Seasonal and Diurnal Changes in Starch Content and Sugar Profiles of Bermudagrass in the Piedmont Region of the United States

Isabelle Ann Kagan, Brett H. Kirch, Craig D. Thatcher, Chris D. Teutsch, François Elvinger, Dare M. Shepherd, Scott Pleasant

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Seasonal and diurnal patterns of sugar accumulation in bermudagrass (Cynodon dactylon) pastures were monitored to evaluate risk factors for pasture-associated laminitis of ponies and horses. Bermudagrass was collected from four plots in the morning and afternoon on a weekly basis, from mid-July until late August. Tissue was air-dried to simulate hay, or frozen to retain the sugar profiles of fresh pasture. Samples were analyzed colorimetrically for total water-soluble and ethanol-soluble carbohydrates, and electrochemically for starch. In addition, sugars were separated and quantified by high-performance liquid chromatography coupled to pulsed amperometric detection. The dominant sugars in extracts were glucose, fructose, and sucrose. Some minor peaks, corresponding to tri- and tetrasaccharides, were also detected in some extracts. Starch increased over time in fresh and dried tissue, and concentrations varied diurnally in fresh, but not in dried tissue (P = .021). Sucrose in dried tissue decreased and then increased, with higher concentrations than in fresh tissue on all sampling dates (P = .024). Glucose and fructose exhibited diurnal variation on one and two dates, respectively (P = .034 and .0028, respectively). These results reveal trends in carbohydrate concentrations and profiles that may help to evaluate the likelihood of equine laminitis outbreaks on bermudagrass.

Original languageEnglish
Pages (from-to)521-529
Number of pages9
JournalJournal of Equine Veterinary Science
Issue number9
StatePublished - Sep 2011

Bibliographical note

Funding Information:
The authors thank Kelly Brown and Brenda Coe for dry matter analysis, Tamara Kays for assistance with extraction and cleanup of HPLC samples, Mac Wilson for providing weather data, and Phil Harrison for standards of orchardgrass fructan, 6-kestose, neokestose, 1-nystose, bifurcose, and 6-nystose. This study was funded by the Virginia Horse Industry Board and the U.S. Department of Agriculture .


  • Cynodon dactylon
  • Laminitis
  • Starch
  • Sugars

ASJC Scopus subject areas

  • Equine


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