What is Ionophore Toxicity?
Horse feed should never contain ionophores. Horses that ingest large amounts of ionophores can become extremely ill or even die. There have been some instances where horse feeds have become contaminated with ionophores. Horses are much more susceptible to ionophore toxicity than other animals.
Since horses are much more susceptible to ionophore poisoning, it is imperative that you keep all feed separate and do not use the same feed scoop for your horse’s feed and other animals’ feed. Do not feed your horses and your cattle together to avoid any cross contamination of ionophore laden feed.
Ionophore antibiotics are added to ruminant, swine and poultry feed to improve weight gain and control coccidiosis. There are several different ionophores that are approved for use in certain animal feed in the United States.
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Symptoms of Ionophore Toxicity in Horses
Symptoms of ionophore toxicity in horses will vary depending on the amount that has been ingested. If you notice your horse acting strangely or exhibiting any of these symptoms, contact your veterinarian for an immediate assessment. Decontamination should be started before symptoms occur to give your horse the best possible chance of a full recovery.
- Poor appetite
- Refusal to eat
- Rapid heart rate
- Wobbly gait
- Profuse sweating
- Recumbency or leaning against objects for support
- Sudden death
Causes of Ionophore Toxicity in Horses
Ionophore toxicity in horses involves ionophore antibiotics that are added to the feed of cattle, swine, goats and poultry for promoting growth and controlling coccidiosis. The drugs that are added are usually lasalocid, monensin, laidlomycin, narasin and salinomycin. Monensin is an additive in several varieties of pellet feed and bulk feed for ruminants.
Horses that come into contact with feed that has ionophore additives can become extremely ill and possibly even die. It is important to keep all feed that has ionophore additives away from your horse or your horse’s feed.
There have been instances in the United States where horse feed has become contaminated during production. This contamination is not caught until the product has been distributed and then a recall is done. Keep a watch on any recalls that might happen for your horse’s feed.
Diagnosis of Ionophore Toxicity in Horses
If you suspect that your horse has ingested animal feed that has ionophore additives, have your veterinarian complete a full physical examination. It can be difficult for your veterinarian to diagnose ionophore toxicity, therefore, you need to be proactive and explain all the symptoms that your horse is experiencing. If there have been any changes in your horse’s feed or other animals on your property, let your veterinarian know what new feed has been introduced.
If you suspect that your horse’s feed is the cause of their illness, remove the feed immediately and save a sample for testing. Also, make note of any other feed that your horse may have been exposed to and if there are any ionophore additives within that food.
Diagnostic testing can be performed on your horse and on their feed. These tests will help in determining the exact cause of your horse’s illness as well as the level of toxicity within your horse’s system.
Treatment of Ionophore Toxicity in Horses
Once your horse has been diagnosed with ionophore toxicity, your veterinarian will need to start treatments immediately. This will mean that your horse will have to go through a decontamination process. In most cases, though, the exposure to the ionophore additives is not detected until clinical symptoms have begun. By that time, decontamination will not be effective.
Once clinical symptoms have presented, there is no antidote that can be given and your veterinarian will begin supportive care. Supportive care will include hospitalization, intravenous fluids, NSAIDs and antibiotics.
Be sure to follow your veterinarian’s treatment plan as directed to ensure that your horse has the best chance of survival. All medications prescribed should be administered as written.
Recovery of Ionophore Toxicity in Horses
Treatments are not always effective and regardless of treatments, death occurs. For those horses that do survive ionophore toxicity, recovery will vary from a few days to several months. Some horses will never fully recover and will develop chronic heart failure that results in poor performance, exercise intolerance and death.
Prevention is the most effective way to avoid ionophore toxicity. Be sure to keep all feed that contains ionophore antibiotics away from your horse and away from your horse’s feed. Be sure to check on all horse feed recalls to ensure that your horse’s feed has not been recalled.