Effects of altering prepartum and postpartum dietary cation-anion difference on calcium concentrations and blood metabolites of Holstein dairy cows.

We determined effects of pre- and postpartum dietary cation-anion difference (DCAD) on urine pH, serum calcium and hormone concentrations, and milk production with 48 multiparous Holstein cows (average body weight = 706 ± 7.3 kg). Treatments were 3 prepartum DCAD concentrations (0, -100, or -180 mEq/kg dry matter [DM]) and 2 postpartum DCAD concentrations (+250 or +350 mEq/kg DM) starting 29 days before parturition through 90 days in milk.