BACKGROUND: In Experiment 1 we studied the effect of malic acid addition at 0, 1, 2 and 3 mg g-1 dry matter (DM) feed on in vitro ruminal fermentation. In Experiment 2, the effect of supplementing malic acid on feed intake, digestion and milk production and composition of lactating cows was studied. 200 multiparous lactating Holstein dairy cows were randomly assigned to two treatments: a basal diet containing concentrate and roughage at 58:42, respectively, with no additive (control treatment) or supplemented with malic acid at 30 g per cow daily (malic treatment). RESULTS: In Experiment 1, malic acid inclusion at 3 mg g-1 DM decreased in vitro methane production by 33%. In Experiment 2, malic acid decreased (P < 0.01) nutrient intake and increased nutrient digestibility. Greater (P < 0.05) milk yields, energy-corrected milk yields and milk component yields were observed in cows supplemented with malic acid. Greater milk (feed) efficiency was observed with malic acid treatment compared with the control treatment. CONCLUSION: The results show that the inclusion of malic acid at 30 g daily in the diet of lactating cows enhanced the nutrient digestibility and increased the milk production as well as feed efficiency.
BACKGROUND: In Experiment 1 we studied the effect of malic acid addition at 0, 1, 2 and 3 mg g-1 dry matter (DM) feed on in vitro ruminal fermentation. In Experiment 2, the effect of supplementing malic acid on feed intake, digestion and milk production and composition of lactating cows was studied. 200 multiparous lactating Holstein dairy cows were randomly assigned to two treatments: a basal diet containing concentrate and roughage at 58:42, respectively, with no additive (control treatment) or supplemented with malic acid at 30 g per cow daily (malic treatment). RESULTS: In Experiment 1, malic acid inclusion at 3 mg g-1 DM decreased in vitro methane production by 33%. In Experiment 2, malic acid decreased (P < 0.01) nutrient intake and increased nutrient digestibility. Greater (P < 0.05) milk yields, energy-corrected milk yields and milk component yields were observed in cows supplemented with malic acid. Greater milk (feed) efficiency was observed with malic acid treatment compared with the control treatment. CONCLUSION: The results show that the inclusion of malic acid at 30 g daily in the diet of lactating cows enhanced the nutrient digestibility and increased the milk production as well as feed efficiency.