title: Relationship between pH and temperature in the ruminal fluid of cows, based on a radio-transmission pH-measurement system.
abstract: To assess the relationship between pH and temperature in the ruminal bottom fluid, circadian changes were monitored using cows fed a control diet (C diet) or a rumen acidosis-inducing diet (RAI diet) by using a wireless radio-transmission pH- measurement system. These two parameters were measured simultaneously at 10-min intervals on day 14 after commencement of feeding. Compared to the mean ruminal pH for 60 min immediately after the morning feeding (0 hr), significantly lower pH was noted 3-13 hr later (P<0.05) and 4-19 hr later (P<0.01) in cows fed the C and RAI diets, respectively, although the reduction in the latter was much higher than that in the former. In contrast, significantly higher ruminal temperature was found at 8 and 12-14 hr later (P<0.05) and 6, 8, and 10-19 hr later (P<0.01) in cows fed the C and RAI diets, respectively. A significant negative correlation was observed between the lowest ruminal pH and its corresponding ruminal temperature in cows fed the C and RAI diets (r=-0.722 and -0.650, P<0.01, respectively), suggesting active fermentation and volatile fatty acid production in the rumen. However, ruminal pH profiles may not be predictable by measuring only ruminal temperature because decreases in ruminal pH were preceded by increases in ruminal temperature, and circadian changes in pH and temperature were associated with ruminal fermentation.
authors.affiliation: United Graduate School of Veterinary Science, Gifu University, Gifu 501-1193, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kimura
authors.forename: Shigeru
authors.initials: S
authors.lastname: Sato
authors.forename: Takuma
authors.initials: T
authors.lastname: Kato
authors.forename: Kentaro
authors.initials: K
authors.lastname: Ikuta
authors.forename: Norio
authors.initials: N
authors.lastname: Yamagishi
authors.forename: Keiji
authors.initials: K
authors.lastname: Okada
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Mizuguchi
authors.forename: Kazunori
authors.initials: K
authors.lastname: Ito
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001826:Body Fluids / Q000737:chemistry*; D002417:Cattle; D018592:Cross-Over Studies; D004032:Diet / Q000662:veterinary; D005260:Female; D006863:Hydrogen-Ion Concentration; D008991:Monitoring, Physiologic / Q000295:instrumentation / Q000662:veterinary*; D011846:Radio Waves; D012417:Rumen / Q000502:physiology*; D013686:Telemetry / Q000662:veterinary; D013696:Temperature