Poison plants for cattle

When I was a kid, part of my summer days was spent with broomsticks and tree limbs in hand, my siblings, mom and I guarding against the herds of cows that traveled from the hills to the valley, but right past our yard. At the time, brooms were our best option to keep the cows from trampling the flowers my mother spend hours a day nurturing.

Whether you run your own cows, or a neighbor has cows, one cause of concern is often how to keep your yard and landscaping safe. A cow will munch on just about anything green, so keeping them away from your plants, gardens, and trees is imperative.

How to stop cows from eating plants:

  • Place Fencing Around the Plants
  • Leave A Buffer Between the Cows and Plants
  • Plant Unappetizing Shrubs in Between the Cows and Plants
  • Provide Enough Food For The Cows
  • Consider a Cattle Dog

With these helpful tips and having extra information about cows on your side, you can defend your plants from the inevitable. We’re going to discuss what cows like to eat (and more importantly what they don’t) and how you can make sure that your plants are free of harm’s way using different methods.

Place Fencing Around the Plants

The absolute best way to keep cows from eating plants is to install a fence around your garden. Fences are ideal as they are likely strong enough to keep cows out of the garden, if with pushing and tugging from the cattle.

There are several different types of fences that can be used to keep cows out. The fence type you choose will depend on a variety of factors, including how many cattle you have, how much strength you require from your fence, and what is aesthetically pleasing to your yard.

There are two imperative characteristics that make up a good fence for cows: first and foremost the fence should offer a physical barrier. The physical barrier will stop cows in their tracks, leading them to turn around and leave your plants alone.

A note about fences:

Cows will constantly push against fences to find a weakness. That’s why electric fences are one of the most popular fences to keep cows contained. My neighbors’ cows get out within minutes of when their electric fence gets turned off.

The cows always know. You can learn all about electric fences in this guide on electric fences.

A visual barrier is also important. Many people may discredit this simple fact.

But just as a physical barrier is necessary to keep cows away from the fence, a visual barrier is important, too. If the cows can’t see the temptation on the other side of the visual barrier, they don’t know what they are missing.

It acts as an extra layer of defense for your plants.

Don’t forget!

Cows are strong. They can destroy fences quickly. They like to rub against fences and push for weaknesses. Other times, they are simply looking for a way to itch a scratch they can’t reach.

Pushing against the fence to ease their itches is just one way in which a fence can be quickly strained, damaged, and broken.

There are a few different types of fencing for cattle available on the market, each with their own price tag:

  • Barbed Wire. This is an effective barrier for cows. Barbed wire with at least five strands is highly recommended, as it will keep cattle at bay with no problem. In some circumstances, you might get by with less wiring.
  • Woven Wire. Woven wire is also a popular choice for farmers and those looking to keep their cattle away from plants. The woven wire is both a physical and visual barrier. Unfortunately, this type of fencing can easily be destroyed by cows.

It is highly recommended to apply a strand of either barbed wire or electric wire to reinforce this type of fence.

  • Electric Fence, also called high Tensile Smooth Wire. High tensile smooth wire is the best option for keeping cows from eating plants. Electric fences can handle a whopping amount of 1,000 pounds of cattle, won’t lose elasticity over time, and won’t require as many repairs. Cows are no match for this type of fence.
  • Wood Board. This fencing doesn’t contain cattle as well, but if you have plenty of wide-open land and prefer the aesthetic look of wood then it may be an ok option.

As you can see, there are several options when it comes to choosing a livestock fence. Some things you should consider before making an ultimate decision includes:

  • The size of your land. The more space you have, the less likely you’re going to need to contain your cattle as aggressively. A barbed-wire fence would work well for this situation, and it is a cost-effective solution to keeping cows from eating plants.
  • The number of cows you own. How many cows you need to contain makes a difference. A farmer with just a few cows may not need an electric fence to keep his livestock at bay, while a farmer with hundreds will certainly need a fence that can handle the load.
  • Your budget. It will all come down to dollars in the end, so make sure you’re finding a fencing solution that matches your funds. Don’t go too cheap, though, or you may end up needing to pay more to have the fence fixed and repaired regularly (or completely redone).
  • What you find aesthetically pleasing. This is always important, especially if you’re someone who finds the look of their yard to look a certain way. Some people might find that the wood board offers old world charm, while others think the glossy visual of high tensile to be modern and ideal.

Tips and Tricks for Fencing Cattle

There are certain things to keep in mind when installing your fences, whether you opt for the high tensile, barbed wire, woven wire, or wood board. These helpful tips and tricks will make sure you get the job done right.

Always Install a Gate

So many times people forget to install the gate. This is mostly due to the fact that they’re scared it will leave a weaker area for cows to breakthrough.

But, a gate allows a way for you to get in and out without compromising the fence.

Firstly, you wouldn’t want to hop over the fence every time you go to tend to your cattle. A gate provides comfort and ease of use for the farmer.

Secondly, if a cow needs to leave the area, you won’t want to create a hole in your fence. Cows can’t just hop over like a human, so ensuring there’s a safe place for the cow to come and go is essential. This, again, will save your fence from potential harm and damage.

The gate should be big enough to let yourself and at least one cow in and out at a time. To make your gate a little bit more effective and deter cows from barging through, toss some barbed wire on the top- just like you would do with any woven wire fence.

Make Sure to Use Proper Bracing

A fence brace is crucial to the overall sturdiness and reliability of the fence. It is the post that will reinforce your fence, which could mean the difference between your cattle breaking down the barrier or holding them back from eating your plants.

Bracing should be at least twice the length of the height of the fence. This will offer you with the right amount of support to keep the cows away from the garden.

Use Proper Planning with Placement

You don’t want to leave an area for a cow to be hemmed in, and you also don’t want to have your posts too close together or too far apart.

Did you know?

Fence posts should typically be no farther apart than 50-100 feet.

Leave A Buffer Between Cows and Plants

This may go without saying, but a lot of people may be unaware of the impact their placement is having on their cows and plants. Proper placement of both the cattle and plants is the simplest, most cost-effective solution to keeping cattle from eating the plants.

A cow will eat just about anything. If the cow can see it, then he is probably going to want it. He could go as far as pushing over a weak fence to get to the tasty plants he sees.

It’s best to keep your plants as far away from the cows as possible. They should be grown far enough away that the cow is unable to see it, and will have enough food around him to keep him happy without scavenging for anything else.

Don’t Place Plants Next to Fences

Always remember not to place your plants directly next to a fence. Cows have the ability to get their mouths on food that is placed nearby.

Even in areas where space is limited, it’s best to keep the plants far enough away from the fence so the cows can’t reach it. They may be tempted to go and grab a bite, but with the right fence- such as an electric they will be stopped in their tracks.

Don’t Tempt the Cows

The best thing to do is not tempt the cows. This will not only save your plants but will also ensure that nothing happens to your fence. If you can, keep the plants completely out of sight from the cows.

Place Unappetizing Shrubs Between the Cows and Plants

Have you ever heard anyone say that a cow will eat anything? They’re mostly correct, but that doesn’t mean that there aren’t still some things that will turn a cow off.

A Cow’s Diet

Before knowing what a cow simply will not eat, it’s important to know what they will eat. And while the saying goes that ‘nothing is off limits’ to a cow, it isn’t because they are simply senseless animals- in fact, they are quite smart.

Aside from their braininess, cows are naturally created with four parts in their stomachs. These four parts allow them to consume almost anything without it hurting their stomachs, whether it’s roughage and grains, or plants and trees.

The majority of a cow’s diet will come down to the following:

  • Roughage. This is the key ingredient to a cow’s diet, as it gives them the bulk they need to grow big and strong and have proper bowel movements. Roughage will include hay and grass, as well as silage.
  • Grains. Grains will give the cows the energy they need, but unfortunately, don’t provide them with much necessary fiber. Grains that are fed to cows include corn, oats, and barley. Cattle do not require as many grains as they do roughage.
  • Oilseeds. Soybeans and canola meal will typically be in a cow’s diet, providing them with a substantial amount of protein, fiber, and energy.

It’s clear to see that the cow is ready to take on any food that comes its way. This, of course, includes those delicious plants found in the garden. However, placing the few unappetizing shrubs in front to block their view will certainly help lessen the chance of cattle getting a hold of your plants.

Shrub Placement is Key

When it comes to deterring cows from eating your plants, a great way to keep their mind off of going any further is to plant some unappetizing shrubs right outside of the fence.

But, a cow may still try and get their hands on these tasteless shrubs.

It’s best to always make sure that these unappealing shrubs are a few feet away from the fence. This may cut into your garden a bit, but it’s much better than having to replace the shrubs every few weeks after they have been munched on.

Don’t Worry- It Won’t Hurt the Aesthetics of the Garden

Some people may be concerned that an unappealing shrub alongside their garden may cause the garden to look less appealing as well. But, there are some beautiful shrubs that are bitter for cows to eat.

A lot of the time, these shrubs will add depth, color, and dimension to your garden in a very pleasing way.

With so many different shrubs to choose from you are bound to find one (or a mix of a couple) that you find aesthetically pleasing. Try to find shrubs that go with the looks of your garden as is, or opt for something completely different to shake up your routine a bit.

List of Plants That Cows Do Not Find Appetizing

  • Wax Mallow
  • West Indian Shrubverbena
  • Winged Sumac
  • Mapleleaf Viburnum
  • Wax Myrtle
  • Yaupon

You have the option of sticking with a single shrub along the fence, or you can mix and match to create a more vibrant scenery. Remember that the shrubs should not be placed directly against the fence where cows can reach them. Instead, keep them a good distance from the fence so that it acts as a deterrent and not a potential snack.

Make Sure the Cows Have Enough Food

This isn’t to say that you’re not feeding your cows correctly; there’s probably nothing wrong with the way you are currently feeding them. But cows can take in mass amounts of food at a time. Having enough readily available is a key part of ensuring they keep their mouths off of your plants.

When it comes to inside the fence, always ensure that there is enough food available for the cows. This means that grass should be kept up and ready for the picking, and hay, corn, and other cow favorites are in good stock.

Having enough food will keep the cows busy and occupied without wondering what’s on the other side of the fence. This will result in less intrusions from the cows, so your garden can grow big and healthy.

Consider a Cattle Dog

Also referred to as ‘herding breeds’, a cattle dog is a simple, cost-effective, and overall fun way to keep cows away from your plants.

Cattle dogs were born with an instinct to control animals. They are also very easy to train, so training your pet how to work for you is a breeze.

While it’s a natural instinct to control animals, you can also help to provide the training to your dog necessary for running the cows out of the garden.

Some of the best herding breeds include the following:

  • Australian Cattle Dog. When you hear of a cattle dog, you likely think of this particular breed. Typically around 40 pounds and 19 inches long, the compact and muscular dog is an excellent herder and extremely intelligent. They are also called ‘Blue Heelers’ and ‘Queensland Heelers’, and they are related to the Australian Dingos.
  • Australian Shepherd. This type of shepherd is typically around 55 pounds and 20 inches long. They’re known for being great ‘ranch dogs’ and will likely be in the company of cowboys, as they enjoy the lifestyle thoroughly.
    • Border Collie. This wonderful herding breed is known to be one of the top workaholics with amazing intelligence. They are smart and energetic, but can also be very cuddly and affectionate after a hard workday.
  • Collie. Everyone knows the beloved and majestic Collie thanks to their time in the movies. But Collie’s can do more than movie-making; they are also devoted to their owners and easy to train, making them a great choice for garden-watching.
  • German Shepherd Dog. This herding breed is said to be the finest worker of all the herders, and their high intelligence, confidence, and courageous attitude make them a top pick for guarding plants against cows. Weighing in at 70 pounds and 25 inches long, they’re a big group of dogs that are strong, noble, and proud.
  • Old English Sheepdog. If you have ever seen an Old English Sheepdog you would never forget them. These adorable shaggy dogs with infamous hairdos are typically up to 100 pounds and around 21 inches long. They’re stocky bodies and bear-like gait are appealing, much like their gentle and smart attitudes.
  • Pembroke Welsh Corgi. This is a smaller breed in the herding division, but still smart and effective nonetheless. They have lively attitudes with strong and athletic bodies, typically weighing only up to 30 pounds and 12 inches long. They are active herders that can get the job done, and don’t require an excessive amount of attention.
  • Shetland Sheepdog. Another smaller watchdog, the Shetland Sheepdog is only around 30 pounds and 14 inches long. They’re quick and intelligent, making them obedient and active herders that can quickly and easily handle any cows that come their way.

Is a Herding Dog Right for Me?

While cattle dogs (herding dogs) can be an effective way to keep cows out of the garden, it doesn’t mean they are the right choice for everyone. There are a lot of things to consider before making a final decision.

Cost to care for the dog.

Like everything else in life, a dog will require you to spend a certain amount of money. You may initially need to pay for the dog and get a certificate to own him. You will also have other things to pay for the dog including food, trips to the vet if needed, and specific things he may need like a leash, a favorite bone, or special brushes for grooming.

Time to train and bond with it

A lot of herding dogs are independent and won’t require too much of your time. In fact, a good percentage of the herding breed will not like to be bothered during the workday.

Dogs like this are better off with some affection at night after the day is done, and they’re likely going to want to cuddle up.

However, some herding dogs require more attention than others. The more independent breeds will only need a small amount of affection and love from their owners (mostly at night), but less independent herding dogs will want affection throughout the day.

Before you choose a cattle dog make sure you know the level of affection they crave. If you’re up to the challenge, consider getting a passionate dog that will be loyal and loving. If you prefer a more independent working breed, seek out that type of dog specifically.

Enough space.

If you’re getting a herding dog to help care for your cows and keeping them away from your garden, you likely have enough room for a herding dog. However, if you are in a smaller area where there isn’t a whole lot of space aside from a few cows and a small garden, it may not be in your best interest.

Cattle dogs are active, energetic breeds that require a lot of space to keep them occupied. Being cooped up in a smaller environment can cause these dogs a lot of distress and depression as their pent up energy isn’t being used.

If you have a smaller area, you might want to consider choosing a herding dog that is smaller in size, such as a Corgi. For wide-open spaces, German Shepherds are a great choice, as well as any other medium to large sized herder.

The amount of training necessary.

A herding dog can sometimes come off as aggressive, as they try and ‘herd’ their owners. This will cause a little bit of nipping and biting, and you will need to set aside time to train the dog to stop doing this.

You will also need to consider the training time necessary to train the dog to keep the cows away from the garden. A lot of time will be needed in order to do this, and you should be patient and persistent with the dog.

The good thing about herding dogs is they learn fairly quickly. However, it won’t happen in an instant. If you do not have the time and energy to train the dog, you should not consider getting one. They may have some instinct already but they will need to be trained to specifically keep cows away from the garden.

Which Animal Is More Profitable Pigs Or Cows?

How Much Does A Cow Cost To Buy?

Fact Sheet: Poisonous Plants For Cattle

See a photo gallery that highlights even more poisonous plants to cattle.

Many poisonous plants emerge in the early spring before grasses begin to grow. During cool wet springs, poisonous plants often gain an advantage over the grasses and if livestock are turned out too early, poisoning may occur. This is especially true for low larkspur, lupines, water hemlock and poison hemlock. Low larkspur is short-lived and high risk in early spring, and once seeds have shattered very little risk from low larkspur remains. Tall larkspurs are often high risk in early to mid summer when the flower/seed heads are prevalent. Storm episodes often drive cattle into areas where tall larkspur is prevalent and large cattle losses may result. Nightshades, while they emerge early, are more likely a contaminant of harvested forages than a risk for pasture-grazing animals. The toxin does not degrade in hay or silage.
These fact sheets provide information about symptoms of each plant toxicity, when and where the plants usually occur, how they affect livestock and how you can reduce loss.

Poisonous Plants Fact Sheets:

  • Lupine
  • Death camas
  • Nightshades
  • Poison hemlock
  • Water hemlock
  • Larkspurs (tall and low)

For more information about poisonous plants, visit these BEEF articles:

  • Don’t Poison Your Cattle By Grazing Poisonous Plants
  • Watch For Poisonous Plants During Drought
  • Tips For Managing Your Locoweed Problem
  • Avoid Livestock Poisoning When Grazing
  • Larkspur Alert

Fact Sheet: Lupine

Signs and lesions of lupine poisoning:

  • Nervousness
  • Excessive salivation, frothing at the mouth
  • Depression
  • Reluctance to move about
  • Lethargy, inappetence
  • Difficulty in breathing
  • Twitching leg muscles
  • Loss of all muscular control
  • Convulsions
  • Coma
  • Death

The greatest risk of lupine is “crooked calf syndrome,” caused by pregnant cows or heifers grazing certain lupines during late first trimester or early second trimester. The species of lupine and the alkaloid profile is required to evaluate risk. Cows may give birth to calves with cleft palate and skeletal defects if the cows ingest certain lupines during early gestation (crooked calf syndrome), during the 40 th to the 100 th day of gestation.
Poisonous species of lupine are toxic from the time they start growth in spring until they dry up in fall. Younger plants are more toxic than older plants; however, plants in the seed stage in late summer are especially toxic because of the high alkaloid content of the seeds. Lupines are legumes and are relatively high in protein, especially the seed pods, and may become a preferred forage species when grasses become mature and dry. Under proper conditions, some lupines make good forage.

Where and when lupines grow:

Lupines grow on foothills and mountain ranges in sagebrush and aspen areas. Lupine populations expand during wet seasons and may die back during dry seasons. The seed reserve in the soil remains high and when environmental conditions are optimum lupine population will increase.

How lupines affect livestock:

The amount of lupine that will kill an animal varies with species and stage of plant growth. It is not safe to let sheep freely graze certain species and the early flower/seed pod stage of plant growth is especially dangerous.

Overt poisoning in cattle occasionally occurs if cattle lack other feed. Signs of poisoning and resultant death depends on the alkaloid content of the plant, how rapid the lupine is ingested and for how long. Smaller amounts may be poisonous if cattle eat lupine daily for 3 to 7 days. The major issue for cattle is the birth defects (crooked legs, spine or neck and/or cleft palate). Pregnant cows/heifers must graze some lupine over multiple days during the sensitive stages of pregnancy (40-100 days for cleft palate and skeletal deformities, or 40-50 days for cleft palate only) for deformities to occur.

How to reduce losses:

Poisoning can be reduced by keeping hungry animals away from lupines in the early growth stage, in late summer when the plant is in the highly toxic seed stage, and from dense plant stands at all times. Supplemental feeding is beneficial, especially when animals are trailed through lupine ranges. If animals are poisoned on lupines, do not try to move them until they show signs of recovery.

If cows in the susceptible gestational period (40th to 100th days of gestation) are kept from lupine when it is most teratogenic (very early growth or mature seed stage), most deformities can be prevented. The congenital deformity hazard is minimal at other gestation periods and after seeds have shattered from pods. The malformations can be avoided by adjusting the breeding season and the grazing of lupine-infested range to avoid the critical periods of gestation.

There is no known treatment for lupine poisoning, except removing the animal from the source and keep the animal calm until recovery occurs..
Lupine can be controlled with 2,4-D (2 lbs. ae/acre), 2,4-D + dicamba (1 + 0.5 lbs. ae/acre), or triclopyr (0.5 to 1.5 lbs. ae/acre). Spray actively growing plants after they are 5 in. high but before they bloom. Reinvasion is rapid and retreatment may be necessary every 4 to 5 years.

Fact Sheet: Death Camas

Signs and lesions of death camas poisoning:

  • Salivation and bloody frothing
  • Nausea and vomiting
  • Muscular weakness and staggering
  • Pulse fast and weak
  • Prostration, labored breathing, gasping
  • Coma
  • Death due to heart failure
  • Death within a few hours to a few days
  • Congestion of lungs and kidneys
  • Minimal necrosis of skeletal and cardiac muscle

Death camas (Zigadenus spp.) is the common name of several species of plants that are poisonous to livestock. The more toxic of these species are grassy death camas (Z. gramineus), meadow death camas (Z. venenosus), foothill death camas (Z. paniculatus), and Nuttall’s death camas (Z. nuttallii). They are found principally in the western range states.

Death camas is one of the first plants to begin growth in early spring. Without sufficient other forage, death camas may be heavily grazed and will cause severe losses. Spring snow storms may cover all forage except death camas, which may protrude through the snow and is available to the livestock. Sheep are most likely to be affected by feeding on death camas. Occasionally, cattle and horses are poisoned.

Death camas contains toxic steroidal alkaloids that occur throughout the plant; plants are dangerous at all times.

The bulb may be mistaken for those of the edible camas or quamash (Cammassia spp.) and can cause severe illness in humans. If bulbs are eaten, take the affected person to the emergency room of the nearest hospital immediately.

Where and when death camas grows:

Some species of death camas thrive on sandy soils; others grow on drier, rocky foothills. The more toxic species are seldom found above elevations of 8,000 ft. Death camas grows early in spring, matures, and enters dormancy during early summer when soil moisture declines.

The leaves appear very early in the spring. In the foothills, death camas generally flowers in April and May. At higher elevations, the plant may flower in late June and July.

How death camas affect livestock:

Death camas causes marked disturbance in respiration and heart action. A 100-lb. sheep may die if it eats ½ to 2 lb of green foliage. The amount of foliage that will cause an animal’s death depends on the species of plant eaten and the rate of consumption. Severely poisoned animals usually die; those less seriously affected may recover.

How to reduce loss:

To avoid poisoning, delay turnout until adequate good forage is available. Do not introduce hungry sheep into heavy stands of death camas. Avoid feeding, bedding, or trailing sheep through heavy stands of death camas.

There is no known treatment for death camas poisoning.

Research results show that early in the season, when plants have three to six leaves, death camas can be controlled by spraying with 2,4-D at the rate of 1½ to 3 lbs. ae/acre. After the flowering stalks appear, spraying is not effective.

Fact Sheet: Nightshade

Signs and lesions of nightshade poisoning:

  • Labored breathing and expiratory grunt
  • Salivation and nasal discharge
  • Body temperature may be slightly elevated
  • Yellow discoloration of the skin may occur in chronic poisoning
  • Apathy, drowsiness, progressive weakness, paralysis, and trembling
  • Increased heart rate
  • Fat may be yellowed and gelatinous
  • Gall bladder may be distended
  • Gastrointestinal irritation including inflammation, hemorrhage and ulceration

There are several species of nightshades that are toxic to horses, cattle, swine, sheep and poultry. The genus includes annual and perennial herbs and shrubs that can be found throughout the U.S.

The principal species that serve as examples of the genus are black nightshade (Solanum nigrum), silverleaf nightshade (S. eleagnifolium), and buffalo burr (S. rostratum). Black nightshade is an introduced herbaceous annual weed that can be found growing mostly on disturbed soils and waste areas in the eastern U.S. and into the Midwest. Silverleaf nightshade is a perennial with long creeping rootstocks. Buffalo burr is an annual native to the Great Plains and introduced to the West Coast.

The toxins include a combination of a number of sugars and at least six different steroidal amines combined to form a variety of glycoalkaloids. One example is the toxin solanine. Potatoes are included with this group because the vines are toxic and tubers that have been exposed to light can be toxic to livestock. Drying does not destroy the toxin.

Nightshade species are not very palatable to livestock. However, these plants often grow as weeds in hay and silage crops and small grains where they can be harvested with the crop and then fed to livestock.

Where and when nightshades grow:

Black nightshade (both the native and introduced varieties) is an annual 6 in. to 3 ft. tall. Leaves are simple, ovate to lanceolate, entire to sinuate-dentate. Flowers are white; berries are black when ripe. It grows peripherally in moist areas of fields and pastures of disturbed loamy or gravelly soils throughout the U.S.

Silverleaf nightshade is a perennial that grows 1 to 3 feet tall with white, hairy leaves and stems. Leaves are simple, thick, lanceolate to linear, entire to sinuate. Stems and ribs usually have short stiff spines. Flowers are violet or blue; berries are yellow or orange. Silverleaf nightshade grows in fields, pastures, and roadsides from Missouri to Texas and California.

Buffalo burr is an annual spiny weed 1-2 ft. tall. Leaves are irregularly round-lobed or once or twice pinnately deeply lobed; veins are spiny. Flowers are yellow, and the berries are enclosed. Native to the Great Plains and introduced to the West Coast, buffalo burr grows in old fields, overgrazed pastures and roadsides.

How nightshades affect livestock:

Nightshades are generally unpalatable and are not grazed by livestock except under the stress of overgrazing or in contaminated hay and grain. Poisoning by this group of plants does not always end in death. In acute poisoning, the nervous symptoms develop rapidly. Death or recovery occurs within a few hours to 1 or 2 days. Death apparently is related to the paralysis. Chronic poisoning is accompanied by emaciation, rough hair coat, anorexia, constipation and ascites.

Losses can be kept at a minimum by good pasture management and weed control. Harvested forage such as hay, grain or silage can be contaminated with nightshades. Contaminated forage can be fed if it is diluted (mixed) with nightshade-free forage: an on/off feeding strategy should be used. Animals being fed this diluted forage should be kept under close surveillance and immediately removed from the contaminated feed if signs of poisoning appear. Submit a sample to the Poisonous Plant Research Lab for analysis.

Fact Sheet: Poison Hemlock

Signs and lesions of poison hemlock poisoning:

  • Nervous trembling
  • Neuromuscular stimulation followed by depression and paralysis
  • Ataxia, especially lower and hind limbs
  • Salivation
  • Lack of coordination
  • Dilation of the pupils
  • Rapid, weak pulse
  • Respiratory paralysis
  • Coma
  • Death
  • Convulsions have been reported
  • Occasionally bloody feces and gastrointestinal irritation

Skeletal birth defects and cleft palate in calves and piglets if cows or sows eat poison hemlock during susceptible stage of gestation: 40th to 100th days for cows, 30th to 60th days for sows

Poison hemlock (Conium maculatum) can be found growing throughout the U.S. Sheep, cattle, swine, horses and other domestic animals are poisoned by eating a small amount. It is also extremely poisonous to humans.

Poison hemlock is sometimes confused with western waterhemlock–a more deadly plant–because the names are similar. (See waterhemlock chapter in this volume.) Poison hemlock has a number of common names, including deadly hemlock, poison parsley, spotted hemlock, European hemlock, and California or Nebraska fern.

Roots of poison hemlock may be mistaken for wild parsnips and eaten by people. The stem of poison hemlock has purple spots on it.

All parts of poison hemlock–leaves, stem, fruit and root–are poisonous. Leaves are especially poisonous in spring up to the time the plant flowers. Fresh leaves are unpalatable, so livestock seldom eat hemlock when other feed is available. The tox­ic compounds are coniine, γ‑coniceine and related piperidine alkaloids.

Where and when poison hemlock grows:

Because of its attractive flowers, poison hemlock was brought to the U.S. from Europe as a garden plant but has escaped cultivation and can be found growing in many pastures and in some areas on rangeland. Poison hemlock is found at roadsides, along fences and ditch banks, on edges of cultivated fields, along creekbeds and irrigation ditches, and in waste areas. It may invade fields or pastures.
Poison hemlock is a biennial and belongs to the carrot family. It starts growing in early spring but does not flower until its second year. In favorable locations it may be a perennial. Poison hemlock harvested with hay can be toxic to livestock and produce birth defects.

How poison hemlock affects livestock:

Poison hemlock ingestion is often fatal. Sheep may be poisoned by eating as little as 4-8 oz. of green leaves. Cattle that eat 10-16 oz. may be affected. Signs usually appear within an hour after an animal eats the plant. Animals die from respiratory paralysis in 2 to 3 hours. Convulsions, which are common in waterhemlock poisoning, seldom occur with poison hemlock.

Skeletal deformities or cleft palate may be induced in offspring of cows, sheep, goats and pigs if poison hemlock is ingested by the mother during susceptible stage of gestation: 40th to 100th days in cows and 30th to 60th days in sheep, goats and pigs. Palate and skeletal deformities in calves are indistinguishable from the lupine-induced crooked calf disease.

Avoid stressing poisoned animals that are not recumbent. For recumbent animals, support respiration and treat with activated charcoal and a saline cathartic. Gastric lavage may be beneficial, with atropine therapy to control parasympathetic signs.

Animals that recover seldom show lingering effects.

Research results show that poison hemlock may be controlled by treating plants before they begin to bud with 2,4-D plus dicamba (2.5 lbs. + 1 lb. ae/acre). Repeat applications may be needed.

Fact Sheet: Waterhemlock

Signs and lesions of water hemlock poisoning:

  • Nervousness
  • Excessive salivation and frothing
  • Muscle twitching
  • Dilation of the pupils
  • Rapid pulse
  • Rapid breathing
  • Tremors
  • Violent convulsions, grand mal seizures
  • Coma
  • Death may occur as early as 15 minutes after a lethal dose is consumed
  • No significant gross lesions

Water hemlock (Cicuta douglasii) is the most violently toxic plant that grows in North America. Only a small amount of the toxic substance in the plant is needed to produce poisoning in livestock or in humans. The toxin, cicutoxin, acts on the central nervous system and is a violent convulsant.

Water hemlock may be confused with poison hemlock because of their similar flowers. However, these two are different plants and cause different types of poisoning. (See poison hemlock chapter in this fact sheet.)

The underground portions of the plant, especially the tuberous roots, are very toxic. People are sometimes poisoned by eating the roots, which they mistake for wild parsnip.

In cases of water hemlock poisoning in humans, take the affected person to the emergency room of the nearest hospital immediately. Call poison control and seek emergency treatment immediately.

Cattle have been known to eat lethal amounts of water hemlock in pastures having adequate forage; therefore, animals should be prevented from grazing over water hemlock-infested areas. Animals have been poisoned by eating roots that have been brought to the surface by plowing or cleaning ditches.
The toxic substance in water hemlock is cicutoxin, a highly poisonous unsaturated alcohol that has a strong carrot-like odor. It is found principally in the tubers but is also present in the leaves, stems, and immature seeds. Leaves and stems lose most of their toxicity as they mature.

Water hemlock is most commonly found growing in wet meadows and pastures and along stream banks. It starts growing in spring. Water hemlock usually flowers in June or July.
How water hemlock affects livestock:

Livestock usually show signs of poisoning 15 minutes to 6 hours after eating the plant. They develop violent convulsions and may die within 15 minutes to 2 hours after signs appear.

The toxic substances act so rapidly that an affected animal can seldom be saved. Treatment consists of preventing seizures with barbiturates or tranquilizers and supporting respiration. Gastric lavage, activated charcoal, or saline cathartic may be helpful. Seek immediate medical or veterinary treatment.

To reduce losses, keep animals away from places where water hemlock grows. Prevent water hemlock poisoning in livestock by carefully surveying pastures and ranges at a time when the plant can be identified, and eradicate it.

The plants, which usually grow in small patches, are easy to locate. They can be eradicated by spraying or grubbing. Actively growing plants can be controlled with 2,4-D at 2 lbs. ae/acre. Repeat spray treatments until eradication is complete. The stems and leaves of water hemlock increase in palatability immediately after being sprayed with herbicide. Therefore, keep animals away from treated plants for 3 weeks after spraying. Most losses occur early in the spring or after the plants have been sprayed with 2,4-D.

Note: If grubbing the water hemlock, use gloves and be careful to get all of the plant, including roots. Gather and burn every part, don’t leave tubers lying around.

Fact Sheet: Larkspurs (tall and low)

Tall larkspurs tend to grow at higher elevations on deep soils where a plentiful supply of moisture is available. They grow in mountain meadows on sites where deep snowdrifts persist well into the growing season, under aspens on north-facing slopes, along streams, or around seeps and springs. Tall larkspur begins growing as soon as snow melts, but at the upper limits of their distribution this may not occur until July.

Low larkspurs tend to grow at lower elevations where they mature and become dormant before the soil moisture is depleted. They begin growing in early spring, often before other forage begins growth. Low larkspurs grow best when springs are cold and wet. Cattle will graze low larkspur at all stages of growth, but most often graze it after flowering.

Plains larkspur is found primarily on the high plains of Colorado and Wyoming. It begins growth in spring before other plants.

How larkspur affects animals:

Plains larkspur may be eaten by cattle at any time during summer, but early green growth and pods may be most appealing to cattle. Both low and plains larkspurs may be the only green herbage available to cattle in early spring.

The larkspurs contain a number of alkaloids of varying toxicity. The most toxic of these are the MSAL (methyl succidimino acetyl lycoctonine) types, which include methyllycaconitine. Submit a sample to the Poisonous Plant Research lab for analysis.

Placing an af­fected animal on its brisket or chest with its head uphill may reduce bloating. Treatment for bloat (intubation or rumen puncture with a trocar) may save some animals. Avoid unduly exciting affected animals.

Toxicity of tall larkspurs declines as it matures through the growing season. Research has identified a toxic window of high risk during the flower and early pod stages when it becomes palatable and toxin levels are moderate.

Since cattle do not generally consume tall larkspurs before flowering, grazing early before plants flower may be an acceptable grazing option. Cattle should be moved off of the larkspur areas during the flower stage but can graze larkspur in the late pod stage when toxicity declines. Using sheep to graze or trample tall larkspur patches ahead of cattle grazing may reduce cattle losses.
Low larkspur losses may be prevented by deferring grazing until plants lose their flowers and pods, as they rapidly senesce after producing pods. This usually occurs in late spring or early summer and grazing is safe after seed shatter.

The cholinergic drug neostigmine (0.02 mg/kg i.m.) has been successfully used under pen conditions to reverse clinical larkspur intoxication. This reversal lasts about 2 hours, and repeated injections of neostigmine are sometimes required. Under field conditions, neostigmine temporarily abates clinical signs and animals quickly (about 15 minutes) become ambulatory. Depending on the larkspur dose, the intoxication can resurface. Nonetheless, there are risks associated with the use of neostigmine. The use of neostigmine-based treatments may actually aggravate losses in the absence of further treatment because suddenly mobile animals may later develop increased muscular fatigue and dyspnea and may die.

Research results show that low lark­spurs can usually be controlled by applying 2,4-D at the rate of 4 lbs. ae/acre when the vegetative development approaches its maximum but before the first flowers open.

Tall larkspur can be controlled with picloram (1 to 2 lbs. ae/acre) up through the flowering stage. Metsulfuron (1-2 oz. of product/acre) is effective when applied in the early vegetative stage of growth. Plains larkspur can be controlled with picloram (0.25 to 0.5 lb. ae/acre) in the bud stage.

Do not graze cattle on larkspur ranges treated with herbicide until larkspur is senescent in the fall. Herbicide treatment may increase palatability to cattle, but toxicity remains high.

Plants are vital to life on Earth.

Their ability to take up carbon dioxide and release oxygen into the atmosphere is critical to our continued survival.

Plants remarkable ability to convert sunlight through photosynthesis and store that energy provides the foundations of the food web which supports all life.

There is incredible diversity in plants which humans have utilised as food, fibre, medicine and tools

We have also learnt through hard experience and scientific studies that many plants can be toxic to our health.

Some of these plants are commonly found in our gardens and even our pantries.

Two or three teaspoons of nutmeg can kill an adult and potatoes turning green from exposure to sunlight produce the toxin solanine which can be fatal.

TOXIC: Green cestrum buds, flowers and fruit. Photo: G. Wisemantel.

Oleander, a common garden plant (a popular planting in primary schools around the 1960s and 1970s) is highly toxic to humans and livestock.

In 2010, a group of boy scouts in America used oleander sticks to roast their marshmallows on the campfire.

Seven died and five were very ill.

Oleander cuttings thrown over the fence have been responsible in the death of livestock.

While it is true to say more animals die from not getting enough food than die from what they eat, as for humans, plants can be toxic to livestock and it pays to be aware of plants in your region that can be potentially toxic to animals on your property.

Due to the fact that there are many causes of death in livestock and often multiple factors involved, it can be difficult to determine plant poisoning as the cause.

Some plants can be safe to stock and then become toxic with changes in conditions.

Stock will often ignore toxic plants until feed becomes scarce or they are moved into a new paddock.

Newly introduced animals may be naïve to suspect plants and fall victim to poisoning while the resident herd have learnt to avoid them.

Some plant poisoning of stock can be sudden, common with green cestrum, but in many cases the animals will exhibit symptoms including:

  • weight loss;
  • diarrhoea;
  • staggers
  • photosensitisation (skin becomes very sensitive to sunburn or causes liver damage);
  • irritation;
  • loss of production (wool contamination etc);
  • congestive heart failure – oedema; and
  • red water (bacterial disease which can result from high nitrate plants).


Primary photosensitisation – a severe inflammatory reaction in the deep skin layers, caused by a reaction between UV radiation from the sun, and plant-derived pigments.

Secondary photosensitisation – a similar reaction, but with chemicals which have built up in the blood stream because of impaired liver function.

Primary photosensitisation is not seen very commonly, but can be caused by plants such as St John’s Wort.

Secondary pphotosensitisation is more common.

Chronic grazing of plants such as heliotrope or Pattersons Curse irreversibly damages the animal’s liver.

The liver is the chief organ responsible for processing toxins in the blood stream.

Without liver function, the animal cannot process a toxin called chlorophyll which is present in all green plants.

This chlorophyll builds up in the animal’s blood stream and reacts with UV light to cause the clinical signs of secondary photosensitisation.

HARMFUL: Stock grazing in Pattersons Curse.

Monitor livestock to avoid nitrate poisoning

During a drought, soil levels of nitrogen increase because of reduced leaching, increased organic matter breakdown and reduced uptake of nitrogen by plants.

When it rains and the drought breaks, nitrogen is taken up by plants in large quantities.

If hungry animals are allowed free access to these plants, stock losses can be disastrous.

Nitrates are caustic to the gut lining and can cause excess salivation, diarrhoea and abdominal pain.

Nitrites are much more toxic. They can be ingested directly or converted in the rumen from nitrate.

When found in feed, it is usually in stored hay that has been allowed to heat up, or attacked by bacteria or fungi.

Nitrites change haemoglobin in the blood so that it can no longer carry oxygen. This causes death.

Much of the world’s soils are deficient in nitrogen.

Newer farming practices aim to increase it’s concentration in the soil by planting legumes or applying fertilisers like urea.

This can increase the risk of poisonings.

Other factors that increase the risk of poisonings include drought, cloudy weather, application of herbicides and wilting.

Nitrate levels are usually higher in young, fast growing plants.

Hay made from plants in drought conditions can contain toxic levels when they heat up, especially oaten hay.

So even plants that are normally perfectly good stock feed can become toxic under certain conditions.

Pigs are the most susceptible, then cattle, then sheep, then horses.

To avoid livestock poisoning, landholders need to be diligent in monitoring the plants on their property.

They should be aware of conditions and factors that increase the likelihood of stock’s vulnerability to toxic plants.

  • Visit www.tocal.nsw.edu.au

Poisonous plants for Livestock

With grass and plant growth at optimum levels and silage being harvested, we have a list of some of the poisonous plants for you to watch out for on your farm this summer. Read more below.

Silage season 2018 is well underway, with the recent upturn in weather conditions providing the perfect platform for grass and plant growth.

Poisoning via plants found in farm pastures has become a problem in recent years, with over 140 animals killed in 2015 as a result. But what plants can be harmful to your livestock? What are the signs of poisoning? Keep reading below and find out!

Bracken –
A very common plant in most pastures, when ingested continually bracken can be very toxic. It can cause acute disease and even death in cattle when high levels are ingested. This usually occurs after the ingestion of younger bracken plants, which causes the suppression of bone marrow and loss of blood cells.

Livestock find the younger plants tastier and easier digested also, making them very dangerous. Bracken poisoning usually occurs in autumn months. Ingestion for prolonged periods can result in tumours in the bladders of older cows and even occasionally in the rumen and oesophagus.

Any cow affected by bracken poisoning will show signs of weakness, which will get progressively worse until death. When bladder tumours are present, blood will be found In the urine of cattle, while they will also suffer from chronic weight loss.

Treatments of bracken poisoning is generally unsuccessful, with prevention the easier option. This can be done through the use of herbicides prior to harvesting of silage, controlled burning or even fencing around areas where the plant is found.

Ragwort –

We all know of this one, but do you know the real dangers? Ragwort poisoning is most common in the Autumn. This is when cattle are most at risk, due to poor grass growth and young plant shoots present on pastures.

One of the greatest risks of ragwort poisoning is when feeding cattle preserved grasses, silage and hay. This is due to preserved ragwort losing none of its toxins and losing its harsh taste due to drying. It does not just affect cattle but horses, chickens, pigs, sheep and many others also. It is caused by a toxin called Pyrrolizdine alkaloids.

It is crucial to spot this early. Early symptoms include weight loss, depression, loss of appetite, mild jaundice (yellowing of the skin) and an increased sensitivity to sunlight. As the poison is further digested into the system, symptoms can get more severe. This can lead to an animal circling, pressing their head against a wall, walking compulsively, extremely depressed and suffering from a slight loss of vision. An animal will be generally uncomfortable, uncoordinated and restless when suffering.

Other more serious signs include: Constipation, a dull coat, loss of condition, seizures and a coma. It generally causes liver damage and usually results in death. Development of disease can be delayed from four weeks to six months after the animal ingesting the plant. Different animals will have different susceptibilities to the toxin.

There are many varying ways to help prevent ragwort growth on your farm. The best way to prevent its ingestion by livestock is simply to prevent access to infected pastures. This is why fields should be checked regularly for signs of ragwort growth.

Grassland management holds one of the keys to fight this battle, whilst ploughing can also be used effectively, as does the improvement of land drainage. Other options include the use of herbicides, prior to harvest and should be used before April/May.

There is no real treatment for ragwort poisoning, again, it usually leads to death.

Water dropwort –

Another potentially toxic plant found in many pastures throughout the country. Also known as the water hemlock, livestock are most at risk to water dropwort poisoning when ditches have recently been cleared out and plants uprooted. This is because the root it the heart of the toxins in this plant.

There is no specific treatment for poisoning by the water hemlock and all stock should be immediately removed from a field where poisoning occurs. Signs include difficulty breathing, convulsions and the collapsing of animals soon after ingestion. The majority of infected animals die, though some do survive, with diarrhoea a sign of recovery.

Another poisonous plant which is found commonly in Ireland, is the Foxglove (Pictured below, bottom right). This is another which is also toxic to animals, pets and Livestock.

Yew Tree – (Top left in Below picture)
This is an ornamental tree found in some gardens. It is generally found in gardens surrounding older buildings and churches and exposure to it can result in rapid death. Ingestion also results in death. There is no cure or treatment, meaning you must be vigilant and ensure any pasture surrounding older buildings have no yew trees nearby.

Acorns from Oak trees produce the same result, severely sick livestock (See above picture – top right). This is usually a problem during autumn months, when disruptive weather knocks acorns onto pastures. Acorn poisoning, depending on the level of ingestion, is often fatal and damages the kidneys of livestock. There is no treatment, making prevention the key and death usually follows after 4-7 days of poisoning. To prevent any such incidences, stock should be moved from pastures which are nearby Oak trees, especially after stormy weather.

Take care this silage season, you can never be too careful!

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PHOTO: lb Aarmo/Flickr by J. Keeler Johnson February 12, 2016

One of the most satisfying aspects of living on a farm is having the ability to plant trees whenever and wherever you want. With lots of open spaces, you can grow a wide variety of native or ornamental trees around your farm without concern about planting them too close to buildings or power lines.

If you have livestock on your farm, such as cows or horses, it’s a nice idea to plant shade trees in their pastures to protect them from the sun. In fact, if you’re carving your pastures out of a lightly wooded area, there may already be some large and suitable shade trees available. However, it’s important to keep in mind that while shade trees are good, some tree species can be toxic to livestock and are best planted somewhere else on your farm. Here are five trees you want to avoid planting to keep your livestock safe.

1. Oak Trees

It might come as a bit of a surprise, given that oak is one of the most common, widespread and popular trees, but it’s actually not the best to have near your livestock. The growing leaves and acorns contain tannin and can be toxic to livestock if eaten in large amounts. That’s not to say that oak trees can’t be somewhat near to your animals as long as there is plenty of grass or other food on hand, but if your animals have a tendency to munch on things other than grass, or if there’s a chance they’ll find acorns appealing in the absence of a better food supply, you might want to take steps to move your livestock or remove the oak tree. In any case, if you’re looking for a spot to plant an oak tree, choose a location that isn’t in or right next to your livestock pastures—it’s better to be safe than sorry.

2. Buckeye Trees

The buckeye family, which includes horsechestnut, yellow buckeye and Ohio buckeye, as well as some smaller shrubs that may grow to the size of small trees, is another group that you won’t want to plant near your livestock. Found primarily in the lower half of the eastern and central United States, Buckeye trees have leaves, nuts and twigs that are poisonous to farm animals. As with oak trees, a buckeye tree or two near your pastures probably won’t cause a problem, but placing them where your livestock could easily munch on the leaves or branches is not a good idea.

3. Walnut Trees

While oak and buckeye trees aren’t a huge concern when it comes to livestock, much more caution should be taken when dealing with walnut trees. Walnuts, which includes the butternut tree, aka the white walnut, release a substance called juglone from their roots, which is toxic to many other trees and plants. Juglone is also found in the leaves, branches and nut hulls, and horses standing in wood shavings made from walnut trees can develop laminitis, a serious and sometimes fatal hoof disease. There is also evidence that simply being around walnut trees may be enough to trigger laminitis in some horses.

In addition, walnut husks can also become toxic to livestock in general—not just horses—as they deteriorate on the ground, and while some people might find that walnut trees don’t cause an issue, to be on the safe side it’s best to keep livestock—especially horses—away from them.

4. Cherry Trees

Cherry trees of one type or another grow throughout much of the country and well into Canada, and while their fruit is generally edible—and eaten by humans and many animals—other parts of cherry trees, such as their leaves, branches and the seeds inside the fruit, possess hydrocyanic acid, which can be toxic to livestock and occasionally cause death. As with other trees, having a cherry tree near your pastures might not cause any problems, but because wilted cherry leaves are particularly toxic to livestock, it’s best to keep cherry trees away in case leaves or broken branches should fall into your pastures.

5. Red Maple Trees

This is another tree that you should be very, very cautious about. Unlike other maple trees, which pose little threat to livestock, the wilted leaves of red maple are highly toxic to horses and can kill them within a day or so if ingested. The live green leaves of red maple have not been known to cause issues, but the wilted leaves can remain a threat for as much as a month. Avoid planting red maple trees in or near your pastures, and if there are already red maple trees in the area, consider removing them to ensure the safety of your horses.

Of course, this is not a complete list of trees that are toxic to livestock—other notables include black locust and box elder—but fortunately, the majority of trees are safe to plant around livestock, and as long as you do a bit of research before planting, you should be good to go!

Poison hemlock. Photo credit: UGA/Bugwood.org

It seems to me that raising livestock as well as farming in general, is often about risk management. Every year I get questions from livestock owners regarding poisonous plants; either for identification or for information on how to manage around a known poisonous plant.

Management is key

Avoiding livestock health problems due to ingestion of poisonous species is a matter of being able to identify potentially poisonous plants, understanding risk factors and taking some proactive management steps.

What are the risk factors for livestock ingestion of poisonous plants? Here is my list:

  • overgrazed pastures
  • drought conditions
  • summer storms
  • well-intentioned neighbors

Common poison species

Some common tree and weed species rated as poisonous species that pose a risk to grazing livestock includes: wild black cherry, red maple, and Ohio buckeye, as tree species and poison hemlock, buttercup/cressleaf goundsel, milkweed, nightshade, horse nettle and star of Bethlehem as weed species.

This is not an inclusive list, but it does include some of the common species associated with pastures. Now let s match up species with risk factors and provide a little more information about the toxicity of each species.

Weed control

One of the general principles of forage weed control, whether in a pasture or hayfield situation, is that 90 to 95 percent of weed control is provided by competition from the forage crop. Proper soil pH and soil fertility are important components to allow forages to grow competitively and thrive.

Another principle is to avoid overgrazing. This management practice will promote a denser pasture sward that will help to keep weeds from invading a pasture, including poisonous species.

Paddock management

Inspect mismanaged and overgrazed pasture paddocks for potential poisonous plants. Recognize that when desirable pasture forage is in short supply, the risk of livestock grazing a poisonous plant if present, is greater. In the spring, buttercup and cressleaf groundsel are both weeds that may appear.

These are weeds that are rated as low to moderate toxicity. They are also low in palatability so generally livestock will avoid ingesting these weeds. Cressleaf groundsel is a weed that is becoming increasingly more common. The compounds responsible for toxicity, pyrrolizidine alkaloids, are not destroyed in the haymaking process, and so inclusion of this weed in significant quantities in dried hay may pose a bigger threat to livestock than in a grazing situation.

Sheep management

Sheep are considered to be more resistant to the pyrrolizidine alkaloids than cattle or horses and reportedly have been used in some areas to control the plant provided the infestation is not too heavy.

Milkweed and nightshade are poisonous plants that are both considered unpalatable to livestock and generally only eaten if there is a shortage of good quality forage. Both of these plants can retain their toxic properties in hay. Cardiac glycosides are the toxic compounds in milkweed and alkaloidal glycosides are responsible for the toxicity of nightshade.

Low toxicity

Milkweed is rated as low toxicity while nightshade is rated as a moderate to highly toxic plant. Both of these plants are toxic to all classes of livestock, but in the case of milkweed, sheep are considered as most at risk from ingestion and poisoning.

Poison hemlock is a biennial plant that is appearing with greater frequency in both pastures and hayfields throughout Ohio. This plant is reminiscent of wild carrot with its finely divided leaves, but its key identification characteristic is the purple blotches or spots on a smooth stem.

Plant ingestion

All parts of the plant are poisonous and all livestock species can be affected if any part of the plant is ingested. The principle toxic compounds in poison hemlock are alkaloids coniine and gamma-conicine. It does not take much to get a lethal dose. In horses 4 to 5 pounds ingested can be lethal, 1-2 pounds in cattle and a mere 4-8 ounces in sheep. Toxicity is not diminished in either the ensiling process or the hay making and drying process so stored feed made from fields where poison hemlock is present is a livestock health concern.

Star of Bethlehem is a perennial, bulbed plant that may remind you of wild garlic or onion, but it does not have the odor. It has star shaped flowers and was originally introduced as a garden ornamental. All parts of this plant are toxic, and especially the bulbs. The toxic components are cardiac glycosides and all grazing livestock are susceptible.

Herbicide options

The bad news is this plant is capable of taking over areas of a pasture paddock and whereas the other poisonous weed species previously mentioned have some herbicide options for control, Star of Bethlehem has limited herbicide options that are only moderately successful in controlling it.

In drought years there are more cases of livestock ingesting poisonous plants. In part this is due to the slow pasture growth that results in livestock not having enough desirable forage available. They may eat plants, including poisonous plants that they otherwise would not eat. Be very diligent about inspecting pasture paddocks for potentially poisonous plants during drought conditions.

Nature’s path

Summer storms and the accompanying downed limbs and trees can present another risk of livestock ingesting poisonous plants, particularly if some of those downed limbs or trees are from wild black cherry, red maple or our state tree, the buckeye.

With regard to red maple only horses are known to be affected. Horse owners need to be aware that red maple leaves are rated as highly toxic to horses, ingestion of as little as 3 pounds can be a lethal dose. Within 48 hours of ingestion, chemicals in the leaves will cause a destruction of red blood cells.

Leave ingestion

The Ohio buckeye as well as a related species, the horse chestnut, are rated as a moderately to highly toxic. Ingestion of the leaves can affect the gastrointestinal and nervous systems of all grazing livestock.

When small amounts are eaten symptoms may be limited to the gastrointestinal system and include excessive salivation, abdominal pain and diarrhea. When larger amounts are consumed neurological symptoms including trembling, staggering and breathing difficulty may be expressed. The issue with wild black cherry trees is that freshly wilted leaves can contain high levels of hydrogen cyanide (HCN) compounds. Young leaves generally have a higher HCN potential than older leaves so as we go through the growing season, HCN levels in wilted leaves decline.

Susceptible to poisoning

However, ruminant animals are very susceptible to poisoning from HCN. Research indicates that the lethal dose for sheep/cattle can be as little 0.46 grams to 1.82 grams of plant material per pound of body weight. To give this some perspective, there are 454 grams in one pound, so this is a small amount. For a 1200 pound cow, consuming 1.2 to 4.8 pounds of wilted black cherry leaves could be a lethal dose.

Signs of HCN toxicity can occur quickly, as soon as 15 to 20 minutes after ingestion. Typical signs are distress, followed by severe weakness to the point where the animal is barely able to stand, or even to the point of collapsing. Animals will exhibit rapid and labored respiration. If they have collapsed there may be kicking/paddling of the legs and/or kicking associated with seizure like symptoms. This entire sequence can progress in 10 to 15 minutes with a high dosage of HCN and up to 45 to 60 minutes with a lower dose.

Recovery is possible

References state that if the animal does not die in the first hour, there is a good chance for recovery. A final risk factor is the well intentioned neighbor. The most common example of a good intention causing a tragedy is when trimmings from a yew plant are dumped into a livestock pasture as a treat for the animals.

Yew plant

Livestock will readily consume the trimmings but yew is a highly toxic plant and death can occur very quickly following ingestion. It has been reported that one mouthful is enough to kill a cow or horse.

There are some good websites available to learn more about poisonous plants and that can help with identification. Some that I use include: http://research.vet.upenn.edu/poisonousplants from the University of Pennsylvania Veterinary School and www.ansci.cornell.edu/plants/index.html from Cornell University Animal Science Department.


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