title: Comparison of pH and refractometry index with calcium concentrations in preparturient mammary gland secretions of mares.
abstract: OBJECTIVE
  To test the usefulness of measuring pH and refractometry index, compared with measuring calcium carbonate concentration, of preparturient mammary gland secretions for predicting parturition in mares.
  
  
  METHODS
  Evaluation study.
  
  
  METHODS
  27 pregnant Thoroughbred mares.
  
  
  METHODS
  Preparturient mammary gland secretion samples were obtained once or twice daily 10 days prior to foaling until parturition. The samples were analyzed for calcium carbonate concentration with a water hardness kit (151 samples), pH with pH test paper (222 samples), and refractometry index with a Brix refractometer (214 samples). The sensitivity, specificity, and positive and negative predictive values for each test were calculated for evaluation of predicting parturition.
  
  
  RESULTS
  The PPV within 72 hours and the NPV within 24 hours for calcium carbonate concentration determination (standard value set to 400 μg/g) were 93.8% and 98.3%, respectively. The PPV within 72 hours and the NPV within 24 hours for the pH test (standard value set at 6.4) were 97.9% and 99.4%, respectively. The PPV within 72 hours and the NPV within 24 hours for the Brix test (standard value set to 20%) were 73.2% and 96.5%, respectively.
  
  
  CONCLUSIONS
  Results suggested that the pH test with the standard value set at a pH of 6.4 would be useful in the management of preparturient mares by predicting when mares are not ready to foal. This was accomplished with equal effectiveness of measuring calcium carbonate concentration with a water hardness kit.
authors.affiliation: Hidaka Training and Research Center, Japan Racing Association, Hokkaido, Japan. Kenji_Korosue@jra.go.jp
authors.forename: Kenji
authors.initials: K
authors.lastname: Korosue
authors.forename: Harutaka
authors.initials: H
authors.lastname: Murase
authors.forename: Fumio
authors.initials: F
authors.lastname: Sato
authors.forename: Mutsuki
authors.initials: M
authors.lastname: Ishimaru
authors.forename: Yasumitsu
authors.initials: Y
authors.lastname: Kotoyori
authors.forename: Koji
authors.initials: K
authors.lastname: Tsujimura
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Nambo
mesh_terms: D000818:Animals; D002118:Calcium / Q000737:chemistry* / Q000378:metabolism; D005260:Female; D006736:Horses / Q000502:physiology*; D006863:Hydrogen-Ion Concentration; D008321:Mammary Glands, Animal / Q000378:metabolism*; D058725:Peripartum Period / Q000502:physiology*; D011247:Pregnancy
chemical_list: D002118:Calcium