THE MOST COMMON FOOD POISONINGS IN HORSES

A horse’s health largely depends on its diet. However, certain toxic plants, forbidden foods, or even feeding mistakes can lead to severe, sometimes fatal, poisonings. Knowing these risks is essential to adopt effective prevention.

Understanding Food Poisoning in Horses

What is food poisoning in horses?

Food poisoning occurs when a horse ingests substances toxic to its body. These may include:

• Toxic plants found in pastures or hay,
• Human foods unsuitable for the equine digestive system,
• Or accidental contamination (mold, heavy metals, pesticides).

Why are horses particularly sensitive?

• Their digestive system is designed for a poor but regular diet (grass, fiber).
• Horses cannot vomit, preventing quick expulsion of toxins.
• Some toxins act rapidly on vital organs (liver, kidneys, nervous system).

Toxic Plants for Horses

Plant poisoning is a frequent cause, especially in poorly managed or overgrazed pastures.

Common toxic plants in pastures and forage

• Yew (Taxus baccata): extremely toxic; ingestion of just a few grams can cause death within minutes.
• Sycamore maple (Acer pseudoplatanus): causes atypical myopathy, often fatal.
• Autumn crocus (Colchicum autumnale): leads to severe digestive disorders.
• Buttercup (Ranunculus acris): irritating when fresh, harmless once dried in hay.
• Bracken fern (Pteridium aquilinum): causes blood and neurological disorders.

Typical symptoms of plant poisoning

• Severe colic
• Tremors, convulsions
• Cardiac or respiratory issues
• Muscle weakness
• Sudden death (especially from yew or sycamore maple).

Forbidden Foods for Horses

Some everyday foods for humans or other animals are dangerous or even lethal for horses.

Foods strictly prohibited

• Chocolate: contains theobromine, toxic for the heart and nervous system.
• Coffee and tea: stimulants that disrupt the heartbeat.
• Raw or green potatoes: contain solanine, toxic for the digestive system.
• Cabbage, broccoli, cruciferous vegetables in excess: cause colic through fermentation.
• Avocado: contains persin, harmful to the heart and lungs.
• Alcohol: dangerous even in small amounts.

Fruits and vegetables to give in moderation

Some are safe in small quantities but become toxic when overfed:

• Apples and carrots (risk of colic or esophageal blockage).
• Dry bread (ferments in the stomach, risk of colic).

Risks Linked to Contaminated Food

Beyond toxic plants and forbidden foods, horses may suffer from accidental contamination.

Molds and mycotoxins

• Found in poorly stored hay or grains.
• Cause liver, respiratory, and digestive disorders.

Heavy metals and pesticides

• Pastures near industrial or intensive farming areas.
• Risk of chronic poisoning (lead, mercury, arsenic).

Poisoning from excess minerals

• Selenium (plants or overdosed supplements) → causes mane and hoof loss.
• Nitrates → blood and respiratory disorders.

Prevention and Response

Best prevention practices

• Regularly check pastures to remove toxic plants.
• Store hay and grains in a dry, ventilated, clean area.
• Never feed horses human leftovers.
• Introduce any new food gradually.

What to do if poisoning is suspected?

• Immediately remove the suspected source.
• Call a veterinarian urgently.
• Keep a sample of the ingested food or plant to help diagnosis.
• Do not attempt self-medication: some products worsen poisoning.

Conclusion

Food poisoning in horses represents a serious but preventable risk. The owner’s vigilance, proper feed management, and knowledge of toxic plants and forbidden foods are the best tools to protect equine health.