MeperidineMetabolomicsMetabolomeIsobutyratesSerumBlood Chemical AnalysisAnimal Nutritional Physiological PhenomenaAnimal FeedShiveringRandom AllocationAnalgesics, OpioidDietAdjuvants, AnesthesiaAnalgesia, ObstetricalPromethazineHydroxyzineDihydroergotamineAlfentanilSerum AlbuminAnalgesia, EpiduralConscious SedationPreanesthetic MedicationChloral HydrateFentanylCesarean SectionAnalgesia, Patient-ControlledBiotransformationButorphanolMorphineDextropropoxypheneChromatography, High Pressure LiquidKetorolac TromethamineSufentanilAnalgesics, Non-NarcoticAnesthesia, SpinalKetorolacSerotonin SyndromeSkin TemperatureTolmetinAnesthesia, DentalAnesthetics, LocalPain MeasurementAnesthesia, Epidural