Limited observations indicate that dairy cows do not all make the same selections when roughages are fed free-choice, and very their consumption when different roughage combinations are available.
Porter, A. R.
"Dairy Cows Vary In Roughage Preferences,"
Iowa Farm Science: Vol. 7
, Article 4.
Available at: https://lib.dr.iastate.edu/farmscience/vol7/iss11/4