Sixteen crossbred (Alpine×Beetal) lactating does were divided into two equal groups on the basis of milk yield, stage of lactation and lactation number. Group I was fed a concentrate containing groundnut cake as the sole protein source. In Group II groundnut cake was replaced with mustard cake containing 139.4μmol/g glucosinolate, on a protein basis. Both concentrate mixtures were isocaloric and isonitrogenuous, however the Group II concentrate contained 57.5μmol/g glucosinolate, resulting in an average 13.04g glucosinolate intake per goat. Dietary glucosinolate affected the palatability of the diet and reduced (P<0.01) the intake and CP digestibility in Group II. Digestibility of dry matter, organic matter, cell wall components, 4% fat corrected milk yield and milk production efficiency were similar in both groups. Dietary glucosinolate increased (P<0.05) the milk thiocyanate and decreased (P<0.01) the iodide content. Milk fat, protein, total solids, solid-not-fat and urea concentration were however not affected. Feeding of glucosinolates diets reduced (P<0.05) the plasma T 4 concentration, with plasma T 3 concentration not being affected. Plasma iodide, total protein, urea and creatinine content as well as activity of γ-GTP were unaffected by dietary glucosinolate. Dietary glucosinolates adversely affected the palatability of the diet, increased milk thiocyanate and reduced milk iodide content and also reduced the plasma T 4 concentration without affecting nutrient utilization, milk yield and other milk composition. Costlier groundnut cake can be totally replaced by high glucosinolate containing mustard cake in the diet of lactating goats.