Bilateral stringhalt associated with Hypochaeris radicata in Uruguayan horses.

The research article focuses on thirteen cases of bilateral stringhalt in horses in Uruguay, which were associated with Hypochaeris radicata during a severe drought in 2023. The study found that nerve and spinal cord damages were significant factors to this condition.

Objective of the Study

This study aimed to:

• Investigate the cases of horses suffering from bilateral stringhalt during a severe drought in the summer of 2023 in Uruguay.
• Analyze the association of this condition with the horse’s ingestion of Hypochaeris radicata, also known as flatweed or cat’s ear.
• Understand the effects of stringhalt on the nervous system of the horses, specifically on peripheral nerves and the spinal cord.

Findings

The researchers made several significant observations:

• All thirteen horses experienced chronic and progressive effects of bilateral hyperflexion of the hindlimbs, a common sign of stringhalt, a nervy equine condition that causes horses to lift their hind legs in a jerking way.
• Two horses which were severely affected had histological lesions, a sign of tissue damage due to disease, which included neuronal chromatolysis and axonal spheroids in the ventral gray horn located in the lumbar and sacral sections of the spinal cord. Neuronal chromatolysis is a reaction of the nerve cell body (neuron) to axonal injury, which may lead to the cessation of the neuron function, while axonal spheroids refer to formations due to injury in the central nervous system.
• Axonal degeneration and digestion chambers were found in the ventral roots fibers and long peripheral nerves of the two severely affected horses. This suggests that the disease was not only affecting the spine but also peripheral nerves that directly control the horses’ muscles and glands, implying extensive nervous system involvement.

Conclusion

This study concluded that:

• There is a significant link between the ingestion of Hypochaeris radicata during severe drought and the occurrence of bilateral stringhalt in horses, although the exact mechanism behind this needs further exploration.
• The nerve and spinal cord lesions played an essential role in the manifestation of the clinical signs of stringhalt in horses.