To determine the effects of DL-
malate on ruminal metabolism, four steers equipped with ruminal cannulas were fed an 80% rolled grain (75% corn:25% wheat) diet twice daily with a DMI equal to 2.0% of BW (485+/-24.8 kg). DL-
Malate was infused into the rumen on two consecutive days in 500 mL of
phosphate buffer to provide 0, 27, 54, or 80 g of DL-
malate/d. Ruminal pH linearly increased (P < .01) with DL-
malate concentration and was greater (P < .01) for DL-
malate than for the control steers (6.07 vs 5.77). DL-
Malate treatment linearly decreased (P < .10) total VFA and tended to linearly increase (P = .10)
acetate concentration.
Propionate,
butyrate, and L-
lactate concentrations and
acetate:
propionate ratio were not affected (P > .10) by DL-
malate. Three finishing studies were conducted to determine the effects of feeding DL-
malate on growth rate and feed efficiency. In a 98-d experiment, 33 crossbred steers were randomly allotted in a
Calan gate feeding system to three DL-
malate levels (0, 40, and 80 g/d). Steers (initial weight = 367+/-4.5 kg) were fed a rolled corn-based diet twice daily. After 84 d on feed, gain efficiency (gain:feed) tended to improve with more DL-
malate (linear, P < .10) and was 8.1% greater (P < .05) for DL-
malate than for the control. The ADG linearly increased (P < .05) with more DL-
malate and was 8.6% greater (P = .10) for DL-
malate than for the control. After 98-d on feed, ADG was linearly increased (P = .09) by DL--
malate, and the greatest increase occurred with 80 g of DL-
malate. In the second performance study, 27 Angus steers were randomly allotted in a
Calan gate feeding system to three DL-
malate concentrations (0, 60, and 120 g/d). Steers (initial weight = 432+/-4.6 kg) were fed diets used in the first finishing study twice daily, but DL-
malate was included during the 10-d step-up period. During the 10-d step-up period, feed efficiency and ADG linearly increased (P = .01) with more DL-
malate. DL-
Malate had little effect on steer and heifer performance or plasma constituents in a 113-d finishing study. Collectively, these results suggest that feeding DL-
malate to cattle consuming high-grain diets alleviates subclinical
acidosis, and it improved animal performance in two finishing studies.