The diets were offered as TMR and formulated to meet or exceed the metabolizable energy and protein requirements of a 550 kg primigravid Holstein cow to gain at least 1.2 kg/d including conceptus when DMI averages 10 kg/d (NRC, 2001). The DCAD (mEq/kg of DM) was calculated assuming exactly the same absorption for the strong ions with the following formula: DCAD = [(mEq of K+ + mEq of Na+) − (mEq of Cl− + mEq of S2−)]. Ingredients were analyzed a priori to design diets to contain either 200 or −100 mEq/kg, a difference of 300 mEq/kg of DM. After diets were prepared and analyzed, there were minor deviations from the expected DCAD and mineral concentrations. Concentrates and forages were the same in all diets, except for the inclusion of acidogenic product and minerals used to alter the DCAD and supply additional salts containing Cl (Table 1). The acidogenic product used (Bio-Chlor, Arm and Hammer Animal Nutrition, Princeton, NJ) is a fermentation product containing dried condensed extracted glutamic acid fermentation product, dried condensed corn fermentation solubles, processed grain by-products, and magnesium chloride. The product contains 9.1% Cl and 3.6% S with a DCAD of −3,884 mEq/kg. Also, at the dietary inclusion in the current experiment, the acidogenic product has been shown to induce a compensated metabolic acidosis and depress DMI in prepartum cows (Lopera et al., 2018; Martinez et al., 2018a).