title: The repeatability of an oral glucose test in ponies.
abstract: BACKGROUND
  Insulin dysregulation can be difficult to diagnose from basal insulin and glucose concentrations, so a field-based oral glucose test (OGT) is preferred. However, the repeatability of this test has not been reported.
  
  
  OBJECTIVE
  To determine the repeatability of an in-feed OGT in ponies and examine some factors affecting the palatability of the test meal.
  
  
  METHODS
  A repeated measures, longitudinal study.
  
  
  METHODS
  An in-feed OGT was performed at 08.00 h on 3 consecutive occasions under controlled conditions in 8 mixed breed ponies. d-glucose (0.75 g/kg bwt) was dissolved in water and combined with wheat bran and lucerne chaff. Blood samples were taken before and 90, 120, 180 min and 24 h after d-glucose. The repeatability of the test was analysed with repeated measures ANOVA. Insulin and glucose responses to d-glucose were also compared to an equivalent dose of dietary carbohydrate provided with a commercial grain mixture.
  
  
  RESULTS
  The overall insulin responses to the OGTs did not differ between tests. Individual insulin responses were more variable (P<0.05) than glucose responses. There was no difference in insulin concentration in post d-glucose samples over time. Insulin and glucose responses to grain and d-Glucose were not different.
  
  
  CONCLUSIONS
  An OGT is reasonably repeatable in ponies. The currently recommended post-glucose sampling time point of 2 h is acceptable, with sampling at 90 min also likely to produce a consistent result. The use of an alternative carbohydrate source to d-glucose, such as a commercial grain-based product, may be a viable and more palatable option for the test.
authors.affiliation: Science and Engineering Faculty, Queensland University of Technology, Brisbane, Australia.
authors.forename: M A
authors.identifier: http://orcid.org/0000-0001-7922-3642
authors.initials: MA
authors.lastname: de Laat
authors.affiliation: Science and Engineering Faculty, Queensland University of Technology, Brisbane, Australia.
authors.forename: M N
authors.initials: MN
authors.lastname: Sillence
mesh_terms: D000821:Animal Feed; D000818:Animals; D001786:Blood Glucose / Q000502:physiology*; D004435:Eating; D005951:Glucose Tolerance Test / Q000662:veterinary*; D006736:Horses / Q000097:blood / Q000502:physiology*; D007328:Insulin / Q000097:blood; D015203:Reproducibility of Results
chemical_list: D001786:Blood Glucose; D007328:Insulin
keywords: equine metabolic syndrome; grain; horse; hyperinsulinaemia; insulin; laminitis