Effects of sensor location during in situ measurements on pH in caecal digesta of the horse, and post-observational treatment of sensor data

ABSTRACT

Measurements of caecal pH are useful when studying the effect of a ration on the hindgut environment in horses. Frequent in situ measurements of caecal pH have been used to measure short-term changes in pH. However, this method also results in a large and complex data set. Transient random influxes of alkaline content from the small intestine might result in short-time elevations in caecal pH that complicates data processing. We used two caecal-cannulated horses fed two different rations in a cross-over design experiment. We compared frequent in situ measurements of caecal pH measured with an unweighted and a weighted pH electrode. Based on our results, we recommend to use a weighted pH electrode situated in the deeper layers of the caecum compared to an unweighted. If an unweighted electrode is used, we present a peak-detecting algorithm to eliminate short-time elevation peaks caused by the ileal influx.

KEYWORDS:

• Cannula
• pH logging
• hindgut
• fermentation

Acknowledgments

The authors are grateful for having collaborated with Dag Austbø who unexpectedly passed away during our work on this study. Dag was a driving force in developing the work with cannulated horses at the Norwegian University of Life Sciences. We also acknowledge Mette Henne at the horse research facility for the daily care of the horses and help during the pH logging days.

Disclosure statement

No potential conflict of interest was reported by the authors.