Background: There is limited information relating bronchoalveolar lavage (BAL) cytology and cytokine messenger ribonucleic acid (mRNA) expression in racehorses with inflammatory airway disease (IAD).Hypothesis and Objective: We hypothesize that cytokine expression in BAL cells would correlate with cytology. Thus, we evaluated the mRNA expression of selected cytokines in BAL cells in racehorses with exercise intolerance and lower airway inflammation.Animals: Thirty-one client-owned Standardbred racehorses with exercise intolerance. Methods: Prospective, observational study. Cells were obtained by BAL, and mRNA expression of interleukin (IL)-1b, IL-4, IL-8, tumor necrosis factor (TNF)-a, and interferon (IFN)-g was determined by reverse transcription quantitative polymerase chain reaction (RT-qPCR).Results: Nine horses had normal BAL cell differential cytology (Controls), while 22 horses had evidence of IAD based on BAL fluid cytology. Relative expressions of TNF-a/glyceraldehyde 3-phosphate dehydrogenase (GAPDH; 0.0092 AE 0.010 versus 0.0045 AE 0.005, P 5 .034), IL-4/GAPDH (0.001 AE 0.002 versus 0.0003 AE 0.0003, P 5 .029), and IFN-g/GAPDH (0.0027 AE 0.003 versus 0.0009 AE 0.001, P 5 .028) were greater in horses with IAD compared with controls. Furthermore, IL-4/GAPDH (0.001 AE 0.002 versus 0.0002 AE 0.0003, P o .0001) and IFN-g/GAPDH (0.003 AE 0.003 versus 0.001 AE 0.001, P 5 .002) mRNA expression was increased in horses with increased metachromatic cell counts compared with horses with normal metachromatic cell counts. Only the mRNA expression of IL-1b/GAPDH (1.1 AE 0.7 versus 0.3 AE 0.3, P 5 .045) was increased with airway neutrophilia.Conclusions and Clinical Importance: Differences in gene expression were associated with the presence of IAD and with specific cell types present in airway secretions of Standardbred racehorses with poor performance. These findings suggest that different pathophysiological pathways are implicated in IAD.

Summary Reasons for performing study: Corticosteroids are currently the most effective drugs for the control of ‘heaves’ in horses. However, there is limited information concerning the comparative efficacy and tolerability of the various corticosteroids when used for treatment. Objectives: To compare the therapeutic and side effects of isoflupredone acetate to those of dexamethasone. Methods: A parallel design to compare the effects of 2 corticosteroids by evaluating lung function, serum cortisol and electrolyte concentrations, response to ACTH stimulation and haematology sequentially during a 14 day control period (no treatment), followed by 14 day treatment with either isoflupredone acetate (0.03 mg/kg i.m. s.i.d., n = 6) or dexamethasone (0.04 mg/kg i.v. s.i.d., n = 6) and 7 days of wash‐out. Results: Both drugs were well tolerated clinically and resulted in a significant improvement in lung function that started on Day 3 and lasted for the treatment and wash‐out periods. Blood cortisol levels were significantly decreased during the treatment period in both groups of horses, but a normal response to ACTH stimulation was preserved. Serum electrolytes concentration of horses receiving dexamethasone was not affected by the treatment, but horses treated with isoflupredone demonstrated a significant decrease in serum potassium level. Both treatments induced stress changes in haematology. Conclusions and potential relevance: Isoflupredone is as effective as dexamethasone in the treatment of ‘heaves’‐affected horses but associated with hypokalaemia. Even if clinical signs of hypokalaemia were not observed, this is a side effect that deserves further investigation.

Summary Reasons for performing study: Previous studies have shown that in man ultrasonography is more accurate than radiography for detecting rib fractures. Objectives: To describe clinical, radiographic and ultrasonographic findings related with rib fractures in newborn foals in an equine critical care unit; and to compare diagnostic accuracy of ultrasonography to radiography. Methods: A prospective ultrasonographic study was performed on 29 foals presented to the emergency unit. This study was performed at the Centre Hospitalier Universitaire Vétérinaire (CHUV), University of Montreal. Physical examination as well as radiographic and ultrasonographic examinations were performed. Results: Thoracic radiographs revealed 10 rib fractures in 5 of 26 (19%) foals. Ultrasonography revealed 49 fractures in 19 of 29 (65%) foals of which fillies (n = 13; 68%) were significantly over represented as were fractures to the left thorax (n = 15; 78%). Seventeen of 19 foals (90%) had rib fractures located 3 cm or less from the costochondral junction, the distal part of the rib being displaced laterally in all cases. In 2 foals, where both thoracic radiographs and ultrasonography detected rib fractures, the site of fractures was located on the mid portion of the rib. Rib fractures were detected only by thoracic radiographs in one foal. Sixty‐five percent (32/49) of fractured ribs had a moderate displacement (1–4 mm). Conclusions: Rib fractures are seen frequently in newborn foals in equine critical care units. Ultrasonography is more accurate than radiography and reveals fractures in most patients presented in emergency. The position (costochondral junction) of rib fractures and of the fragments suggest that most thoracic trauma probably occurs during parturition. Potential relevance: Ultrasound imaging increases awareness and improves the diagnosis of rib fractures in newborn foals.

Background: Results of arterial blood gas analysis can be biased by pre-analytical factors, such as time to analysis, syringe type, and temperature during storage. However, the acceptable delay between time of collection and analysis for equine arterial blood gas remains unknown. Hypothesis: Dedicated plastic syringes provide better stability of arterial blood gases than multipurpose plastic syringes. Animals: Eight mares, 1 stallion, and 1 gelding, ages 3 to 10 years old. Methods: Arterial blood samples were collected in a glass syringe, a plastic syringe designated for blood gas collection, and a multipurpose tuberculin plastic syringe. Blood samples were stored at ambient temperature or in iced water. For each sample, partial pressure of oxygen in arterial blood (PaO 2), partial pressure of carbon dioxide in arterial blood (PaCO 2), and pH were measured within a few minutes of collection and at 5, 20, 30, 60, 90, and 120 minutes after collection. Results: Collection into glass syringes stored in iced water provided adequate PaO 2 results for up to 117 6 35 minutes, whereas blood collected in either of the plastic syringes resulted in a variation .10 mm Hg after 10 6 3 to 17 6 2 minutes, depending on the storage conditions. Plastic syringes kept at ambient temperature offered more stability for PaCO 2 analysis because they could be stored up to 83 6 16 minutes without significant variations. Values of pH did not show variations more than 0.02 for the first hour, irrespectively of storage condition. Conclusions and Clinical Importance: Glass syringes placed on ice are preferable for analysis of PaO 2. Blood collected in plastic syringes should be analyzed within 10 minutes, irrespective of the storage temperature, to ensure the accuracy of PaO 2 values.