Small intestinal strangulation associated with ischaemia-reperfusion injury (IRI) is common in horses. In laboratory animals IRI can be ameliorated by ischaemic preconditioning (IPC) and pharmacological preconditioning (PPC) with dexmedetomidine. The aim of this study was to determine the effect of PPC with dexmedetomidine or IPC in an equine model of small intestinal ischaemia-reperfusion (IR). In a randomized controlled experimental trial, 15 horses were assigned to three groups: control (C), IPC, and PPC with dexmedetomidine (DEX). All horses were placed under general anaesthesia and 90% jejunal ischaemia was induced for 90 minutes, followed 30 minutes of reperfusion. In group IPC, three short bouts of ischaemia and reperfusion were implemented, and group DEX received a continuous rate infusion of dexmedetomidine prior to the main ischaemia. Jejunal biopsies were collected before ischaemia (P), and at the end of ischaemia (I) and reperfusion (R). Mucosal injury was assessed by the Chiu-Score, inflammatory cells were stained by cytosolic calprotectin. The degree of apoptosis and cell necrosis was assessed by cleaved-caspase-3 and TUNEL. Parametric data were analyzed by two-way ANOVA for repeated measurements followed by Dunnetts t-test. Non parametric data were compared between groups at the different time points by a Kruskal-Wallis-Test and a Wilcoxon-2-Sample-test. The mucosal injury score increased during I in all groups. After reperfusion, IRI further progressed in group C, but not in IPC and DEX. In all groups the number of cleaved caspase-3 and TUNEL positive cells increased from P to I. The number of TUNEL positive cells were lower in group DEX compared to group C after I and R. Infiltration with calprotectin positive cells was less pronounced in group DEX compared to group C, whereas in group IPC more calprotectin positive cells were seen. In conclusion, IPC and DEX exert protective effects in experimental small intestinal ischaemia in horses.

Pain assessment is very important for monitoring welfare and quality of life in horses. To date, no studies have described pain scales for objective assessment of pain in foals. Studies in other species have shown that facial expression can be used in neonatal animals for objective assessment of acute pain. The aim of the current study was to adapt a facial expression-based pain scale for assessment of acute pain in mature horses for valid pain assessment in foals. The scale was applied to fifty-nine foals (20 patients and 39 healthy controls); animals were assessed from video recordings (30–60 s) by 3 observers, who were blinded for the condition of the animals. Patients were diagnosed with acute health problems by means of clinical examination and additional diagnostic procedures. EQUUS-FAP FOAL (Equine Utrecht University Scale for Facial Assessment of Pain in Foals) showed good inter- and intra-observer reliability (Cronbach’s alpha = 0.95 and 0.98, p < 0.001). Patients had significantly higher pain scores compared to controls (p < 0.001) and the pain scores decreased after treatment with NSAIDs (meloxicam or flunixin meglumine IV) (p < 0.05). Our results indicate that a facial expression-based pain scale could be useful for the assessment of acute pain in foals. Further studies are needed to validate this pain scale.

In tropical and subtropical climates, infection of periocular tissue by Habronema larvae is a recognised cause of conjunctivitis or blepharitis. To the authors’ knowledge, only a few cases of habronemiasis have been described in Western Europe, and it has not been documented previously in the Netherlands. The objective of this report is to describe the occurrence of five cases of (peri)ocular habronemiasis in the Netherlands, of which four date from the past few years. The diagnosis was based on the history, clinical signs and histopathologic examination of biopsy specimens. A granulomatous conjunctivitis/dermatitis and sulphur‐like granules were present in all cases. Histopathology showed an eosinophilic granulomatous inflammation, and three out of five (60 per cent) samples revealed one or more nematodes on section. Treatment combinations with surgical excision, local corticosteroid and/or anthelmintic drugs were used. Furthermore, all horses received ivermectin or moxidectin. Treatment resulted in healing of the lesions in four horses. One case, which was refractory to treatment, resolved spontaneously after the onset of colder weather. This case series suggests an increased prevalence of (peri)ocular habronemiasis in the Netherlands. This diagnosis should therefore be considered when being presented with a horse with granulomatous conjunctivitis/dermatitis in Western Europe, especially during the summer months.

Background: Pharmacological preconditioning of dexmedetomidine on small intestinal ischaemia/reperfusion injury has been reported in different animal models including horses. Objectives: The objective was to assess if xylazine and lidocaine have a preconditioning effect in an experimental model of equine jejunal ischaemia. Study design: Terminal in vivo experiment. Methods: Ten horses under general anaesthesia were either preconditioned with xylazine (group X; n = 5) or lidocaine (group L; n = 5). A historical untreated control group (group C; n = 5) was used for comparison. An established experimental model of equine jejunal ischaemia was applied, and intestinal samples were taken pre‐ischaemia, after ischaemia and following reperfusion. Histomorphological examination was performed based on a modified Chiu score. Immunohistochemical staining for cleaved caspase‐3, TUNEL and calprotectin was performed, and positive cell counts were expressed in cells/mm ² . Results: There was no progression of histomorphological mucosal injury from ischaemia to reperfusion, and there were no differences in histomorphology between the groups. After ischaemia, group X had significantly less caspase‐positive cells compared to the control group with a median difference of 227% ( P = .01). After reperfusion, group X exhibited significantly lower calprotectin‐positive cell counts compared to the control group, with a median difference of 6.8 cells/mm ² in the mucosa and 44 cells in the serosa ( P = .02 and .05 respectively). All groups showed an increase in caspase‐ and calprotectin‐positive cells during reperfusion ( P < .05). TUNEL‐positive cells increased during ischaemia, followed by a decrease after reperfusion ( P < .05). Main limitations: The small sample size and the use of a historical control group. Preconditioning effects of the tested drugs may be masked by the protective effects of isoflurane in the anaesthetic protocol. Conclusions: Preconditioning with lidocaine did not have any effect on the tested variables. The lower cell counts of caspase‐ and calprotectin‐positive cells in group X may indicate a beneficial effect of xylazine on ischaemia/reperfusion injury. Due to the absence of a concurrent reduction of histomorphological injury, the clinical significance remains uncertain.

Summary: Background: Ischaemic postconditioning (IPoC) has been shown to ameliorate ischaemia reperfusion injury in different species and tissues. Objectives: To assess the feasibility of IPoC in equine small intestinal ischaemia and to assess its effect on histomorphology, electrophysiology and paracellular permeability. Study design: Randomised in vivo experiment. Methods: Experimental jejunal ischaemia was induced for 90 min in horses under general anaesthesia. In the control group (C; n = 7), the jejunum was reperfused without further intervention. In the postconditioning group (IPoC; n = 7), reocclusion was implemented following release of ischaemia by clamping the mesenteric vessels in three cycles of 30 seconds. This was followed by 120 minutes of reperfusion in both groups. Intestinal microperfusion and oxygenation was measured during IPoC using spectrophotometry and Doppler flowmetry. Histomorphology and histomorphometry of the intestinal mucosa were assessed. Furthermore, electrophysiological variables and unidirectional flux rates of ³ H‐mannitol were determined in Ussing chambers. Western blot analysis was performed to determine the tight junction protein levels of claudin‐1, claudin‐2 and occludin in the intestinal mucosa. Comparisons between the groups and time points were performed using a two‐way repeated measures analysis of variance (ANOVA) or non‐parametric statistical tests for the ordinal and not normally distributed data (significance P < .05). Results: IPoC significantly reduced intestinal microperfusion during all clamping cycles yet affected oxygen saturation only during the first cycle. After reperfusion, Group IPoC showed significantly less mucosal villus denudation (mean difference 21.5%, P = .02) and decreased mucosal‐to‐serosal flux rates (mean difference 15.2 nM/cm ² /h, P = .007) compared to Group C. There were no significant differences between the groups for the other tested variables. Main limitations: Small sample size, long‐term effects were not investigated. Conclusions: Following IPoC, the intestinal mucosa demonstrated significantly less villus denudation and paracellular permeability compared to the untreated control group, possibly indicating a protective effect of IPoC on ischaemia reperfusion injury.