Our objective was to determine if supplementing fatty acid blends (FAB) to transition dairy cows improves production and reproduction metrics in the next lactation. In trial 1, 249 cows were balanced by previous 305-d mature-equivalent milk yield and parity then randomly assigned to 1 of 3 dietary treatments: control, calcium salt FAB, or plant FAB. Cows were individually fed prepartum treatments 3 weeks ahead of expected calving date then individually fed a common diet postpartum with individual milk yield and composition out to d 70, and individual reproductive metrics for 5 services. In trial 2, 805 cows on 3 commercial farms with each farm having a pen fed either control (3 pens) or plant FAB dietary treatments (3 pens) in a randomized design from 3 weeks before expected calving date until calving. Milk yield until 90 DIM and reproductive metrics for 5 services were monitored. Data were analyzed using the PROC MIXED procedure (SAS) with differences noted at P < 0.05 and trends at P < 0.15. In trial 1, control cows gave more 3.5% FCM (1.4 kg / d; P < 0.15) and energy corrected milk (ECM - 1.3 kg / d; P < 0.15) than cows fed the plant FAB. Control cows had a higher fat yield (0.07 kg / d; P < 0.08) compared with plant FAB cows. Plant FAB cows tended to have lower milk fat percentage (0.09%; P < 0.12) and less ketosis (3.8%; P < 0.09) than control cows. Plant FAB cows increased confirmed pregnant on first service (12.6%; P < 0.09) over calcium salt FAB cows. Plant FAB cows had a greater number pregnant by 100 (16.2%; P < 0.03) and 125 (13%; P < 0.04) DIM versus control fed cows. In trial 2, milk yield was affected by parity with aged cows fed plant based FAB having greater ECM yield (1.32 kg/ d; P < 0.05), higher milk protein yield (0.05 kg / d; P < 0.01) and more milk fat yield (0.04 kg; P < 0.12). Plant FAB cows had fewer services per conception (0.18 services; P < 0.13), and tended to have higher pregnancy probability (5.72%; P < 0.07) by 75 DIM. Feeding the plant FAB prepartum appears to yield variable production and metabolic disease incidences but consistently enhanced reproductive metrics in the next lactation.