Effect of level and origin of rumen degradable nitrogen on rumen microbial growth and nitrogen utilisation efficiency of animals fed maize silage at maintenance Veerle Fievez, Kristof De Fauw, Kurt Notteboom and Daniël DemeyerReprod. Nutr. Dev., 41 4 (2001) 349-364DOI: https://doi.org/10.1051/rnd:2001136