Ruminal pH was measured and recorded continuously
(1-min intervals) using a cordless indwelling pH
electrode as described by AlZahal et al. (2007b). Briefly,
a pH electrode was inserted through the cannula and
connected to a data logger for data acquisition. The
electrodes were attached a 0.5-kg stainless steel weight
to ensure that they resided in the ventral sac of the
rumen. The data were downloaded daily for pH evaluation
and analysis. Ruminal pH was recorded on d 1
(regular TMR), d 36 (HF diet), d 50 (transition to the
HG diet), d 51 (first day on the HG diet), and d 71 and
72 (on the HG diet).