An object of the present invention is to provide a feed additive composition for ruminants, which has high protection in the rumen, and is also superior in dissolution in the gastrointestinal tract.The present invention relates to a feed additive composition for ruminants containing (A) at least one selected from hydrogenated vegetable oil and hydrogenated animal oil each having a melting point of higher than 50°C and lower than 90°C, (B) lecithin, (C) a biologically active substance, (D) a natural vegetable oil, and water, wherein when a scattering profile is measured after maintaining at 40°C for 15 min, and then measured by further maintaining at 40°C for 30 min by a small-angle and wide-angle x-ray scattering method, a peak having the maximum peak intensity in a region where the scattering angle 2θ is not more than 5° has a ratio (t/s) of 0.9 - 1.1 wherein s is peak intensity when maintained at 40°C for 15 min and t is peak intensity when maintained at 40°C for 45 min, and a peak having the maximum peak intensity in a region where the scattering angle 2θ is 17° - 23° has a ratio (y/x) of 0.7 - 0.9 wherein x is peak intensity when maintained at 40°C for 15 min and y is peak intensity when maintained at 40°C for 45 min.
