Effects of supplemental dietary sodium bicarbonate on performance of lactating Holstein cows during the summer season in Brazil

Our objective was to evaluate the effect of dietary cation-anion difference (DCAD) on DMI, milk production, and DMI:milk production ratio (feed efficiency) in cows after peak lactation. Eight multiparous lactating Holstein cows were allotted to a 4 x 4 replicated Latin square, for 72 days during the summer season. Four diets with different sodium bicarbonate concentrations were formulated to have +150, +250, +400, and +500 meq/kg (DM-basis) DCAD levels. The measured DCAD values were +155, + 289, +410, and +491 meq/kg, respectively. Increasing DCAD resulted in greater (P < 0.05) dry matter intake (DMI) and milk production. There was no difference in feed efficiency among treatments. Due to increased DMI and milk production, a beneficial effect of cationic diets was observed after peak lactation. Because increasing DCAD concentration resulted in a linear increase in DMI and milk production, studies with greater DCAD concentrations will be required to determine the optimal DCAD for maximum DMI and milk production, during the summer season. Published by Elsevier B.V.