Two trials, ten animals in Trial 1 and 12 animals in Trial 2, were conducted to study the effect of feeding program on milk production, milk constituents, and rumen volatile fatty acids. A switchback design was used consisting of 7-wk periods, 3-wk changeover periods, and 4-wk comparison periods. Treatments in Trial 1 were (1) 10 lb pineapple bran plus concentrate, (2) Treatment 1 with 2.91% sodium acetate in concentrate, (3) 12 lb pineapple bran, 50 lb chopped Napier grass and concentrate. Treatments in Trial 2 were (1) 10 lb pineapple bran plus concentrates, (2) Treatment 1 with 2.83% sodium acetate in concentrate, (3) Treatment 1 with 5.66% sodium acetate in concentrate.Data from cows in Trial 1 on Treatments 1, 2, and 3, respectively, were: 4% FCM 35.35a, 37.13a, and 39.74a lb; milk fat 2.79a, 2.94a, and 3.79b%; total solids 11.05a, 11.10a, and 12.44b%; SNF 8.22a, 8.16a, and 8.45b%. In Trial 2, the values for Treatments 1, 2, and 3, respectively, were: 4% FCM 30.30a, 32.85b, and 34.17e lb; milk fat 3.42a, 3.96b, and 4.18b%; total solids 11.94a, 12.49b, and 12.63b%; SNF 8.50a, 8.50a, and 8.43a%. Values in the same category with different superscripts are significantly different by Duncan's multiple range test. No significant differences were observed in pounds of milk produced daily and body weight change in either trial. Rumen fluid from cows on Treatment 3 in Trial 1 contained significantly more acetic and less propionic, valeric, and longer-chain acids than from cows on Treatment 1.