Subclinical (SCK) and clinical (CK) ketosis is a metabolic disease common in dairy cattle and can decrease milk production, reproductive efficiency, and increase risk of being culled from the herd. Traditionally, cows have been supplemented with glucogenic precursors either by drenching or inclusion in the TMR to decrease ketone formation and increase blood glucose levels. The objective of this experiment was to examine the incidence of SCK and CK, levels of ketones and glucose in blood, and milk yield in Holstein dairy cattle fed a molasses-based sodium propionate supplement (Innovative Liquids LLC) for the first 14 DIM. On a commercial dairy in California, a total of 226 cows and 102 heifers were systematically enrolled in C with a subset of 74 cows and 39 heifers bled, and 200 cows and 106 heifers were enrolled in GP with a subset of 81cows and 36 heifers bled in a switchback design. Blood glucose and β-hydroxybutyric acid (BHB) concentrations were measured on 3, 7, and 14 DIM using NovaMax meters (Nova Diabetes Care Inc., Billerica, MA). Ketosis was defined as BHB levels of 1.0–1.4 mmol/L for SCK or BHB levels of > 1.4 mmol/L for CK. Glucose concentrations were defined as low (≤40 mg/dL) or adequate (>40 mg/dL). Data were analyzed using the Mixed Procedure of SAS (v. 9.4, SAS Institute, 2015). Results are presented as least squares means ± standard error. Average blood BHB and glucose concentrations did not differ between treatments for primiparous or multiparous cows (C 0.53 ± 0. 02, GP 0.55 ± 0.02 mmol/L BHB, P = 0.5; C 44 ± 0.77, GP 43 ± 0.78 mg/dL glucose, P = 0.6). Concentration of blood glucose was inversely related to BHB (P < 0.01). Treatment GP did not affect milk yield compared with C for primiparous or multiparous cows during the first 21 DIM (C 29.5 kg milk /d ± 0.94, GP 30.0 ± 0.96 kg milk/d; P = 0.5). The incidence of SCK and CK was low during this study; 9 C cows and 7 GP cows were subclinical, and 6 C cows and 9 GP cows were clinical. Therefore, in this study there was little improvement in the incidence of CK and SCK or increase in milk yield with supplementation.