P. 2003. Characteristics and in situ degradability of whole crop faba bean, pea, and soybean silages. Can. J. Anim. Sci. 83: 793-799. The objective of this study was to determine the ensiling characteristics and ruminal nutrient degradabilities of faba bean (FS, Vicia faba L.), soybean (SS, Glycine max (L.) Merr.) and pea (PS, Pisum sativum L.) silages. Forages were harvested between the beginning-and full-seed stages and ensiled in mini-silos for 0, 2, 4, 16, and 45 d. Two lactating Holstein cows fitted with ruminal fistulae were used to determine ruminal nutrient degradabilities. Results showed that all silages went through a rapid fermentation as indicated by rapid decline in pH and sharp increase in lactic acid concentration within the first 2 d of ensiling. Extensive proteolysis took place between day 0 and day 4 post-ensiling as indicated by a significant reduction in true protein (TP) and a significant increase in non-protein nitrogen (NPN). During the 45 d of ensiling, TP decreased (P < 0.05) by 26, 31, and 45% while NPN increased (P < 0.05) by 82, 54, and 47% for FS, SS, and PS, respectively. Chemical analysis showed that the three 45-d silages contained a similar level of neutral detergent fiber (NDF, average 421 g kg -1 ). Crude protein (CP) was highest (P < 0.05) for FS, intermediate for SS, and lowest for PS. Distribution of protein fractions showed that soluble protein and NPN were highest (P < 0.05) for PS, intermediate for SS, and lowest for FS. Neutral (NDICP) and acid (ADICP) detergent insoluble protein levels followed an opposite order to that observed for soluble crude protein (SCP) and NPN. Results of the in situ study showed that SS and PS had a similar ruminal degradability of dry matter (average 68.8%) and CP (82.9%), which were higher (P < 0.05) than those of FS (66.2 and 79.4%, respectively). However, no differences in ruminal degradability of NDF (average 34.7%) were observed between the three legume silages. . Les fourrages ont été récoltés du début à la fin de la production des graines puis stockés dans des silos miniatures pendant 0, 2, 4, 16 et 45 jours. Les chercheurs ont ensuite utilisé deux vaches Holstein en lactation pourvues d'une fistule au rumen pour vérifier la dégradation des éléments nutritifs. Les ensilages connaissent une fermentation rapide, comme le révèle la brusque chute du pH et la forte hausse de la concentration d'acide lactique au cours des deux premiers jours. Une forte protéolyse survient entre le jour 0 et le jour 4, ainsi qu'en témoignent la réduction appré-ciable de la concentration de vraies protéines (VP) et la hausse sensible de la teneur en azote non protéique (ANP). Pendant les 45 jours d'ensilage, la concentration de VP de l'EF, de l'ES et de l'EP baisse (P < 0,05) respectivement de 26, de 31 et de 45 % alors que celle d'ANP augmente (P < 0,05) de 82, de 54 et de 47 %. L'analyse chimique révèle que les trois ensilages contiennent une concentration analogue de fibres au détergent neutre après 45 jours d'ensilage (421 g par kilo, en moyenne). C'est l'...