Lupine and Castor Bean Poisoning

...and on the eighth day God created the horse in perfect image, to romp, graze, gallop, play and make manure wherever it darn well pleases, in divine grace.

Lupines, or Lupinus, are gorgeous perennials that bloom during the summer months, showing up in shades of purples and pinks, yellow, white and even red, on long, tall spikes. They are a member of the pea family, and indigenous peoples of the Americas would eat the seeds. The arrival of the

Spaniards changed the culinary ways of these peoples, and it is only recently that Lupines have come into favor in the kitchen again.

The pods are soaked and then cooked or toasted, to remove bitterness or toxins. There are secondary compounds within the plant and people with peanut allergies show response. The European Commission requires labeling of products using Lupines. (1)

The plants resemble Blue Bonnets, and are called such, along with the name Quaker Bonnets, and there are over 200 species of them.

Specific names of Lupine plant species will not be mentioned.

If the horse eats Lupine seeds, the result is diarrhea and gastrointestinal irritation. Additionally, symptoms may include weakness, depression, laying out flat and even coma. Lack of appetite is obvious, in-coordination and sensitivity to light may be seen. More severe effects may be liver damage, with the horse walking around aimlessly and lifting its feet unusually high. Convulsions and coma precede death. (2)

There is no cure or treatment for Lupine poisoning. Not sure if activated charcoal would work in a home-style remedy.

Obviously pastures, fields and paddocks should be free of Lupine flowers and seeds at all times, nor should the horse be able to lean over a fence to get at them. This requires diligence on the part of the horse owner.

Castor Bean, Ricinus communis, is harvested to manufacture castor oil. Castor plants are often seen as ornamental shrubs in the southwestern US. The large, leafy plants are decorative and horses may have access to them over fences or at the edge of a paddock. They are used around barns and corrals in landscaping.

Horses only have to ingest a small number of the beans in order to get sick. Ricin is a poison contained within the plant.

The plant itself is not poisonous, and only the seeds contain Ricin.

Young horses or horses new to a corral may be attracted to the plant.

Approximately 150 seeds can cause the death of a horse, but there are veterinary cases where only 20 seeds were consumed to kill the animal. (3)

The acids and enzymes in the horse’s stomach and digestive tract do not break down the ricin in the Castor Bean. The Ricin acts on the membranes in the intestines and in the nervous system.

Severe inflammation and irritation in the digestive system are seen, and the nervous system degenerates, resulting in death. (4)

No symptoms are visible at first, then severe enteritis is noted after a time period of anywhere between a couple of hours to 2 or 3 days. Then symptoms become very obvious as rapid decline ensues, and symptoms becoming severe.

The first signs are a lethargy or dull attitude in the horse, followed by in-coordination. Sweating also develops and then progresses to profuse amounts. Heartbeat becomes heavy and muscle spasms may appear in the shoulders and neck. The pulse becomes so strong that the whole body shakes with the “force of it.” (5)

If the horse does not die at this point, a severe, colicky diarrhea develops that is thin and watery, but without blood or clots. The horse will appear to be colicky, this progresses to enteritis.

Prevention is the best method of treatment. Do not decorate your lawn or barn with Castor Bean plants, you’re just asking for trouble.

The Veterinarian may be able to obtain an antidote for Castor Bean poisoning, but it is very difficult to procure.

Fluids and supportive therapy may also help during treatment.

Reference book did not indicate whether intestinal villi (singular: villus) would be damaged due to poisoning by either of these two plants, if the animal survives.

Article is meant as a reference and not Veterinary analysis. Always call the Vet if you suspect your horse has eaten something that is poisoning him or making him sick.

Until next time, closing with the immortal words of Roy Rogers and Dale Evans, “Happy Trails to You.”

1: Wikipedia/Internet

2-5: “Horseman’s Veterinary Encyclopedia,” by Will A. Hadden III, DVM