AbstractDifferent proportions of forage to concentrate in total mixed rations (TMR), for cows in earlier and later lactation, were tested in a two-phase (I and II) experiment. During phase I (120 days), nine control cows rotationally grazed unfertilized, dry season, grass pastures and were group-fed supplemental concentrates (treatment A), while their pair mates in confinement received a TMR of 40% grass hay, 25% of which was finely ground (FG) and 15% coarsely chopped (CC), and 60% concentrates (treatment B). During phase II (37 days), the TJV1R was 50% hay (35% FG, 15% CC) and 50% concentrates; control (A) as previously. Mean results for A and B in I were: daily yield of milk, 16.1 vs. 17.8 kg, and of 4% fat-corrected milk (FCM), 11.4 vs. 14.9 kg; percentage concentration of milk fat (MF), 2.05 vs. 2.91 and protein, 3.13 vs. 3.19; daily liveweight (LW) gain, 0.20 vs. 0.03 kg. Treatments differed (P = 0.01) in FCM yield and MR Dry matter intake (DMI) in B was 18.2 kg/day and feed efficiency (FCM yield/DMI), 0.82; for A, DMI from concentrates was 7.3 kg/day and partial efficiency (FCM yield/concentrate DMI), 1.57. In II, A and B means were: milk yield, 13.7 vs. 15.5 kg/day; FCM yield, 11.7 vs. 13.6 kg/day; MF, 3.07 vs. 3.22; LW gain, 0.30 vs. 0.75 kg/day, without significant differences. Feed efficiency and partial efficiency were 0.77 (B) and 1.71 (A). These TMR resulted in satisfactory animal performance, but should be used with higher producing cows for better feed efficiency.
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