Digestibility of Alfalfa Hay and Reed Canary Grass Hay Measured by Two Procedures

Abstract

Summary A feeding trial with four mature, rumen-fistulated cows was conducted using alfalfa and reed canary hay as the sole ration. Digestibility was determined by the total feces collection procedure and by the dacron bag technique. Results of the fodder analysis plus cellulose, lignin, pentosans, and gross energy showed that the only significant differences in composition between the two hays were in lignin and pentosans. Reed canary hay proved more digestible than alfalfa in all entities determined except protein, nitrogen-free extract, and lignin. But only the differences of crude fiber and cellulose digestibility were significant. This confirms the results of a previous study with alfalfa and timothy hay (1). There was no significant differences between individual cows in their ability to digest the two hays. The only significant difference between breeds was in the digestion of fiber; average for the Ayrshire cows was 76.0%, for the Holsteins 70.2% (P Considerably greater digestibility of crude protein, N-free extract, ether extract, energy, and lignin, and a lesser digestibility of crude fiber with the dacron bag technique, led to the tentative conclusion that the conventional procedure of a total collection digestion trial is the more reliable method for determining the digestibility of forages. A significant inverse relationship between lignin content of hay and its digestibility, and a possible direct relationship between pentosan content and digestibility, suggest that more rapid evaluation of forages may possibly be achieved through research to simplify and shorten present methods for determination of these two constituents.