Response to thyrotropin-releasing hormone (TRH) in a horse with hyperthyroidism associated with a functional thyroid adenoma.

A 16-year-old American Paint Horse gelding was presented for evaluation of weight loss and high serum thyroid hormone concentrations resulting from a functional thyroid adenoma. The horse showed no response to a thyrotropin-releasing hormone (TRH) stimulation test. Clinical signs resolved following surgical removal of the adenoma.

Réponse à l'hormone relâchant la thyrotropine (TRH) chez un cheval avec hyperthyroïdisme associé à un adénome thyroïdien fonctionnel. Un cheval American Paint Horse hongre âgé de 16 ans fut présenté pour évaluation à la suite d'une perte de poids et d'une concentration sérique élevée d'hormone thyroïdienne résultant d'un adénome thyroïdien fonctionnel. Le cheval ne démontrait aucune réponse au test de stimulation de l'hormone relâchant la thyrotropine. Les signes cliniques se sont réglés après le retrait chirurgical de l'adénome.(Traduit par Dr Serge Messier).

The use of equine surfactant and positive pressure ventilation to treat a premature alpaca cria with severe hypoventilation and hypercapnia.

A 5-hour-old, premature alpaca cria was presented with failure to nurse, weakness, hypoglycemia, hypercapnia, and respiratory distress. The cria was treated with 3 doses of fresh, crude equine surfactant, positive pressure ventilation, and supplemental intranasal oxygen. Recovery to discharge was uneventful, and the cria regained apparently normal respiratory function. Three years after hospital discharge, the alpaca was a healthy adult.

Utilisation du surfactant équin et de la ventilation à pression positive pour traiter un jeune alpaga atteint d'hypoventilation grave et d'hypercapnie. Un jeune alpaga né prématurément et âgé de 5 heures a été présenté pour une absence d'allaitement, une faiblesse, l'hypoglycémie, l'hypercapnie et la détresse respiratoire. Le jeune a été traité à l'aide de 3 doses de surfactant équin frais et brut, une ventilation à pression positive et de l'oxygène intranasal supplémentaire. Le rétablissement et le congé se sont bien passés et la fonction respiratoire normale du jeune s'est apparemment rétablie. Trois ans après le congé de l'hôpital, l'alpaga était un adulte en santé.(Traduit par Isabelle Vallières).

Large intra-abdominal abscess treatment by marsupialization in 2 alpacas.

OBJECTIVES: To report the clinical signs, diagnostic findings, surgical treatment, postoperative complications, and long-term outcome in 2 adult alpacas with large intra-abdominal abscesses treated by marsupialization of the abscess to the ventral body wall. STUDY DESIGN: Clinical report. ANIMALS: Alpacas (n = 2). METHODS: Two alpacas each presented with decreased appetite, lethargy, poor body condition, and marked abdominal distension. A complete physical examination, abdominal radiography, and ultrasonography confirmed the presence of large intra-abdominal abscesses. Streptococcus equi ssp. zooepidemicus was cultured from the abscess fluid of alpaca 1, and a Gram-negative bacillus from alpaca 2. RESULTS: Both alpacas had exploratory celiotomy with marsupialization of the abdominal abscess to the ventral body wall. Postoperatively, alpacas were administered systemic antibiotics and non-steroidal anti-inflammatory drugs, and the abscesses were lavaged for several days. Alpaca 2 required a second surgical procedure. The abscesses ultimately resolved in both alpacas, with body wall hernia formation as the only major complication. Both alpacas had good long-term outcomes. CONCLUSION: Marsupialization to the ventral abdominal wall with concurrent antibiotic treatment should be considered as a treatment option for alpacas with large intra-abdominal abscesses in which complete surgical resection of the abscess is not possible. An abdominal wall hernia can result from this procedure, and clients should be informed of this potential complication before surgery.

The effect of agility exercise on eicosanoid excretion, oxidant status, and plasma lactate in dogs.

BACKGROUND: The objective was to determine the effects of agility exercise on dogs of different skill levels with respect to urinary eicosanoids, urinary 15F2t-isoprostane (lipid peroxidation marker) and hematological/biochemical changes in plasma. Fifteen adult dogs had blood and urine samples obtained prior to, immediately and 4-hours following an agility exercise. RESULTS: Hematocrit, red blood cells (RBC), albumin, and hemoglobin increased following exercise, with greatest increases correlating to increased skill group (novice, intermediate, masters); at 4-hours post-exercise, hematocrit, RBC, and hemoglobin were decreased. Phosphorus increased following exercise with the greatest increase in novice and intermediates. Plasma lactate increased 3.6-fold in masters, 3.2-fold in intermediates, and 1.2-fold in novice dogs. Urine thromboxane B2 (TXB2) more than tripled 4-hours post-exercise while 6-keto prostaglandin F1α (PGF1α, prostacyclin metabolite), prostaglandin E2 metabolites (13,14-dihydro-15-keto-prostaglandin A2 and 13,14-dihydro-15-keto-prostaglandin E2), and 13,14-dihydro-15-keto prostaglandin F2α were unaffected as determined by a competitive enzyme immunoassay and standardized by division with urine creatinine. Urine 15F2t-isoprostane increased insignificantly. CONCLUSIONS: Alterations in the plasma post-exercise were likely due to hemoconcentration from insensible water loss, splenic contraction and sympathetic stimulation while 4-hours later autohemodilution reduced RBC parameters. Elevations in plasma lactate and urinary TXB2 correlated with advanced skill level/speed of the dogs.

Premature parturition, edema, and ascites in an alpaca infected with Anaplasma phagocytophilum.

An 8-year-old alpaca was presented for fever, anorexia, edema, ascites, and premature parturition. She was determined to have Anaplasma phagocytophilum infection based on positive blood polymerase chain reaction (PCR) and positive acute and convalescent serum titers. Antibiotics and supportive therapies were administered and the alpaca made a complete recovery.

Parturition prématurée, œdème et ascite chez un alpaga infecté parAnaplasma phagocytophilum. Un alpaga femelle âgé de 8 ans a été présenté pour une fièvre, de l'anorexie, de l'œdème, de l'ascite et une parturition prématurée. On a déterminé qu'elle avait une infection à Anaplasma phagocytophilum en se fondant sur le résultat positif d'un test d'amplification en chaîne par la polymérase (PCR) effectué sur un échantillon sanguin et des titres sériques aigus et convalescents positifs. Des antibiotiques et des thérapies de soutien ont été administrés et l'alpaga s'est rétabli complètement.(Traduit par Isabelle Vallières).

3 Dimensional photonic scans for measuring body volume and muscle mass in the standing horse.

REASONS FOR PERFORMING STUDY: Although muscle mass strongly influences performance, there is currently no effective means to measure the 3-dimensional muscle mass of horses. We evaluated a 3-dimensional (3D) scanning methodology for its ability to quantify torso and hindquarter volumes as a proxy for regional muscle mass in horses. OBJECTIVES: Determine the repeatability of 3D scanning volume (V) measurements and their correlation to body weight, estimated body volume and muscle/fat ultrasound (US) depth. METHODS: Handheld 3D photonic scans were performed on 16 Quarter Horses of known body weight 56 days apart (n = 32 scans) with each scan performed in duplicate (n = 32 replicates). Tail head fat, gluteal and longissimus dorsi muscle depths were measured using US. Processed scans were cropped to isolate hindquarter (above hock, caudal to tuber coxae) and torso (hindquarter plus dorsal thoracolumbar region) segments and algorithms used to calculate V. Torso and hindquarter volume were correlated with body weight and US using Pearson's correlation and with estimated torso volume (50% body weight / body density) with Bland-Altman analysis. RESULTS: Scans took 2 min with < 3.5% error for duplicate scans. Torso volume (R = 0.90, P< 0.001) and hindquarter volume (R = 0.82, P< 0.001) strongly correlated with body weight and estimated BV (R = 0.91) with low bias. Torso volume moderately correlated to mean muscle US depth (R = 0.4, P< 0.05) and tail head fat (R = 0.42, P< 0.01). Mean muscle US depth moderately correlated to body weight (R = 0.50, P< 0.01). MAIN LIMITATIONS: 3D Scans determine body volume not muscle volume. CONCLUSIONS: The hand-held 3D scan provided a rapid repeatable assessment of torso and hindquarter volume strongly correlated to body weight and estimated volume. Superimposition of regional scans and volume measures could provide a practical means to follow muscle development when tail head fat depth remain constant.

Pharmacokinetics and bioavailability of metformin in horses.

OBJECTIVE: To determine pharmacokinetics and oral bioavailability of metformin in healthy horses. ANIMALS: 4 adult horses. PROCEDURES: 6 g of metformin was administered 3 times IV and PO (fed and unfed) to each horse, by use of a crossover design, with a 1-week washout period between treatments. Plasma metformin concentration was determined via high-pressure liquid chromatography. RESULTS: Mean +/- SD distribution half-life of metformin following IV administration was 24.9 +/- 0.4 minutes with a volume of distribution of 0.3 +/- 0.1 L/kg. Mean area under the curve was 20.9 +/- 2.0 h.microg/mL for IV administration; PO administration resulted in area under the curves of 1.6 +/- 0.4 h.microg/mL in unfed horses and 0.8 +/- 0.2 h.microg/mL in fed horses. Bioavailability was determined to be approximately 7.1 +/- 1.5% in unfed horses and 3.9 +/- 1.0% in fed horses. The maximal concentration following PO administration in unfed horses was 0.4 +/- 0.1 microg/mL with a time at maximal concentration of 0.9 +/- 0.1 hours. In fed horses, maximal concentration was reduced to 0.3 +/- 0.04 microg/mL with a time at maximal concentration at 1.3 +/- 0.3 hours. CONCLUSIONS AND CLINICAL RELEVANCE: The low bioavailability of metformin may explain the reported lack of clinical success in improving insulin sensitivity with metformin treatment in horses. Dosages and dose intervals previously used may have been insufficient to achieve plasma concentrations of drug comparable to the therapeutic range achieved in humans. Therefore, a larger and more frequently administered dose may be required to fully evaluate efficacy of metformin in horses.

Optimal diet of horses with chronic exertional myopathies.

Chronic exertional rhabdomyolysis represents a syndrome of recurrent exercise-associated muscle damage in horses that arises from a variety of etiologies. Major advances have been made in the understanding of the pathophysiology of this disease, and causative genetic defects have been recently identified for two conditions-polysaccharide storage myopathy of quarter horses, paints, warm bloods, and draft breeds. Dietary management in combination with a regular exercise regimen comprises the most effective means for control of clinical signs.

Impact of alpha-tocopherol deficiency and supplementation on sacrocaudalis and gluteal muscle fiber histopathology and morphology in horses.

BACKGROUND: A subset of horses deficient in alpha-tocopherol (α-TP) develop muscle atrophy and vitamin E-responsive myopathy (VEM) characterized by mitochondrial alterations in the sacrocaudalis dorsalis medialis muscle (SC). OBJECTIVES: To quantify muscle histopathologic abnormalities in subclinical α-TP deficient horses before and after α-TP supplementation and compare with retrospective (r)VEM cases. ANIMALS: Prospective study; 16 healthy α-TP-deficient Quarter Horses. Retrospective study; 10 retrospective vitamin E-responsive myopathy (rVEM) cases . METHODS: Blood, SC, and gluteus medius (GM) biopsy specimens were obtained before (day 0) and 56 days after 5000 IU/450 kg horse/day PO water dispersible liquid α-TP (n = 8) or control (n = 8). Muscle fiber morphology and mitochondrial alterations were compared in samples from days 0 and 56 and in rVEM cases. RESULTS: Mitochondrial alterations more common than our reference range (<2.5% affected fibers) were present in 3/8 control and 4/8 treatment horses on day 0 in SC but not in GM (mean, 2.2; range, 0%-10% of fibers). Supplementation with α-TP for 56 days did not change the percentage of fibers with mitochondrial alterations or anguloid atrophy, or fiber size in GM or SC. Clinical rVEM horses had significantly more mitochondrial alterations (rVEM SC, 13% ± 7%; GM, 3% ± 2%) and anguloid atrophy compared to subclinical day 0 horses. CONCLUSIONS AND CLINICAL IMPORTANCE: Clinically normal α-TP-deficient horses can have mitochondrial alterations in the SC that are less severe than in atrophied VEM cases and do not resolve after 56 days of α-TP supplementation. Preventing α-TP deficiency may be of long-term importance for mitochondrial viability.

Insulin sensitivity in Belgian horses with polysaccharide storage myopathy.

OBJECTIVE: To determine insulin sensitivity, proportions of muscle fiber types, and activities of glycogenolytic and glycolytic enzymes in Belgians with and without polysaccharide storage myopathy (PSSM). ANIMALS: 10 Quarter Horses (QHs) and 103 Belgians in which PSSM status had been determined. PROCEDURES: To determine insulin sensitivity, a hyperinsulinemic euglycemic clamp (HEC) technique was used in 5 Belgians with PSSM and 5 Belgians without PSSM. Insulin was infused i.v. at 3 mU/min/kg for 3 hours, and concentrations of blood glucose and plasma insulin were determined throughout. An i.v. infusion of glucose was administered to maintain blood glucose concentration at 100 mg/dL. Activities of glycogenolytic and glycolytic enzymes were assessed in snap-frozen biopsy specimens of gluteus medius muscle obtained from 4 Belgians with PSSM and 5 Belgians without PSSM. Percentages of type 1, 2a, and 2b muscle fibers were determined via evaluation of >or= 250 muscle fibers in biopsy specimens obtained from each Belgian used in the aforementioned studies and from 10 QHs (5 with PSSM and 5 without PSSM). RESULTS: Belgians with and without PSSM were not significantly different with respect to whole-body insulin sensitivity, muscle activities of glycogenolytic and glycolytic enzymes, or proportions of muscle fiber types. However, Belgians had an increased proportion of type 2a and decreased proportion of type 2b muscle fibers, compared with proportions in QHs, regardless of PSSM status. CONCLUSIONS AND CLINICAL RELEVANCE: PSSM in Belgians may be attributable to excessive glycogen synthesis rather than decreased glycogen utilization or enhanced glucose uptake into muscle cells.

Cryptosporidiosis in 20 alpaca crias.

CASE DESCRIPTION: 20 alpaca crias (13 females and 7 males) were examined for diarrhea (n=20), weight loss (15), and poor appetite (5). Fourteen crias were between 8 and 18 days of age at time of admission. CLINICAL FINDINGS: Cryptosporidiosis was diagnosed in all crias. Common biochemical abnormalities included acidemia, hyperlactemia, azotemia, and hyperglycemia and increases in aspartate transaminase and gamma-glutamyltransferase activities. Serum sodium and chloride concentrations were high or low. Other potential gastrointestinal tract pathogens were identified in only 7 crias. TREATMENT AND OUTCOME: Supportive care was instituted, including i.v. administration of fluids with partial parenteral administration of nutrients (n=19 crias), antimicrobials (19), supplemental orally administered nutrients (11), administration of plasma (10), and insulin treatment (9). Other palliative treatments used by attending clinicians were sucralfate, flunixin meglumine, vitamin A/D/E/B complex, antiparasitic agents, antidiarrheal agents, and azithromycin. Three crias with inadequate urine production and severe azotemia were treated with furosemide administered i.v. as a bolus or as a constant-rate infusion. Treatment resulted in a successful outcome in 16 of 20 crias. Weight loss and refractory azotemia were common in nonsurvivors but not in surviving crias. CLINICAL RELEVANCE: Findings suggested that Cryptosporidium spp may be a diarrheal pathogen of unweaned alpaca crias that may be more widespread than has been recognized and can become endemic on some farms. Metabolic derangements were unpredictable and should be determined by biochemical analysis before fluid and electrolyte replacement is initiated. Cryptosporidiosis has zoonotic potential, and the infection can be self-limiting in alpacas receiving supportive treatment.

Eimeria macusaniensis infection in 15 llamas and 34 alpacas.

CASE DESCRIPTION: 15 llamas and 34 alpacas between 3 weeks and 18 years old with fecal oocysts or intestinal coccidial stages morphologically consistent with Eimeria macusaniensis were examined. Nineteen of the camelids were admitted dead, and 30 were admitted alive. Camelids admitted alive accounted for 5.5% of all camelid admissions during this period. CLINICAL FINDINGS: Many severely affected camelids had signs of lethargy, weight loss, decreased appetite, and diarrhea. Camelids with clinical infection also commonly had evidence of circulatory shock, fat mobilization, and protein loss. Nonsurviving camelids also had evidence of shock, edema, bile stasis, renal insufficiency, hepatic lipidosis, muscle damage, relative hemoconcentration, and sepsis. Postmortem examination frequently revealed complete, segmental replacement of the mucosa of the distal portion of the jejunum with coccidial meronts and gamonts. For 17 of 42 camelids, results of initial fecal examinations for E macusaniensis were negative. TREATMENT AND OUTCOME: Most camelids admitted alive were treated with amprolium hydrochloride, plasma, and various supportive treatments. Fifteen of the 30 treated camelids died or were euthanized. CLINICAL RELEVANCE: Findings suggest that E macusaniensis may be an important gastrointestinal tract pathogen in camelids of all ages. Clinical signs were frequently nonspecific and were often evident before results of fecal examinations for the parasite were positive. As with other coccidia, severity of disease was probably related to ingested dose, host immunity, and other factors. The clinical and herd relevance of positive fecal examination results must be determined.

Serum creatine kinase response to exercise during dexamethasone-induced insulin resistance in Quarter Horses with polysaccharide storage myopathy.

OBJECTIVE: To determine effects of dexamethasone on insulin sensitivity, serum creatine kinase (CK) activity 4 hours after exercise, and muscle glycogen concentration in Quarter Horses with polysaccharide storage myopathy (PSSM). ANIMALS: 4 adult Quarter Horses with PSSM. PROCEDURE: A 2 x 2 crossover design was used with dexamethasone (0.08 mg/kg) or saline (0.9% NaCl) solution administered IV every 48 hours. Horses were exercised on a treadmill daily for 3 wk/treatment with a 2-week washout period between treatments. Serum CK activity was measured daily 4 hours after exercise. At the end of each treatment period, serum cortisol concentrations were measured, a hyperinsulinemic euglycemic clamp (HEC) technique was performed, and muscle glycogen content was determined. RESULTS: Mean +/- SEM serum cortisol concentration was significantly lower after 48 hours for the dexamethasone treatment (0.38 +/- 0.08 mg/dL), compared with the saline treatment (4.15 +/- 0.40 mg/dL). Dexamethasone significantly decreased the rate of glucose infusion necessary to maintain euglycemia during the HEC technique, compared with the saline treatment. Muscle glycogen concentrations and mean CK activity after exercise were not altered by dexamethasone treatment, compared with the saline treatment. CONCLUSIONS AND CLINICAL RELEVANCE: Dexamethasone significantly reduced whole-body insulin-stimulated glucose uptake in Quarter Horses with PSSM after a 3-week period but did not diminish serum CK response to exercise or muscle glycogen concentrations in these 4 horses. Therefore, a decrease in glucose uptake for 3 weeks did not appear to alleviate exertional rhabdomyolysis in these horses. It is possible that long-term treatment may yield other results.

Prevalences and clinical signs of polysaccharide storage myopathy and shivers in Belgian draft horses.

OBJECTIVE: To determine prevalences of polysaccharide storage myopathy (PSSM) and shivers in Belgian Draft Horses (BDHs) and determine whether there was an association between these 2 conditions. DESIGN: Prospective cohort study. ANIMALS: 103 BDHs > 1 year old. PROCEDURE: Owners were questioned regarding clinical signs of PSSM, shivers, and hindquarter weakness, defined as poor hindquarter muscling and lack of propulsion. Blood samples were collected for determination of serum creatine kinase and aspartate transferase activities and serum selenium and vitamin E concentrations. A biopsy sample from the gluteus medius muscle was submitted for histologic, histochemical, and biochemical analysis. A diagnosis of PSSM was made if abnormal amylase-resistant polysaccharide inclusions were seen histologically. RESULTS: 37 (36%) horses had PSSM and 19 (18%) had shivers, but only 6 (6%) had both PSSM and shivers, whereas 31 (30%) had PSSM alone, 13 (13%) had shivers alone, and 53 (51%) had neither, and a significant association between PSSM and shivers was not detected. Hindquarter weakness was found in 30 horses. Only 13 of 37 (35%) horses with PSSM and 11 of 19 (58%) horses with shivers had hindquarter weakness. Serum creatine kinase and aspartate transferase activities and serum selenium and vitamin E concentrations were not significantly different between horses with and without PSSM or between horses with and without shivers. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that PSSM and shivers are common but unrelated disorders in BDHs.

Effects of training at a walk on conventional and underwater treadmills on fiber properties and metabolic responses of superficial digital flexor and gluteal muscles to high-speed exercise in horses.

OBJECTIVE: To compare effects of training on conventional and underwater treadmills on fiber properties and metabolic responses of the superficial digital flexor (SDF) and gluteal muscles to high-speed exercise in horses. SAMPLE: 6 unconditioned Quarter Horse-type horses. PROCEDURES: 6 horses were walked on underwater and conventional treadmills for 5 d/wk (maximum, 40 min/d) for 8 weeks in a randomized crossover design (60-day detraining period). Horses underwent a standardized exercise test (SET) at high speed before and after training. Analyte concentrations and fiber characteristics were measured in muscle biopsy specimens obtained from horses before and after each SET. RESULTS: Lactate concentration increased 2- to 3-fold in SDF and gluteal muscle after SETs. No training effect was identified on muscle fiber type composition, type II fiber diameter, muscle analyte concentrations, blood lactate concentration, or heart rate responses. Maximum diameters of type I fibers decreased significantly in gluteal muscle with conventional treadmill training and decreased in SDF muscle with both types of training, with maximum diameters greater for horses after underwater versus conventional treadmill training. No change was identified in minimum fiber diameters. CONCLUSIONS AND CLINICAL RELEVANCE: SETs involving near-maximal exertion resulted in an anaerobic response in SDF and gluteal muscles of horses. Eight weeks of conventional or underwater treadmill training resulted in minor changes in type I muscle fiber sizes, with no effect on muscle metabolic or heart rate responses to SETs. After rehabilitation involving underwater treadmills, training at progressing speeds is recommended for horses to develop the required fitness for speed work.

Necropsy findings in 62 opportunistically collected free-ranging moose (Alces alces) from Minnesota, USA (2003-13).

The Minnesota, US moose population has declined dramatically since the 1990s. All 54 carcasses of moose that died of unknown cause or were euthanized by gun shot by tribal or Department of Natural Resources personnel because of perceived signs of illness between 2003 and 2013 and eight carcasses of moose that died from vehicular accidents between 2009 and 2013 were submitted to the Minnesota Veterinary Diagnostic Laboratory and included in our study. The majority of the animals were underweight or cachectic (n = 53; 85%). Neural migration presumably by Parelaphostrongylus tenuis was a common finding (n = 28; 45%). Moderate to marked Dermacentor albipictus ("winter tick") ectoparasitism with widespread alopecia was the cause or a contributing cause of death in 14 (23%) cases in which grossly apparent anemia was associated with exhaustion of hepatic iron stores. Hepatic lesions associated with Fascioloides magna were common (n = 37; 60%) but were unlikely to be the cause of death. Environmental factors favoring winter tick survival, habitat expansion of white-tailed deer (Odocoileus virginianus), and the survival of terrestrial and aquatic snails (serving as intermediate hosts for P. tenuis and F. magna), might contribute to the seemingly severe parasitic burden in Minnesota's moose population.

Epidemiologic characteristics and management of polysaccharide storage myopathy in Quarter Horses.

OBJECTIVE: To characterize onset and clinical signs of polysaccharide storage myopathy (PSSM) in a well-defined population of affected Quarter Horses, identify risk factors for PSSM, determine compliance of owners to dietary and exercise recommendations, and evaluate the efficacy of dietary and exercise recommendations. ANIMALS: 40 Quarter Horses with PSSM and 37 unaffected control horses. PROCEDURES: Owners of horses with PSSM completed a retrospective questionnaire concerning their horse's condition. RESULTS: Between horses with PSSM and control horses, no significant differences were found in sex distribution (21 vs 15 females and 16 vs 22 males, respectively), temperament, muscle build, diet, or amount of turnout. In horses with PSSM, signs of muscle stiffness, muscle fasciculations, sweating, exercise intolerance, weakness, muscle wasting, reluctance to move, colic, abnormal gait, recumbency, lameness, and swollen muscles began between the age of 1 day and 14 years (mean age, 4.9 +/- 3.5 years). Five horses with PSSM developed acute muscle atrophy. Sixty-three percent (25/40) of owners fed the recommended diet, 55% (22/40) provided regular exercise, and 40% (16/40) followed both dietary and exercise recommendations. Owners of affected horses for which a decrease in severity or frequency of PSSM was not found did not follow the exercise, dietary, or both recommendations. All horses for which both dietary and exercise recommendations were followed had improvement in signs of PSSM. CONCLUSIONS AND CLINICAL RELEVANCE: n addition to exertional rhabdomyolysis, signs of PSSM include acute muscle atrophy and gait abnormalities. It appears that PSSM can be managed by following dietary recommendations combined with gradual increases in daily exercise.

Impact of walking surface on the range of motion of equine distal limb joints for rehabilitation purposes.

The aim of this study was to evaluate the effect of three footing surfaces on the flexion/extension, and range of motion (ROM) of the carpus, tarsus and fetlocks in the horse. The percentage of stride spent in the stance phase of sound horses at the walk was also measured. Nine sound horses were walked on hard ground (HD), soft ground (SF) and a land treadmill (LT), and five complete gait cycles were recorded by a digital video camera. Retro-reflective markers were placed on the skin at four anatomical locations on the left fore and hind limbs, and data were analyzed using two-dimensional (2D) motion-analysis software. Maximal flexion/extension angles and range of motion were calculated for each joint, and the percentage of the stride spent in stance phase was determined for each stride. Maximal flexion of the tarsus and hind fetlock was greater on LT and SF compared to HD, while maximal flexion of the carpus was greater on LT compared to HD and SF. Maximal extension of the carpus was greater on HD compared to SF and LT, maximal extension of the tarsus was greater on HD and SF compared to LT, and maximal extension of the forelimb and hind limb fetlocks was greater on LT compared to HD and SF. The greatest overall ROM of the carpus and fetlocks was achieved on LT, while the greatest overall ROM of the tarsus was achieved on SF. The stance percentage of the stride for the hind limb was significantly different between all surfaces. In conclusion, walking surface influences flexion/extension of the carpus, tarsus and fetlocks in healthy horses, which should be considered when walking equine rehabilitation cases.

Evaluation of insulin secretion and action in New World camelids.

OBJECTIVE: To measure and compare insulin secretion and sensitivity in healthy alpacas and llamas via glucose clamping techniques. ANIMALS: 8 llamas and 8 alpacas. PROCEDURES: Hyperinsulinemic euglycemic clamping (HEC) and hyperglycemic clamping (HGC) were performed on each camelid in a crossover design with a minimum 48-hour washout period between clamping procedures. The HEC technique was performed to measure insulin sensitivity. Insulin was infused IV at 6 mU/min/kg for 4 hours, and an IV infusion of glucose was adjusted to maintain blood glucose concentration at 150 mg/dL. Concentrations of blood glucose and plasma insulin were determined throughout. The HGC technique was performed to assess insulin secretion in response to exogenous glucose infusion. An IV infusion of glucose was administered to maintain blood glucose concentration at 320 mg/dL for 3 hours, and concentrations of blood glucose and plasma insulin were determined throughout. RESULTS: Alpacas and llamas were not significantly different with respect to whole-body insulin sensitivity during HEC or in pancreatic ß-cell response during HGC. Alpacas and llamas had markedly lower insulin sensitivity during HEC and markedly lower pancreatic ß-cell response during HGC, in comparison with many other species. CONCLUSIONS AND CLINICAL RELEVANCE: New World camelids had lower glucose-induced insulin secretion and marked insulin resistance in comparison with other species. This likely contributes to the disorders of fat and glucose metabolism that are common to camelids.

Effect of water depth on amount of flexion and extension of joints of the distal aspects of the limbs in healthy horses walking on an underwater treadmill.

OBJECTIVE: To determine the maximum amount of flexion and extension of the carpal, tarsal, metacarpophalangeal, and metatarsophalangeal joints and the percentage duration of the stance and swing phases of the stride for horses walking on an underwater treadmill in various water depths. ANIMALS: 9 healthy adult horses. PROCEDURES: Zinc oxide markers were placed on the forelimbs and hind limbs of the horses. Video was recorded of horses walking (0.9 m/s) on an underwater treadmill during baseline conditions (< 1 cm of water) or in various amounts of water (level of the metatarsophalangeal, tarsal, and stifle joints). Maximum amount of joint flexion and extension, range of motion (ROM), and the percentage durations of the stance and swing phases of the stride were determined with 2-D motion analysis software. RESULTS: The ROM was greater for all evaluated joints in any amount of water versus ROM for joints in baseline conditions (primarily because of increases in amount of joint flexion). The greatest ROM for carpal joints was detected in a tarsal joint water depth, for tarsal joints in a stifle joint water depth, and for metacarpophalangeal and metatarsophalangeal joints in metatarsophalangeal and tarsal joint water depths. As water depth increased, the percentage durations of the stance and swing phases of the stride significantly decreased and increased, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Results of this study suggested that exercise on an underwater treadmill is useful for increasing the ROM of various joints of horses during rehabilitation and that the depth of water affects the amount of flexion and extension of joints.