A total mixed ration (TMR) containing 40% grass hay (half chopped, half finely ground) and 60% concentrates, was fed to 16 cows in groups of 4, while 12 control cows rotationally grazed grass pasture and received individual concentrate supplementation, during 90 days of comparison. Mean results for control and TMR treatments were daily milk production, 14.5 vs. 15.8 kg; milk fat percentage, 2.98 vs. 3.03; ratio of milk produced per concentrates consumed, 2.50 vs. 1.55, respectively. The latter difference was significant (P =.01). Daily intake of TMR was 17.0 kg and the ratio of milk yield/TMR intake was 0.93. The 40% hay: 60% concentrates TMR, with half of the hay in large-particle form, represents a promising alternative feeding system, but would give more competitive efficiency of concentrate utilization if fed to cows of greater productive potential than those of the present experiment.