5.3. Fermentation Profile
Ruminal pH was measured in each fermenter vessel using a portable pH meter (Thermo Scientific Orion Star A121, Thermo Fisher Scientific Inc., Waltham, MA, USA) at 0, 1, 2, 4, 6, and 8 h post-morning feeding during d 8 and 9 of each period. Aliquots of approximately 15 mL of ruminal content from each fermenter were filtered through four layers of cheesecloth to obtain a 10-mL sample that was immediately acidified with 0.1 mL of 50% H