The objective of the present study was, therefore, to determine (i) the extent of ruminal protein degradation, (ii) the energetic value, and (iii) the side-effects on overall ruminal fermentation of ethanol/acetone-extracted ML (EML) or unextracted ML when included in ruminant diets. For that purpose, various chemical analyses and in vitro techniques were applied and comparisons were made with soybean meal and rapeseed meal, either when investigated alone or in complete isonitrogenous diets. The latter two feedstuffs were employed, as they are among the most common protein supplements in ruminant nutrition.