Pasture Maintenance

Continuing from the last blog about pasture maintenance, I thought it was important to provide a list of trees, plants and shrubs which are toxic to horses. In this era of AI, social media, and photoshopping, we see so many photographs of horses standing in fields that contain toxic trees or weeds, and how many barn photos have we seen that show them beautifully decked out with landscaping and hanging baskets? We look at those photos of the barns with hanging baskets of flowers and think how lovely it would be to have flowers in the barn! Keep in mind that these photos have been staged and many times these photos are usually of toxic plants and flowers!

It is a misconception that horses will avoid eating plants that are poisonous. Especially if grass is scarce, horses are apt to eat anything. Young horses as well as those who are bored may also sample toxic plants.

While some plants are not palatable, others may be tasty, especially in the early stages of growth, when the tender young shoots are sprouting.

There are many factors that influence the toxicity of plants and weeds, including the horse’s health, size, immune system, the amount digested, previous toxic events, soil composition, water intake, weather and seasons. Some weeds or plants have a cumulative effect, and a horse can eat it for weeks or months before showing a reaction, at which time it may be too late for treatment. Therefore, removing toxic weeds and not overgrazing pastures is essential. If grass is not abundant, supplement with a round bale or pasture block, or toss flake of hay into tubs or onto rubber mats.

Weather can cause plants to produce toxins, especially after rains in the fall, when it follows a dry summer. These rains can cause new growth, which can be toxic. These include:

• Sudangrass

• Johnsongrass

• Redroot pigweed

• Black nightshade

• Horse nettle

• Russian thistle

• Kochia

• Lambsquarters

Additionally, toxic weeds have been known to find their way into cut hay and grain. Therefore, it is best to purchase only high-quality grain from a reputable dealer or grower.

The effects of poisonous weeds and plants can include skin irritation, colic, organ failure, weight loss, and death. Depending upon the plant, the poisoning can occur with just one mouthful, or it can take eating the plant over a long period before any symptoms are noticed. Death can be instant, or the horse can suffer for weeks, until euthanasia is the only option. Symptoms may often go undiagnosed, such as when the horse colics. Owners are so worried about resolving the colic, that they don’t focus on what is causing it, which may very well be a toxic plant.

Managers and owners should do everything possible to remove toxic plants and weeds. Just because one horse has never had an issue with a toxic plant doesn’t mean other horses won’t. It is best to hand pull toxic plants to ensure you get all of the roots and place them in a trash can: never put on a compost pile! Before planting anything near your barn or pastures, use Google to determine if that plant is safe!

I once worked at a high end hunter barn where over half of the horses suffered from crusty sores and digestive issues, including chronic diarrhea. The horses who were turned out overnight would come in every morning with new oozing sores, especially around their mouths. I mentioned to the barn manager that she should have our county agricultural agent out to walk the property. She had never heard of this service! When I inquired a few weeks later as to whether or not she had contacted the agent, her reply was that the owner of the farm didn’t want to have the agent out, as they didn’t want word to get out in the community that they had toxic plants on the property! But I guess it was ok to have a barn full of sick horses? (scratches head over that one)

Most Common Toxic Plants and Trees:

• Angel Trumpet: Weight loss, thirst, diarrhea, death

• Apple Tree: Cyanide poisoning and death

• Avocado: Colic, death

• Black Locust: Diarrhea, weakness, severe gastro irritation, posterior paralysis

• Black Walnut: Laminitis from use in shavings, depression, respiratory

• Bracken Fern: Depression, muscle tremors, paralysis, colic, rapid heart rate & temperature. Takes one month for symptoms to appear

• Cherry Tree: Fatal cyanide poisoning

• Common Boxwood: Weakness, convulsion, resp. failure, death

• Jasmine: Muscle weakness, colic, death. Symptoms occur within hours of ingesting

• Jimsonweed: Bloat, staggering, seizures, death. Symptoms occur within hours of ingesting

• Milkweed: Convulsions, neuro and gastro disorders, congestion in lungs, heart

• Nightshade: Anorexia, colic, kidney failure, death

• Oak Tree: Diarrhea, paralysis, cardiac arrest, death

• Oleander: Rapid respiration, death

• Peach Tree: Oral irritation, colic, death

• Pokeweed: Anemia, weakness, death

• Red Maple: Kidney and liver damage, death

• Rhododendron/Azalea: Acute and chronic cyanide poisoning, death

• Sudangrass/Johnsongrass: Fatal. Liver damage in horses who survive

• Water Hemlock: Death

Flowers that are toxic include foxglove, tulips, daylilies, hydrangeas, lantana, morning glory, daffodil, iris, wisteria, clemantis, bleeding heart, English ivy, lupine, and privet, to name a few.

In my book, Common Sense Horse Keeping, I go into further details of toxic plants, including what parts of the plant are of concern, treatment, and the region where found.

The ASPCA or your local county agricultural agent will have extensive lists of toxic plants and trees that are found in your area.

Good grazing management and planting will affect your grass’s pasture yield and nutrient value. Maintaining a lush pasture is hard work, but there are excellent resources that will guide you. Each state has a county agriculture extension office or a soil and water conservation district, which offer low cost or even free services to help manage your pastures, from fertilizing, to seeding, to identifying toxic weeds and plants. Several good sites on social media are dedicated to improving pastures as well, and many universities have valuable information on their websites.

As I mentioned in my last blog, I am about to experiment with planting crabgrass in some of my pastures. It is palatable for horses, easy to grow in sandy soil and has a low NSC. It took a while to locate the seed (type in crabgrass seed and mostly what you get are sites for crabgrass killer!) and it arrived this week. I started spreading the seed yesterday and will finish up today, just in time for the rain that we are expected to get this weekend! I am excited for this experiment and will keep you all posted as to how well it goes!

Don’t forget to hug your horse!

Lori