Simple SummaryImprovements in health-promoting milk fatty acids by feeding oil mixtures have been reported in dairy cows. However, in some cases, oil addition reduces milk yield and milk fat content. It is unknown whether the inclusion of linseed oil and fish oil at a high level in goat diets increases health-promoting fatty acids in milk without affecting milk production. The objective of this study was to investigate the effect of linseed oil added alone at 2.5% or in combination with tuna fish oil at 2.5% or 4.16% in goat diets on intake, milk yield, and milk fatty acid profiles. Compared with the control without oil addition, feeding linseed oil and fish oil at 4.16% markedly increased the levels of health-promoting fatty acids in milk such asc9,t11 conjugated linoleic acid, and docosahexaenoic acid but decreased milk total saturated fatty acids, atherogenicity, and thrombogenicity indices. Oil addition did not have a negative effect on intake, milk yield, and milk fat content. Thus, supplementing linseed oil and fish oil at 4.16% in the diet of lactating goats could have a positive impact on human health without any adverse effects on animal performance.AbstractThis study aimed to evaluate the effect of incorporating linseed oil and fish oil in the diet on intake, ruminal fermentation, milk yield, and milk fatty acid profiles in dairy goats. Four crossbred Saanen lactating goats in mid-lactation and milking 1.30 ± 0.28 g/day were used in a 4 × 4 Latin square design. The basal diet contained concentrate and Para grass (C:F 40:60). Treatments included a basal diet without oil supplementation (Ctrl) or with 2.5% linseed oil (LO2.5), 2.5% linseed oil and fish oil (3:2,w/w, LFO2.5), and 4.16% linseed oil and fish oil (3:2,w/w, LFO4.16). Diets had no effect on intake, milk yield, milk composition, or ruminal fermentation (p> 0.05). Compared with Ctrl, lower (p< 0.05) proportions of C10:0–C14:0 in milk fat were observed with LFO4.16. Compared with the Ctrl and linseed oil added alone, feeding LFO4.16led to a greater (p< 0.01) concentration of C18:1t11. Compared with both the Ctrl and LO2.5diets, milkc9,t11 CLA was 4.53 and 2.94 times greater with the LFO4.16diet. Compared with Ctrl and LO2.5diets (0.06% and 0.08%), goats fed LFO2.5,and LFO4.16had greater (p< 0.001) concentrations of C22:6n-3 (0.63% and 0.87%). Overall, the combined data suggested that including 4.16% linseed oil and fish oil in the diet of dairy goats was effective in improving the concentrations of health-promoting fatty acids in milk without affecting milk production.