[Animal nutrition for veterinarians–recent cases of clinical disorders in horses after intake of ionophore-containing feed].

The research article reports on clinical disorders in horses that consumed feed containing ionophores from five different stables. It was found that horses fell ill displaying colic-like symptoms soon after consuming new types or batches of feed. High levels of ionophores, particularly monensin, were found in the feed. The study highlights the urgent need for veterinarians to be aware of this unusual but severe form of horse intoxication.

Incidence of Clinical Disorders

• This study focuses on different cases of horses displaying clinical disorders after consuming feed laced with ionophores. These events emerged from five different stables, indicating the geographic spread and potential gravity of the issue.
• The symptoms surfaced within a few hours or days after the horses consumed new types or batches of feed concentrates. This timespan implies that the effects of ionophores on horses are relatively rapid and severe.
• The clinical traits exhibited by the sick horses centered around colic-like symptoms, intense sweating, and ataxia (the loss of full control of bodily movements). These symptoms typically indicate nervous or muscular system issues, commonly associated with feed toxicity.
• Many of the affected horses died within a short span, pointing to the fatal nature of ionophore ingestion in horses.

Feed Examination and Ionophore Contamination

• The research describes techniques for examining the contaminated feed. Using these methods, the samples were analyzed for types and amounts of ionophore contaminations.
• In four instances, the concentrated fodder was found tainted with monensin at concentrations ranging from less than 5 mg to 679 mg per kg of the feed. Monensin is a commonly used ionophore antibiotic that can be toxic to horses.
• One feed sample contained both monensin and salinomycin. The study did not provide details about the combined effects of these ionophores.
• In another case, lasalocid was detected in the feed. Similar to monensin, lasalocid is a feed additive used primarily for poultry but can be lethal to horses.

Post-mortem Examination and Conclusions

• A post-mortem examination was conducted on a horse from a stable where the concentrate contained 679 mg/kg feed of monensin. The horse showed typical signs of monensin intoxication, like severe myocardial degeneration, which indicates damage to the heart muscle fibers.
• The paper concludes by emphasizing that veterinarians need to be vigilant about this less frequent but life-threatening intoxication in horses.