Simultaneous Estimation of the pH of Rumen and Reticulum Fluids of Cows Using a Radio-Transmission pH-Measurement System

Abstract

ABSTRACT. Circadian pH changes in the fluid of the rumen (bottom and middle) and reticulum were assessed simultaneously using wireless and wired radio-transmission pH-measurement systems in cows fed a control diet (C diet) or rumen-acidosis-inducing diet (RAI diet). The pH in the three sites decreased following the morning and evening feedings. In cows fed the C diet, the bottom-rumen and reticular pH reverted to the basal level by the next morning, while the middle-rumen pH did not recover completely, suggesting that active fermentation occurred in the middle of the rumen. The mean pH at 1 hr intervals was higher in the reticulum than at the bottom and in the middle of the rumen. The relatively stable reticular pH may result from dilution due to salivation. In cows fed the RAI diet, the bottom-rumen pH fell to approximately 5.2 after the evening feeding, but returned to the basal level by the next morning. In contrast, the middle-rumen pH did not return to the basal level (6.5) within 24 hr, presumably owing to continuous, vigorous fermentation. There were positive correlations between the pH at the bottom and in the middle of the rumen and at the bottom of the rumen and in the reticulum. These findings indicate that our radio-transmission pH-measurement system may be suitable tool for simultaneous measurement of pH in the rumen and reticulum fluid. Subacute ruminal acidosis (SARA) affects the health and production of dairy herds [20], decreasing feed intake, milk production, and rumen digestion, while causing diarrhea and rumen mucosal damage [2,14]. Moreover, SARA provokes various diseases and their preconditions, including laminitis, reduced and erratic feed intake, a low body condition score (BCS), low milk fat syndrome, abomasal displacement and ulceration, and rumenitis [8,23].SARA is characterized by the presence of an abnormally low rumen pH [7,8,24] of less than 5.5; a pH of 5.8 is the marginal threshold for SARA [9-11, 14, 21]. Repeated collections of rumen fluid are needed to measure pH, which can lead to peritonitis following rumenocentesis with a trocar and esophageal injuries induced by oro-ruminal probe suction. Moreover, the reliability of the rumen pH likely depend on the operator's skill, the sampling site (bottom vs. middle of the rumen and rumen vs. reticulum), and sampling procedure (rumenocentesis vs. an oro-ruminal probe) [3,6,9,17,25]. An indwelling wire system has been used to measure the pH at the bottom of the rumen [2,18,19,22,23], but there are no reports on simultaneous pH measurements of fluids at the bottom and in the middle of the rumen and in the reticulum (i.e., three sites) of cows. The objective of this study was to assess the possible use of radio-transmission pH-measurement system for measurement of pH in the rumen (bottom and middle) and reticulum. First, we compared the circadian pH changes in the three sites for cows fed either a control diet (C diet) or a rumen-acidosis-inducing diet (RAI diet) using a wireless and wired systems. Then we examined the relationship betwe...

Relationship between pH and Temperature in the Ruminal Fluid of Cows, Based on a Radio-Transmission pH-Measurement System

“…After reaching their lowest level, increases in ruminal pH by the next morning may have been related to the absorption of lactic acid and VFA from the ruminal epithelium, dilution by sodium bicarbonate in saliva, or mixing of ruminal contents by movement [5]. Furthermore, the 24-hr mean and minimum pH were lower in cows fed the RAI diet than those fed the C diet, as reported previously [13]. The mean duration of pH<5.8 in cows fed the RAI diet was significantly longer compared to that in cows fed the C diet.…”

“…The pH sensor was calibrated at the start of each experiment with pH 4 and 7 buffer solutions and was placed in the ventral sac of the rumen through the rumen cannula. The ventral sac of the rumen, the site of rumenocentesis [9], showed stable pH values compared to those at the other ruminal site [13]. The ruminal pH and temperature were measured simultaneously on day 14 after commencement of each feeding protocol, because the circadian changes in these two items became stable from 7-10 days after feeding exchange.…”

“…Recently, we developed a novel radio-transmission pHmeasurement system that can be used on commercial dairy farms and can continuously estimate ruminal pH in cows with experimentally induced SARA [24,25]. This system measures fluid pH simultaneously in the ruminal bottom, middle, and reticulum along with their temperatures [13].…”

Pathophysiological evaluation of subacute ruminal acidosis (SARA) by continuous ruminal pH monitoring

“…2012a). Eight primiparous non‐lactating, rumen‐cannulated Holstein cattle weighting 620‐720 kg were used.…”

Changes in reticulorumen content temperature and pH according to time of day and yearly seasons

“…The ruminal pH profiles may not be predictable by only measuring ruminal temperature, because decreases in the ruminal pH were preceded by increases in the ruminal temperature, and the pH levels were associated with ruminal fermentation (Kimura et al 2012). Circadian changes in pH have been measured in the rumen of cannulated cattle using an indwelling ruminal pH system (Dado L. 1993, Strabel et al 2007, Alzahal et al 2008, Kaur et al 2010, Hook et al 2011.…”