The Dangers of St. Jacob's Ragwort and How to Remove It from Horse Fields

Ragwort might look harmless with its bright yellow, daisy-like flowers, but don’t be fooled! This plant is highly toxic to horses and ponies. It’s crucial to understand the dangers of this plant and know how to protect your horses. In this blog, you’ll learn how to recognize, understand the risks, and remove this toxic and dangerous plant.

How to Recognize Ragwort?

Key characteristics include the distinct rosettes when the plants are not yet in bloom, and the purple-stemmed stalks on which the flowers grow. The flowers are bright yellow and resemble daisies. It spreads quickly and can take over entire fields. This plant grows from the second half of June until October and begins flowering from July. Typically, it is a biennial plant.

The Dangers Of Ragwort For Horses

Even small, repeated amounts of ragwort are toxic to horses. Eating ragwort can lead to severe liver damage. One of the biggest dangers of ragwort for horses is that it remains toxic even in dried form. This means that hay can become contaminated, causing your horse to ingest it unknowingly. Therefore, it is crucial to thoroughly inspect your pasture before harvesting hay. For a 500 kg horse, ingesting just 5 kg of dried ragwort is already toxic. In its fresh state, horses would need to consume four times as much to reach the same level of toxicity.

Ragwort poisoning is often only recognized when it’s too late. This weed causes significant liver damage in horses, and once symptoms appear, the damage is often irreversible. The disease manifests in various symptoms in your horse or pony, such as:

• Loss of appetite and increased thirst
• Straining, sometimes followed by watery diarrhea
• Unexpected sunburn
• Abdominal bloating due to fluid retention, sometimes accompanied by shortness of breath

In later stages, the damage can even affect the brain, leading to lethargy, restlessness, or even paralysis.

If you’re unsure about symptoms in your horse, do not hesitate to contact your veterinarian. Better safe than sorry!

How to Control Ragwort

Manual Removal

• Pull the plants out by the root before they flower.
• Wear gloves to avoid skin contact!
• Remove the plants by burning them or sealing them in bags, not by composting.

Manual removal is preferred as it avoids the use of chemicals, ensuring the health and safety of your horses and preserving the natural balance of the pasture.

Pasture Management

• Regularly inspect fields for ragwort.
• Maintain a densely grown pasture to outcompete weed growth.

Biological Control

• Consider introducing natural enemies like the larvae of the cinnabar moth as part of an integrated strategy. Ragwort is the primary food source for the zebra caterpillar, the larva of the cinnabar moth (Tyria jacobaeae). These moth larvae are adapted to eating ragwort and are not susceptible to poisoning by pyrrolizidine alkaloids (PAs). 

Chemical Control

• Use selective herbicides during the rosette stage.
• Follow professional advice and manufacturer’s instructions.

Additional Support for Your Horse’s Liver Health

During July and August, when ragwort is widespread, it is beneficial to support your horses' liver health with supplements such as Curafyt’s Detox&Drain, which contains milk thistle and MSM. Milk thistle contains silymarin, a powerful antioxidant that protects liver cells and promotes regeneration. However, a supplement can never replace good pasture management or medication if liver damage is already present.