Abstract
High performance liquid chromatography (HPLC) was used to measure serumβ-carotene in dairy cows. When a Zorbax-ODS column, which is a non-aqueous reversed-phase (NARP) column, was used, a reliable routine method was assumed to be one with a methanol/chloroform (85/15) solution was used as a mobile phase.
When estimated by this method through out a year, serumβ-carotene levels of 8 cows fed sufficient roughage were about 350μg/dlin winter and about 600μg/dlin summer. This difference in level was considered to depend on the amount of green grass fed to the cows.
