title: Use of a breath test to determine the fate of swallowed fluids in cattle.
abstract: OBJECTIVE
  To investigate a [13C]octanoic acid breath test as a means of detecting reticular groove contraction in cattle.
  
  
  METHODS
  19 adult dairy cows with fistulated rumen, 10 yearling bulls, and 6 yearling steers.
  
  
  METHODS
  Cows were given 200 mg of [13C]octanoic acid in the caudal portion of the rumen, reticulum, or omasum/abomasum through the reticulo-omasal orifice, or were given the same dose of label with a drench of water or sodium bicarbonate. Collected breath was analyzed for 13C in CO2 for up to 3 hours. Breath of yearlings was analyzed for 13C in CO2 over 20 minutes after drenching with 200 mg of [13C]octanoic acid with water or sodium chloride and after sucking 200 mg of [13C]octanoic acid with molasses and water.
  
  
  RESULTS
  In cows, enrichment of 13C in breath CO2 peaked at 20 to 30 minutes after placement of [13C]octanoic acid through the orifice, compared with a lower peak at 60 and 90 minutes after placement in the reticulum and rumen, respectively. The maximal increase in enrichment after placement of [13C]octanoic acid in the reticulum did not overlap with the minimal increase when placed through the reticulo-omasal orifice. Enrichment values in cows after drenching were consistent with values obtained after direct placement of [13C]octanoic acid. In yearlings, the inclusion of sodium chloride in the drench greatly increased enrichment, compared with water, but enrichment was greatest after sucking of the molasses, water, and [13C]octanoic acid combination.
  
  
  CONCLUSIONS
  This breath test provides a simple, repeatable, nonradioactive, and noninvasive means of detecting the fate of swallowed fluids in cattle, thus revealing the route taken of orally administered therapeutic agents or nutrients.
authors.affiliation: Department of Biological Sciences, University of Waikato, New Zealand.
authors.forename: L M
authors.initials: LM
authors.lastname: McLeay
authors.forename: V R
authors.initials: VR
authors.lastname: Carruthers
authors.forename: P G
authors.initials: PG
authors.lastname: Neil
mesh_terms: D000018:Abomasum / Q000378:metabolism / Q000502:physiology; D000284:Administration, Oral; D000818:Animals; D001944:Breath Tests / Q000379:methods*; D002210:Caprylates / Q000378:metabolism; D002245:Carbon Dioxide / Q000378:metabolism; D002247:Carbon Isotopes; D002417:Cattle / Q000378:metabolism / Q000502:physiology*; D003679:Deglutition / Q000502:physiology*; D005260:Female; D008297:Male; D008965:Molasses; D012159:Reticulum / Q000378:metabolism / Q000502:physiology; D012417:Rumen / Q000378:metabolism / Q000502:physiology; D013997:Time Factors; D014867:Water
chemical_list: D002210:Caprylates; D002247:Carbon Isotopes; D014867:Water; D002245:Carbon Dioxide