The present study conducted to assess dairy feed resources mineral composition and dairy cow blood mineral profiles in selected districts of East Shoa Zone, and assess the effects of dicalcium phosphate supplementation on milk yield and composition in Crossbred Dairy Cows. The whole work was conducted in two major parts with sub-activities in each part. The first activity of part one was surveyed to assess the socioeconomic status of dairy farmers and feed resources available with feeding patterns in the urban and peri-urban production system of Adaâ€™a and Adama district. The second activity of part one was minerals profile assessment both from dairy feeds resources and from dairy cow serum at different physiological status. The assessment was performed in a wet and dry season of the year. Part two was on-station mineral supplementation experimental trial to investigate the effect of mineral supplementation on blood, feed, milk, urine and feces mineral profile, feed intake, milk yield and composition of crossbred dairy cows. For part one, the sampling frame comprises farmers keeping crossbred dairy cows and a total of 250 households were purposively selected. The study districts and the production systems (urban and peri-urban) were selected purposively based on the availability of dairy farms, having crossbreed dairy cows. A total of 240 blood samples (120 at dry and 120 at wet season) and 140 feed samples were collected from the dairy farms where blood was taken. Feed samples were categorized based on the production system and seasons and were dried and grounded. The grounded feed samples and serum were stored at -200C until to be analyzed. The serum and feed samples were analyzed for Calcium (Ca), Magnesium (Mg), phosphorus (P), Copper (Cu), Iron (Fe), zinc (Zn) and Cobalt (Co). The mean value of calcium ranges from (0.13 to 0.55 %); (0.14 to 0.64 %); (0.34 to 0.69 %) respectively, in roughage, Cereal grain & oilseed cakes and non-conventional. Out of the total feeds analyzed 26.92%, roughage (natural grass hay, sugar cane tops, and silage) and 66.15% cereal grain & oilseed cakes, showed deficiency in Ca. The mean magnesium and Iron values were not deficient in analyzed feeds. The mean Copper concentrations were ranges from in (6.99 to 10.65 ppm); (6.67 to 8.78 ppm); (6.31 to 9.72 ppm) respectively, roughages, Cereal grain & oilseed cakes and non-conventional. When the Cu concentration values are compared to the critical value (