title: Effect of a feed/fast protocol on pH in the proximal equine stomach.
abstract: BACKGROUND
  Risk factors for the development of gastric squamous ulcers include various management procedures, such as intermittent feed deprivation that can occur during weight management regimens or stall and dry lot confinement.
  
  
  OBJECTIVE
  To investigate the effect of intermittent feed deprivation relative to continuous feed intake on proximal intragastric pH, specifically in the region of the squamous mucosa of the lesser curvature.
  
  
  METHODS
  In 6 horses, pH electrodes were placed just inside of the oesophageal sphincter in the stomach for each of two 72 h protocols (A and B) in a randomised, cross-over design. Protocol A consisted of 12 h fed, 12 h fasted, 24 h fed and 24 h fasted, in sequence. Protocol B consisted of 72 h fed. During the fed periods of each protocol, horses had ad libitum access to coastal Bermuda hay and were fed sweet feed (1 kg, b.i.d.). Horses had ad libitum access to water at all times.
  
  
  RESULTS
  Proximal intragastric pH was significantly lower during protocol A, than during protocol B. However, hourly mean pH was significantly different only during the day and evening hours between protocols. During protocol B, mean proximal pH decreased significantly from 03.00 to 09.00 compared to 19.00 to 23.00 h. A moderate positive correlation of hay intake vs. proximal gastric pH could be established.
  
  
  CONCLUSIONS
  Intermittent feed deprivation decreased proximal gastric pH in horses relative to those horses for which feed was not restricted. However, the effect was only significant when fasting occurred during the day and evening hours, as a nocturnal decrease in pH occurred simultaneously in the fed horses.
  
  
  CONCLUSIONS
  Episodes of daytime feed deprivation should be avoided if possible, as proximal gastric acid exposure rapidly increases during such events.
authors.affiliation: Department of Large Animal Sciences, Faculty of Life Sciences, University of Copenhagen, Taastrup, Denmark.
authors.forename: L
authors.initials: L
authors.lastname: Husted
authors.forename: L C
authors.initials: LC
authors.lastname: Sanchez
authors.forename: K E
authors.initials: KE
authors.lastname: Baptiste
authors.forename: S N
authors.initials: SN
authors.lastname: Olsen
mesh_terms: D000821:Animal Feed; D000822:Animal Husbandry; D000818:Animals; D005508:Food Deprivation; D006736:Horses / Q000502:physiology*; D006863:Hydrogen-Ion Concentration; D013270:Stomach / Q000502:physiology*