a fairly quick and easy process. Prevent your residents from accessing buildings and fences with old paint, as they may chew or lick these objects and ingest lead.

Sheep with low levels of lead toxicity do not generally exhibit signs. In severe cases, you may see the following symptoms:

  • loss of appetite
  • weight loss
  • lethargy and weakness
  • incoordination
  • anemia
  • unusual manure consistency or diarrhea
  • respiratory distress or blindness

Consult a veterinarian immediately if you suspect a sheep has ingested lead or is beginning to show symptoms of lead poisoning.

Mycotoxins

Mycotoxins are a toxin produced by molds (fungi) that are harmful to many animals. Mycotoxins can affect sheep through contaminated food or bedding. Moist, warm environments make a perfect recipe for mold reproduction. While sheep are more resistant to the effects of mycotoxin than horses, they can still be affected. The type and amount of mycotoxin a sheep digests affects whether the health issues are immediate and short-lived or may become chronic issues. Pregnant sheep and young sheep are more susceptible. Some general signs of poisoning include:

  • appetite loss
  • weight loss
  • respiratory issues
  • increased susceptibility to infectious diseases (poor immune function)
  • poor growth rate

Prevention is key in avoiding serious health issues. Luckily, there are a number of steps you can take to help ensure resident sheep do not suffer the ill effects of mycotoxin poisoning:

  • Be sure to keep food, grain, and hay storage areas clean, dry, and cool
  • Try to keep food storage areas protected from mice and rats and other wildlife, as they can chew holes in food bags, increasing the likelihood of grain being exposed to damp conditions
  • Always feed the oldest bags of food first. Try to use up open bags within a few weeks after opening in the winter and in even less time in the summer
  • Clean any storage bins or cans thoroughly to remove old grain that gets stuck in cracks and crevices
  • Check with your food manufacturer or supplier to see if they regularly test for the presence of mycotoxins in grains before mixing food. If they do not, avoid using them and find another supplier

If you are concerned about the possibility of mycotoxin contamination, have your food stores tested. This could be especially important if you have a sheep that shows initial signs of mycotoxin exposure.

Pesticides, Herbicides, And Rodenticides

It may not come as a surprise that herbicides and rodenticides can cause toxicosis in sheep if ingested. If sheep ingest plants that have been sprayed with phenoxy acid herbicides, they can become ill or even die. For this reason, it is imperative that sheep are not given treated plants or are allowed access to pastures that have been treated with herbicides.

While rats and mice can pose challenges for sanctuaries, it is important to respect them and use compassionate mitigation practices. Many rodenticides are anticoagulants and act by preventing the blood to clot. These products may be appealing to sheep as well, and they may attempt to lick or eat them if discovered. For this reason, it is imperative that they do not come into contact with these poisons. There are many new and innovative ways to address rodent populations that are more effective and compassionate.

Pesticides may affect the nervous system in sheep and can be fatal if not treated with the antidote. Early treatment is critical. If you suspect a sheep may have ingested any of the poisons above, contact your veterinarian immediately. Blood tests may confirm poisoning.

Snakebites

Venomous snakebites are not common, but when they occur, should be treated seriously and immediately. The most common location for a sheep to be bitten are on the nose or leg. It is possible for a snake to bite several times, so if you notice a snakebite, look for others. Snake venom varies by species, and the severity of a bite can also be influenced by size, age, and the number of bites. Most venoms can impair blood clotting and damage the heart, while some others contain neurotoxins. Signs of a snakebite may include:

  • pain
  • swelling at the bite site
  • one or more puncture wounds
  • sloughing of tissues near the bite site
  • cardiac arrhythmias
  • impaired ability for their blood to clot
  • shock
  • collapse
  • paralysis
  • death

Seek veterinary care immediately if a sheep is bitten by a venomous snake. Do NOT try to suck the venom out or place a tourniquet. Keep the sheep calm while seeking immediate veterinary care. Depending on the severity of the bit, treatments may include antivenin, pain medications, fluid therapy, wound treatment, tetanus vaccination, and antibiotics. Check out our Compassionate Wildlife Practices At Your Animal Sanctuary for some tips on how to dissuade snakes from your property.

Wood Stains And Paints

Some wood stains and paints can be toxic to sheep. Sheep may try to chew on painted surfaces and can become ill if the stain or paint is toxic. Try and purchase paints and stains that are specially made for barns and fencing and listed as animal or “livestock” friendly.

Foods That You Should Not Feed To Sheep

Use Caution
You may have experience successfully feeding one of the foods on this list to your sheep residents. For this list, we erred on the side of caution, including foods that are well known to be toxic to others that some have had success in feeding to residents but still are known to contain potential toxins. Some foods are only problematic in large doses or in their raw state or only their seeds or roots. Some are very toxic while others have milder effects on the individual. There is a lot of information on the internet, much of it conflicting or lacking the necessary detail to prove especially helpful. Having a better understanding of which parts or in what state some foods are toxic can help you make safe choices for your residents. Always use caution and speak with your veterinarian.

In addition to the above, these foods should be avoided:

  • Animal products of any kind
  • Avocado (Any part of the plant (fruit, leaves, stems, bark, and seeds) can be toxic to sheep. The toxic element in avocado is persin)
  • Brassicas -Broccoli, cauliflower, cabbage, brussel sprouts. Turnips and kale are also in this family. Turnips have some specific toxicity issues concerning thyroid production. (Use caution. Don’t feed large amounts. Avoid seeds and roots.)
  • Celery (Use caution. Celery contains furocoumarins which can cause photosensitisation. Never feed roots or seeds.)
  • Citrus (Citrus can cause gastric distress in larger amounts or if fed regularly.)
  • Chocolate (While there aren’t many sources to confirm whether chocolate is a great danger to sheep, it does contain theobromine which can be toxic in a number of other mammals. There are limited studies indicating certain amounts can be toxic so it is best to use caution and avoid altogether.)
  • Nightshade “vegetables” (Use caution. Do not feed green, immature fruits or leaves, vines or roots of any nightshade vegetable, such as eggplant, tomatillo, pepper, or tomatoes.)
  • Onions (While sheep have a greater resistance to toxicity issues than some other mammals, onions are not a great treat.)
  • Parsley (Parsley contains furocoumarins which can cause photosensitisation)
  • Potatoes (The skin, particularly green skin, and “eyes” contain glycoalkaloids and solanine toxins; leaves and vines can be toxic as well.)
  • Rhubarb (There are a number of factors that affect levels of toxins in rhubarb; the leaves are particularly toxic but it is better to avoid the whole plant as it contains oxalic acid. Cooking it may reduce toxin levels in the stems.)
  • Un-Pitted stone fruits (Pits can lodge in the intestines and pits contain toxins.)

For more information on what you should feed sheep, check out our resource here.

While this list isn’t exhaustive, it can certainly help you keep resident sheep safe, healthy, and happy!

SOURCES:

Is There Lead In Your Pasture? | Of Horse

Animal Friendly Barn And Fence Paint For Horse Stalls | Stuff For Petz

Overview Of Copper Poisoning | Merck Manual Veterinary Manual

Brassicas: Be Aware Of The Animal Health Risks | University Of Kentucky (Non-Compassionate Source)

Forage Of The Month: Brassicas | University Of Kentucky (Non-Compassionate Source)

Common Poisonous Plants | Ohio State University (Non-Compassionate Source)

Guide to Poisonous Plants | Colorado State University (Non-Compassionate Source)

Blister Beetles | North Carolina State University Extension Service (Non-Compassionate Source)  

The Danger Of Mycotoxins | The Horse (Non-Compassionate Source)

Grain Overload, Acidosis, Or Grain Poisoning In Stock | Department Of Primary Industries And Regional Development’s Agriculture And Food (Non-Compassionate Source)

Toxin Topic: Snakebites And Horses | The Horse (Non-Compassionate Source)

Poisoning of Livestock by Plants | Ontario Ministry Of Agriculture, Food And Rural Affairs (Non-Compassionate Source)

Common Weeds Poisonous to Grazing Livestock | Ontario Ministry Of Agriculture, Food And Rural Affairs (Non-Compassionate Source)

Protect You Horses And Livestock From Toxic Plants | Washington State Department Of Agriculture (Non-Compassionate Source)

Non-Compassionate Source?

If a source includes the (Non-Compassionate Source) tag, it means that we do not endorse that particular source’s views about animals, even if some of their insights are valuable from a care perspective. See a more detailed explanation here.

Updated on July 9, 2021

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