During the fresh period after calving through ~21 d postpartum, dairy cows are often in negative energy balance (NEB) due to high energy demands to support rapidly rising milk output at a time of relatively low dry matter intake (DMI). This NEB makes cows susceptible to ketosis, fatty liver, metritis, and displaced abomasum, which can lead to decreased performance and eventual culling. A possibility to reduce the extent of NEB is to feed niacin (Ni) as nicotinic acid (NA) to reduce milk fat production, thereby minimizing body weight loss to reduce ketogenesis, all to reduce the extent of NEB thereby creating a more successful lactation. Multiparity Holstein cows (672) on a California dairy farm were used from 14 d pre-calving through 150 d in milk (DIM). While in the close-up dry pen (−14 to 1 DIM), cows were comingled and fed the same total mixed ration (TMR), in the fresh pens (1 to ~22 DIM) cows were fed the same TMR, except for inclusion of ruminally protected (RP) Ni (rumen escape estimate = 66%), in separate pens at 0, 3.5, 7 or 14 g NA/cow/d. Cows were comingled in the high pen (~23 to 150 DIM) and fed the same TMR. DMI was tabulated by treatment in the fresh pens, blood samples were collected for NEFA and BHBA analysis during the dry and fresh periods, and fertility data was tabulated through 150 DIM. Feeding 3.5 g/d RPNi increased DMI from 19.3 to 21.5 kg/d in the fresh period, but RPNi at 14 g/d reduced it to below Control cows (Quadratic P = 0.07). Ketosis prevalence (% cows with BHBA ≥ 1.44 mg/dl) decreased from 36 to 20% in the fresh period with 3.5 g/d, but RPNi at 14 g/d did not differ from levels of Control cows (Quadratic P = 0.06). Niacin feeding had no effect on any fertility measure, with averages for 1st service conception (%) being 44.6 ± 4.38, pregnancy (%) being 76.2 ± 3.70 and services/conception being 1.58 ± 0.082. Short-term fresh period RPNi feeding at the 3.5 g/d level reduced the incidence of ketosis caused by NEB, but feeding higher levels removed those benefits. No RPNi feeding level during the fresh period affected fertility parameters through 150 DIM.