Dreamcatcher Alpacas
Plant safety · Caution

Can Alpacas Eat Horsetail?

Horsetail (Equisetum arvense) — a wild plant. Here is what alpaca owners need to know.

Updated 2026-10-02By the Dreamcatcher Alpacas editorial team
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Use caution — it depends on the amount and the situation.

Occasional nibbles are usually tolerated, but problems occur with large amounts, certain plant stages or vulnerable animals.

Horsetail (Equisetum arvense)
Horsetail (Equisetum arvense). Photo: botany08, CC BY 4.0 via Wikimedia Commons.
Status
Caution
Scientific name
Equisetum arvense
Family
Equisetaceae
Plant type
Wild plant
Also known as
Field Horsetail
Toxic parts
Whole plant, especially in hay
Toxic compound
Thiaminase, alkaloids

Why it matters

A wet-ground plant; mainly a problem when it is baled into hay.

Signs of horsetail poisoning in alpacas

  • Weakness and incoordination (thiamine deficiency)
  • Weight loss

If your alpaca ate a lot of horsetail

  1. Remove access and estimate how much was eaten.
  2. Watch for the signs listed above over the next 24–72 hours.
  3. Call your vet if any signs appear or if a pregnant, young or sick animal ate a large amount.
  4. Reduce the plant in your pasture and keep good forage available so alpacas aren't driven to eat it.

About the plant

Equisetum arvense, commonly known as field horsetail or common horsetail, is a species of vascular plant in the horsetail family Equisetaceae. Like all horsetails, it is a type of fern. It is native throughout the arctic and temperate regions of the Northern Hemisphere. It has two distinct growth forms, a fertile spore-bearing stem and a sterile green stem. It is sometimes confused with mare's tail, Hippuris vulgaris.From Wikipedia — “Equisetum arvense”, licensed under CC BY-SA 4.0.

Where it grows

GBIF, the Global Biodiversity Information Facility, holds 1,024,830 recorded observations of Equisetum arvense L. worldwide, including 37,535 in the United States. It belongs to the Equisetaceae family. See the occurrence map on GBIF.

Frequently asked questions

Is horsetail poisonous to alpacas?
It can be. Use caution — it depends on the amount and the situation. A wet-ground plant; mainly a problem when it is baled into hay.
What part of horsetail is toxic to alpacas?
Whole plant, especially in hay.
What are the symptoms of horsetail poisoning?
Weakness and incoordination (thiamine deficiency) and weight loss.
Is dried horsetail safe?
No — the toxin in this plant remains active when dried, so contaminated hay and dried clippings are still dangerous.

Keeping pastures safe

  • Walk every paddock and fence line each season and remove toxic plants, including roots.
  • Never throw garden, hedge or lawn clippings over the fence.
  • Check pastures after storms for fallen branches (cherry, red maple).
  • Buy hay from known sources and inspect it for weeds.
  • Keep pastures well managed — hungry alpacas eat plants they would normally avoid.

Browse the full toxic plant checker, the printable list of poisonous plants and the list of safe plants.

This page is educational and does not replace advice from a veterinarian who has examined your animals. Camelid medicine uses many drugs “extra-label”, so dosing must come from your vet. In an emergency, call your vet first. Read our disclaimer · How we write and review content.

Data: plant status compiled from veterinary toxicology references (see sources); taxonomy and occurrences from GBIF; identifiers from Wikidata Q107592.