In Vitro Rumen Fermentation Characteristics, Estimated Utilizable Crude Protein and Metabolizable Energy Values of Grass Silages, Concentrate Feeds and Their Mixtures
X Muqier,
Margrete Eknæs,
Egil Prestløkken,
Rasmus Bovbjerg Jensen,
Katrine Sømliøy Eikanger,
Inger Johanne Karlengen,
Gisken Trøan,
Stine Gregersen Vhile,
Alemayehu Kidane
Affiliations
X Muqier
Department of Animal and Aquacultural Sciences, Faculty of Biosciences, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, N-1432 Ås, Norway
Margrete Eknæs
Department of Animal and Aquacultural Sciences, Faculty of Biosciences, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, N-1432 Ås, Norway
Egil Prestløkken
Department of Animal and Aquacultural Sciences, Faculty of Biosciences, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, N-1432 Ås, Norway
Rasmus Bovbjerg Jensen
Department of Animal and Aquacultural Sciences, Faculty of Biosciences, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, N-1432 Ås, Norway
Katrine Sømliøy Eikanger
Department of Animal and Aquacultural Sciences, Faculty of Biosciences, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, N-1432 Ås, Norway
Four formulations of concentrate feeds, three contrasting qualities of grass silages, and mixtures of the silages (55%) and concentrates (45%, dry weight) were tested for in vitro fermentation kinetics, in vitro dry matter degradation (IVDMD), utilizable crude protein (uCP), and metabolizable energy (ME) values. The concentrates were pelleted control concentrate for dairy cows (CONT-P); pelleted alkaline concentrate with ammoniated cereal grains (ALKA-P); mash form concentrate with ALKA-P main ingredients but with feed-grade urea and barley replacing ammoniated cereal grain (UREA-M); and mash form of ALKA-P ingredients prior to alkalization (ALKA-M). The grass silages were early cut, late cut, and a mixture (1:1) of early and late cut. The objectives were to test if the feeds differed in the tested parameters within each feed category and assess the modulatory effect of concentrate feeds on the grass silage fermentation characteristics in the mixed diets. No interaction effects of the concentrate feeds by silage quality were observed for the tested parameters in the mixed diets. For concentrates, the pelleted diets were higher (p p p < 0.05) with increasing stage of maturity. In conclusion, the ALKA-P could match the CONT-P in uCP and ME values and fermentation characteristics. Results for silages and their mixtures with concentrates highlight the importance of silage quality in dietary energy and protein supply for ruminants.