The present invention provides an orally administered agent for ruminants which reaches lower digestive tract without decomposition in the rumen by avoiding the destruction thereof due to rumination, and is disintegrated and dissolved in vivo. The present invention provides an orally administered agent for ruminants, of which the specific gravity is 1.17 to 2.00, the maximum particle size and minimum particle size are either within the range of 4 to 10 mm, and the breaking strength of a portion having the minimum particle size under body temperature environment of the ruminants is within the range of 0.5 to 5.0 N. The present invention further provides ruminant feed containing the orally administered agent and a method of orally administering a drug to ruminants.
