The Relationship of Leaf Strength to Cattle Preference in Tall Fescue Cultivars

Low values of leaf blade tensile and shear strength have been related to herbivore preference and intake in perennial ryegrass (Lolium perenne L.) and other forage grasses. This study examined relationships between leaf strength and cattle (Bos taurus) preference for eight cultivars of tall fescue (Festuca arundinacea Schreb.). Both tensile strength and shear strength of tall fescue leaf blades were measured, along with several leaf blade anatomical characteristics. Leaf tensile strength was negatively correlated (r = −0.20, P ≤ 0.01) with preference in this study. ‘Mozark’, the cultivar with the highest leaf tensile strength, also had the highest proportion of structural tissue in leaf blade transverse sections. Shear strength was also negatively correlated with preference (r = −0.16, P ≤ 0.05). Leaf strength of both chamber‐ and field‐grown plants was negatively correlated with both leaf blade width and thickness. Leaf width and thickness increased together and were positively correlated with preference in all experiments. Wider leaves also had greater distance between veins and therefore more mesophyll tissue volume. We concluded that leaf width would be a useful trait in the selection of grasses for cattle preference, since it would result in grasses with a higher proportion of cell contents to fiber. This conclusion is supported by the positive correlation of preference with total nonstructural carbohydrates in an earlier study of the same tall fescue cultivars.