Bilateral stringhalt associated with Hypochaeris radicata

Though this report comes from South America this weed has spread world-wide and is common in stressed pastures. The flowers strongly resemble that of a dandelion but the stem to the flower is much tougher and somewhat longer.
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Bilateral stringhalt associated with Hypochaeris radicata in Uruguayan horses

Toxicon. 2024 May 29:245:107780. doi: 10.1016/j.toxicon.2024.107780. Online ahead of print.
Authors
Mizael Machado 1 , Ana Laura Camacho 2 , Charles Coubrough 3 , Cintia R R Queiroz-Machado 4 , Camila Custodio 5 , Claudio S L Barros 6 , Franklin Riet-Correa 7 , Alejo Menchaca 8
Affiliations

1 Plataforma de Investigación en Salud Animal (PSA), Instituto Nacional de Investigación Agropecuaria (INIA), Estación Exprerimental Tacuarembó, Uruguay. Electronic address: mmachado@inia.org.uy.
2 Independent Consultant, Maldonado, Uruguay.
3 Independent Consultant, Montevideo, Uruguay.
4 Centro Universitario Regional Noreste (CENUR), Universidad de la República (UdelaR), Tacuarembó, Uruguay.
5 Programa de Posgrados de la Facultad de Veterinaria, Universidad de la República (UdelaR), Montevideo, Uruguay.
6 Faculdade de Medicina Veterinária e Zootecnia (FMZV), Universidade Federal de Mato Grosso do Sul (UFMS), Campo Grande, Mato Grosso do Sul, Brazil.
7 Programa de Pós-graduação em Ciência Animal nos Trópicos, Universidade Federal da Bahia (UFBA), Salvador, Bahia, Brazil.
8 Plataforma de Investigación en Salud Animal (PSA), Instituto Nacional de Investigación Agropecuaria (INIA), Estación Exprerimental Tacuarembó, Uruguay.

PMID: 38821321
DOI: 10.1016/j.toxicon.2024.107780

Abstract

We reported thirteen cases of bilateral stringhalt associated with Hypochaeris radicata that occurred in horses in Uruguay during a severe drought in the summer of 2023. All horses were affected chronically and progressively by bilateral hyperflexion of hindlimbs. In two severely affected horses, the main histological lesions included neuronal chromatolysis and axonal spheroids in the ventral gray horn in the lumbar and sacral spinal cord and axonal degeneration and digestion chambers in ventral roots fibers and long peripheral nerves. We suggest that in addition to injuries to peripheral nerves, lesions in the spinal cord play an important role in the clinical signs of stringhalt in horses.

Keywords: Axonal degeneration; Hypochaeris radicata; Neuronal chromatolysis; Poisonous plants, Spinal cord lesions.