Corn grain processing and its partial replacement by pelleted citrus pulp on performance, nutrient digestibility and blood parameters of dairy cows

Abstract

Four lactating cows were assigned to a 4x4 Latin square design with a 2x2 factorial arrangement for the following treatments: coarsely ground corn; steam-flaked corn; coarsely ground + citrus pulp; steam-flaked + citrus pulp. Steam-flaking grain (processing effect) increased total tract digestibility (%) of DM, OM, starch and protein; decreased rumen NH₃-N and acetate and increased ruminal propionate. Feed efficiency, milk protein content and yield tended to be higher for flaked corn. Inclusion of citrus pulp did not affect DM intake and increased fiber digestibility. Inclusion of citrus pulp increased starch digestibility (%) in the case of coarsely ground corn diet. Rumen ammonia nitrogen and molar proportion of propionate were not affected by citrus pulp; ruminal acetate, however, was significantly increased. There was an interaction between grain processing and citrus pulp on plasma glucose concentration. Fat corrected milk, feed efficiency, milk fat content and yield were increased by citrus pulp.