Chemical Composition and Nutritive Value of Four Grass Hays and Their Component Parts1

Astract Four first‐growth forages, ‘Sterling’ orchardgrass (Dactylis glomerata L.), ‘Canada common’ and ‘Sac’ smooth bromegrass (Bromus inermis Leyss.), and ‘Climax’ timothy (Phleum pratense L.) were harvested at approximately 50% inflorescence emergence, artificially dried, and fed to dairy goats in total collection digestion trials. Canada common and Sac bromegrass and Climax timothy were separated into headed and nonheaded tillers. Headed tillers were fractionated into an inflorescence portion and by internode into leaf blade, leaf sheath, and stem portions. Nonheaded tillers were divided into leaf blade, leaf sheath, and stem fractions. Sterling orchardgrass was higher than Canada common and Sac bromegrass in the apparent digestibility of dry matter, crude protein, and acid‐detergent fiber; however, there was no difference in dry matter intake. Digestibilities of the two bromegrass varieties were not different. Climax timothy was lowest in digestibility and intake. Top portions of the headed tillers were lower in acid‐detergent fiber and lignin and higher in Kjeldahl nitrogen and in vitro dry matter digestibility than their corresponding basal fractions. Leaf blade, leaf sheath, and stem portions of Canada common bromegrass were generally highest in Kjeldahl nitrogen and in vitro dry matter digestibility and lowest in acid‐detergent fiber and lignin. Sac bromegrass components were intermediate and Climax timothy fractions were lowest in quality. Leaf blades of both headed and nonheaded tillers were generally lowest in acid‐detergent fiber and lignin and highest in Kjeldahl nitrogen and in vitro dry matter digestibility. The reverse was true of the leaf sheaths, while the stems were intermediate.