There is interest in increasing the content of omega-3 (n-3) fatty acids in bovine milk, primarily because of their beneficial effects on human health. This study investigated the effects of extrusion and the inclusion of condensed tannins (CT) in a flaxseed product on rumen fermentation characteristics, animal performance and milk fatty acid composition in dairy cows. Eight Holstein cows were used in a replicated 4 × 4 Latin Square with 28-d periods (20 d for dietary adaptation and 8 d for collection). Four cows in one Latin square were ruminaly-cannulated. Cows were fed either a control diet (CTL) or one of 3 treatment diets that consisted of the daily substitution of 3 kg of the CTL concentrate pellet with 3 kg of either a non-extruded flaxseed and pea product (55% flaxseed, 36% peas,8% alfalfa,1% antioxidant; designated RAW), a extruded flaxseed and pea product (55% flaxseed, 36% peas,8% alfalfa,1% antioxidant; designated LPR), or a extruded flaxseed and high-tannin fava bean product (55% flaxseed, 36% fava beans,8% alfalfa,1% antioxidant; designated LPF). Diets were fed twice daily as total mixed rations. Dry matter intake was lower for cows fed LPR compared with those fed CTL (P < 0.05). Milk yield was unaffected by dietary treatment (P > 0.05). Rumen pH was not affected by dietary treatment (P > 0.05). Rumen ammonia concentration was lower in animals fed CTL compared with those fed RAW, LPR or LPF (P = 0.04). Propionate concentrations were higher for animals fed LPR compared with those fed RAW (P = 0.04), while acetate concentrations did not differ between dietary treatments (P > 0.05). Total n-3 and CLA milk contents were higher in cows fed LPR and LPF compared with those fed RAW and CTL (P < 0.01). Milk fat content was lower for cows fed LPF compared with those fed CTL (P = 0.03); however, milk fat yield was unaffected by dietary treatment (P > 0.05). The use of extruded flaxseed products is an effective strategy for increasing the n-3 and CLA concentrations of bovine milk without negatively affecting rumen fermentation or animal production; however, the inclusion of CT in the extruded product had no additional benefit.