An experiment was conducted at Guduru Animal Production and Research Center (GAPRC) of Wollega University to evaluate effects of different levels of formulated concentrate supplementation on milk yield, milk compositions, feed intake and body weight gain of Horro cows. Sixteen early lactating Horro cows with the same body weight and condition were selected from GAPRC. Experimental cows were assigned to four dietary treatments using a randomized complete block design with four replications. Cows that varied in parity were used as blocking factors in the present trial. The treatments used were: RGH +0.5Kg of concentrate (T1), RGH +2Kg of concentrate (T2), RGH + 3Kg of concentrate (T3), and RGH + 4Kg of concentrate (T4). The experiment was conducted for 90 days with an acclimatization period of 15 days. Dry matter and nutrient intakes of cows significantly (p<0.05) varied between treatment groups. Mean dry matter intake was 5.98%. Mean total crude protein, total neutral detergent fiber, total acid detergent fiber, total acid detergent lignin and total organic matter intake (%) were, 0.78, 4.74, 2.26, 1.44, and 4.89 respectively. Total dry matter intake of cows fed on T4 was higher than those cows maintained on dietary T1, T2, and T3. The mean milk yield per cow per day was 3.12 liter. It has increased across the dietary treatment with an increase in the rate of concentrate supplementation. Protein, fat, total solid, solid-not-fat, and Ash composition of milk (%) were, , 3.41, 3.48, 13.37, 9.89, and 0.75 respectively, where milk compositions except for Lactose (5.73%) content had significant difference (P0.05) with changes in dietary treatments. In general, cows supplemented with 4kg of formulated concentrate had improved feed intake, milk yield and milk nutrient compositions than cows on the remaining dietary treatments. The further study shall be conducted on the productive and economic response of local cows maintained on such diet over successive lactation to evaluate the significance of the study at the field level.
