Monensin poisoning in Brazilian horses.

The research article discusses three outbreaks of Sodium Monensin poisoning in Brazilian horses which led to significant deaths due to a mistakenly fed commercial ration meant for feeder calves.

Summary of Findings

• The research investigates three outbreaks of Monensin poisoning in Brazilian horses that led to the death of 12 horses from a total of 16. These horses fed on the same batch of commercial food designated for calves, mistakenly. This feed contained high levels of Sodium Monensin (180 +/- 20 ppm).
• The mortality rate was found to be high, with lethality percentages of 60%, 75%, and 100% for the three respective outbreaks.

Clinical Signs and Symptoms

• The horses exhibited multiple clinical signs post-ingestion of the commercial ration. These included tachycardia (abnormally fast heart rate), cardiac arrhythmia (irregular heartbeats), audible discomfort (groaning), loss of coordination, excessive sweating (sudoresis), an inability to stand (recumbency), and uncontrolled repetitive movement with the limbs.
• In addition, two horses had a significant symptom of producing dark discolored urine, referred to as myoglobinuria. This is often an indication of significant muscle damage.

Biochemical and Necropsy Findings

• The cases also exhibited disturbed biochemical indicators. The serum levels of creatine phosphokinase, an enzyme that indicates muscle damage, were increased in the affected horses.
• The primary postmortem findings revealed significant damages in the skeletal muscles and the myocardium (muscular tissue of the heart), directly linking the cause of death to Monensin poisoning.

Conclusion

• The research concludes that the ingestion of Sodium Monensin, especially through mistaken feed meant for other livestock, can lead to severe poisoning and high mortality rates in horses. This highlights the urgent need for meticulous feed management and raises concerns about possible cross-contamination between feeds for different species.