Summary Background Inhaled corticosteroids are effective in the treatment of equine asthma. A recent study reported that nebulisation of injectable dexamethasone had low systemic bioavailability in healthy horses and could represent a cost‐effective therapy for equine inflammatory lung diseases. Objectives To determine the effects of dexamethasone nebulisation on lung function in severe asthmatic horses. It was hypothesised that dexamethasone administered by nebulisation would be more effective than the same dose administered orally. Study design Randomised blinded experimental study in severe asthmatic horses. Methods Twelve severe asthmatic horses in clinical exacerbation were randomly assigned to treatment with 5 mg of dexamethasone sodium phosphate by nebulisation (n = 6) or by oral administration (n = 6), once daily for 7 days. Lung function was evaluated at baseline, after four treatment days (D4) and 24 h after the last dose (D8). The presence of residual bronchospasm was assessed on D8 with N‐butylscopolammonium bromide administration (0.3 mg/kg i.v.). A respiratory clinical score was performed daily. Serum cortisol concentration was measured at baseline, D4 and D8. Results The pulmonary elastance was unchanged in both groups while pulmonary resistance was significantly improved in the oral group on D8 (mean reduction in 1 cm H2O/L/s [CI: 0.34–1.65, P = 0.003]). All horses had residual bronchospasm at the end of the study. There was a group difference in the respiratory clinical score as it was significantly reduced in the oral group, from D5 to D8. Serum cortisol concentration decreased in all subjects. Main limitations Low number of horses and lack of placebo group. Conclusions Considering the lack of improvement of lung function and the hypothalamic‐pituitary‐adrenal axis suppression, the results of this study do not support aerosolisation of an injectable form of dexamethasone for the treatment of severe equine asthma at the dose and with the nebuliser evaluated.

Summary Background Locally administered corticosteroids are commonly used to treat joint diseases in sport and racehorses. As they are also the most potent drugs for the treatment of equine asthma, we hypothesised that the intra‐articular corticosteroids used to treat joint diseases also improve the lung function in horses with severe asthma, thus potentially delaying the diagnosis of this common lung condition. Objectives To compare the effects of intra‐articular (IA) and intramuscular (IM) triamcinolone acetonide (TA) on lung function in horses with severe asthma. Study design Randomised and controlled experiment on asthma‐prone research animals. Methods Horses with severe asthma in clinical exacerbation were given either 20 mg of TA in both tarsocrural joints (n = 5; 40 mg/horse) or 40 mg of TA intramuscularly (n = 5). Lung function and TA serum concentrations were measured weekly for 35 days. TA serum concentrations were also evaluated on day 3. Results The pulmonary resistance (RL) and elastance (EL) values decreased by day 7 in the IA group (P<0.0001 and P = 0.003, respectively) and by day 14 in the IM group (P = 0.002 and 0.03, respectively). Lung function was improved up to days 21 and 28 in the IA and IM groups, respectively, when compared with baseline. TA serum levels were below the quantification limit (100 pg/ml) for 4 and 3 of the 5 horses in the IA and IM groups, respectively, on day 7. The area under the curve for RL, EL and the serum concentrations of TA were similar in both groups. Main limitations The response of horses with severe asthma might differ from that of high‐performance horses with mild/moderate asthma. Conclusions Intra‐articular administration of TA improves lung function in horses with severe asthma, an effect that persists when TA serum concentration is below the quantification level that is employed as a threshold by the International Association of Racing Commissioners.

Objective Evaluate the effect of repeated doses of topical 1% cyclopentolate hydrochloride alone and in combination with topical 2.5% phenylephrine on pupil diameter (PD), tear production (STT‐1), intraocular pressure (IOP), digestive function (gut motility and feces production), and heart rate (HR). Animal studied: Six healthy mares. Procedures In a prospective, randomized, controlled, and crossover design study, the left eye of six healthy mares was administered 0.2 mL of cyclopentolate alone and in combination with 0.2 mL of phenylephrine. The drugs were administered 3 times a day for 1 day, twice a day for 1 day, and then once a day for 2 days, as commonly used in practice. Daily and two days after the last topical drug administration, HR, digestive auscultation, feces production, STT‐1, IOP, and PD were recorded. Results The cyclopentolate alone significantly increased the horizontal and vertical PD of the treated eye from day 2 to day 6 (p < .0001) compared with the baseline value. The combination with topical phenylephrine did not have any additional effect on mydriasis compare with the cyclopentolate alone. The other ocular and digestive parameters were not affected by repeated doses of cyclopentolate alone or combined. Conclusions Repeated administration of cyclopentolate alone or combined with phenylephrine induce a significant mydriasis for at least 48 h after the last administration in normal horses’ eyes, and do not affect STT‐1, IOP, digestive function, and HR. The phenylephrine combined with the cyclopentolate did not potentiate the pupil dilation when compared with cyclopentolate alone in healthy horses.

SummaryA 22‐year‐old pony mare was presented at the Equine Hospital of the Faculty of Veterinary Medicine with a pedunculated exuberant granulation tissue (EGT) located at the lateral bulbar conjunctiva of the right eye. The granulation tissue, diagnosed by histology, grew over three and a half weeks after a superior and inferior Gundersen inlay flap procedure. The pony's underlying ocular pathology was diffuse corneal oedema, suspected to be related to immune‐mediated keratitis affecting the endothelium. Despite several surgical resections, topical corticosteroid treatment, intralesional injection of methylprednisolone acetate and electrosurgical cauterisation, the combination of a ligature at the peduncle base of the mass, intralesional injection of methylprednisolone acetate and removal of the facemask seemed to be the most efficient treatment. The mass did not recur after 33 months of follow‐up. Similar healing tissue has been reported, secondary to surgical ophthalmic procedures in human medicine, in which it is called a conjunctival pyogenic granuloma (CPG).

Background There is a remodeling of the central airways in horses with severe asthma but whether a similar process occurs in horses with the mild or moderate asthma (MMA) is unknown. Objectives To evaluate lesions affecting the central airways of horses with MMA. Animals Twelve horses with MMA and 8 control horses. Methods Case‐control retrospective study of horses classified as MMA affected or controls based on history and bronchoalveolar lavage fluid cytology. Endobronchial biopsies were analyzed using histomorphometry and a semiquantitative histologic scoring system. Results Histomorphometry identified epithelial hyperplasia (47 μm 2 /μm [34‐57 μm 2 /μm]; P = .02), a thickened lamina propria (166 μm [73‐336 μm]; P = .04), and smooth muscle fibrosis (42% [33%‐78%]; P = .04) in horses with MMA when compared to controls horses (24 μm 2 /μm [21‐80 μm 2 /μm]; 76 μm [36‐176 μm]; and 33% [26%‐52%], respectively). The semiquantitative score results indicated, in horses with MMA, the presence of epithelial hyperplasia (7 of the 12 horses with MMA and only 1 of the 8 control horses had a score of 1/1), and submucosal inflammatory leucocytes in the central airway (11 of the 12 horses with MMA and only 4 of the 8 control horses had a score ≥ 1/2). Conclusions and Clinical Relevance Tissue remodeling of the bronchial lamina propria, epithelium, and smooth muscle was present in horses with MMA.