NAVLE Multisystemic

Bovine Ionophore Toxicosis Study Guide

Ionophore toxicosis is a dose-dependent toxic syndrome caused by excessive ingestion of polyether ionophore antibiotics, most commonly monensin (Rumensin), lasalocid (Bovatec), or laidlomycin propionate (Cattlyst).

Overview and Clinical Importance

Ionophore toxicosis is a dose-dependent toxic syndrome caused by excessive ingestion of polyether ionophore antibiotics, most commonly monensin (Rumensin), lasalocid (Bovatec), or laidlomycin propionate (Cattlyst). These compounds are widely used in beef and dairy cattle production for improved feed efficiency, growth promotion, and coccidiosis prevention and control.

Ionophores are lipid-soluble molecules produced by Streptomyces species that transport ions across cell membranes, disrupting normal ionic gradients. While safe at recommended doses, toxicosis occurs when cattle ingest excessive amounts due to feed mixing errors, incorrect product selection, or concurrent use with certain antibiotics that inhibit ionophore metabolism.

High-YieldIonophore toxicosis is a HIGH-YIELD topic for NAVLE. When you see a bovine case with sudden death, anorexia, diarrhea, muscle weakness, and cardiac failure following a recent feed change, think ionophore toxicosis first. Remember that there is NO ANTIDOTE - treatment is supportive only.
Ionophore Trade Name Manufacturer Species Approved
Monensin Rumensin, Monovet 90 Elanco, Huvepharma Cattle, chickens, goats, turkeys
Lasalocid Bovatec Zoetis Cattle, sheep, chickens, rabbits, turkeys
Laidlomycin propionate Cattlyst Zoetis Cattle only

Ionophores: Background and Approved Uses

Approved Ionophores for Cattle in the United States

Normal Uses and Benefits in Cattle

Approved indications for monensin in beef cattle:

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