The effects of rumen-protected choline and B vitamins (RPB) on β-hydroxybutyrate (BHBA), nonesterified fatty acids (NEFA), total cholesterol, triglycerides, HDL, LDL and VLDL and milk fat to protein ratio (FPR) were evaluated in periparturient dairy cows. In a commercial farm in Southern Brazil, 132 Holstein cows (104 multiparous and 28 primiparous) were blocked by parity, expected day of calving and body condition score (BCS). The supplementation period was 18 d pre and 21 d postpartum. Cows in the treatment group were individually top-dressed with 100 g/d Vicomb (Jefo, Quebec, Canada), to provide 20.9 g of rumen-protected choline plus protected riboflavin and folic acid, while the control cows (CON) were supplemented with corn meal. Five blood samples were collected from each animal (14 d and 7 d before calving, at calving, 7 d and 14 d after calving). Additionally 4 samples were collected (3, 5, 7 and 10 d after calving) for BHBA analysis using a Precision Xtra meter. Milk samples to estimate FPR were collected on d 7, 14 and 21 after parturition. Data were analyzed using MIXED procedure of SAS with a model containing the effects of block, treatment, time, and treatment × time interaction as fixed effects and cow within treatment as a random effect. The incidence of hyperketonemia (BHBA concentration ≥1.2 mmol/L) was 25.0% (16/64) for RPB and 30.0% (19/63) for CON. Body weight and BCS did not differ (P > 0.05) between RPB and CON cows in all 3 observations (21 d before calving, at calving, and 21 d after calving). No differences on serum metabolites between RPB and CON cows were detected (P > 0.05). NEFA concentrations peaked (P < 0.01) at calving; 0.82 ± 0.04 mmol/L, whereas BHBA peaked (P < 0.01) at 7 d after calving; 0.78 ± 0.05 mmol/L. The lowest cholesterol concentration was at calving; 73.78 ± 1.53 mg/dL. Finally no milk FPR differences (P > 0.05) were observed between RPB and CON cows in the first 3 weeks after calving; 1.29 vs. 1.31. In the particular conditions of this on-farm trial with low incidence of hyperketonemia no benefits on RPB supplementation were detected.