Chemical Composition of Tobosa Grass Collected by Hand-Plucking and Esophageal-Fistulated Steers

Abstract

Organic matter recovery of seven feeds collected through esophageal fistulae of three steers averaged 90.4%. Six of the seven fistula samples contained significantly more ash than the feeds offered. Fistula samples of grazed tobosa (Hilaria mutica (Buckl.) Benth.) contained less A.O.A.C. fiber but more silica, ash, protein, ether extract, detergent fiber and detergent lignin than hand-plucked grass. Except for ash, the differences in chemical composition between hand-plucked and esophageal-fistula samples were apparently due to selectivity by the grazing steers. We assume that samples collected by means of an esophageal fistula are more nearly representative of the forage consumed by grazing steers than samples hand-plucked by a technician.