Measuring O in hypoxic and hyperoxic conditions using dynamic gas mixing with a flow-through indirect calorimeter.

Measurements of gas exchange while breathing gases of different O concentrations are useful in respiratory and exercise physiology. High bias flows required in flow-through indirect calorimetry systems for large animals like exercising horses necessitate the use of inconveniently large reservoirs of mixed gases for making such measurements and can limit the amount of equilibration time that is adequate for steady-state measurements. We obviated the need to use a pre-mixed reservoir of gas in a semi-open flow-through indirect calorimeter by dynamically mixing gases and verified the theoretical accuracy and utility of making such measurements using the mass-balance N-dilution method.

The Effects of Equine Assisted Therapy on Plasma Cortisol and Oxytocin Concentrations and Heart Rate Variability in Horses and Measures of Symptoms of Post-Traumatic Stress Disorder in Veterans.

With the increase in the number of horses being used in Equine-Assisted Activities and Therapies (EAAT) programs and with the increasing concern for animal welfare, it is important to understand the impact of such interventions on the stress level and quality of life for the horses involved. The purpose of the present pilot study was to test the hypothesis that participation in EAAT would acutely alter physiological markers of stress and well-being, including plasma cortisol, plasma oxytocin, and heart rate variability (HRV), in horses and that symptoms of posttraumatic stress disorder (PTSD) would be reduced after five sessions of EAAT in veterans who had previously been diagnosed with PTSD. Nine healthy geldings, of various breeds, ages 10-23 years, conditioned and experienced as therapeutic riding horses, were selected to participate in the study.

Comparison of echocardiographic measurements in elite and nonelite Arabian endurance horses.

Objective: To determine whether echocardiographic variables differed between successful (elite) and less successful (nonelite) Arabian endurance horses.

Animals: 34 Arabian horses that competed in endurance racing.

Procedures: Horses were assigned to either an elite or nonelite group on the basis of results of a previous competition, and a standardized echocardiographic examination was performed on each horse within 1 to 4 weeks after that competition.

Cardiac troponin I concentrations in horses with colic.

Objective: To determine prevalence of myocardial injury in horses with colic on the basis of high concentrations of cardiac troponin I (cTnI), frequency of cardiac arrhythmias within the first 24 to 48 hours after hospital admission or surgery because of colic, and associations between high cTnI concentrations and cardiac arrhythmias, clinical course, and outcome (survival to discharge from hospital vs nonsurvival [death or euthanasia]).

Design: Prospective observational study.

Animals: 111 horses with colic.

A modified laryngoplasty approach promoting ankylosis of the cricoarytenoid joint.

Objective: To perform a modification to the standard laryngoplasty procedure in vivo that would result in ankylosis of the cricoarytenoid (CA) joint, and determine the stability provided to the abducted arytenoid in vitro.

Study Design: Experimental study.

Animals: Horses (n=8).

Cardiac output determination by use of lithium dilution during exercise in horses.

Objective: To compare cardiac output (CO) obtained by the lithium dilution method (LiDCO) with CO calculated from the Fick principle (FickCO), in horses maximally exercising on a high-speed treadmill.

Animals: 13 Thoroughbreds.

Procedures: In part 1 of the study, 5 horses performed a warm-up (walk, trot, and canter) and exercise test (walk, trot, canter, and gallop [90% to 100% maximum oxygen consumption [{VO(2)max}]) with measurements of LiDCO and FickCO obtained simultaneously after 60 seconds at each exercise level, for a total of 7 measurements.

Cardiac output technologies with special reference to the horse.

Critical illness, anesthesia, primary cardiovascular disease, and exercise may result in marked hemodynamic alterations. Measuring cardiac output (CO) is central to defining these alterations for both clinician and researcher. In the past 10 years, several new methods of measuring CO have been developed for the human medical market.

Exercise-induced pulmonary hemorrhage.

EIPH is a condition affecting virtually all horses during intense exercise worldwide. The hemorrhage originates from the pulmonary vasculature and is distributed predominantly bilaterally in the dorsocaudal lung lobes. As the condition progresses, the lung abnormalities extend cranially along the dorsal portions of the lung.

Quantification of clenbuterol in equine plasma, urine and tissue by liquid chromatography coupled on-line with quadrupole time-of-flight mass spectrometry.

Clenbuterol (CBL) is a potent beta(2)-adrenoceptor agonist used for the management of respiratory disorders in the horse. The detection and quantification of CBL can pose a problem due to its potency, the relatively low dose administered to the horse, its slow clearance and low plasma concentrations. Thus, a sensitive method for the quantification and confirmation of CBL in racehorses is required to study its distribution and elimination.