March fiddleneck bloom toxic to horses

Diane Sieker

Staff Writer

Winter rain and snow are bringing forth lovely wildflower blooms across the Anza Valley. One of the earliest blossoms to emerge is the infamous fiddleneck.

There are several native fiddleneck species in California. Amsinckia intermedia, the Common Fiddleneck, or Intermediate Fiddleneck is a common annual herb species in the Boraginaceae family, the Borage or Forget-me-not family of plants.

However, some varieties of fiddlenecks can be a problem in crop fields, orchards and pastures. In fact, the seeds can be toxic to livestock when ingested in large amounts.

Poisonings most often occur when livestock eat grain or feed contaminated with fiddleneck seeds.

Cattle and horses are most sensitive to fiddleneck poisoning, while pigs and chickens are less sensitive, and sheep, goats and turkeys are the least sensitive.

These plants can be found in disturbed or open grasslands, fields and roadsides. Of the many Amsinckia species in California, many are regarded as weeds. Cotyledons, the seed leaves, are shaped like the letter Y with tiny blisters and fine hairs. Early leaves are longer than they are wide and have coarse, sharp hairs. Fully grown fiddlenecks can reach four feet in height.

The distinctive spiked flower heads curl like the neck of a fiddle and the yellow, funnel-shaped, five-lobed flowers attach on one side of the spike. The flowers vary from yellow-orange and orange, to dark yellow. At maturity, the four-lobed fruit breaks into four gray, brown or black seeds called nutlets.

Insects such as Painted Lady butterflies and Alfalfa Looper moths depend on the flowers for food.

Fiddleneck poisoning in horses can be an issue. These plants contain pyrrolizidine alkaloids, which are toxic in large amounts when eaten.

Although the plant is common, poisonings are quite rare because the weeds do not taste good to livestock.

"Fiddleneck is indeed toxic to equines but like most animals, they will only eat it if they're starving," fourth generation horseman and author Cezanne Ryerson-Jodka said. "Most will leave it alone. They're not stupid. They have survived thousands of years without us mothering them along."

In the uncommon instances of horses that develop symptoms of poisoning, the animals usually suffer irreversible liver damage. However, if caught early, management techniques may improve and extend the animal's life.

Symptoms of fiddleneck poisoning include aimless wandering, blindness, head pressing, circling, swollen legs, seizures, dermatitis, jaundice, weakness, lack of coordination, loss of appetite, photosensitivity and weight loss. Although an animal may develop symptoms from one large serving of fiddleneck seeds, in most cases this happens over many feedings. In most horses, the signs of liver damage take several months after exposure to develop.

A veterinarian will gather as much information regarding the amount of plant material that was eaten and how long it has been since it was ingested by the horse. Standard blood tests, including a complete blood count and biochemistry profile, are used to evaluate if any infections are present as well as establishing the levels of liver and kidney enzymes found in the blood. These tests are likely to show high levels of liver metabolites and enzymes.

The veterinarian will also recommend an ultrasound of the abdomen to see the current shape and size of the liver, and a biopsy of the tissues will help to identify the fibroids indicative of liver damage due to pyrrolizidine alkaloids, and to estimate the progression of the disease.

The vet may perform a gastric irrigation procedure to remove as much of the toxic material from the digestive system as possible. It is also common to administer activated charcoal in fiddleneck poisonings, to prevent any further absorption of the pyrrolizidine alkaloids into the bloodstream.

Unfortunately, by the time symptoms have become apparent, irreversible liver damage has already occurred. Intravenous fluids may be administered to prevent dehydration and combinations of electrolytes and sugars given to adjust for imbalances that may have developed.

Although the damage to the liver is not curable, it can sometimes be moderated by switching to a low-protein diet with added vitamins and potassium. Medications to reduce the amount of ammonia in the gut can also be helpful in slowing the progression of the disease. However, most animals are not able to recover from fiddleneck poisoning. In cases showing extreme symptoms, veterinarians recommend euthanasia in order to prevent prolonged suffering.

Veteran horsemen advise mowing down fiddlenecks that sprout up in horse arenas, pastures and common areas.

While fiddleneck flowers signal the coming of spring, they also present a threat to horses that equestrians need to familiarize themselves with and do what they can to avoid.

Diane Sieker can be reached by email at [email protected].