Technical note: Evaluation of a real-time wireless pH measurement system relative to intraruminal differences of digesta in dairy cattle1,2

Abstract

The aim of this study was to evaluate the accuracy and precision of indwelled wireless sensors relative to intrareticuloruminal differences in dairy cows transitioned from a forage to a high-concentrate diet. A feeding trial was performed with 8 rumen-cannulated Holstein cows. The cows were stepwise switched from 0 to 60% concentrate in the diet and fed 5 wk. Samples from the free ruminal liquid (FRL) from the ventral rumen and from the particle-associated ruminal liquid (PARL) in the rumen mat were manually taken at 0, 4, and 8 h after the morning feeding on d 0, 7, 14, and 34 of the experiment through the ruminal cannula to measure pH in FRL and PARL using a pH electrode. Additionally indwelling reticular wireless pH sensors were used to measure reticular pH every 10 min throughout the experiment. Precision and accuracy properties as a measure of reproducibility of the methods were statistically evaluated. Data showed significant differences among pH readings of indwelling sensors and pH measurements taken by means of a conventional electrode in both FRL and PARL (P<0.05). These differences became more evident when 60% concentrate diet was fed. Across all experimental days, the pH of the FRL was greatest and the pH reported by indwelling sensors intermediate, whereas the pH of PARL was lowest. The concordance correlation coefficient (CCC) analysis revealed a high agreement between indwelling sensors and FRL (CCC=0.709) but a low agreement with the pH of PARL (CCC=0.495). In conclusion, the study indicated that wireless sensors can satisfactorily reflect the pH of FRL but poorly reflect that of PARL.

Long-term reticuloruminal pH dynamics and markers of liver health in early-lactating cows of various parities fed diets differing in grain processing

“…One concern of the indwelling sensors is that they provide data of pH only in the site they are located, namely in the reticulum as they are located in the reticulum within 24 h after administration (Gasteiner et al, 2009). The sensors used in this study were recently evaluated and have shown to satisfactorily reflect the pH of the free rumen liquid (Klevenhusen et al, 2014). Thus, the term reticuloruminal pH is used here.…”

“…Because this disorder lacks overt clinical signs, its diagnosis relies mostly on ruminal pH measurements; however, single-point measurements of rumen pH are not reliable for predicting the Long-term reticuloruminal pH dynamics and markers of liver health in earlylactating cows of various parities fed diets differing in grain processing E. Humer,* 1 A. Khol-Parisini,* 1 L. Gruber, † J. Gasteiner, † Sh. M. Abdel-Raheem,* 2 and Q. Zebeli* 3 risk of SARA compared with measuring the duration of pH below certain SARA thresholds (Penner et al, 2007), which can be obtained by continuous monitoring of rumen pH (Penner et al, 2007;Klevenhusen et al, 2014). Subacute ruminal acidosis is a prevalent metabolic disorder of cattle, and metabolic stress associated with SARA primarily afflicts the energy and lipid metabolism in different body tissues, most importantly in the liver and the mammary gland (Bionaz et al, 2007;Zebeli and Ametaj, 2009;Chang et al, 2015).…”

Intramammary infusion of Escherichia coli lipopolysaccharide negatively affects feed intake, chewing, and clinical variables, but some effects are stronger in cows experiencing subacute rumen acidosis

“…Reticuloruminal pH and temperature were measured continuously throughout the experiment using wireless bolus sensors (Smaxtec Animal Care Sales GmbH, Graz, Austria). By using an applicator, these validated bolus sensors (Klevenhusen et al, 2014) were manually administered via the esophagus into the reticulorumen. Prior to their use, the boli were calibrated using a buffer solution at pH 7.0 following the company instructions and were registered to the computer software device afterward.…”

Metabolic adaptation and reticuloruminal pH in periparturient dairy cows experiencing different lipolysis early postpartum

“…These wireless pH-transmitting units (3.5 cm i.d., 12 cm long and weighing 210 g), validated previously (Klevenhusen et al, 2014), were manually inserted into the reticulorumen via the esophagus on day 17 postpartum (Humer et al, 2015b). Before their use, the units were calibrated by a two-point calibration using a buffer of pH 4.0 and one of pH 7.0 following the company's instruction protocol.…”