REDUCTION IN PARTICLE SIZE DURING RUMINATION IN CATTLE

Abstract

Measurements of chewing behavior and of large particle breakdown during rumination were made with two steers given chaffed alfalfa or brome grass once daily for 4 h. Large particle content of boli retained in the mouth for chewing was enhanced by 38% compared to that in the regurgitated bolus, since some small particles were swallowed immediately with fluid. 58–75% of this coarse material was reduced to small particles by rumination. Specific fragility of both roughages was doubled at 16 vs. 4 h after feeding. Key words: Rumination, chewing, cattle