5.2. Dual-Flow Continuous Culture System Operation and Experimental Period
A dual-flow continuous culture system [Two ruminally cannulated lactating Holstein cows were used as ruminal content donors. Donor cows were fed a total mixed ration containing (DM basis) corn silage (40%), alfalfa hay (3%), ground corn (27.3%), soybean meal 44% (15.5%), citrus pulp (9.2%), and mineral and vitamin premix (5%). Approximately 2 h after morning feeding, ruminal contents were manually collected and filtered through four-layer cheesecloth into prewarmed thermos flasks, which were kept airtight until transported to the laboratory for pooling across cows (50:50 mix; vol/vol). Pooled ruminal content was added to each prewarmed (39 °C) fermenter vessel until it reached the solid effluent outflow.On d 5 of each period, artificial saliva was exchanged for 