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OBJECTIVE To evaluate, following colic admission during pregnancy, (1) broodmare survival; (2) the frequency of recurrent colic in broodmares and its associated variables, and (3) pregnancy outcome and the variables associated with a negative pregnancy outcome. STUDY DESIGN Ambidirectional observational cohort study. ANIMALS One hundred and four client-owned broodmare admissions. METHODS Admissions of pregnant mares from June 2010 until October 2016 were included. Data were collected until November 2017. Cox proportional hazards regression analysis was performed to evaluate variables associated with broodmare survival. Logistic regression analysis was used to examine the variables associated with recurrent colic and pregnancy outcome. RESULTS Broodmares from 73/104 (70.2%) admissions were discharged alive. Lesion category, admission hyperlactatemia (hazard ratio (HR) 3.24, 95%, CI 1.28-8.22, P = .013), and admission high packed cell volume (HR 2.89, 95% CI 1.29-6.47, P = .010) were associated with reduced survival. Recurrent colic was observed in broodmares from 33/70 admissions (47.1%). The final multivariable model for recurrent colic included Thoroughbred breed (OR 5.09, 95% CI 1.58-16.4, P = .006) and age (OR .876, 95% CI .747-1.03, P = .105). Overall, negative pregnancy outcome was 14/65 (21.5%). Lesion category, evidence of systemic inflammatory response syndrome (SIRS) in hospital (OR 31.2, 95% CI 2.09-466.5, P = .013), and diarrhea in hospital (OR 379.3, 95% CI 97.1-1482.0, P

Background An association between equine gastrointestinal disease causing colic signs and changes in faecal bacterial microbiota has been identified. The reasons for these changes and their clinical relevance has not been investigated. Withholding feed, which is an integral part of managing horses with colic, may contribute to the observed changes in the microbiota and impact interpretation of findings in horses with colic. Study objectives were, therefore, to determine the effect of withholding feed for 24 h on equine faecal bacterial microbiota in healthy mares to differentiate the effects of withholding feed from the changes potentially associated with the disease. Results Species richness and Shannon diversity (alpha diversity) were significantly lower at the late withheld (10–24 h post withholding feed) and early refed (2–12 h post re-feeding) time points compared to samples from fed horses (P BS11 and Firmicutes Christensenellaceae, Christensenella, and Dehalobacteriaceae were significantly increased in horses withheld from feed primarily during the late withheld and early refed time points. Bacteroidetes Marinilabiaceae and Prevotellaceae, Firmicutes Veillonellaceae, Anaerovibrio, and Bulleidia, and Proteobacteria GMD14H09 were significantly decreased in horses with feed withheld at late withheld, early refed, and late refed time periods (P Conclusions Withholding feed has a significant effect on faecal bacterial microbiota diversity and composition particularly following at least 10 h of withholding feed and should be taken into consideration when interpreting data on the equine faecal bacterial microbiota in horses.

Objective To determine whether perioperative variables can be used to differentiate a medical vs a surgical reason for postoperative reflux (POR) after small intestinal (SI) surgery in horses. Study design Retrospective study. Sample population Horses >1 year of age that recovered from SI surgery and had POR. Methods Medical records of horses that underwent SI surgery and developed POR from 2009-2015 were reviewed. Surgical reasons for POR were defined as an anastomosis complication, mechanical obstruction, or nonviable intestine identified at repeat celiotomy/necropsy. A medical reason for POR was presumed when the POR improved with medical treatment or when no surgical reasons were identified at repeat celiotomy/necropsy. Perioperative variables were analyzed and used to develop a logistic regression model. Results Fifty-one horses had POR after SI surgery. After initial SI surgery, 14 horses had surgical reasons for POR diagnosed at repeat celiotomy or necropsy. Thirty-seven horses were considered to have medical reasons for POR because their POR resolved with medical management or functional ileus was diagnosed at repeat celiotomy/necropsy. A greater volume and a greater duration of POR were not associated with a surgical reason for POR. Rather, a postoperative (PO) fever and the timing of colic in the PO period were associated with a surgical reason for POR. Conclusion Horses that developed a fever and colic in the PO period after SI surgery were more likely to have a surgical reason for POR. Clinical significance These findings may provide guidance for clinicians when they are making decisions about repeat celiotomy in horses with POR after SI surgery.

BackgroundIncisional complications are a common cause of morbidity following laparotomy. Although uncommon, acute abdominal dehiscence (AAD) is a potentially fatal post-operative complication. However, few AAD cases are described in the literature.ObjectivesTo describe common features of cases of AAD following ventral midline laparotomy, management and outcomes.Study designRetrospective case series.MethodsHospital records of horses that underwent a ventral midline laparotomy at nine hospitals in the UK, Ireland and USA over a 10-year period (2009-2019) were reviewed. Data were collected for pre-, intra- and post-operative factors that were considered relevant. Descriptive statistical analysis was performed.ResultsA total of 63 cases of AAD were identified. AAD occurred due to tearing of sutures through the linea alba or rupture of the body wall adjacent to the suture line in 46 horses (73%). AAD occurred at a median of 5 days (0.5-70 days) post-operatively and broodmares accounted for 25% of the cases (n = 16). Surgical site infection developed prior to AAD in 28 horses (44%); leakage of peritoneal fluid occurred in 5% of horses prior to AAD being identified. Surgical repair was performed in 27 horses (43%), 10 (16%) were treated conservatively and 26 (41%) were euthanised immediately. Repair was most frequently performed using suture (n = 14), wire (n = 5) or a combination (n = 5). Overall survival to hospital discharge was 39% (24/63). Where surgical repair was performed, 15 horses (56%) survived to hospital discharge; 9 horses (90%) managed conservatively survived to hospital discharge.Main limitationsFollow-up was not performed for all cases following hospital discharge and some data were incompletely recorded in hospital files.ConclusionsPreviously stated causative factors for AAD were not consistent features in the present study. Surgical site infection following laparotomy and pregnant or early post-partum mares may be important risk factors for AAD and warrant further investigation.

The horse is uniquely adapted for hindgut fermentation, and the microbiota within the hindgut contribute to immune system stimulation, protection against harmful pathogens and toxins, and regulation of gene expression within the host. Many factors, such as dietary changes, antimicrobials, pathogens, and changes in management, can perturb the microbial communities leading to gastrointestinal complications such as colitis and colic in horses. With advances in genomic tools to characterize microbiota, efforts to expand the body of knowledge on the community structure and function of equine gut microbiota in health and disease are increasing within the equine research community. Colic is an important equine disease. While epidemiological studies have identified risk factors for colic, and intestinal inflammation may play a role in some horses with recurrent colic, there are very few studies investigating the role of the intestinal microbiota in colic. We compared the microbial communities of horses admitted to the hospital for colic to those of horses admitted for an elective procedure. We found a significant difference at the community level (alpha and beta diversity) and also between individual bacterial populations. Furthermore, we also found that location of lesions in the GI tract, duration of colic (acute vs. chronic), and other factors altered the microbial ecology of the equine gut microbiota. Notably, we also investigated whether the changes in microbiota induced by colic were confounded by withholding feed. We found that withholding feed from horses for 24 h induced a significant shift in the microbiota, which reverted to normal within 12 h after the horses gained access to feed. From our experiments, it is becoming increasingly clear that colic in horses induces changes in specific bacterial populations along with generalized changes that are confounded with many other factors. Further research is needed particularly in horses with recurrent colic to determine the association between the intestinal microbiota, diet and management factors, and inflammation.

BACKGROUND Previous studies have identified alterations in the faecal microbiota of horses with colic; however, further work is needed to interpret these findings. OBJECTIVES To compare the faecal microbiota of horses presenting for colic at hospital admission, day 1 and day 3/discharge and with different colic duration and lesion locations. STUDY DESIGN Prospective observational clinical study. METHODS Faecal samples were collected from 17 colic cases at hospital admission, on day 1 and on day 3 post-admission or at the time of hospital discharge if prior to 72 hours. Faecal samples were extracted for genomic DNA, PCR-amplified, sequenced and analysed using QIIME. Species richness and Shannon diversity (alpha diversity) were estimated. The extent of the relationship between bacterial communities (beta diversity) was quantified using pairwise UniFrac distances, visualised using principal coordinate analysis (PCoA) and statistically analysed using permutational multivariate analysis of variance (PERMANOVA). The relative abundance of bacterial populations at the different time points and in different types of colic was compared using ANCOM. RESULTS There was a decrease in species richness from admission to day 3/hospital discharge (P

Identifying therapies that mitigate ischemic colonic injury and improve mucosal healing and intestinal viability are crucial to improving survival in horses with ≥360° large colon volvulus (LCV). Ethyl pyruvate is the ethyl ester of pyruvate with diverse pharmacologic effects that limit ischemic injury and hasten intestinal mucosal repair in preclinical rodents, sheep and swine models. The objective of this study was to determine the effects of ethyl pyruvate on systemic indices of colon viability, expression of inflammatory genes in whole blood, morbidity and survival after surgical correction of LCV compared to controls. Horses received either 150 mg/kg ethyl pyruvate in 1 liter lactated Ringer's solution (LRS) or 1 liter LRS intravenously (IV) every 6 h for 24 h following surgical recovery for correction of LCV. Colic duration, perioperative heart rate (HR), packed cell volume (PCV), total solids (TS), blood L-lactate concentration, surgical time, intraoperative episodes of hypoxemia and hypotension, expression of inflammatory cytokine genes, fecal consistency and survival to hospital discharge were compared between ethyl pyruvate treated horses and controls. Twenty-two horses, 12 receiving ethyl pyruvate and 10 controls, were enrolled in the study. Ethyl pyruvate was safely administered to horses following surgical correction of LCV. No significant effects of ethyl pyruvate on post-operative variables, including survival, were found. Seven of 12 ethyl pyruvate treated horses and 5/10 controls survived to hospital discharge. Higher HR, PCV and blood L-lactate concentration at the time of hospital admission, P = 0.005, 0.01, 0.04, respectively, 24 h after surgery, P = 0.001, 0.03, 0.02, respectively, were associated with death. Heart rate, P = 0.005, 48 h after surgery was associated with death. Ethyl pyruvate was safely administered to horses following correction of LCV with no apparent adverse events but was not associated with improved post-operative outcomes including survival. A larger, randomized control trial is needed to fully evaluate the effectiveness of ethyl pyruvate. A major limitation of this investigation is the small sample size, making the study underpowered and creating a high possibility of type II error.

BACKGROUND The faecal microbiota is emerging as potentially important in intestinal disease. More research is needed to characterise the faecal microbiota from horses with colic. OBJECTIVES To compare the relative abundance of bacterial populations comprising the faecal microbiota in horses presenting for colic compared with an elective surgical procedure. STUDY DESIGN Prospective observational clinical study. METHODS Admission faecal samples were collected from horses presenting for colic and elective surgical procedures. Faecal samples were extracted for genomic DNA, PCR- amplified, sequenced and analysed using QIIME. Species richness and Shannon diversity were estimated for each faecal sample. The extent of the relationship between bacterial communities (beta diversity) was quantified using pairwise UniFrac distances, visualised using principal coordinate analysis (PCoA) and statistically analysed using PERMANOVA. The relative abundance of bacterial populations between the two treatment groups were compared using ANCOM. RESULTS Faecal bacterial communities in horses presenting for colic had fewer species (P

OBJECTIVE To describe gastrointestinal histologic findings for horses with recurrent colic and evaluate possible associations between initial clinical signs, biopsy method, histologic diagnosis, and outcome 1 year after hospital discharge. DESIGN Retrospective case series. ANIMALS 66 horses with a history of recurrent colic for which gastrointestinal specimens had been submitted for histologic examination. PROCEDURES Histologic diagnosis was categorized as inflammatory, neoplastic, ischemic, other, and undiagnosed. Relationships among initial clinical features, biopsy method, histologic diagnosis, and outcome 1 year after hospital discharge (ie, alive vs dead and persistent recurrent colic [yes vs no]) and between corticosteroid treatment and outcome were investigated. Odds ratios and hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated. RESULTS Inflammatory disease (36/66 [55%]) was the most common histologic diagnosis. Horses undergoing rectal biopsy alone were significantly (OR, 14.4; 95% Cl, 2.7 to 76.1) more likely to not have a histologic diagnosis than were horses in which other biopsy methods were used. In multivariable modelling, persistence of recurrent colic (HR, 15.2; 95% Cl, 1.9 to 121.2) and a history of weight loss (HR, 4.9; 95% Cl, 1.4 to 16.5) were significantly associated with outcome (alive vs dead) 1 year after surgery. Corticosteroid treatment was not significantly associated with either outcome. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that a high proportion (36/66 [55%]) of horses with recurrent colic had inflammatory gastrointestinal disease. Use of rectal biopsy alone to obtain biopsy specimens was more likely to result in no histologic diagnosis. Use of corticosteroids in horses with inflammatory gastrointestinal disease was not associated with outcome but warrants further investigation.

Duodenitis–proximal jejunitis (DPJ) is an idiopathic and potentially fatal disease of horses characterized by abdominal pain, proximal intestinal inflammation, and subsequent gastric and small intestinal fluid accumulation. Although this disease is known to be costly and life threatening in the equine industry, the severity of clinical signs can vary widely, and an exact etiology has yet to be elucidated. This study looked to identify differences in clinical parameters of horses with DPJ between geographic regions in an effort to corroborate anecdotal reports and support theories of differing etiologies. Case records were compared from veterinary academic referral hospitals in three different geographic locations in the United States to determine if significant differences in clinical, clinicopathologic, and prognostic characteristics exist among horses with DPJ. Clinical measurements on presentation that were significantly different between regions included heart rate, peritoneal total protein, albumin, anion gap, aspartate aminotransferase, gamma-glutamyl transferase, sodium, chloride, potassium, and creatinine. Duration of hospitalization and maximum body temperature while hospitalized were also different between regions. There were no significant differences in peritoneal cell count, total white blood cell count, neutrophil count, band neutrophils, calcium, total plasma protein, temperature on presentation, duration of reflux, total reflux volume, or age between hospitals. The mortality rates between hospitals were not significantly different. Increased severity of clinical signs and biochemical abnormalities were identified in the Southeastern United States hospital compared with the Northeastern and Western hospitals. A prospective, multicenter case–control study could identify risk factors contributing toward regional differences in this disease in the future.

OBJECTIVE To evaluate effects of poly(ADP-ribose) polymerase-1 (PARP1) inhibitors on the production of tumor necrosis factor-α (TNF-α) by interferon-γ (IFN-γ)– and lipopolysaccharide (LPS)-stimulated peripheral blood mononuclear cells (PBMCs) of horses as an in vitro model of inflammation in horses. SAMPLE 1,440 samples of PBMCs from 6 healthy research horses. PROCEDURES From heparinized whole blood samples, PBMC cultures were obtained. An initial dose-response trial on 48 PBMC samples from 2 horses (24 samples each) was used to determine concentrations of IFN-γ and LPS for use as low- and high-level stimulation concentrations. Seventy-two PBMC samples from 6 horses were assigned equally to 1 of 4 PARP1 inhibition categories: no PARP1 inhibitor (PARP1 inhibition control); 2-((R)-2-methylpyrrolidin-2-yl)-1H-benzimidazole-4-carbozamide dihydrochloride (ABT888);4-(3-(1-(cyclopropanecarbonyl)piperazine-4-carbonyl)-4-fluorobenzyl)phthalazin-1(2H)-one (AZD2281); or N-(6-oxo-5,6-dihydrophenanthridin-2-yl) -N,N-dimethylacetamide hydrochloride (PJ34). Samples of PBMCs from each horse and each PARP1 inhibition category were then assigned to 1 of 3 levels of IFN-γ and LPS stimulation: none (control), low stimulation, or high stimulation. After a 24-hour incubation period, a TNF-α ELISA was used to measure TNF-α concentration in the supernatant. Results were compared across treatments and for each horse. Data were analyzed with repeated-measures ANOVA. RESULTS Median TNF-α concentration was significantly lower for PJ34-treated, high-level stimulated PBMCs than for PARP1 inhibition control, high-level stimulated PBMCs; however, no other meaningful differences in TNF-α concentration were detected among the inhibition and stimulation combinations. CONCLUSIONS AND CLINICAL RELEVANCE Findings suggested that PJ34 PARP1 inhibition may reduce TNF-α production in horses, a potential benefit in reducing inflammation and endotoxin-induced damage in horses.

OBJECTIVE To characterize the fecal microbiota of horses and to investigate alterations in that microbiota on the basis of sample collection site (rectum vs stall floor), sample location within the fecal ball (center vs surface), and duration of environmental exposure (collection time). ANIMALS 6 healthy adult mixed-breed mares. PROCEDURES From each horse, feces were collected from the rectum and placed on a straw-bedded stall floor. A fecal ball was selected for analysis immediately after removal from the rectum and at 0 (immediately), 2, 6, 12, and 24 hours after placement on the stall floor. Approximately 250 mg of feces was extracted from the surface and center of each fecal ball, and genomic DNA was extracted, purified, amplified for the V1-V2 hypervariable region of the 16S rDNA gene, and analyzed with a bioinformatics pipeline. RESULTS The fecal microbiota was unique for each horse. Bacterial community composition varied significantly between center and surface fecal samples but was not affected by collection time. Bacterial community composition varied rapidly for surface fecal samples. Individual bacterial taxa were significantly associated with both sample location and collection time but remained fairly stable for up to 6 hours for center fecal samples. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that, for horses, fecal samples for microbiota analysis should be extracted from the center of fecal balls collected within 6 hours after defecation. Samples obtained up to 24 hours after defecation can be analyzed with the realization that some bacterial populations may deviate from those immediately after defecation.

BACKGROUND: Small intestinal strangulating obstruction (SISO) is associated with endotoxaemia which leads to an increased risk of death. Nonsteroidal anti-inflammatory drugs (NSAIDs) are used to treat signs of endotoxaemia by inhibiting cyclo-oxygenases (COX). COX-1 is expressed constitutively and promotes gut barrier function, whereas COX-2 is inducible and contributes to the signs of endotoxaemia. In preclinical SISO trials, intestinal barrier recovery was more complete with reductions in endotoxin permeability in horses treated with COX-2 selective NSAIDs as compared with horses treated with flunixin meglumine. OBJECTIVES: We hypothesised that treatment of post-surgical SISO horses with firocoxib (COX-2 selective) would reduce the signs of endotoxaemia to a greater extent than flunixin meglumine (nonselective COX inhibitor) while continuing to provide similar levels of pain control. STUDY DESIGN: Blinded randomised clinical trial. METHODS: In addition to clinical monitoring, preoperative and 12-, 24- and 48-h post-operative plasma samples were assessed for prostaglandin E(2) (PGE(2)), thromboxane B(2) (TXB(2)), TNFα and soluble CD14 (sCD14). RESULTS: In 56 recruited SISO horses, either flunixin meglumine (1.1 mg/kg, i.v., q12h) or firocoxib (0.3 mg/kg, i.v. loading dose; 0.1 mg/kg, i.v., q24h) was given in the post-operative period in three university hospitals from 2015 to 2017. COX-2 selectivity was confirmed by a relative lack of inhibition of the COX-1 prostanoid TXB(2) by firocoxib and significant inhibition by flunixin meglumine (P = 0.014). Both drugs inhibited the COX-2 prostanoid PGE(2). There were no significant differences in pain scores between groups (P = 0.2). However, there was a 3.23-fold increased risk (P = 0.04) of increased plasma sCD14 in horses treated with flunixin meglumine, a validated biomarker of equine endotoxaemia. MAIN LIMITATIONS: Horses were all treated with flunixin meglumine prior to referral. In addition, many horses were treated with lidocaine, which has been shown to mitigate the deleterious effects of flunixin meglumine. CONCLUSIONS: In SISO cases, firocoxib reduced a biomarker of endotoxaemia as compared with flunixin meglumine while continuing to provide similar levels of pain control.

Objectives To evaluate the poly (ADP-ribose) polymerase-1 (PARP1) enzyme and its inhibition in horses and explore its potential as a novel therapeutic target for equine intestinal ischemia-reperfusion injury by (1) identifying poly (ADP-ribose) (PAR) as an indication of PARP1 activation in equine cells using available immunoblot analytical techniques, (2) inducing PARP1 activation in an in vitro oxidative DNA damage model, (3) and demonstrating the inhibition of PARP1 in equine cells using commercially available PARP1 inhibitors. Design Experimental study. Animals Blood samples were collected from systemically healthy ponies (n = 3) and horses (n = 3). Interventions (1) Equine peripheral blood mononuclear cells were exposed to 3 different concentrations of hydrogen peroxide (H2 O2 ) and were lysed at specific time points. PARP1 activity was then assessed by using immunoblot analyses to determine PAR levels. (2) Equine peripheral blood mononuclear cells were preincubated with defined concentrations of PARP1 inhibitors prior to H2 O2 -mediated PARP1 stimulation. PAR levels reflecting PARP1 activity were determined using immunoblot analyses. Measurements and main results Commercially available anti-PAR antibodies were used successfully to identify equine PAR. There was a significant increase in PAR accumulation following treatment with H2 O2 . All of the tested PARP inhibitors significantly reduced PAR accumulation to or below basal levels following treatment with H2 O2 . Conclusions This proof of principle study demonstrated that PAR, an indicator of PARP1 activity, can be identified in the equine species using immunoblot techniques, that equine PARP1 can be activated by H2 O2 -induced DNA damage, and that this activation can be inhibited by PARP1 enzyme inhibitors. The data suggest that the PARP1 pathway plays a role in the equine cellular response to oxidative DNA damage and supports its potential as a novel therapeutic target. Further research documenting an increase in PAR levels in vivo and the efficacy of PARP1 inhibitors in an equine intestinal ischemia-reperfusion model is needed.

Summary Three Standardbred foals, a colt approximately one month old and 2 fillies approximately 4.5 months old, from the same farm, presented to University of Pennsylvania's New Bolton Centre over the course of 3 months for further evaluation due to acute onset of colic. All foals had a history of diarrhoea prior to presentation. On presentation, the foals had abdominal distension, dull demeanour and repeatedly lay down and rolled. Exploratory celiotomy revealed a segment of stenotic (lumen diameter 1–4 mm) small colon with marked distension of the colon proximal to the stenotic segment. Post mortem examination of the foals confirmed stenosis of the small colon with a segment of ulcerative colitis associated with the stenotic region. An aetiological agent was not identified.

Background Auscultation and ultrasonography are noninvasive techniques used to assess gastrointestinal motility in horses. Recently, noninvasive acoustic gastrointestinal surveillance (AGIS) biosensors evaluating intestinal motility have been validated in humans. Objectives To compare AGIS to auscultation and ultrasonography for detecting decreased motility after xylazine administration. Study design Randomised, blinded, controlled cross-over proof of principle study. Methods Six healthy horses were evaluated under fasted and nonfasted conditions and randomly assigned to receive treatment with 0.4 mg/kg xylazine or an equivalent volume of 0.9% NaCl intravenously. After a 48-h washout period, the process was repeated with the alternate treatment. Motility was assessed pre and posttreatment. Borborygmi were assessed in each abdominal quadrant and graded on a scale of 0-3, with 3 being continuous borborygmi. Duodenal, jejunal and caecal contractions were assessed ultrasonographically in consistent locations. Four AGIS biosensors were applied in standardised locations (duodenum, caecum, ventral midline, right dorsal colon). The biosensors measure acoustic signals and data were recorded in transport metric. Data were analysed using cross-classified multilevel random effects logistic regression including area under the receiver operator characteristic curve (AUC ROC). Sensitivity, specificity and accuracy were calculated for each modality. Results All three modalities detected a reduction in gastrointestinal motility following xylazine administration with AUC ROC being 0.85, 0.84 and 0.86 for auscultation, ultrasonography and AGIS respectively. The sensitivity, specificity and accuracy for auscultation was 88, 71 and 75%; for ultrasonography was 67, 63 and 64%; and for AGIS was 69, 70 and 70%, respectively. Main limitations The study was performed in normal healthy horses and application of this device to clinical patients warrants further investigation. Conclusions In this proof of principle study, AGIS was able to discriminate between horses given xylazine from those given 0.9% NaCl with comparable accuracy as auscultation and ultrasonography. The Summary is available in Spanish - see Supporting Information.

Objective To determine serum amyloid A (SAA) concentrations in the postoperative (PO) colic horse and its association with PO complications and infection. Study design Prospective case series. Animals Fifty-one horses after colic surgery. Methods Blood samples from horses undergoing exploratory celiotomy were analyzed for quantitative SAA and fibrinogen concentrations and for neutrophil count at days 0, 1, 2, and 4-6 and at hospital discharge. Results Complications developed in 35 (69%) horses and included PO colic (n = 13, 25%), PO reflux (n = 11, 22%), intravenous catheter (IVC) complications (n = 11, 22%), low-grade fever (n = 11, 22%); surgical site infection (SSI; n = 9, 18%), high-grade fever (n = 7, 14%), and diarrhea (n = 4, 8%). There was an association between day 2 SAA and PO colic (P = .004), diarrhea (P = .042), IVC complications (P = .008), and PO reflux (P = .008) as well as day 4-6 SAA and PO colic (P = .004) and diarrhea (P = .018). Discharge SAA concentration was associated with SSI (P = .001). Fibrinogen concentrations at days 4-6 and at discharge were associated with PO colic (P = .003), diarrhea (P = .004), IVC complications (P = .002), and PO reflux (P = .023). No differences were seen in SAA, fibrinogen, or neutrophils between horses with PO infection vs those with non-infection-associated complications. Conclusion Serum amyloid A was markedly increased in the PO period in all horses but did not differ between PO infection and noninfection complications. The amount of inflammation associated with PO colic and colic surgery was high and may have affected the predictive value of SAA for early PO infection. Clinical significance Although increases occurred earlier, measurement of SAA with a point-of-care analyzer may not be a more sensitive indicator of infection in the early PO colic horse than fibrinogen concentration. Serum amyloid A may help detect SSI in the late PO period.

Objective To evaluate short- and long-term outcome after medical and surgical management of horses with cecal impaction and to determine reasons for death or euthanasia. Study Design Retrospective case series. Animals Horses (n = 150). Methods Data collected from medical records (1991–2011) of horses with a diagnosis of cecal impaction, included signalment, history of recent disease/surgical procedure, admission data, management (medical, typhlotomy alone, jejunocolostomy), complications, and outcome. Short-term outcome (alive or dead at discharge) and long-term outcome (alive or dead at ≥1 year) were determined by telephone interview. Data were analyzed using a χ2 or Fisher's exact test. Level of significance was P

Objective To compare in geriatric and mature horses the occurrence of short-term complications and short-term outcome associated with complications after colic surgery. Study Design Retrospective case–control study. Sample Population Horses aged ≥20 years (geriatric, n = 78) and 4–15 years (mature non-geriatric, n = 156) that had exploratory celiotomy for colic and survived recovery from general anesthesia. Methods Medical records (2000–2010) of horses that recovered from general anesthesia after colic surgery were reviewed. Postoperative complications evaluated included postoperative reflux (POR), diarrhea, inappetence, fever, leukopenia, incisional infection, incisional dehiscence, thrombophlebitis, colic, repeat celiotomy, pneumonia, and laminitis. Short-term outcome (alive vs. dead at hospital discharge) of geriatric and mature horses with these complications were compared. Data were analyzed using a χ2 or Fisher's exact test or an ANOVA. Level of significance P

Objectives To determine factors associated with postoperative reflux, postoperative colic, repeat celiotomy, and survival in horses after end-to-side (E2S) or side-to-side (S2S) jejunocecostomy. Study Design Retrospective, multicenter study. Sample Population Horses (n = 150). Methods Admissions, intra- and postoperative data were collected from medical records of horses that had E2S or S2S jejunocecostomy. Descriptive statistics were calculated and data were analyzed using parametric and nonparametric tests, linear and multivariate logistic regression with significance set at P

Objective To report the results of a survey of opinions on current treatments and estimated outcomes of ascending colon volvulus in horses. Study Design Web-based survey. Sample Population American College of Veterinary Surgeons (ACVS) Diplomates (n = 151) who perform gastrointestinal surgery in horses. Methods ACVS Diplomates with credentials in the large animal specialty obtained by examination in 2010 or earlier (n = 410) were solicited by e-mail to complete a web-based survey designed to determine ascending colon volvulus treatment preferences and outcomes. Results Responses were obtained from 162 ACVS Diplomates, of which 151 currently performed gastrointestinal surgery in horses. Horses surgically treated with ascending colon volvulus accounted for ≤20 cases/year and primary treatment was most often anatomic reduction with or without pelvic flexure enterotomy. Median estimated survival rate was 70% and surgical treatments were not associated with estimated survival (P = .27). Diplomates identified early surgical correction as the single most important factor impacting survival of horses surgically treated for ascending colon volvulus. Conclusions Reported survival rates for horses with ascending colon volvulus were good. Respondents indicated this might be due in part to early surgical treatment. Survey investigations can provide preliminary data for future prospective studies and facilitate a consensus among Diplomates in treatment of surgical disease.

Objective—To document causes of colic in equine neonates, evaluate clinical features of neonates managed medically versus surgically, determine short- and long-term survival rates for neonates with specific medical and surgical lesions, and assess ability of patients to achieve intended use. Design—Retrospective case series. Animals—137 client-owned equine neonates (< 30 days old) with a history of colic or signs of colic within 1 hour after hospital admission examined between 2000 and 2010. Procedures—Signalment, history, results of physical examination, laboratory data, ancillary diagnostic tests, details of treatment, primary diagnosis, concurrent diseases and short-term survival rate were obtained from the medical records. Long-term follow-up information was obtained through phone survey. Results—137 neonates with colic were included. The majority (122 [89%]) of neonates were managed medically. The 3 most common diagnoses associated with colic were enterocolitis (37 [27%]), meconium-associated colic (27 [20%]), and transient medical colic (26 [19%]). The most common reason for surgery was small intestinal strangulating obstruction, and these neonates were more likely to have severe, continuous pain and were less responsive to analgesics. Concurrent diseases were common (87 [64%]) but did not significantly impact survival rate. Short-term survival rate was not significantly different between medically (75%) and surgically (73%) managed neonates. Long-term survival rate was excellent (66/71 [93%]) for horses that survived to hospital discharge. Most neonates surviving to maturity were used as intended (49/59 [83%]). Conclusions and Clinical Relevance—Most neonates examined for signs of colic can be managed medically. Short-term survival rate in medically and surgically treated neonates was good. Long-term survival rate of foals discharged from the hospital was excellent, with most achieving intended use.

Summary Reasons for performing the study There is disagreement among surgeons over whether jejunoileostomy (JI) or jejunocaecostomy (JC) is the better method of anastomosis following proximal ileal resection. Objective To compare short- and long-term complications and outcome in horses undergoing jejunojejunostomy (JJ), JI and JC and to test the hypotheses that a higher proportion of horses undergoing JI would have short-term complications and mortality compared with horses undergoing JC or JJ and that JC would be associated with a higher long-term mortality and occurrence of colic. Study design Retrospective cross-sectional study. Methods Medical records of horses undergoing celiotomy for a small intestinal obstruction and JJ, JI or JC from 2005 to 2010 were reviewed. Post operative complications were recorded. Short-term outcome was alive vs. dead at hospital discharge and was analysed using a Chi-squared test. Long-term follow-up was obtained and a Kaplan–Meier estimate of the survivor function was performed. Results There were 112 horses included. A higher proportion of JI horses had a repeat celiotomy during hospitalisation compared with horses undergoing JC. The number of horses alive at hospital discharge was not different between groups: JJ 79% (95% confidence interval [CI] 68–90%), JI 78% (95% CI 61–96%), JC 83% (95% CI 71–96%). Among horses discharged with long-term follow-up, more horses had colic after JC compared with JJ or JI. Long-term post discharge survival based on the Kaplan–Meier survivor function was lower for horses undergoing JC than JJ or JI (P = 0.04). Conclusion While there was no difference in short-term outcome between groups, more horses with JI underwent a repeat celiotomy during hospitalisation. Horses with a JC were more likely to have long-term complications with colic. Horses that were subjected to euthanasia because of colic within 12 months of hospital discharge either had a JC or repeat celiotomy. The results suggest that, when possible, a JI may be the preferred method of anastomosis based on more favourable survival and lower occurrence of colic long term.

Objective To compare long-term outcome of Salmonella-positive versus Salmonella-negative horses discharged from hospital after colic surgery. Study design Retrospective case-control. Animals Horses discharged from the hospital after colic surgery. For each horse with positive culture for Salmonella enterica (SAL-POS, n = 59), at least 2 horses testing negative for S. enterica (SAL-NEG, n = 119) were enrolled. Methods Owners were interviewed via phone at least 12 months after surgery regarding: (1) complications after discharge from the hospital; (2) duration of survival; and (3) return to prior or intended use. Association between immediate postoperative clinical variables such as Salmonella status and long-term measures of outcome was tested via ratios (odds ratio [OR]) and 95% confidence intervals. Data were analyzed for survival using a Cox proportional hazards model and for return to use using multivariable logistic regression. Results SAL-POS horses had a higher OR of surgical site infection (2.7 [1.1-6.9] P = .027) and weight loss (6.8 [1.8-26.1] P = .002). At the time of follow-up, there were 53/56 (95%) SAL-POS and 99/118 (84%) SAL-NEG horses alive. The final multivariable model for nonsurvival included postoperative colic (hazard ratio 7.6 [2.8-19.2] P = .002) and the interaction between Salmonella status and duration of rectal temperature > 103°F postoperatively (SAL-POS 1.04 [1.01-1.07] and SAL-NEG 1.16 [1.06-1.25], P = .005). The majority of horses returned to their intended use regardless of their SAL-POS (38/50, 76%) or SAL-NEG (77/96, 80%, P = .498) status. Conclusion Salmonella-positive horses that survive to discharge from the hospital after colic surgery have similar risks of long-term complications (colic/diarrhea), survival, and return to function than Salmonella-negative horses.

It is our clinical impression that age and incision length are more strongly associated with surgical site infection (SSI) following colic surgery than skin closure or wound protection method. Therefore, the objective of this observational clinical cohort study was to identify the risks for SSI in horses undergoing colic surgery. Data collection included pre-, intra-, and postoperative variables. Variables with P 0.2 following univariable analysis were used in a logistic regression multivariable model. Variables with P 0.05 were included in the final model. Odds ratios (OR; 95% confidence intervals, 95% CI) were determined. The area under the curve (AUC) for the receiver-operator characteristic was calculated. The final multivariable model included breed (P = 0.008), incision length (P = 0.004), surgical procedure classification (P 0.001), and postoperative (PO) colic (P = 0.037; overall model P 0.001, and AUC was 0.81 [excellent discrimination between SSI vs. no SSI]). Warmbloods (OR 12.0; 95% CI 2.7-74.8), American breeds (OR 6.4; 95% CI 1.2-43.0), and Thoroughbreds (4.5; 95% CI 1.1-25.5) more commonly had SSI than other breeds (ponies/miniature horses, Draft breeds, Standardbreds, Arabians, and Crossbreeds [referent]). A higher SSI rate was associated with incision lengths27 cm (3.7; 95% CI 1.5-9.9), heavily contaminated procedures (12.0; 95% CI 3.3-49.9), and horses with PO colic (2.7; 95% CI 1.1-6.8). SSI appeared to be more common after heavily contaminated procedures and in horses with PO colic, which probably resulted in more incisional contamination and trauma. Some breeds appeared to have higher odds of SSI. Age was not associated with SSI. The risk of developing SSI was higher for horses with an incision27 cm; therefore, surgeons are encouraged to use the minimum incision length required to accomplish the necessary abdominal exploration and bowel manipulation in the safest manner possible.

Objective To evaluate the effect of PERIDAN™ Concentrate on clinical findings, infection, and tissue healing in adult horses undergoing celiotomy and jejunojejunostomy. Study Design Block randomized blinded experimental in vivo study. Animals Adult horses (n = 12). Methods Horses had jejunojejunostomy at 2 sites and were administered 5 L of diluted PERIDAN™ Concentrate (6 horses) or Lactated Ringer's Injection (LRS) control intraperitoneally (6 horses) before body wall closure. Postoperative monitoring comprised physical examinations, serial hematology, coagulation and chemistry panels, and ultrasonographic examination. Horses were euthanatized 10 days postoperatively. Anastomoses and linea alba incisions were tested for mechanical strength; and tissue healing, inflammation, and infection were assessed by histological evaluation. Data were analyzed using a mixed model ANOVA. Level of significance was P < .05. Results No physical examination differences were observed between groups. Statistically significant differences were observed in leukocyte and neutrophil counts, prothrombin time, antithrombin III activity, intestinal bursting pressures, and histologic healing grade in the mid region of the linea alba. These differences were minimal, and of no observable clinical significance. Other blood variable and histologic differences between groups were not significant. Conclusions PERIDAN™ Concentrate was safely administered intraperitoneally to healthy horses undergoing celiotomy and anastomosis.

SummaryObjective: To examine the efficacy and biocompatibility of a thiolated gelatin-thiolated carboxymethyl hyaluronan (CMHA-SGX) sponge as an osteoconductive device in an equine second and fourth metacarpal bone defect model.Methods: Seven millimetre segmental ostectomies were created bilaterally in the second and fourth metacarpal bones of four horses. The left and right metacarpal defects were randomly assigned to (1) be filled with a CMHA-SGX sponge (treated) or (2) were left unfilled (control). The duration of the study was nine weeks. Bone healing was evaluated using serial radiology, as well as histologically and histomorphometrically. Data were analyzed using an analysis of variance (ANOVA). The level of significance was p Results: Serial radiographic evaluation revealed improved healing in the treated compared to the control defects at weeks eight and nine (p = 0.02). This finding was not corroborated histologically. Histomorphometry did not reveal any significant differences in healing between experimental groups. The CMHA-SGX sponge did not inhibit bone formation, induce local inflammation or lead to surgical site infection.Clinical significance: While further optimization to improve osteoconductive properties should be considered, the CMHA-SGX sponge appears to be a biocompatible orthopaedic implant and its use as a carrier for osteogenic proteins warrants further investigation.

Summary Reasons for performing study: Infections are common complications in post operative colic patients. It is the impression of some surgeons that pyrexia in the early post operative period is a sign of infection and appropriate timing of perioperative antimicrobials will decrease the incidence of post operative infection. Objective: To determine the association between 1) post operative pyrexia and development of infection and 2) perioperative antimicrobial drug use and infection rate in post operative colic patients. Methods: Medical records of patients undergoing surgical treatment for colic were reviewed. Horses recovering from surgery and surviving >48 h were included. Data relating to case details, duration of surgery, post operative infection, peri- and post operative antimicrobial administration, presence, intensity and duration of pyrexia, were recorded. Data were analysed using standard statistical methods for simple comparisons between groups and by logistic regression for more complex comparisons. Results: One-hundred-and-thirteen horses were included in the final analyses, 48 (43%) of which were diagnosed with a post operative infection. Duration of surgery and anaesthesia were associated with post operative infection. Eighty-five percent of horses (n = 96) exhibited pyrexia (rectal temperature >38.3°C) post operatively. Peak temperature >39.2°C, time post surgery to peak temperature >48 h and duration of pyrexia >48 h were significantly associated with infection. In a combined model, time to first pyrexic >48 h post surgery, peak temperature and time to peak >48 h were equally weighted and the model’s positive predictive value for post operative infection was 72%. Timing and dose rate of preoperative antimicrobials were not associated with infection but duration of post operative antimicrobial drug use was. Conclusion and clinical relevance: Slight to mild pyrexia (38–39.4°C) in the early post operative period is not necessarily associated with impending bacterial infection in colic patients and the use of antimicrobials in these patients may be costly and unnecessary.

Objective - To determine: (1) changes in blood ammonia, bile acid (BA), bilirubin, triglyceride, and glucose concentrations and liver enzyme activities in perioperative colic patients and (2) the association between these laboratory findings and short-term survival. Design - Prospective observational clinical study. Animals - Thirty-two adult horses undergoing exploratory celiotomy for colic. Interventions - None. Measurements and Main Results - Blood samples were collected preoperatively and at 24-36 and 72-84 hours postoperatively and analyzed for blood ammonia, BA, bilirubin, triglyceride, and glucose concentrations and sorbitol dehydrogenase (SDH) and gamma glutamyl transferase (GGT) activities. Short-term survival was defined as survival to hospital discharge. Data were analyzed using a Fisher's exact test and analysis of variance. Mildly increased blood ammonia concentrations were present in 2 horses at admission. Postoperative blood ammonia concentrations were within reference intervals in all horses. There were increases in liver enzyme activities as well as in BA, triglyceride, and total bilirubin concentrations. Horses with markedly increased admission BA concentrations and SDH activities did not survive. BA concentrations and SDH activities decreased postoperatively. There was no association between GGT activity and survival; GGT activity remained increased postoperatively. Blood triglyceride concentration was increased in almost all horses postoperatively; horses that did not survive had higher triglyceride concentrations at 24-36 hours postoperatively than horses that survived. Conclusion - Alterations in metabolism and hepatobiliary function are common in colic patients. The results of this study provide further prognostic indices for colic patients and highlight areas for improvement in patient management. (J Vet Emerg Crit Care 2010; 20(6): 578-586) doi:10.1111/j.1476-4431.2010.00597.x

Summary Reason for performing study: Owners and veterinarians are often concerned about mortality of geriatric horses following colic surgery. Objective: To compare treatment, diagnosis and short-term survival for geriatric compared to mature nongeriatric horses with colic. Methods: Medical records of horses admitted with a presenting complaint of colic between 2000 and 2006 were reviewed. Geriatric horses were aged ≥16 years (n = 300) and subcategorised as age ≥20 years (n = 134). Mature nongeriatric horses were age 4–15 years (n = 300). Information obtained included medical (included horses subjected to euthanasia without surgery) vs. surgical management, lesion location, type and classification, surgical procedures performed and short-term survival. Data were analysed using a Chi-squared test or an analysis of variance. Level of significance was P

Summary Reason for performing study: It is the impression of some surgeons that geriatric horses have a lower survival rate compared to mature nongeriatric horses following colic surgery. One possible reason for this is that geriatric horses may be more critically ill at admission and have more severe disease than mature nongeriatric horses. Objective: To compare admission historical, physical examination and laboratory data for geriatric and mature nongeriatric horses referred for signs of colic. Methods: Medical records of horses admitted with a presenting complaint of colic between 2000 and 2006 were reviewed. Geriatric horses 16 years (n = 300) and mature nongeriatric horses 4–15 years (n = 300). Information obtained included duration of colic prior to admission, admission level of pain, heart rate, intestinal borborygmi, packed cell volume (PCV), plasma creatinine and blood lactate concentrations and peritoneal fluid total protein. Data were analysed using a Chi-squared test or an analysis of variance. Level of significance was P

Objective: To describe a novel surgical technique for management of right dorsal colitis in the horse. Study Design: Clinical report. Animals: 14-year-old Warmblood gelding. Methods: The horse was referred for treatment of a stromal abscess and signs of right dorsal colitis. Plasma chemistry revealed marked hypoproteinemia. Abdominal ultrasonographic examination showed a thickened right dorsal colon (RDC). Medical treatment was unsuccessful. With the horse in left lateral recumbency under general anesthesia, an approach to the right side of the abdomen through a 16th rib resection was made. The thoracic cavity was entered during the approach. Surgical resection of the RDC and side-to-side anastomosis of the diaphragmatic flexure to the small colon (bypass) was performed. The thoracic cavity was closed by attaching the diaphragm to the body wall and air was removed at the completion of surgery. Results: Resection of the RDC and bypass of the resected area was successfully performed. The colic signs and hypoproteinemia resolved. Complications of surgery included a deep surgical site infection with development of a large intrathoracic abscess. The abscess was managed with drainage and long-term antimicrobial treatment. Conclusion: Right dorsal colitis can be treated successfully with resection and bypass of the RDC. In cases where the thoracic cavity is penetrated during the abdominal approach, the diaphragm should be sutured to the body wall at the beginning of surgery to avoid development of an infection within the thoracic cavity. Clinical Relevance: RDC resection and bypass may be an alternative approach for management of horses with right dorsal colitis.

Recurrent colic is a frustrating problem to manage in horses, particularly following abdominal surgery for gastrointestinal disease. Possible causes of post operative recurrent colic are shown in Table 1. Colic was the most frequently reported shortand long-term complication following abdominal surgery, with 30–35% of horses having at least one episode of colic following hospital discharge (Proudman et al. 2002; Mair and Smith 2005). Importantly, most signs of colic occurred within the first 100 days of surgery and only 5% of horses had more than 3 colic episodes (Proudman et al. 2002). While at an initial glance these numbers may be somewhat of a deterrent to recommending colic surgery, it is important to recognise that 95% of horses had either none or only one episode of colic after surgery! Reasons for post operative recurrent colic should be identified so that every effort toward prevention is made. The role of recurrent colic prior to the episode requiring surgery also needs consideration when evaluating horses with signs of colic following surgery and deciding on a management strategy. Reasons for post operative recurrent colic are different for horses with small vs. large intestinal lesions. Horses with small intestinal lesions, particularly necessitating resection and anastomosis, reportedly had a higher occurrence of colic after surgery than horses with large intestinal lesions (Mair and Smith 2005). Intra-abdominal adhesion formation was an important reason for recurrent colic following small intestinal surgery (Mair and Smith 2005). Some of the factors associated with colic and adhesion formation included packed cell volume, total plasma protein, serosanguinous peritoneal fluid, resection and anastomosis, and the development of post operative ileus and the need for repeat laparotomy (Mair and Smith 2005; Proudman et al. 2005). Most of these factors are a reflection of lesion severity and the extent of cardiovascular compromise emphasising the importance of early referral and surgical intervention not only in the prevention of short-term but also long-term complications including problems with adhesion formation and recurrent colic. On the other hand, gas colic and recurrence of colonic displacement or volvulus is the most common cause of post operative recurrent colic for horses with large colon disease. Recurrence rates for nephrosplenic entrapment of the colon were most recently reported to be 8% (Hardy et al. 2000) and 15% for right dorsal colon displacement and volvulus (Hance and Embertson 1992). Horses with right dorsal displacement of the large colon were significantly more likely to experience recurrent episodes of colic requiring veterinary intervention post operatively (42%) compared to other types of displacement, particularly nephrosplenic entrapment (8%) (Smith and Mair 2010). Reasons for this disparity are unknown. Surprisingly, there was only one horse in the latter study that had recurrent episodes of colic prior to the one necessitating surgery. In another study, horses that had experienced signs of colic prior to the episode necessitating surgery for large colon displacement or volvulus had a higher occurrence of colic post operatively compared to horses with no prior history of colic (Southwood 2006). These findings suggested that there may be management factors or underlying motility disorders associated with colic in some of these patients. Motility disorders may be associated with reduced myenteric plexus and neuron density. Schusser and White (1997) found that horses with chronic colonic obstruction (>24 h duration) or with previous obstruction had significantly lower neuron density than normal horses in the pelvic flexure. Myenteric plexus and neuron density in horses with strangulating large colon volvulus was significantly less than normal and horses with colon strangulation that survived had significantly greater neuron density than horses with colon strangulation that died. Horses with chronic recurrent caecal impactions also had lower linear neuron densities compared to normal horses (Schusser et al. 2000). While findings suggest an association between lower neuron and myenteric plexus density and colonic or caecal *Corresponding author email: samhart@vet.upenn.edu 408 EQUINE VETERINARY EDUCATION Equine vet. Educ. (2010) 22 (8) 408-411 doi: 10.1111/j.2042-3292.2010.00087.x

Objective: To compare the mechanical properties and failure modes of a standardized short oblique distal radial metaphyseal osteotomy stabilized using either a transfixation pin cast (TPC), a modular-sidebar external skeletal fixator (ESF), or a solid-sidebar ESF (modular- or solid-ESF, respectively) using static or cyclic axial loading to failure. Study Design: In vitro study. Animals: Equine cadaver forelimbs. Methods: A 30° oblique distal radial osteotomy was created and stabilized using 1 of the 3 fixation methods: (1) TPC, (2) modular-ESF, or (3) solid-ESF. Limbs were tested using static (TPC, modular-ESF, and solid-ESF) or cyclic (TPC and solid-ESF) axial loading to failure. The stiffness, yield load, yield displacement, failure load, and failure displacement for static loading and the cycles to failure for cyclic loading at 75% failure load were obtained. Data were analyzed using a Kruskal–Wallis test. Level of significance was P

Summary Reasons for performing study: Obtaining data on emergency admission survival rates is important to provide clients with an estimate of prognosis and to identify areas in which improvements in case management can be achieved. Objective: To determine the short-term outcome of equine emergency admissions to a university referral hospital during a 12 month period. Methods: Short-term outcome was defined as survival to discharge or died/euthanasia during hospitalisation. The overall death (euthanasia) rate was calculated; and rate for horses with different categories of: age; admission month, day and time; presenting complaint (PC); duration of clinical signs prior to presentation; clinical pathology abnormalities; and therapy/therapeutic-related procedures performed was recorded. Results: There were 918 admissions. The overall death rate was 24%. Foals (34%) and geriatric (40%) subjects had a death rate that was higher than that for mature horses (21%, referent). The death rate was highest in March (37%). Horses with a PC categorised as neurological (46%) or neonatal (41%) had the highest and as ophthalmological (5%) or trauma/skin (13%) the lowest death rates. There was no difference in death rate between different admission days or times or the duration of clinical signs prior to presentation. The death rates for horses with abnormal peritoneal fluid (71%), coagulopathy (63%), acid-base abnormalities (52%), hypoproteinaemia (47%), dehydration (43%), hypoxia/hypercapnia (48%), leucopenia (44%), electrolyte abnormalities (39%), hyperlactataemia (39%) or azotaemia (35%) were high. The death rate for horses treated with intranasal oxygen (57%), plasma (34%) or polymixin B (35%) was high and for horses undergoing laceration repair/joint (0%) or synovial cavity lavage (4%) was low. Conclusions: Age and critical illness were important contributing factors to a higher death rate. Potential relevance: Improving the understanding of disease processes in and developing treatment strategies for neonatal and geriatric patients as well as critically ill patients is required.