Poster: Temperature Responses
Abs #
201: Total Nonstructural Carbohydrates and Fructan in Nine Cool Season Grasses
Recent studies of equine diets suggest that high fructan in cool season grasses contribute to laminitis and other digestive disorders in horses. This study quantified carbohydrate metabolism in nine grass species. The selected native and introduced cool season grasses include grasses with adaptations to either mesic or semi-arid environments. Cool temperature treatments were used to manipulate carbohydrate metabolism. Changes were monitored by quantifying changes in total nonstructural carbohydrates (TNC) and fructan content. In general, transferring plants from 20/20 C day/night temperatures to 10/5 C increased fructan content from approximately 4% to about 20% by the second day. After 21 days of cold treatment several species (meadow brome, smooth brome and orchard grass) had TNC concentrations near 40% dry weight. In contrast, TNC in reed canary grass and big bluegrass remained near 20% dry weight. Similarly, the latter species contained about ½ the fructan accumulated in orchard grass and the two brome grasses. Forages for cattle are often selected for high quality and high engery, i.e., low fiber and high TNC. It appears from this study that some species have lower TNC content than others when subjected to cool temperatures. The modern tools of plant breeding and molecular biology provide opportunities to develop grasses with the lower carbohydrate content appropriate to the needs of more sedentary animals and thus help avoid feed-induced metabolic problems common to many horses.
