Emergency Management for Donkeys and Mules.

This article provides an overview of initial assessment and management of common emergency presentations in donkeys and mules. The principles are similar to those in horses (and ponies), but clinicians must be aware of differences in recognition of signs of pain/disease, approach to handling, pharmacology of some drugs, and subtle differences in the physiology and local anatomy in donkeys and mules. The epidemiology of common disease presentations will vary between pet/companion or working/farmed donkeys and mules. Regular dental checks, deworming, vaccination, and monitoring of behavior and quality of life are important aspects of preventive care.

Acute changes in the colonic microbiota are associated with large intestinal forms of surgical colic.

BACKGROUND: Horses that undergo surgery for treatment of primary large colon disease have been reported to be at increased risk of developing recurrent colic episodes postoperatively. The reasons for this are currently unknown. The aim of the current study was to characterise the faecal microbiota of horses with colic signs associated with primary large colon lesions treated surgically and to compare the composition of their faecal microbiota to that of a control group of horses undergoing emergency orthopaedic treatment. Faecal samples were collected from horses in both groups on admission to hospital, during hospitalisation and following discharge from hospital for a total duration of 12 weeks. Additionally, colonic content samples were collected from surgical colic patients if pelvic flexure enterotomy was performed during laparotomy. A total of 12 samples were collected per horse. DNA was extracted from samples using a commercial kit. Amplicon mixtures were created by PCR amplification of the V1 - V2 regions of the bacterial 16S rRNA genes and submitted for sequencing using the Ion Torrent PGM next-generation sequencing system. Multivariate data analysis was used to characterise the faecal microbiota and to investigate differences between groups. RESULTS: Reduced species richness was evident in the colonic samples of the colic group compared to concurrent sampling of the faeces. Alpha and beta diversity differed significantly between the faecal and colonic microbiota with 304 significantly differentially abundant OTUs identified. Only 46 OTUs varied significantly between the colic and control group. There were no significant differences in alpha and beta diversity of faecal microbiota between colic and control horses at admission. However, this lack of significant differences between groups should be interpreted with caution due to a small sample size. CONCLUSIONS: The results of the current study suggest that faecal samples collected at hospital admission in colic cases may not accurately represent changes in upper gut microbiota in horses with colic due to large colon disease.

Has intravenous lidocaine improved the outcome in horses following surgical management of small intestinal lesions in a UK hospital population?

BACKGROUND: Perioperative lidocaine treatment is commonly used in horses that undergo surgical treatment of colic, to prevent or treat postoperative ileus and reduce the effects of intestinal ischaemia-reperfusion injury. However, its clinical efficacy has not been evaluated in a large population of horses undergoing small intestinal surgery. The aim of the current study was to evaluate whether systemic lidocaine administration reduced the prevalence, volume and duration of postoperative reflux and improved rates of survival following surgical treatment of small intestinal lesions. Data were collected as a part of two prospective studies investigating postoperative survival of surgical colic patients admitted to a UK equine referral hospital during the periods 2004-2006 and 2012-2014. Kaplan-Meier plots of cumulative probability of survival and the log-rank test were used to compare survival between horses that did or did not receive lidocaine. The Wilcoxon rank-sum test was used to compare the total reflux volume and duration of reflux between the groups. A multivariable Cox proportional hazards model was used to identify pre- and intraoperative risk factors for non-survival. RESULTS: Data from 318 horses were included in the final analysis. The overall prevalence of postoperative reflux was 24.5 %. This was significantly higher (34.8 %) in horses admitted in 2012-2014 compared to the 2004-2006 cohort (16.7). Perioperative lidocaine treatment had no effect on total reflux volume, duration of reflux or rates of postoperative survival nor was it a risk factor associated with altered postoperative survival. Variables identified to be associated with increased risk of postoperative mortality included packed cell volume on admission (hazard ratio [HR] 1.03 95 %, 95 % confidence interval [CI] 1.004-1.06, p = 0.024), heart rate on admission (HR 1.014, 95 % CI 1.004-1.024, p =0.008) and duration of surgery (HR 1.007, 95 % CI 1.002-1.01, p = 0.008). CONCLUSIONS: Lidocaine therapy had no effect on the prevalence of postoperative reflux, total reflux volume and duration of reflux nor did it have any effect on postoperative survival in horses undergoing surgical management of small intestinal disease for treatment of colic. There is a need for a well-designed multicentre, prospective randomised controlled trial to fully investigate the efficacy of lidocaine across different hospital populations.

Prevalence of and risk factors for colic in horses that display crib-biting behaviour.

BACKGROUND: Crib-biting and windsucking (CBWS) behaviour in horses has been associated with increased risk of colic in general, recurrence of colic and specific forms of colic. The aims of the present study were to determine the prevalence of colic within a population of horses that display CBWS behaviour and to identify risk factors for colic. METHODS: Owners/carers of horses in the general UK equine population that display CBWS behaviour were invited to participate in a questionnaire-based survey about the management and health of these horses. Data were obtained for a number of variables considered to be possible risk factors for colic. The prevalence of colic was calculated and multivariable logistic regression was used to identify associations between horse- and management-level variables for two outcomes of interest: a history of colic ever and a history of colic in the previous 12 months. RESULTS: Data were obtained for 367 horses. One or more episodes of colic had been observed in 130 horses (35.4%). A total of 672 colic episodes were reported and 13 colic episodes required surgical intervention in 12 horses. Where the horse/pony had been in that persons care over the previous 12 months (n=331), colic had been observed in 67 horses (20.2%) during that time. A total of 126 colic episodes were reported in the preceding 12 months of which veterinary attendance was required in 69 (54.8%) episodes. Increased duration of ownership, increased duration of stabling in the Autumn months (September-November), crib-biting/windsucking behaviour associated with eating forage and horses that were fed haylage were associated with increased risk of colic (ever). Increasing severity (frequency) of CBWS behaviour and increased duration of stabling in the Autumn were associated with increased risk of colic in the previous 12 months. CONCLUSIONS: The prevalence of colic in a population of horses that display CBWS appeared to be relatively high. The results of this study can be used to identify horses that display CBWS who are at increased risk of colic and identifies areas for further research to determine if there are ways in which this risk might be reduced.

Could it be colic? Horse-owner decision making and practices in response to equine colic.

BACKGROUND: Little is known about lay understanding and decision making in response to colic. Horse-owners/carers are key to identifying colic and initiating veterinary intervention. Understanding how owners think and act in relation to colic could assist veterinary surgeons in tailoring information about colic with the aim of improving colic outcomes. METHODS: A mixed methods approach was employed including qualitative in-depth interviews and a cross-sectional questionnaire. Qualitative data were analysed using Grounded theory to conceptualise processes involved in horse-owner management of colic. Following this, a cross-sectional survey was designed to test these concepts. Cluster analysis explored the role of the human-horse relationship upon colic management strategies. RESULTS: Fifteen horse-owners with a range of colic experience participated in the interviews. A theoretical conceptual model was developed and described how horse-owners' recognised, assessed and responded to colic. Three main management strategies were used including 'wait and see', 'lay treatments' and 'seek veterinary assistance'. Actions in response to colic were moderated by owners' experience of colic and interpretation of the severity of colic signs. A postal questionnaire gathered data from 673 horse-owners from the North-West of the UK. The majority (605, 89.9%) of respondents were female. Cluster analysis revealed 5 meaningful groups of horse-owners based upon assessment of questionnaire items on the human-horse relationship. These groups included 2 professional and 3 amateur owner typologies. There were differences in the responses to some questionnaire items among the identified groups. CONCLUSIONS: This study describes lay understanding and management of colic among a population of horse-owners from the North-West of the UK. The information may serve as a basis upon which to tailor existing programmes designed to educate owners about colic management strategies, and may inform veterinarians' interactions with horse-owners.

Clinical features and outcome of 40 horses with mesodiverticular bands identified during exploratory laparotomy for management of acute colic.

BACKGROUND: Mesodiverticular bands (MDBs) are an embryonic remnant of the vitelline artery. Information about the clinical significance of equine MDBs is currently limited. OBJECTIVES: To report the clinical features, surgical findings and outcomes of horses undergoing exploratory laparotomy where a MDB was identified. STUDY DESIGN: Retrospective case series. METHODS: Case records of horses undergoing exploratory laparotomy for colic over a 14-year period (2009-2022) were reviewed. MDBs identified at laparotomy were classified as the primary or contributory cause of abdominal pain, or as incidental. RESULTS: MDBs were identified in 40/1943 horses (2.1%) and 15 were primary (32.5%), 10 contributory (25%) and 15 incidental (32.5%). Horses with primary MDBs (median 2 years, IQR 1-12) were significantly younger than horses with incidental MDBs (median 8 years, IQR 6-16; P = 0.01). MDBs were more likely to be incidental if located in the mid-jejunum (5/5) (P < 0.001) or where a mesenteric pocket was absent (11/15) (P = 0.01). Primary MDBs caused extra-mural obstruction due to mesenteric shortening (n = 4), small intestinal entrapment within the MDB pocket (n = 5) or in an adjacent mesenteric rent (n = 4), and volvulus around the MDB (n = 2), with intestinal resection required in 8/15 cases. For horses with primary MDBs, survival to hospital discharge was 60% overall (9/15) and 75% for horses that stood following anaesthesia (9/12) with 88.9% of cases discharged from hospital (8/9) surviving >1 year. Excision of MDB tissue was not associated with complications but 3/4 non-incidental MDBs left in situ required relaparotomy to treat MDB-associated colic. MAIN LIMITATIONS: Retrospective single centre data. CONCLUSIONS: Most MDBs in horses undergoing surgical treatment of colic in this population were not incidental. MDB-associated colic was most commonly classified as strangulating obstruction, but non-strangulating extra-mural compression was also identified. Excision of MDB tissue should be undertaken where possible, particularly in non-incidental cases.

Outcome following emergency laparotomy in 33 UK donkeys: A retrospective multicentre study.

BACKGROUND: Emergency laparotomies in donkeys are infrequently performed and there is limited literature on the subject. OBJECTIVES: To determine findings and associated outcomes of exploratory laparotomies in donkeys. STUDY DESIGN: Descriptive retrospective study. METHODS: Donkeys undergoing emergency exploratory laparotomy for investigation and treatment of colic at seven UK referral hospitals between 2005-2017 were included. Data were retrieved from available hospital records. Descriptive statistics and inferential statistical analysis of outcomes of interest was performed in three steps. RESULTS: Thirty-three cases fulfilled the inclusion criteria. Clinical signs on presentation were available for 32 donkeys, of which 53.1% (17/32) presented for investigation of colic while in 46.9% (15/32) the presenting complaint was non-specific. Primary lesion location included small intestine (42.4%, 14/33), large colon (39.3%, 13/33), caecum (6.1%, 2/33), stomach (6.1%, 2/33) and 6.1% (2/33) had multiple abnormal findings without a clear primary lesion. Overall survival to discharge was 54.5% (18/33). Five donkeys (15.2%, 5/33) were euthanased at surgery and of those recovering from general anaesthesia a further 35.7% (10/28) were euthanased or died prior to discharge. Six donkeys (21.4%, 6/28) required a second laparotomy of which 4 (66.7%, 4/6) survived. Post-operative complications occurred in 82.1% (23/28) of cases and included hyperlipaemia (42.9%, 12/28), incisional complications (21.4%, 6/28), ileus (21.4%, 6/28) and persistent colic (17.9%, 5/28). When adjusted for other complications, donkeys with primary gastric lesions were less likely to have presented with severe colic compared with those with primary small intestinal lesions (OR: 0.07, 95% CI 0.01-0.95, p = 0.05). Only age was positively associated with death prior to discharge (OR: 1.18, 95% CI 1.03-1.36, p = 0.02). MAIN LIMITATIONS: Small sample size and retrospective design. CONCLUSION: Donkeys with abdominal lesions may present with a range of signs often not including colic. Surgical findings were diverse and survival to discharge appears to be lower than in horses.

Dog Walking before and during the COVID-19 Pandemic Lockdown: Experiences of UK Dog Owners.

BACKGROUND: This study investigated the impacts of the first COVID-19 UK lockdown on dog walking and ownership. METHODS: An online survey was circulated via social media (May-June 2020). Completed responses (n = 584) were analysed using within- and between-group comparisons, and multivariable linear and logistic regression models were created. Open-ended data were coded into key themes. RESULTS: During lockdown, dogs were walked less frequently, yet for a similar duration per week and closer to home. Dogs whose owners lived alone, or whose owners or household members had heightened vulnerability to COVID-19 were walked less than before, as were high-energy dogs. A minority of owners continued dog walking despite exhibiting symptoms or needing to self-isolate, justifying lack of help, dog behavioural problems, living in less populated areas, and the importance of outdoor exercise for their mental health. Dog ownership had multiple benefits (companionship, purpose and motivation; break from bad; positive to focus on) as well as challenges (changes in dog behaviour, balancing dog needs with public health guidance, accessing pet food/supplies and services, and sharing crowded outdoor spaces with others). Most did not have an emergency care plan for their pet before the pandemic and only a handful developed one. CONCLUSIONS: Findings can be used to inform public health and dog welfare strategies for future lockdown situations or other disasters and emergencies likely to impact on daily routines.

Bacterial translocation in horses with colic and the potential association with surgical site infection: a pilot study.

BACKGROUND: Surgical site infection (SSI) is a leading cause of morbidity in horses undergoing emergency exploratory laparotomy for the treatment of acute colic. The exact mechanism by which SSI develops in these cases is unclear. This prospective observational study investigated whether bacterial translocation occurs in horses with acute colic and if there is an association between bacterial translocation and development of SSI. METHODS: Peripheral venous blood (PVB) and peritoneal fluid (PF) samples were collected on admission and PF samples were collected at the end of surgery from horses presenting for investigation of acute colic. Any discharge from the laparotomy incision in horses that developed SSI was also collected. All samples were submitted for bacterial culture. RESULTS: In total, 7.7 per cent of PVB samples (3/39), 11.8 per cent (4/34) of admission PF samples and 8.7 per cent (2/23) of the PF samples at surgery were culture positive. The prevalence of SSI was 10.2 per cent. No association was identified between a positive PVB or PF culture and development of a SSI or survival to hospital discharge. CONCLUSION: Bacterial translocation can occur in some horses with acute colic. However, we were unable to identify any association between bacterial translocation and the development of SSIs following emergency exploratory laparotomy.

A longitudinal study of the faecal microbiome and metabolome of periparturient mares.

BACKGROUND: Periparturient mares are at increased risk of colic including large colon volvulus, which has a high mortality rate. Alterations in colonic microbiota related to either physiological or management changes, or both, that occur at this time have been suggested as potential causes for increased colic risk in this population of horses. Although the effect of management changes on the horse faecal microbiota has been investigated, limited work has been conducted to investigate changes in faecal microbiota structure and function in the periparturient period. The objectives of the current study were to investigate temporal stability of the faecal microbiota and volatile organic compounds (VOCs) of the faecal metabolome in periparturient mares. METHODS: Faecal samples were collected weekly from five pregnant mares from 3 weeks pre-foaling to 7 weeks post-foaling. The microbiome data was generated by PCR amplification and sequencing of the V1-V2 regions of the bacterial 16S rRNA genes, while the VOC profile was characterised using headspace solid phase microextraction gas chromatography mass spectrometry. RESULTS: The mare faecal microbiota was relatively stable over the periparturient period and most variation was associated with individual mares. A small number of operational taxonomic units were found to be significantly differentially abundant between samples collected before and after foaling. A total of 98 VOCs were identified. The total number of VOCs did not vary significantly between individual mares, weeks of sample collection and feeds available to the mares. Three VOCs (decane, 2-pentylfuran, and oct-2-ene) showed significant increase overtime on linear mixed effects modelling analysis. These results suggest that the mare faecal microbiota is structurally and functionally stable during the periparturient period. The findings also suggest that if changes in the gut microbiota are related to development of colic postpartum, altered risk may be due to inherent differences between individual mares. VOCs offer a cost-effective means of looking at the functional changes in the microbiome and warrant further investigation in mares at risk of colic.

Survey of UK horse owners' knowledge of equine arboviruses and disease vectors.

Increased globalisation and climate change have led to concern about the increasing risk of arthropod-borne virus (arbovirus) outbreaks globally. An outbreak of equine arboviral disease in northern Europe could impact significantly on equine welfare, and result in economic losses. Early identification of arboviral disease by horse owners may help limit disease spread. In order to determine what horse owners understand about arboviral diseases of horses and their vectors, the authors undertook an open, cross-sectional online survey of UK horse owners. The questionnaire was distributed using social media and a press release and was active between May and July 2016. There were 466 respondents, of whom 327 completed the survey in full. High proportions of respondents correctly identified photographic images of biting midges (71.2 per cent) and mosquitoes (65.4 per cent), yet few were aware that they transmit equine infectious diseases (31.4 per cent and 35.9 per cent, respectively). Of the total number of respondents, only 7.4 per cent and 16.2 per cent correctly named a disease transmitted by biting midges and mosquitoes, respectively. Only 13.1 per cent and 12.5 per cent of participants identified specific clinical signs of African horse sickness (AHS) and West Nile virus (WNV), respectively. This study demonstrates that in the event of heightened disease risk educational campaigns directed towards horse owners need to be implemented, focussing on disease awareness, clinical signs and effective disease prevention strategies.

Variation in faecal microbiota in a group of horses managed at pasture over a 12-month period.

Colic (abdominal pain) is a common cause of mortality in horses. Change in management of horses is associated with increased colic risk and seasonal patterns of increased risk have been identified. Shifts in gut microbiota composition in response to management change have been proposed as one potential underlying mechanism for colic. However, the intestinal microbiota in normal horses and how this varies over different seasons has not previously been investigated. In this study the faecal microbiota composition was studied over 12 months in a population of horses managed at pasture with minimal changes in management. We hypothesised that gut microbiota would be stable in this population over time. Faecal samples were collected every 14 days from 7 horses for 52 weeks and the faecal microbiota was characterised by next-generation sequencing of 16S rRNA genes. The faecal microbiota was dominated by members of the phylum Firmicutes and Bacteroidetes throughout. Season, supplementary forage and ambient weather conditions were significantly associated with change in the faecal microbiota composition. These results provide important baseline information demonstrating physiologic variation in the faecal microbiota of normal horses over a 12-month period without development of colic.

Environmental surveillance identifies multiple introductions of MRSA CC398 in an Equine Veterinary Hospital in the UK, 2011-2016.

Bacterial environmental and surgical site infection (SSI) surveillance was implemented from 2011-2016 in a UK Equine Referral Veterinary Hospital and identified 81 methicillin-resistant Staphylococcus aureus (MRSA) isolates. A cluster of MRSA SSIs occurred in early 2016 with the isolates confirmed as ST398 by multilocus sequence typing (MLST), which prompted retrospective analysis of all MRSA isolates obtained from the environment (n = 62), SSIs (n = 13) and hand plates (n = 6) in the past five years. Sixty five of these isolates were typed to CC398 and a selection of these (n = 38) were further characterised for resistance and virulence genes, SCCmec and spa typing. Overall, MRSA was identified in 62/540 (11.5%) of environmental samples, 6/81 of the hand-plates (7.4%) and 13/208 of the SSIs (6.3%). spa t011 was the most frequent (24/38) and Based Upon Repeat Pattern (BURP) analysis identified spa t011 as one of the two group founders of the main spa CC identified across the five years (spa CC011/3423). However, 3 singletons (t073, t786, t064) were also identified suggesting separate introductions into the hospital environment. This long-term MRSA surveillance study revealed multiple introductions of MRSA CC398 in a UK Equine Hospital, identifying an emerging zoonotic pathogen so far only sporadically recorded in the UK.

Is equine colic seasonal? Novel application of a model based approach.

BACKGROUND: Colic is an important cause of mortality and morbidity in domesticated horses yet many questions about this condition remain to be answered. One such question is: does season have an effect on the occurrence of colic? Time-series analysis provides a rigorous statistical approach to this question but until now, to our knowledge, it has not been used in this context. Traditional time-series modelling approaches have limited applicability in the case of relatively rare diseases, such as specific types of equine colic. In this paper we present a modelling approach that respects the discrete nature of the count data and, using a regression model with a correlated latent variable and one with a linear trend, we explored the seasonality of specific types of colic occurring at a UK referral hospital between January 1995-December 2004. RESULTS: Six- and twelve-month cyclical patterns were identified for all colics, all medical colics, epiploic foramen entrapment (EFE), equine grass sickness (EGS), surgically treated and large colon displacement/torsion colic groups. A twelve-month cyclical pattern only was seen in the large colon impaction colic group. There was no evidence of any cyclical pattern in the pedunculated lipoma group. These results were consistent irrespective of whether we were using a model including latent correlation or trend. Problems were encountered in attempting to include both trend and latent serial dependence in models simultaneously; this is likely to be a consequence of a lack of power to separate these two effects in the presence of small counts, yet in reality the underlying physical effect is likely to be a combination of both. CONCLUSION: The use of a regression model with either an autocorrelated latent variable or a linear trend has allowed us to establish formally a seasonal component to certain types of colic presented to a UK referral hospital over a 10 year period. These patterns appeared to coincide with either times of managemental change or periods when horses are more likely to be intensively managed. Further studies are required to identify the determinants of the observed seasonality. Importantly, this type of regression model has applications beyond the study of equine colic and it may be useful in the investigation of seasonal patterns in other, relatively rare, conditions in all species.

Obstruction of equine small intestine associated with focal idiopathic eosinophilic enteritis: an emerging disease?

Idiopathic focal eosinophilic enteritis (IFEE) is a rare disease in the horse and few cases have been reported in the literature. The objective of this paper was to describe the clinical, surgical, histological features and post-operative progress of 12 horses with IFEE, a disease that had not been identified in the authors' hospital population prior to 2000. Diagnosis of IFEE was made at laparotomy and confirmed by histological examination of resected abnormal small intestine. In all 12 horses colic was associated with jejunal obstruction involving visibly striking and palpably thickened serosal plaques or circumferential constrictions. Surgical resection of affected intestine was performed in 10 horses, of which seven completely recovered. In one horse, on which surgical resection was not performed, ingesta re-obstructed post-operatively at one of the lesions. Histological examination of resected intestines revealed, in all cases, severe transmural enteritis in which eosinophilic leucocytes were the predominant inflammatory cells. No helminths were identified and the cause of this lesion is not known. IFEE is an uncommon but significant cause of small intestinal obstruction for which surgical resection can be curative. The gross lesions may be under-recognised and histology is essential for diagnosis.

Association between cribbing and entrapment of the small intestine in the epiploic foramen in horses: 68 cases (1991-2002).

OBJECTIVE: To determine whether there was an association between a history of cribbing and epiploic foramen entrapment (EFE) of the small intestine in horses. DESIGN: Retrospective study. ANIMALS: 68 horses examined at the University of Illinois or the University of Liverpool veterinary teaching hospitals. PROCEDURE: For horses examined at the University of Illinois that underwent surgery because of strangulating small intestine lesions, information about cribbing was obtained through telephone calls with owners. For horses examined at the University of Liverpool that underwent surgery for colic for any reason, information about cribbing was obtained through a preoperative questionnaire. RESULTS: 13 of 19 (68%) horses with EFE examined at the University of Illinois had a history of cribbing, compared with only 2 of 34 (6%) horses with other strangulating small intestine lesions (odds ratio, 34.7; 95% confidence interval, 6.2 to 194.6). Similarly, 24 of 49 (49%) horses with EFE examined at the University of Liverpool had a history of cribbing, compared with 72 of 687 (10.5%) horses with colic caused by other lesions (odds ratio, 8.2; 95% confidence interval, 4.5 to 15.1). CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that there may be an association between cribbing and EFE in horses, with horses with a history of cribbing more likely to have EFE than horses without such a history.

Idiopathic focal eosinophilic enteritis (IFEE), an emerging cause of abdominal pain in horses: the effect of age, time and geographical location on risk.

BACKGROUND: Idiopathic focal eosinophilic enteritis (IFEE) is an emerging cause of abdominal pain (colic) in horses that frequently requires surgical intervention to prevent death. The epidemiology of IFEE is poorly understood and it is difficult to diagnose pre-operatively. The aetiology of this condition and methods of possible prevention are currently unknown. The aims of this study were to investigate temporal and spatial heterogeneity in IFEE risk and to ascertain the effect of horse age on risk. METHODOLOGY/PRINCIPAL FINDINGS: A retrospective, nested case-control study was undertaken using data from 85 IFEE cases and 848 randomly selected controls admitted to a UK equine hospital for exploratory laparotomy to investigate the cause of colic over a 10-year period. Generalised additive models (GAMs) were used to quantify temporal and age effects on the odds of IFEE and to provide mapped estimates of 'residual' risk over the study region. The relative risk of IFEE increased over the study period (p = 0.001) and a seasonal pattern was evident (p<0.01) with greatest risk of IFEE being identified between the months of July and November. IFEE risk decreased with increasing age (p<0.001) with younger (0-5 years old) horses being at greatest risk. The mapped surface estimate exhibited significantly atypical sub-regions (p<0.001) with increased IFEE risk in horses residing in the North-West of the study region. CONCLUSIONS/SIGNIFICANCE: IFEE was found to exhibit both spatial and temporal variation in risk and is more likely to occur in younger horses. This information may help to identify horses at increased risk of IFEE, provide clues about the aetiology of this condition and to identify areas that require further research.