Oats, wheat and triticale as feeds for dairy cows - Effects on feed intake, rumen metabolism, milk production and health

Two change-over trials were carried out during two consecutive years. In each year nine cows, as similar as possible with respect to age, stage of lactation and daily milk yield were divided into groups of three. They were all fed a basic ration of 2 kg hay, 5-6 kg silage dry matter, 0.5-1.0 kg dried beet pulp and minerals. Moreover, they got concentrates (a commercial protein feed and grains) according to daily milk yield. Different grains were fed during periods of five weeks, including two weeks for adaptation, in a series of Latin squares. Grain diets were: 100% oats (first and second year), 50% oats and 50% triticale (first year) or 50% oats and 50% wheat (second year), and 100% triticale (first year) or 100% wheat (second year). Daily milk yield was determined once a week and rumen samples were taken twice a week for evaluation of the rumen metabolism. At the end of each dietary test period arterial blood samples were taken for measuring the metabolic acid-base balance. Cows fed triticale or wheat as the only grain had lower intakes of concentrates and lower milk yields than the other groups. Since there were no indications of any acidifying challenge either in the rumen or in the systemic circulation, these adverse effects were considered to be caused solely by a reduced palatability of triticale and wheat when fed as the only grain.