Feeding trials were performed with two groups of dairy cows receiving ammonized straw pellets supplemented with varying levels of concentrates as sole basal diet. The trials were carried out over periods of 546 days and 120 days. An annual milk production of 4217.9 kgs (calculated on the basis of 3.5% of milk fat) per cow was achieved in group I by feeding 3060.6 kgs of straw pellets and 2014.7 kgs of concentrates per animal. After subtracting all additives an amount of 2641.1 kgs of pure straw (= 52%) and of 2434.2 kgs of concentrated food (= 48%) remained so that the resulting amount of dry feed consumed per 100 kg of milk was 120.3 kg. A total of 6309.6 kgs of milk was produced per cow over a period of 546 days of trial. During this period the average weight gain per cow was 98.4 kgs. 1517.3 kgs of milk (calculated on the basis of 3.5% milk fat) per cow were produced in group II (56 cows) over a period of 105 days by feeding 892.5 kgs of straw pellets and 682.5 kgs of concentrate pellets. The concentrate pellets contained 50% of ammonized dried sugar beet chips but not extracted meals.