Objective—To determine the effect of a tongue-tie on
upper airway mechanics in clinically normal horses
exercising on a treadmill following sternothyrohyoid
Procedure—Upper airway mechanics were measured
with horses exercising on a treadmill at 5, 8,
and 10 m/s 4 weeks after a sternothyrohyoid myectomy
was performed. Pharyngeal and tracheal inspiratory
and expiratory pressures were measured by use
of transnasal pharyngeal and tracheal catheters connected
to differential pressure transducers. Horses
were fitted with a facemask and airflow was measured
by use of a pneumotachograph. Horses underwent
a standardized exercise protocol on a treadmill
at 5, 8, and 10 m/s with and without a tongue-tie in a
randomized cross-over design. Inspiratory and expiratory
airflow, tracheal pressure, and pharyngeal pressure
were measured, and inspiratory and expiratory
resistances were calculated.
Results—We were unable to detect an effect of a
tongue-tie on any of the respiratory variables measured.
Conclusions and Clinical Relevance—Results indicate
that a tongue-tie does not alter upper airway
mechanics following sternothyrohyoid myectomy in
clinically normal horses during exercise. (Am J Vet
Objective—To determine the pharmacokinetics of morphine after IM administration in a clinical population of horses.
Design—Prospective clinical study.
Procedures—Morphine sulfate (0.1 mg/kg [0.045 mg/lb], IM) was administered to horses, and blood samples were obtained at predetermined time points. Plasma morphine concentrations were measured via liquid chromatography and mass spectrometry. In preliminary investigations, samples were obtained from 2 healthy horses at 12 time points (up to 12 hours after drug administration) and analyzed via 2-stage pharmacokinetic analysis. In the clinical phase, blood samples were obtained from 75 hospitalized horses at various times (total, 2 to 3 samples/horse) up to 9 hours after drug administration, and data were analyzed via a naïve pooled pharmacokinetic model.
Results—In the clinical phase, the apparent terminal half-life (t½) of morphine was approximately 1.5 hours, volume of distribution per bioavailability was approximately 4.5 L/kg, and clearance per bioavailability was approximately 35 mL/kg/min. Peak plasma concentration in naïve pooled analysis was 21.6 ng/mL and occurred approximately 4 minutes after administration. Morphine concentrations were below the limit of quantification ≤ 7 hours after administration in 74 horses. Adverse effects attributed to morphine administration were uncommon and considered mild.
Conclusions and Clinical Relevance—The short t½ of morphine in horses suggested frequent administration may be needed to maintain targeted plasma concentrations. Variations in plasma concentrations suggested optimal dosages may differ among horses. The drug was well tolerated at the described dose, but patients receiving morphine should be monitored carefully.
Objective—To determine survival rate and athletic ability after nonsurgical or surgical treatment of cleft palate in horses.
Design—Retrospective case series.
Animals—55 horses with cleft palate.
Procedures—13 of the 55 horses died or were euthanized without treatment and were not included in all analyses. Medical records were reviewed for signalment, history, method of diagnosis, soft or hard palate involvement, type of surgical procedure performed, postoperative complications, and survival to hospital discharge. Information on athletic ability was acquired from race records and follow-up conversations with owners, trainers, or referring veterinarians.
Results—The predominant reason for initial evaluation was milk or feed in the nostrils (60%). The diagnosis was confirmed by means of videoendoscopy of the upper portion of the airway in all cases. Most cases involved the soft palate only (92.7%). Twenty-six of the 55 (47.3%) horses underwent surgical repair, and 12 of these had dehiscence at the caudal edge of the soft palate. Among potential racehorses, 14 of 33 had surgery. Of these, 12 of 14 survived to discharge and 2 horses raced. Among potential racehorses, 10 of 33 were discharged without surgery and 2 of these raced. Among nonracehorses, 12 of 22 underwent surgery and 11 survived to discharge. All horses that were discharged and for which follow-up information was available survived to 2 years of age or older without ill thrift despite dehiscence at the caudal edge of the soft palate and continued mild nasal discharge.
Conclusions and Clinical Relevance—Horses with cleft palate had a higher survival rate than previously reported.