Todayโs path rounds are on ๐ฆ๐จ๐ง๐๐ง๐ฌ๐ข๐ง ๐ญ๐จ๐ฑ๐ข๐๐ข๐ญ๐ฒ!
๐๐ก๐๐ญ ๐ข๐ฌ ๐ข๐ญ?
๐๐จ๐ง๐๐ง๐ฌ๐ข๐ง is an ๐ข๐จ๐ง๐จ๐ฉ๐ก๐จ๐ซ๐, which are common feed additives found in ruminant diets that helps promote growth. However, these compounds are ๐๐จ๐ฌ๐-๐๐๐ฉ๐๐ง๐๐๐ง๐ญ toxins, meaning that having too much is a bad thing!
๐๐ก๐จ ๐ ๐๐ญ๐ฌ ๐ข๐ญ?
Although we can see this condition in ruminants, we most commonly think of it in horses! Horses seem extremely sensitive to this toxin, for unknown reasons.
๐๐ก๐๐ญ ๐๐๐ฎ๐ฌ๐๐ฌ ๐ข๐ญ?
Usually, these toxicities arise from errors at the feed mill. In the case of ruminants, that might mean accidentally adding too much product to a batch of feed. With horses, it often results from failure to properly clean equipment in between batches of ruminant feed and horse feed. Feed mills must be very careful to prevent cross-contamination!
๐๐ก๐ฒ ๐ข๐ฌ ๐ญ๐ก๐ข๐ฌ ๐ ๐ฉ๐ซ๐จ๐๐ฅ๐๐ฆ?
Monensin is a ๐๐๐ซ๐๐ข๐จ๐ญ๐จ๐ฑ๐ข๐ง, meaning it directly impacts the heart. The toxin causes ๐๐๐ซ๐๐ข๐จ๐ฆ๐ฒ๐จ๐๐ฒ๐ญ๐ (muscle cells of the heart) ๐ง๐๐๐ซ๐จ๐ฌ๐ข๐ฌ (cell death), which can lead to fatal ๐๐ซ๐ซ๐ก๐ฒ๐ญ๐ก๐ฆ๐ข๐๐ฌ (irregular beats). If the animal survives the initial toxic event, they are often left with long-term cardiac problems.
๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐๐ข๐๐ ๐ง๐จ๐ฌ๐๐?
Diagnosis is usually based on a history of potential exposure, combined with ultrasound findings of heart disease. However, horses are frequently found dead because of how quickly the toxin can cause damage.
๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐ญ๐ซ๐๐๐ญ๐๐?
Unfortunately, there is no specific treatment available, and supportive care is only minimally helpful in preventing death. Because of the long-term cardiac problems that occur afterwards, often these animals are euthanized, even if they survive the initial toxicity.
๐๐ก๐จ๐ญ๐จ๐ฌ
1-5) Pale, sad heart muscle after monensin ingestion.
๐๐จ๐ฎ๐ซ๐๐๐ฌ
Maxie, G. Jubb, Kennedy and Palmerโs Pathology of Domestic Animals, Volume 3. Sixth Edition.
Photos 1-2 ยฉ University of Calgary Diagnostic Services Unit.
Photos 3-5 ยฉ Noahโs Arkive contributors Hedstrom, Doster licensed under CC BY-SA 4.0.
