Year of Publication


Document Type





Plant and Soil Science

First Advisor

S. Ray Smith


Microhistological analysis is a highly effective microscopic technique of determining botanical composition of animal diets by visual recognition of fecal plant fragments, and has been widely used in range studies. The objective of this study was to use microhistological techniques to predict the botanical composition of domesticated horse diets when grazing mixed cool-season pasture. Samples of tall fescue [Lolium arundinaceum (Schreb.) S.J. Darbyshire], Kentucky bluegrass (Poa pratensis L.) and orchardgrass (Dactylis glomerata L.) were evaluated for microscopically unique characteristics. Cool season pasture grazing studies were conducted in October 2006 and May 2007 in Lexington, KY. Eight thoroughbred mares were placed in individual paddocks of varying botanical compositions to graze for six days. For each percent increase of tall fescue or orchardgrass in the paddock, there was a corresponding increase of 0.44% and 0.42%, respectively, in the diet. In conclusion, microhistological analysis is a useful tool for determining botanical composition of horse diets when grazing cool season grass pastures.