Subclinical ketosis (SCK) is an economic significant event in early lactation dairy cows. A field study was conducted to evaluate the feeding of 2 new commercial ammonium-lactate products, GlucoBoost Liquid or GlucoBoost Dry, on the prevalence rate (PR) of sub-clinical ketosis in postpartum, lactating dairy cows. Subclinical ketosis, defined as blood BHB ≥1.2 mmol/L, was evaluated using a Precision Xtra (Abbott Laboratories, Abbot Park, IL) handheld ketone meter. Samples were collected from postpartum 1–14 DIM primiparous and multiparous dairy cows. The test population was 51 herds, representing 84 separate trials. The herds were a convenience sample of herds that agreed to test the product and allow pre and post exposure testing. The herds were tested at a minimum of 2-week intervals for all cows in the post fresh pen 1–14 DIM up to a max of 100 cows per lactation. The herds were fed TMR diets containing either GlucoBoost Dry at 1 lb./cow/d and GlucoBoost Liquid at 2 lb./cow/day, both targeted to contained 336 g of lactate. The study included 5,972 first lactation, 4,750 second lactation, and 6,420 third or greater lactation cows. The 52 herds were analyzed for risk factors for prevalence of subclinical ketosis with SAS 9.4 (SAS Institute Inc., Cary, NC), using Proc GLIMMIX as a Poisson distribution, with herd as a repeated measure. Herds were stratified with “Low” ≤ 10% prevalence; “Mid” herds were > 10% and ≤25%, and “High” herds were > 25% starting prevalence. The final multivariable Poisson model included Product (Dry or Liquid), Strata (Low, Mid or High), and the Quarter of the year the test was conducted. The PR was calculated from the parameter estimate in the GlIMMIX model by taking the anti-log of the −2 Res Log Pseudo Likelihood estimate. The PR for feeding Dry GlucoBoost was 0.718 (CI = 0.639–0.806, P ≤ 0.001), and feeding Liquid GlucoBoost form of ammonium lactate had a PR of 0.653 (CI = 0.581–0.735. P ≤ 0.001). The intercept was 0.086. This study suggests both liquid and dry form of ammonium lactate are effective at lowering the prevalence of SCK, defined as blood BHB levels ≥1.2 mmol/L, by 30 to 35%.