This study compared physiological and productive parameters in 3/4 Holstein × 1/4 Gir dairy cows receiving a prepartum concentrate containing traditional anionic salts to reduce urine pH to 7.0 (CON; n = 17), or an anionic supplement (Animate; Phibro Animal Health, Teaneck, NJ) to reduce urine pH to 6.0 (SUPP; n = 17). Nonlactating, multiparous, pregnant cows were ranked by parity, body weight (BW), and body condition score (BCS), and assigned to receive SUPP or CON for 21 d before expected calving. Cows were maintained in single drylot pen with ad libitum access to corn silage, and individually received their prepartum concentrate once daily before calving. Cows from both treatments completely consumed their concentrate allocation within 30 min after feeding. Cow BW and BCS were recorded weekly, urine pH measured every 3 d, and blood samples collected on d −21, −14, −9, −6, and −3 relative to expected calving. Cows were moved to an adjacent drylot pen with ad libitum access to water and a total-mixed ration after calving (d 0), and were milked twice daily. Cow BW and BCS were recorded weekly, and daily milk production recorded until 30 d in milk (DIM). Blood samples were collected before each milking during the initial 5 DIM, and at 6, 9, 16, 23, and 30 DIM before the morning milking. Based on actual calving dates, cows receiving SUPP or CON for (mean ± standard error) 19.2 ± 1.2 and 19.0 ± 0.9 d, respectively. Urine pH was less (P < 0.01) in SUPP vs. CON cows during the last 15 d of gestation (6.12 vs. 7.15, respectively). Milk yield during the experimental period was greater (P = 0.04) in SUPP vs. CON cows (by 14%). Serum concentrations of fatty acids were greater (P ≤ 0.01) in SUPP vs. CON cows 3 d before and at calving (by 52 and 22%, respectively), whereas SUPP cows had less (P ≤ 0.03) serum glucose and cortisol concentration at calving (by 23 and 27%, respectively). Hence, SUPP decreased prepartum urine pH to 6.0 in Holstein × Gir dairy cows without depressing concentrate intake, and increased milk yield compared with CON.