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An 11-year-old crossbreed mare was presented with a nodular, pink mass at the temporal corneolimbal junction of the right eye. Histopathology confirmed the diagnosis of invasive squamous cell carcinoma. The mare underwent lamellar keratectomy and conjunctivectomy under general anaesthesia, followed by adjunctive topical chemotherapy with 1% 5-fluorouracil solution for 10 days post-operatively. Adverse effects included moderate conjunctival inflammation and exuberant granulation tissue formation at the surgical site, responding to surgical debulking and topical corticosteroid application. No mass regrowth was present at 12 months following discharge. This report describes the successful use of topical 1% 5-FU as an adjunctive treatment for equine ocular squamous cell carcinoma.

The following case report documents the investigation and progression of two cases of hepatic failure and hyperferraemia in Shetland ponies in Scotland exposed to high environmental levels of iron in groundwater, and to the authors’ knowledge describes the first use of deferoxamine in adult ponies. The importance of consideration of serum iron levels in cases of equine hepatic disease is highlighted and it is suggested that reduction in serum iron by phlebotomy or treatment with deferoxamine may be beneficial in cases displaying hyperferraemia.

Theileria equi, one of the primary pathogens causing equine piroplasmosis, has previously been sub-classified into a number of clades on the basis of 18S SSU rRNA gene sequence diversity. This partitioning of the parasite population has potential implications for host immunity, treatment and vaccine development. To detect and identify different clade genotypes among and within individual equine blood samples, a novel PCR-based technique was designed and optimized. Theileria equi has only recently been described in The Gambia, and the developed genotyping technique was used to analyse blood samples taken from 42 piroplasmosis-positive horses and donkeys within the country. Three different T. equi genotypes were detected within the population, including the same genotype as the recently described Theileria haneyi, with 61.9% of individuals found to be infected with more than one genotype. Overall, there was a trend that males were more likely to have a multiple genotype infection. Thus, the novel genotyping technique has been shown to be effective in analysis of field populations and offers researchers a rapid method of identifying multiple T. equi genotypes both within individuals and equine populations in epidemiological studies.

Understanding multi-host pathogen maintenance and transmission dynamics is critical for\ud disease control. However, transmission dynamics remain enigmatic largely because they are\ud difficult to observe directly, particularly in wildlife. Here, we investigate the transmission\ud dynamics of canine parvovirus (CPV) using state-space modelling of 20-years of CPV serology\ud data from domestic dogs and African lions in the Serengeti ecosystem. We show that, although\ud vaccination reduces the probability of infection in dogs, and despite indirect enhancement of\ud population seropositivity as a result of vaccine shedding, the vaccination coverage achieved\ud has been insufficient to prevent CPV from becoming widespread. CPV is maintained by the\ud dog population and has become endemic with ~3.5-year cycles and prevalence reaching ~80%.\ud While the estimated prevalence in lions is lower, peaks of infection consistently follow those\ud in dogs. Dogs exposed to CPV are also more likely to become infected with a second multihost\ud pathogen, canine distemper virus. However, vaccination can weaken this coupling raising\ud questions about the value of monovalent versus polyvalent vaccines against these two\ud pathogens. Our findings highlight the need to consider both pathogen- and host-level\ud community interactions when seeking to understand the dynamics of multi-host pathogens and\ud their implications for conservation, disease surveillance and control programmes.

Background Globally, working equines have a continued and growing socioeconomic role in supporting the livelihoods of between 300–600 million people in low income countries which is rarely recognised at a national or international level. Infectious diseases have significant impact on welfare and productivity in this population and equine trypanosomiasis is a priority disease due to its severity and prevalence. Strategies are required to improve the prevention, diagnosis, management and treatment of trypanosomiasis in equines and more data are required on the efficacy and safety of current trypanocidal drugs. Methods A prospective randomised, open-label non-inferiority trial was performed in The Gambia on horses and donkeys that fulfilled 2/5 clinical inclusion criteria (anaemia, poor body condition, pyrexia, history of abortion, oedema). Following randomised trypanocidal treatment (diminazene diaceturate, melarsomine dihydrochloride or isometamidium chloride), animals were observed for immediate adverse drug reactions and follow-up assessment was performed at 1 and 2 weeks. Blood samples underwent PCR analysis with specific Trypanosoma sp. primers. Treatment efficacy was assessed by measuring changes in clinical parameters, clinicopathological results and PCR-status post-treatment after evaluating for bias. Using PCR status as the outcome variable, non-inferiority of isometamidium treatment was determined if the upper bound limit of a 2-sided 95% CI was less than 10%. Results There was a significant beneficial effect upon the Trypanosoma sp. PCR positive population following trypanocidal treatment for all groups. The findings of clinical evaluation and PCR status supported a superior treatment effect for isometamidium. Melarsomine dihydrochloride efficacy was inferior to isometamidium. There were immediate, self-limiting side effects to isometamidium in donkeys (26%). Diminazene had the longest duration of action as judged by PCR status. Conclusions The data support the continued use of isometamidium following careful dose titration in donkeys and diminazene for trypanosomiasis in equines using the doses and routes of administration reported., Author summary Equine trypanosomiasis is endemic in many areas of the world with high morbidity and mortality in affected populations. Trypanocides form an essential part of current treatment strategies but evidence regarding efficacy in equines is scarce. In order to inform disease management, the efficacy of three trypanocidal drugs was assessed in horses and donkeys that fulfilled 2/5 clinical inclusion criteria for trypanosomiasis in The Gambia. Selected equines received randomised treatment with either isometamidium, diminazene or melarsomine dihydrochloride and were observed for adverse drug reactions. Follow-up was performed at 1 and 2 weeks. Blood collected at each timepoint was analysed for Trypanosoma spp. using a PCR approach. Within the selected population 66% were PCR positive pre-treatment for Trypanosoma spp.. Trypanosome positive individuals responded favourably to each treatment, but clinical evaluation and PCR status post-treatment supported a superior effect for isometamidium. Melarsomine dihydrochloride had inferior efficacy to isometamidium. Immediate adverse side effects were only documented following isometamidium administration in donkeys (26%) and these were self-limiting. Diminazene had the longest duration of action as judged by PCR status. The data support the continued use of isometamidium and diminazene but not melarsomine dihydrochloride for trypanosomiasis in equines at the doses and routes of administration reported.

Although several studies have assessed the short-term effect of dietary supplements on the treatment and prevention of gastric ulceration in horses, few have assessed the response over a duration of more than 30 days. A blinded randomized noninferiority clinical trial was conducted using 42 Thoroughbred horses in race training with squamous ulceration of ≥ grade 2/4, randomly assigned to one of two treatment groups for a period of 90 days: omeprazole at the full label dose of 4 mg/kg or the Succeed digestive conditioning supplement. Noninferiority analyses and Wilcoxon sign rank tests were used to analyze the data. At day 90, Succeed was noninferior to 4 mg/kg omeprazole administered daily in terms of the proportion of horses with complete resolution of squamous ulceration. At day 30, Succeed was found to be inferior to omeprazole in terms of the proportion of horses with grade ≤1/4 squamous ulceration. The proportion of horses with reducing squamous ulcer score (compared with day 0) was statistically significant for both treatments at days 30 and 60. At day 90 of the 17 horses on Succeed, nine had a reducing squamous ulcer score (P value = .049), and of the 19 horses on omeprazole, 10 had a reducing squamous ulcer score at day 90 (P value = .091). The noninferiority of Succeed compared to omeprazole at 90 days for the complete resolution of squamous ulceration and the reduced efficacy of omeprazole following 90 days of treatment are likely to be of interest to practitioners managing gastric ulceration in performance horses.

Summary Mycobacterial infections in equids are relatively rare but the case report (Charlesworth 2017) detailed in this issue highlights that Mycobacterium bovis infections may still result in clinical signs in this incidental host and have zoonotic potential. Most reported cases of M. bovis in horses have a protracted disease course, with features including pyrexia, weight loss and oedema with a nonspecific inflammatory profile. As such, the clinical features of disease overlap with conditions such as neoplasia, peritonitis, protein-losing enteropathies and bacterial infections including Rhodococcus equi and Lawsonia intracellularis. In this clinical satellite article, mycobacterial infections in equids are considered in terms of incidence and mode of transmission, key clinical features and perhaps most importantly, in terms of the diagnostic techniques that can be used in order to reach a definitive (ante mortem) diagnosis. The major zoonotic risk to veterinary personnel is likely to occur at the time of post-mortem examination of infected horses, and awareness of these potential risks remains of the utmost importance.

Background Equine piroplasmosis (EP) is a notifiable disease in Ireland and a significant concern to domestic and international equine industries. Information regarding EP presence in Ireland is currently limited. This retrospective surveillance study describes a serological and molecular analysis of blood samples submitted to the Irish Equine Centre for EP testing between January 2013 and April 2016. Methods Following serological testing, seropositive samples were screened using a PCR targeting the 18S ribosomal RNA gene. Amplicon sequences were bioinformatically analysed to identify the parasite species and to assess genetic diversity. Results From 2099 screened equine blood samples, 2.5 per cent and 1 per cent were seropositive for Theileria equi and Babesia caballi, respectively. T equi DNA was detected in 9 per cent of the seropositive samples while B caballi DNA was not detected in any sample. The T equi DNA sequences displayed no genetic diversity at this locus, in contrast to samples from the UK and from endemic areas. Conclusion Detection of EP-seropositive and parasitaemic horses in Ireland indicates a clear and present health risk to the equine population. It is recommended that owners adopt appropriate biosecurity measures and that clinicians are mindful of this disease as a differential diagnosis.

Introduction:\ud Infection of equids with Trypanosoma brucei (T. brucei) ssp. is of socioeconomic importance across sub-Saharan Africa as the disease often progresses to cause fatal meningoencephalitis. Loop-mediated isothermal amplification (LAMP) has been developed as a cost-effective molecular diagnostic test and is potentially applicable for use in field-based laboratories.\ud \ud Part I:\ud Threshold levels for T. brucei ssp. detection by LAMP were determined using whole equine blood specimens spiked with known concentrations of parasites. Results were compared to OIE antemortem gold standard of T. brucei-PCR (TBR-PCR).\ud \ud Results I:\ud Threshold for detection of T. brucei ssp. on extracted DNA from whole blood was 1 parasite/ml blood for LAMP and TBR-PCR, and there was excellent agreement (14/15) between tests at high (1 x 103/ml) concentrations of parasites. Detection threshold was 100 parasites/ml using LAMP on whole blood (LWB). Threshold for LWB improved to 10 parasites/ml with detergent included. Performance was excellent for LAMP at high (1 x 103/ml) concentrations of parasites (15/15, 100%) but was variable at lower concentrations. Agreement between tests was weak to moderate, with the highest for TBR-PCR and LAMP on DNA extracted from whole blood (Cohen’s kappa 0.95, 95% CI 0.64–1.00).\ud \ud Part II:\ud A prospective cross-sectional study of working equids meeting clinical criteria for trypanosomiasis was undertaken in The Gambia. LAMP was evaluated against subsequent TBR-PCR.\ud \ud Results II:\ud Whole blood samples from 321 equids in The Gambia were processed under field conditions. There was weak agreement between LWB and TBR-PCR (Cohen’s kappa 0.34, 95% CI 0.19–0.49) but excellent agreement when testing CSF (100% agreement on 6 samples).\ud \ud Conclusions:\ud Findings support that LAMP is comparable to PCR when used on CSF samples in the field, an important tool for clinical decision making. Results suggest repeatability is low in animals with low parasitaemia. Negative samples should be interpreted in the context of clinical presentation.

Equine piroplasmosis (EP) has historically been of minor concern to UK equine practitioners, primarily due to a lack of competent tick vectors. However, increased detection of EP tick vector species in the UK has been reported recently. EP screening is not currently required for equine importation, and when combined with recent relaxations in movement regulations, there is an increased risk regarding disease incursion and establishment into the UK. This study evaluated the prevalence of EP by both serology and PCR among 1242 UK equine samples submitted for EP screening between February and December 2016 to the Animal and Plant Health Agency and the Animal Health Trust. Where information was available, 81.5 per cent of submissions were for the purpose of UK export testing, and less than 0.1 per cent for UK importation. Serological prevalence of EP was 8.0 per cent, and parasite DNA was found in 0.8 per cent of samples. A subsequent analysis of PCR sensitivity in archived clinical samples indicated that the proportion of PCR-positive animals is likely to be considerably higher. The authors conclude that the current threat imposed by UK carrier horses is not adequately monitored and further measures are required to improve national biosecurity and prevent endemic disease.

Summary Fasciola hepatica infestation is reported as a cause of severe eosinophilic cholangiohepatitis in a 28-year-old Warmblood cross pony gelding. The gelding presented initially for investigation of acute laminitis found to be secondary to pars pituitary intermedia dysfunction (PPID). Six weeks of treatment including administration of pergolide achieved good control of the laminitis but there was a marked general clinical deterioration over this period with notable weight loss, tachycardia, anorexia and ventral oedema. Hepatobiliary enzymes were increased significantly and there was mild elevation of plasma bile acid concentration. An eosinophilia in both blood and peritoneal fluid specimens and histopathological confirmation of an eosinophilic cholangiohepatitis on examination of liver biopsies supported a primary parasitic aetiology. The pony was treated for Fasciola hepatica with triclabendazole 12 mg/kg bwt but clinical signs continued to progress. Due to poor clinical response the pony was subjected to euthanasia and post mortem examination revealed an overwhelming infestation of the biliary tracts with Fasciola hepatica and a secondary chronic and severe cholangiohepatitis with marked fibrosis. To the authors' knowledge this is the first equine report demonstrating the relationship between the clinical disease syndrome, eosinophilic cholangiohepatitis and hepatic fluke infestation. Depending on geographical location, fasciolosis should be considered as a differential diagnosis for equine hepatopathies and can result in severe disease.

Summary Most disorders of the equine cervical oesophagus present with a similar range of clinical signs, resulting from acute, chronic or recurrent impediment to the transit of ingesta and saliva. These include profuse frothy nasal discharge and dysphagia with gagging and coughing. Rupture of the cervical oesophagus is characterised by a painful ventral swelling at the affected site with crepitus, cellulitis and potential drainage of necrotic material. Disorders of the thoracic and abdominal segments of the oesophagus are less well recognised and clinical signs are more insidious in onset. Catastrophic damage to the thoracic oesophagus may occur without previous signs of obstruction. Pyrexia, tachycardia, tachypnoea and vague colic signs may be the first manifestations of perforation of the thoracic oesophagus, resulting from a progressive septic pleural effusion. Rupture of the thoracic oesophagus should be a differential in any horse presenting with an unexplained pleural effusion and ruled out by careful endoscopic examination.

Sarcocystis fayeri is a canine protozoan parasite with an equine intermediate host. Historically classified as an incidental pathogen, recent literature has described the toxic effects of Sarcocystis fayeri in human food poisoning, and highlighted potential involvement in equine neuromuscular disease. Until now, horses were believed to be the exclusive intermediate host. This study reports the first molecular confirmation of S. fayeri in a donkey, and gives rise to the consideration of donkeys being a potential reservoir for the parasite. This finding is of particular importance in understanding the epidemiology of this disease.

Background: \ud Tuberculosis caused by Mycobacterium bovis (M. bovis) is very uncommon in horses worldwide.\ud \ud Case presentation: \ud In the current study, an eight-year-old male Thoroughbred in good body condition was admitted to the Equine Clinic at the Onderstepoort Veterinary Academic Hospital in 2005 due to bilateral epistaxis accompanied by coughing. Routine examinations were conducted to determine the cause of the condition. Endoscopic examination revealed the major source of the epistaxis as the trachea, whereas thoracic radiography indicated the presence of a primary pulmonary mass. M. bovis was isolated from a broncho-alveolar lavage (BAL) sample collected. The pulmonary mass reduced in size three months later following an oral administration of enrofloxacin (7.5 mg/kg PO SID). Genetic fingerprinting by spoligotyping identified the M. bovis isolate as spoligotype SB0868 strain. This M. bovis strain type was never described previously in South Africa (SA). This is the first case of M. bovis infection in a horse in SA which has been fully documented including clinical findings, isolation and genetic characterisation of the causative pathogen.\ud \ud Conclusions: \ud This report indicates that horses may contract and harbour M. bovis despite their lower susceptibility compared to other domestic animals. It also suggests that the infection may be more easily contained and eliminated from the host.

Summary Reasons for performing study Imidocarb dipropionate is the drug of choice for equine piroplasmosis but its administration causes severe colic and diarrhoea. An imidocarb protocol that reduces these effects is needed. Objectives 1) Quantification of the effects of imidocarb dipropionate on equine orocaecal transit time (OCTT), with and without atropine or glycopyrrolate premedication and 2) investigation of an improved pretreatment regimen for imidocarb administration. Hypothesis Treatment with imidocarb dipropionate will result in colic and reduced OCTT as demonstrated by the lactose 13C-ureide breath test which will be ameliorated by premedication with either atropine or glycopyrrolate. Methods The effects of 3 drug therapies on OCTT were compared in 6 healthy horses in a randomised double-blind study vs. a saline control: 1) imidocarb dipropionate 2.4 mg/kg bwt administered intramuscularly (i.m.) with saline administered intravenously (i.v.; imidocarb/saline); 2) imidocarb dipropionate 2.4 mg/kg bwt administered i.m. with atropine 0.035 mg/kg bwt administered i.v. (imidocarb/atropine) and 3) imidocarb dipropionate 2.4 mg/kg bwt administered i.m. with glycopyrrolate 0.0025 mg/kg bwt administered i.v. (imidocarb/glycopyrrolate). The lactose 13C-ureide breath test was used to measure OCTT in each case and significance of treatment effect determined by a linear model analysis of variance. Results Imidocarb/atropine treatment caused an increase in OCTT (P

Idiopathic muscular hypertrophy of the oesophagus (IMHO) is reported in equids as an incidental post mortem finding, infrequently associated with clinical signs of oesophageal dysfunction or additional oesophageal abnormalities. Clinicopathological and post mortem findings are presented from a 15-year-old gelding that developed a spontaneous perforation of the distal, intrathoracic oesophagus, in association with IMHO. The majority of oesophageal perforations documented in the equine literature have been related to external or iatrogenic trauma resulting in rupture of the cervical portion of the oesophagus. In this case, the early presenting features included pyrexia and inappetance, and progressed over a 4 day period to include signs of tachypnoea, tachycardia and endotoxaemia due to the development of a fatal septic pleuritis and pleural effusion. Oesophageal obstruction was not a presenting feature. Diagnostic investigation in cases of unexplained septic pleural effusion should include oesophageal endoscopic evaluation to rule out perforation of the intrathoracic oesophagus. IMHO may represent a clinically significant, primary disease entity with the potential to lead to oesophageal perforation.

Purpose of the study: The analyses of exhaled breath (EB) andexhaled breath condensate (EBC) have been established as meth-ods for the diagnosis and monitoring of lung inflammatory dis-eases in human medicine. The application of non-invasivediagnostic techniques in the investigation of lower airway inflam-mation in horses holds much appeal. The aims of this study wereto (i) investigate whether both EB and EBC could be obtainedfrom Thoroughbred racehorses in the field setting, and (ii) inves-tigate the effects of exercise per se on the concentrations ofexhaled nitric oxide (NO) and carbon monoxide (CO) and EBCpH.Methods: EB and EBC were obtained from 23 Thoroughbredracehorses (median age 4 years, range 2-10) over a 5 day period,prior to and immediately following exercise. A single sample ofEB was collected for off-line measurement of NO and CO usinga chemiluminescence gas analyser (LR1800, Logan ResearchUK). EBC was collected by directing EB through a condensingchamber, chilled to -70oC with dry ice. EBC samples were keptfrozen until time of analysis when, after defrosting, the pH of theneat EBC was measured using a bench top pH meter (pH21,Hanna Instruments Ltd). For each horse and sampling period,the ambient temperature and humidity, respiratory rate prior toand during sample collection were recorded. Paired data werecompared using a paired T-test and Wilcoxon signed-rank test,where appropriate. With outcome set as the difference betweenthe exhaled biomarkers before and after exercise, univariant andmultivariant general regression analysis was used to investigateany association between individual outcomes and the recordedvariables.Results: EB and EBC were collected successfully from allhorses before and after exercise with all horses tolerating the col-lection process. The volume of EBC collected was 1.4 ± 0.3mland 1.8 ± 0.4ml before and after exercise, respectively. ExhaledNO concentrations were above the detection limit of the analyser(1ppb) in only 8 of the 46 EB samples collected; NO was notincluded in further analysis. CO was measurable in all pre-exer-cise EB samples (median 1ppb, inter-quartile range 0.6-1.6ppb)and the concentration of exhaled CO decreased significantly afterexercise (median 0.4ppb, inter-quartile range 0.0-0.8ppb; p =0.005). Before exercise, pH of EBC was 4.52 ± 0.25 with a trendfor increased pH exercise (4.77 ± 0.60) which approached signifi-cance (p = 0.06). Horses housed in one specific barn were signifi-cantly more likely to have an increase in EBC pH post exercise(p = 0.005), suggesting an environmental or managemental influ-ence on this exhaled biomarker.Conclusions: This study is the first to document the successfulcollection of both EB and EBC from Thoroughbred racehorsesin a field setting. CO was detected in EB of all horses beforeexercise, which has not been recorded previously (Wyse et al2005). The cause of the significant decrease in CO after exerciseof the horses remains to be established, however enhanced alveo-lar diffusion capacity of CO, increases in airway volume, polyp-noea and alterations in haemoglobin affinity for CO may beinvolved. The trend toward increased EBC pH after exercise mayreflect alterations in concentrations of exhaled volatiles (e.g.ammonia) and deserves consideration in the application of thisbiomarker to the investigation of lower airway inflammation inhorses. Furthermore, the identification of a possible environmen-tal association with EBC pH is in agreement with results from aprevious study (Whittaker et al 2009) and the relationshipbetween environmental factors, pulmonary inflammation andEBC pH are worthy of further investigation.

13 C-ureide breath test; 13 C-octanoic acid breath test; orocaecal transit time; dual stable isotope breath test; small intestinal transit Summary Reasons for performing study: Application of the lactose 13 C- ureide breath test (LUBT) for measurement of equine orocaecal transit time (OCTT) has not been reported previously. The ability to assess OCTT noninvasively, and to investigate its relationship to gastric emptying rate and small intestinal transit, would be of both clinical and research value. Objectives: 1) Assessment of the LUBT in healthy horses, with comparison of induced versus noninduced test protocols. 2) Application of a new dual stable isotope breath test (lactose 13 C-ureide and 13 C-octanoic acid) for gastrointestinal transit measurement. Hypothesis: The LUBT will allow quantification of equine OCTT, and test efficacy will be enhanced by prior administration of lactose 12 C-ureide as shown in vitro. The dual tracer breath test will permit simultaneous measurement of gastric emptying, OCTT and small bowel transit times. Methods: Induced and noninduced LUBTs were performed in 3 healthy mature horses in randomised order using a standard test meal and protocol. Combined LUBT and 13 C-octanoic acid breath tests ( 13 C-OABT) were performed in 4 individuals on 4 occasions at weekly intervals. Expiratory isotopic recovery was modelled to allow generation of gastric emptying data, small bowel transit times and caecal transit parameters. Results: The induction protocol for the LUBT increased the rate and magnitude of expiratory 13 CO2 significantly. Mean s.d. values for OCTT, caecal lag phase (tlag) and caecal t1/2 using the induced LUBT were 3.24 0.65 h, 5.62 1.22 h and 6.31 1.21 h, respectively. Dual stable isotope tests resulted in the production of 2 discrete peaks in expiratory 13 CO2 in 15/16 tests from which gastric t1/2, OCTT and small bowel transit (SBT) parameters could be calculated. Conclusions: The induced LUBT provides a reliable noninvasive measure of equine OCTT and can be paired with the 13 C-OABT to provide further information about small

REASONS FOR PERFORMING STUDY Validation of a reliable, noninvasive clinical test for quantification of equine orocaecal transit time (OCTT) is required. This would facilitate an evidence-based approach to investigation and treatment of equine small intestinal disorders. OBJECTIVES 1) Comparison of the lactose (13) C-ureide breath test (LUBT) with the hydrogen breath test (H(2) BT) for OCTT measurement. 2) Identification of the characteristics of gastrointestinal microbial glycosylureide hydrolase activity in vitro. 3) Production of an optimised protocol for the LUBT for in vivo measurement of equine OCTT. HYPOTHESIS Significant lactose (13) C-ureide ((13) C-LU) hydrolase activity is restricted to the large bowel. The rate of expiratory (13) CO(2) production after ingestion of the isotope will provide an indirect quantifiable measure of orocaecal transit rate. Requisite bacterial activity may be enhanced by a primer dose of unlabelled substrate as shown in Man. METHODS Combined LUBT and H(2) BT were performed in 8 healthy individuals. Analysis of sequential end expiratory breath samples was used to calculate OCTT and results compared. Digestion of (13) C-LU was investigated in vitro using fresh faecal material or intestinal aliquots collected post mortem. Isotopic fermentation rate was measured by rate of appearance of (13) CO(2) . RESULTS Peaks in expiratory (13) CO(2) occurred in all individuals after ingestion of the labelled test meal, whereas H(2) expiration was variable. Both faecal and intestinal microbial digestion of (13) C-LU were maximised by prior exposure to (12) C-LU. Induced bacterial glucoseureide hydrolase activity was significantly greater in the caecum than in the small intestine (n = 10, P

This report describes the clinical and pathological features of 4 horses affected by caecocaecal or caecocolic intussusceptions associated with larval cyathostomiasis. In each case, there was clinical and/or pathological evidence of concurrent larval cyathostomosis. They all demonstrated variable signs including diarrhoea, pyrexia, weight loss and subcutaneous oedema and cyathostome larvae were identified in the faeces of 3 of the horses. These cases highlight the need to consider caecal intussusceptions as a possible complication in horses affected by larval cyathostomosis, especially where signs of abdominal pain are severe or persistent.

The 13C-octanoic acid breath test has been correlated significantly to radioscintigraphy for measurement of gastric emptying indices in healthy horses. The objective of this study was to investigate the validity of the test for measurement of equine delayed gastric emptying, prior to its potential clinical application for this purpose. A model of atropine-induced gastroparesis was used. Gastric emptying rate was measured twice in 8 horses using concurrent radioscintigraphy and/or breath test after treatment i.v. with either atropine (0.035 mg/kg bwt) or saline in randomised order. Analysis of both data sets demonstrated that the atropine treatment had caused a significant delay in gastric emptying rate. Paired breath test data showed an atropine-induced delay in gastric half-emptying time (t 1/2), with no overlap in the 99% CI range (P < 0.001). Significant correlations were found between scintigraphy and 13C-octanoic acid breath test for calculation of both t 1/2 (P < 0.01) and lag phase duration (P < 0.05) in the atropine-delayed emptying results. The mean (s.d.) bias in breath test t 1/2 when compared with scintigraphy was 1.78 (0.58) h. The results demonstrated that the 13C-octanoic acid breath test was an effective diagnostic modality for the measurement of equine delayed gastric emptying. The technique offers advantages to existing methods for clinical investigation, as it is noninvasive, not radioactive, quantitative and requires minimal equipment or training to perform.

Reasons for performing study: Disordered gastric motility may be a significant factor in the pathogenesis of many equine conditions. Although tests for liquid phase emptying rate have been validated in the horse, there are no effective tests for solid phase emptying measurement that can be performed routinely in the field. Objectives: The objective of this study was the assessment of a novel stable isotope technique, the 1 3 C-octane acid breath test ( 1 3 C-OABT), for the measurement of gastric emptying of solid ingesta, by direct comparison with the optimum method of gastric scintigraphy. Methods: To facilitate dual measurement of gastric emptying, a test meal was used containing baked egg yolk labelled with both 1 3 C-octanoic acid and 9 9 m technetium sulphur colloid. Simultaneous, serial lateral gastric scintigraphs and expiratory breath samples were obtained in 12 healthy horses after voluntary ingestion of the test meal. Analysis of breath 1 3 CO 2 : 1 2 CO 2 ratio was performed by continuous flow isotope ratio mass spectrometry. Power regression was used to determine the gastric emptying coefficient, the gastric half-emptying time (t 1 / 2 ) and duration of the lag phase (tag). Results: Significant correlations (P

The aim of this study was to measure the effects of specific commonly used sedative protocols on equine solid phase gastric emptying rate, using the 13C-octanoic acid breath test (13C-OABT). The gastric emptying of a standard 13C-labelled test meal was measured once weekly in 8 mature horses over two 4 week treatment periods. Each horse acted as its own control. In treatment Period 1, saline (2 ml i.v.), xylazine (0.5 mg/kg i.v.), detomidine (0.01 mg/kg i.v.) or detomidine/butorphanol combination (0.01/0.02 mg/kg i.v.) was administered in randomised order after ingestion of the test meal. During treatment Period 2, test meal consumption was followed by saline, xylazine (1.0 mg/kg i.v.), or detomidine (0.03 mg/kg i.v.) administration, or preceded by acepromazine (0.05 mg/kg i.m.) in randomised order. The 13C:12C ratio of sequential expiratory breath samples was determined by isotope ratio mass spectrometry, and used to measure the gastric half-emptying time, t 1/2, and duration of the lag phase, t lag, for each of the 64 tests. In treatment Period 1, detomidine/butorphanol prolonged both t 1/2 and t lag with respect to xylazine 0.5 mg/kg and the saline control (P < 0.05). In Period 2, detomidine 0.03 mg/kg delayed each parameter with respect to saline, acepromazine and xylazine 1.0 mg/kg (P < 0.001). Xylazine 1.0 mg/kg also lengthened t lag relative to the saline control (P = 0.0004), but did not cause a significant change in t 1/2. Comparison of treatment periods showed that the inhibitory effect of detomidine on gastric emptying rate was dose related (P

A 15-year-old Clydesdale cross gelding was investigated and managed over a 2-year period for intermittent collapse. The\ud horse presented initially after an observed episode of collapse at rest, and had a resting tachycardia, elevated Cardiac\ud Troponin I and polycythaemia. Multiple dysrhythmias were detected on telemetric electrocardiography. Vital parameters,\ud cardiac rhythm and red cell count returned to reference range with prolonged rest but further resting syncopal episodes\ud were observed, and due to safety concerns and limited treatment options the horse was euthanased. Post mortem\ud evaluation identified extensive infiltration and replacement of right and left ventricular myocardial fibres with adipose\ud and fibrous tissue, consistent with arrhythmogenic right ventricular cardiomyopathy. This report provides further\ud information regarding the clinical and pathological features of this rarely reported condition

Gastric emptying is the process by which food is delivered to the small intestine at a rate and in a form that optimizes intestinal absorption of nutrients. The rate of gastric emptying is subject to alteration by physiological, pharmacological, and pathological conditions. Gastric emptying of solids is of greater clinical significance because disordered gastric emptying rarely is detectable in the liquid phase. Imaging techniques have the disadvantage of requiring restraint of the animal and access to expensive equipment. Radiographic methods require administration of test meals that are not similar to food. Scintigraphy is the gold standard method for assessment of gastric emptying but requires administration of a radioisotope. Magnetic resonance imaging has not yet been applied for assessment of gastric emptying in small animals. Ultrasonography is a potentially useful, but subjective, method for assessment of gastric emptying in dogs. Gastric tracer methods require insertion of gastric or intestinal cannulae and are rarely applied outside of the research laboratory. The paracetamol absorption test has been applied for assessment of liquid phase gastric emptying in the dog, but requires IV cannulation. The gastric emptying breath test is a noninvasive method for assessment of gastric emptying that has been applied in dogs and cats. This method can be carried out away from the veterinary hospital, but the effects of physiological and pathological abnormalities on the test are not known. Advances in technology will facilitate the development of reliable methods for assessment of gastric emptying in small animals.

Imidocarb dipropionate is the drug of choice for equine piroplasmosis but its administration causes severe colic and diarrhoea. An imidocarb protocol that reduces these effects is needed.1) Quantification of the effects of imidocarb dipropionate on equine orocaecal transit time (OCTT), with and without atropine or glycopyrrolate premedication and 2) investigation of an improved pretreatment regimen for imidocarb administration.Treatment with imidocarb dipropionate will result in colic and reduced OCTT as demonstrated by the lactose 13C-ureide breath test which will be ameliorated by premedication with either atropine or glycopyrrolate.The effects of 3 drug therapies on OCTT were compared in 6 healthy horses in a randomised double-blind study vs. a saline control: 1) imidocarb dipropionate 2.4 mg/kg bwt administered intramuscularly (i.m.) with saline administered intravenously (i.v.; imidocarb/saline); 2) imidocarb dipropionate 2.4 mg/kg bwt administered i.m. with atropine 0.035 mg/kg bwt administered i.v. (imidocarb/atropine) and 3) imidocarb dipropionate 2.4 mg/kg bwt administered i.m. with glycopyrrolate 0.0025 mg/kg bwt administered i.v. (imidocarb/glycopyrrolate). The lactose 13C-ureide breath test was used to measure OCTT in each case and significance of treatment effect determined by a linear model analysis of variance.Imidocarb/atropine treatment caused an increase in OCTT (P0.05) whereas imidocarb/saline produced a nonsignificant decrease in OCTT. Imidocarb/saline caused colic and diarrhoea in 4 of 6 horses, which were not seen in any of the horses treated with imidocarb/atropine or imidocarb/glycopyrrolate or administered the saline control. Intestinal borborygmi were increased in imidocarb/saline and decreased in imidocarb/atropine treated horses, respectively.Imidocarb/saline treatment induced colic signs and a potential reduction in OCTT while imidocarb/atropine treatment increased OCTT significantly when compared with imidocarb/saline. Both atropine and glycopyrrolate premedication ameliorated the clinical gastrointestinal effects of imidocarb but atropine produced significant inhibition of gastric and/or small intestinal motility not detected with glycopyrrolate. Premedication with glycopyrrolate is recommended when using imidocarb for treatment of equine piroplasmosis.

Analyses of exhaled breath (EB) and exhaled breath condensate (EBC) are non-invasive modalities for assessing the lower airways but these methods have not been applied to Thoroughbred racehorses in training. The aims of this study were to determine whether EB and EBC could be obtained from Thoroughbred racehorses in the field and to investigate the effects of exercise per se and during different ambient temperatures and humidity on exhaled concentrations of nitric oxide (eNO), carbon monoxide (eCO) and EBC pH. EB and EBC samples were obtained from 28 Thoroughbred racehorses pre- and post-exercise during warm (n = 23) and/or cold (n = 19) ambient temperatures. eNO was detected in 19/84 EB samples. eCO was measured in 39/42 EB samples pre-exercise (median 1.3 ppm) and concentrations decreased significantly post-exercise (median 0.8 ppm, P < 0.005) and were associated with ambient temperature. EBC pH was 4.51 ± 0.23 pre-exercise and increased significantly post-exercise (4.79 ± 0.59, P = 0.003). The study documented the collection of EB and EBC from Thoroughbred racehorses in a field setting. Alterations in concentrations of volatile gases and EBC pH occurred in response to exercise, and were likely to have been influenced by environmental factors.

Validation of a reliable, noninvasive clinical test for quantification of equine orocaecal transit time (OCTT) is required. This would facilitate an evidence-based approach to investigation and treatment of equine small intestinal disorders.1) Comparison of the lactose (13) C-ureide breath test (LUBT) with the hydrogen breath test (H(2) BT) for OCTT measurement. 2) Identification of the characteristics of gastrointestinal microbial glycosylureide hydrolase activity in vitro. 3) Production of an optimised protocol for the LUBT for in vivo measurement of equine OCTT.Significant lactose (13) C-ureide ((13) C-LU) hydrolase activity is restricted to the large bowel. The rate of expiratory (13) CO(2) production after ingestion of the isotope will provide an indirect quantifiable measure of orocaecal transit rate. Requisite bacterial activity may be enhanced by a primer dose of unlabelled substrate as shown in Man.Combined LUBT and H(2) BT were performed in 8 healthy individuals. Analysis of sequential end expiratory breath samples was used to calculate OCTT and results compared. Digestion of (13) C-LU was investigated in vitro using fresh faecal material or intestinal aliquots collected post mortem. Isotopic fermentation rate was measured by rate of appearance of (13) CO(2) .Peaks in expiratory (13) CO(2) occurred in all individuals after ingestion of the labelled test meal, whereas H(2) expiration was variable. Both faecal and intestinal microbial digestion of (13) C-LU were maximised by prior exposure to (12) C-LU. Induced bacterial glucoseureide hydrolase activity was significantly greater in the caecum than in the small intestine (n = 10, P0.05).Significant (13) C-LU digestion is restricted to the equine large intestine under normal conditions, and is enhanced by prior exposure to (12) C-LU, making (13) C-LU a suitable noninvasive marker of equine OCTT. The LUBT is more reliable than the H(2) BT for measurement of equine OCTT.

Application of the lactose (13) C-ureide breath test (LUBT) for measurement of equine orocaecal transit time (OCTT) has not been reported previously. The ability to assess OCTT noninvasively, and to investigate its relationship to gastric emptying rate and small intestinal transit, would be of both clinical and research value.1) Assessment of the LUBT in healthy horses, with comparison of induced versus noninduced test protocols. 2) Application of a new dual stable isotope breath test (lactose (13) C-ureide and (13) C-octanoic acid) for gastrointestinal transit measurement.The LUBT will allow quantification of equine OCTT, and test efficacy will be enhanced by prior administration of lactose (12) C-ureide as shown in vitro. The dual tracer breath test will permit simultaneous measurement of gastric emptying, OCTT and small bowel transit times.Induced and noninduced LUBTs were performed in 3 healthy mature horses in randomised order using a standard test meal and protocol. Combined LUBT and (13) C-octanoic acid breath tests ((13) C-OABT) were performed in 4 individuals on 4 occasions at weekly intervals. Expiratory isotopic recovery was modelled to allow generation of gastric emptying data, small bowel transit times and caecal transit parameters.The induction protocol for the LUBT increased the rate and magnitude of expiratory (13) CO(2) significantly. Mean ± s.d. values for OCTT, caecal lag phase (t(lag) ) and caecal t(1/2) using the induced LUBT were 3.24 ± 0.65 h, 5.62 ± 1.22 h and 6.31 ± 1.21 h, respectively. Dual stable isotope tests resulted in the production of 2 discrete peaks in expiratory (13) CO(2) in 15/16 tests from which gastric t(1/2), OCTT and small bowel transit (SBT) parameters could be calculated.The induced LUBT provides a reliable noninvasive measure of equine OCTT and can be paired with the (13) C-OABT to provide further information about small intestinal motility.

KNOWLEDGE of the clinical signs, incidence, aetiology, management, treatment and prevention of equine gastric squamous mucosal ulceration has developed since the original groundbreaking work performed by Murray and others over 20 years ago (Murray and others 1989). Equestrian disciplines in which horses have been found to have a high incidence of squamous ulceration include racing (Murray and others 1996), endurance (Tamzali and others 2011) and showing (McClure and others 1999), but significant proportions of horses used for less demanding pleasure pursuits may also have gastric ulceration (Luthersson and others 2009). Although omeprazole has been shown to be highly effective in suppressing gastric acid production and enhancing the rate of ulcer healing (Murray and others 1997), it is expensive and not permitted for use in many competitive events. There is therefore great demand for the production of alternatives, such as gastroprotective feed supplements, that are allowed according to competition rules. Many such products are available, but very few are supported by convincing clinical evidence regarding their efficacy in suppressing ulcer development. On p 147 of this issue of Veterinary Record , Sanz and others (2014) report a prospective crossover study designed to assess the ability of an oral pectin-lecithin complex to prevent the development of ulcers in an experimental model. The evidence published previously regarding the efficacy of this complex in either preventing or treating equine gastric …

The analysis of exhaled breath is a potentially useful method for application in veterinary diagnostics. Breath samples can be easily collected from animals by means of a face mask or collection chamber with minimal disturbance to the animal. After the administration of a 13C-labelled compound the recovery of 13C in breath can be used to investigate gastrointestinal and digestive functions. Exhaled hydrogen can be used to assess orocaecal transit time and malabsorption, and exhaled nitric oxide, carbon monoxide and pentane can be used to assess oxidative stress and inflammation. The analysis of compounds dissolved in the aqueous phase of breath (the exhaled breath condensate) can be used to assess airway inflammation. This review summarises the current status of breath analysis in veterinary medicine, and analyses its potential for assessing animal health and disease.