Effects of high and low ruminal degradability of starch and nitrogen sources on milk production

Abstract

Four Holstein cows were tested in a Latin square with treatments in a 2x2 factorial arrangement to investigate the effects on milk production of four isonitrogenated and isoenergetic concentrates consisting of high (triticale) and low (corn) ruminal degradability starch sources and high (canola bran and urea) and low (cottonseed bran, meat and bone meal) ruminal degradability nitrogen sources. Dry matter (DM), crude protein (CP), gross energy (GE) and starch (S) intakes were affected by the interaction of starch and nitrogen sources. Dry matter and protein intakes were higher when corn and triticale combined with nitrogen source of low ruminal degradability were fed. Gross energy intake was higher when high degradability starch and nitrogen sources or low degradability starch and nitrogen sources were combined. Starch digestibility was higher for triticale-based diets. On the other hand, milk production was not affected by the treatments.