Induced juglone toxicosis in ponies and horses.

This research article investigates whether juglone, a compound found in the walnut tree family Juglans, is involved in laminitis, a hoof disease in horses, linked to black walnut shavings. The study found that oral juglone administration led to inconsistent laminitis signs in ponies, caused skin irritation when applied topically to horse digits, and resulted in acute pulmonary edema in some horses when administered intravenously.

Background

• The researchers of this study were focused on Juglone, a toxic compound found in all parts of walnut trees. They wanted to investigate whether this compound was possibly linked to black walnut shaving-associated laminitis in horses.
• Laminitis is a serious and painful condition affecting the feet of horses, which can lead to lameness. There have been previous associations between black walnut shavings used as bedding and occurrences of laminitis in horses.

Juglone Administration and Effects

• Different methods of administration (oral and topical) and different quantities of juglone on ponies and horses were tried to determine its impact.
• Large amounts, up to 1 gram, of juglone were given orally to ponies. However, this led to inconsistent and mild signs of laminitis. This suggests that juglone alone, at least orally administered, cannot be firmly identified as a cause of laminitis.
• When juglone was applied topically to the digits (i.e., the hoof area) of horses, it led to local skin irritation but did not induce laminitis. This suggests that external contact with juglone does not, in itself, trigger laminitis.

Intravenous Juglone Administration

• The most significant findings were related to the intravenous administration of juglone. This method induced acute pulmonary edema (fluid accumulation in the lungs causing difficulty in breathing) in some individuals that were previously exposed to juglone orally or intravenously.
• This reaction suggests a serious adverse systemic reaction to juglone when it enters the bloodstream, implying horses exposed to juglone could face severe health risks.

Conclusion

• The study’s results indicated that while juglone can induce certain adverse reactions in horses, its role in causing laminitis when administered orally or topically remains unclear due to inconsistent results.
• Nonetheless, the induced pulmonary edema following intravenous administration of juglone suggests significant potential health risks for horses exposed to this compound, particularly if it enters the bloodstream.