Abstract
Eighteen Holstein cows of approximately 550 kg mean live weight (LW), and 57 ± 24 days in milk at the start, were divided into six groups of three each for use in a single-reversal design, with two 5-wk experimental periods, to compare two treatments: T1, including a liquid feed (85% SynerMax5:15% cane molasses) offered in lick-wheel tanks to three groups between 7:00 a.m. and 2:00 p.m. (1.7-kg daily intake), plus a concentrate of solid ingredients (theoretically 1.8 Meal NEL/kg, 16% crude protein) fed individually according to milk yield, a small offering of grass hay (<3 kg consumed daily), and rotational grazing at night in four paddocks on mixed tropical grasses; T2, as in T1 but without liquid feed, rather including a larger concentrate allowance (10.5- vs. 11.6-kg intake). Mean results obtained with TI and T2, respectively: daily milk yield, 22.45 vs. 22.55 kg; milk fat percentage, 3.03 vs. 2.94; milk protein percentage, 2.68 vs. 2.76 (P < 0.01). Intakes of dry matter (DM) from high-energy supplements (solid concentrate plus liquid feed) were 10.2 vs. 10.3 kg, respectively. Daily DM intake from grazed forage by cows of both treatments in common pastures was estimated by a disk-drop method as 9.31 ± 2.68 kg. It is concluded that the liquid feed, when constituting 4 or 5% of total dietary DM, had a feeding value equal to that of the solid concentrate on a DM basis, but no synergistic effect was substantiated.