Basis on nutrition and fatty acid profiles of 20 concentrate and forage feed for dairy cow tested by chemical analytical method and gas chromatography, the objective of this study was to evaluate changes of ruminal fermentation parameters, the activities of filter paper and lipases, and rumen bacteria population colony counts by hungate roll tube technique and quantification of bacteria DNA by real time PCR approach during supplementation of soybean oil and linseed oil. Four primiparous Holstein c...