The objective of this study was to determine if corn treated with foliar fungicide and ensiled as corn silage would increase milk production and efficiency in dairy cattle. This study utilized 64 Holstein cows with parity 2.53 ± 1.5, BW 653 ± 80 kg, and 161 ± 51 d in milk (DIM). Cows were blocked and randomly assigned to 1 of 4 treatments to be included in the total diet (35% of the DM as corn silage). Treatments were as follows: Control (CON), corn silage with no applications of a foliar fungicide, Treatment 1 (1×), corn silage received application of pyraclostrobin (PYR) foliar fungicide (Headline; BASF Corp.) at corn stage V5; treatment 2 (2×), corn received the same application as 1× and another application of a mixture of PYR and metconazole (MET; Headline AMP; BASF Corp.) at corn stage R1; and treatment 3 (3×), corn the same applications as 2× as well as third application of PYR and MET at R3. Corn was harvested at the 3/4 milk line stage of growth and ensiled for 200 d. The trial was conducted in 2 consecutive periods each consisting of 1 wk for adaptation (covariate) followed by 5 wk of measurements where cows received assigned treatments. Body weight, BCS, and lame scores were assessed weekly. Milk production, and DMI were measured daily. Milk samples for milk composition analysis were collected during wk 5. Blood samples were taken on d1 (covariate) and d 29 to assess blood metabolites. Data were analyzed using a MIXED procedure in SAS (v9.4). Dry matter intake was 23.78, 22.95, 19.54, and 21.33 kg for CON, 1×, 2× and 3×, respectively. There was a linear (P = 0.08) tendency for DMI. Milk yield (34.5, 34.5, 34.2, 34.4 kg/d) and milk components did not differ (P > 0.05) among treatments. However, there were trends for increased FCM/DMI (1.65 vs. 1.47. P = 0.08) and ECM/DMI (1.60 vs. 1.43. P = 0.09) for cows fed corn silage with fungicide compared with CON (P < 0.09). Serum glucose was lower for cows receiving treated silage with fungicide when compared with CON (51.1 vs. 63.4 mg/dL, P < 0.01). In conclusion, cows receiving corn silage treated with foliar fungicide had increased feed conversion when compared with CON.