Case Report: Investigating an outbreak of tremorgenic mycotoxicosis in beef cows on pasture in Mississippi due to ergot (Claviceps paspali) infection in Dallisgrass (Paspalum dilatatum)

Authors

  • W. Isaac Jumper College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762
  • Clare C. Brown College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762
  • Stephen T. Lee United State Department of Agriculture, Agriculture Research Service, Poisonous Plant Research Laboratory, Logan, UT 84341
  • Daniel Cook United State Department of Agriculture, Agriculture Research Service, Poisonous Plant Research Laboratory, Logan, UT 84341
  • Justin M. Stilwell College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762
  • Kelsey M. Harvey Prairie Research Unit, Mississippi State University, Prairie, MS 39756

DOI:

https://doi.org/10.21423/bpj20249035

Keywords:

ataxia, cattle, plant toxicity, staggers, tremors

Abstract

 

The Mississippi State University College of Veterinary Medi­cine Ambulatory Service examined a 3-year-old Charolais-cross cow on October 19, 2023, for lateral recumbency, inabil­ity to rise and generalized tremors. Within 4 hours following initial case discovery, 20 additional cases were discovered in 2 adjacent pastures, including one mortality. Clinical signs ranged in severity from mild tremors to severe ataxia, hy­perexcitability, aggression, lateral recumbency and death. All affected cows had calved in the spring of 2023, and all 2023 spring calves were weaned 3 days prior on October 16. Overnight on October 16-17, one group of cows pushed down a fence, and 32 cows entered a pasture adjacent to their weaned calves. Following discovery of cases on October 19, all cattle were removed from the affected pasture and grass hay was provided immediately. Necropsy of 2 affected animals as well as serum chemistries of 5 affected cows revealed non-specific findings. However, abundant dallisgrass (Paspalum dilatatum) with obvious Claviceps paspali infection was present on the pasture that the cattle entered overnight on October 16-17. High-performance liquid chromatography-mass spectrom­etry (HPLC-MS) analysis of samples collected from C. paspali infected pasture as well as rumen and abomasum contents collected at necropsy revealed several tremorgenic indole di­terpene alkaloids. Additionally, DNA metabarcoding of rumen contents and forage samples confirmed the ingestion of dallis­grass infected with C. paspali. Upon recheck on October 20, all previously affected cows appeared to be recovering, and com­plete resolution of clinical signs had occurred by October 23.

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Published

2024-08-30

How to Cite

Jumper, W. I., Brown, C. C., Lee, S. T., Cook, D., Stilwell, J. M., & Harvey, K. M. (2024). Case Report: Investigating an outbreak of tremorgenic mycotoxicosis in beef cows on pasture in Mississippi due to ergot (Claviceps paspali) infection in Dallisgrass (Paspalum dilatatum). The Bovine Practitioner, 58(2), 59–68. https://doi.org/10.21423/bpj20249035

Issue

Section

Descriptive Studies - Case Report

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