Dreamcatcher Alpacas
Alpaca health · Poisoning

Ionophore (Monensin) Toxicity in Alpacas

Updated 2026-10-02By the Dreamcatcher Alpacas editorial team6 peer-reviewed references
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Emergency — call your vet now

This condition can kill within hours. Get veterinary help immediately.

Camelids are sensitive to ionophore additives in cattle and poultry feeds, which damage heart and skeletal muscle.

Category
Poisoning
Urgency
Emergency
Also called
Monensin poisoning, Rumensin toxicity

Signs & symptoms

  • Weakness and reluctance to move
  • Muscle tremors, staggering
  • Heart failure signs: rapid breathing, collapse
  • Sudden death days to weeks after exposure

Related symptom guides: Sudden Death in an Alpaca.

What causes it?

Eating feed or mineral tubs containing monensin (Rumensin), lasalocid or similar ionophores.

Risk factors

  • Access to cattle, goat or poultry feed
  • Mixing errors at feed mills

How vets diagnose it

Feed testing and muscle enzyme blood tests.

Treatment

Supportive vet care only.

Do not wait to see if it improves. Camelids hide illness, and by the time signs are obvious the problem is often advanced. Call your veterinarian.

Prevention

  • Read every feed label
  • Keep cattle and poultry feed out of reach
  • Buy camelid feed from mills that segregate ionophore products

Background

Monensin is a polyether antibiotic isolated from Streptomyces cinnamonensis. It is widely used in ruminant animal feeds.From Wikipedia — “Monensin”, licensed under CC BY-SA 4.0.

Research & references

PubMed lists 4,529 peer-reviewed papers on this topic in camelids. The most relevant include:

  1. Camelid cardiology. Margiocco ML, Scansen BA, Bonagura JD The Veterinary clinics of North America. Food animal practice, 2009. PubMed 19460649 · DOI · cited 20×
  2. Camelid wellness. Bennett MM, Richards NL The veterinary clinics of North America. Exotic animal practice, 2015. PubMed 25902272 · DOI · cited 3×
  3. Hematology of camelids. Vap L, Bohn AA The veterinary clinics of North America. Exotic animal practice, 2015. PubMed 25421025 · DOI · cited 15×
  4. Llama DNA Immunization and Isolation of Functional Single-Domain Antibody Binders. Trempe F, Rossotti MA, Maqbool T et al. Methods in molecular biology (Clifton, N.J.), 2022. PubMed 35157268 · DOI · cited 7×
  5. Update. Llama nutrition. Johnson LW The Veterinary clinics of North America. Food animal practice, 1994. PubMed 7953953 · DOI · cited 13×
  6. Encephalomyocarditis virus infection in alpacas. O'Connor TW, Finlaison DS, Manning LK et al. Australian veterinary journal, 2020. PubMed 32794196 · DOI · cited 2×

Frequently asked questions

What is ionophore (Monensin) Toxicity in alpacas?
Camelids are sensitive to ionophore additives in cattle and poultry feeds, which damage heart and skeletal muscle.
What are the signs of ionophore (Monensin) Toxicity?
Weakness and reluctance to move, muscle tremors, staggering, heart failure signs: rapid breathing, collapse and sudden death days to weeks after exposure.
How do you prevent ionophore (Monensin) Toxicity?
Read every feed label. Keep cattle and poultry feed out of reach. Buy camelid feed from mills that segregate ionophore products.
Is ionophore (Monensin) Toxicity an emergency?
Emergency — call your vet now. This condition can kill within hours. Get veterinary help immediately.

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.