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Recurrent colic occurs frequently in the general horse population but little evidence exists about what factors place horses at greater risk of recurrent colic.To quantify time-varying and non time-varying risk factors for recurrent colic among horses attended by first-opinion veterinary surgeons in northwest England.Nested case-control study.A nested case-control study was conducted on data from a prospective longitudinal cohort study of 127 horses recruited subsequent to an episode of medical colic. Data were collected on management and recurrent colic episodes at 4-monthly intervals by telephone questionnaires. All recurrent colic episodes were selected as cases; controls were unmatched and randomly selected from all horse-time at risk. Data relating to the 30 days prior to the date of colic or control selection were used to determine exposure status. Multivariable logistic regression analyses were used to determine risk factors for recurrent colic.In total, 59 cases and 177 controls were included. The final model showed that horses that displayed crib-biting/windsucking (odds ratio [OR] 10.1, 95% confidence interval [CI] 2.5-41.0) or weaving behaviour (OR 3.9, 95% CI 1.5-10.1) had an increased risk of recurrence of colic. Increasing time at pasture reduced the risk of recurrence (OR 0.99, 95% CI 0.99-1.0). A significant interaction was found suggesting that the risk associated with crib-biting/windsucking may be modified by feeding fruit/vegetables; however, further research is required before recommendations for feeding practices can be made.This study suggests that sufficient access to pasture may be an important means of reducing recurrent colic risk. The behavioural risk factors highlight individuals who may be at increased risk of recurrent colic and whose colic prevention strategies should be carefully managed.

Metabonomics is emerging as a powerful tool for disease screening and investigating mammalian metabolism. This study aims to create a metabolic framework by producing a preliminary reference guide for the normal equine metabolic milieu.To metabolically profile plasma, urine and faecal water from healthy racehorses using high resolution (1) H-nuclear magnetic resonance (NMR) spectroscopy and to provide a list of dominant metabolites present in each biofluid for the benefit of future research in this area.This study was performed using 7 Thoroughbreds in race training at a single time point. Urine and faecal samples were collected noninvasively and plasma was obtained from samples taken for routine clinical chemistry purposes.Biofluids were analysed using (1) H-NMR spectroscopy. Metabolite assignment was achieved via a range of one- and 2-dimensional experiments.A total of 102 metabolites were assigned across the 3 biological matrices. A core metabonome of 14 metabolites was ubiquitous across all biofluids. All biological matrices provided a unique window on different aspects of systematic metabolism. Urine was the most populated metabolite matrix with 65 identified metabolites, 39 of which were unique to this biological compartment. A number of these were related to gut microbial host cometabolism. Faecal samples were the most metabolically variable between animals; acetate was responsible for the majority (28%) of this variation. Short-chain fatty acids were the predominant features identified within this biofluid by (1) H-NMR spectroscopy.Metabonomics provides a platform for investigating complex and dynamic interactions between the host and its consortium of gut microbes and has the potential to uncover markers for health and disease in a variety of biofluids. Inherent variation in faecal extracts along with the relative abundance of microbial-mammalian metabolites in urine and invasive nature of plasma sampling, infers that urine is the most appropriate biofluid for the purposes of metabonomic analysis.

The intestinal bacterial community of the horse is a key determinant of intestinal and whole body health. Understanding the bacterial community structure and function is an important foundation for studies of intestinal health and disease.To describe the faecal bacterial community and volatile organic compounds (VOCs) of the faecal metabolome of healthy Thoroughbred racehorses and to characterise responses to dietary supplementation with amylase-rich malt extract.Intervention study.Faecal samples were collected noninvasively before and 6 weeks after supplementation in 8 privately owned Thoroughbred racehorses in active race training. Faecal metabolome was characterised using thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS), with spectral analysis performed using AMDIS and compared against the NIST database. Taxonomic description of the faecal microbiota was achieved using error-corrected 454 pyrosequencing data from 16S rRNA gene amplicons.The faecal metabolome of our study population was dominated by organic acids, alcohols and ketones. We identified 81 different VOCs only 28 of which were present in50% of samples indicating functional diversity. Faecal VOC profiles differed between first and second sampling point, some VOCs being significantly reduced post supplementation, consistent with a marked response to dietary amylase-rich malt extract. Faecal microbiota was characterised as highly diverse; samples demonstrated verifiable diversity in the range 1200-3000 operational taxonomic units (OTUs) per individual. The methods used also describe high levels of infrequent, low abundance OTUs. Faecal microbial community structure was found to be different following dietary supplementation. Differences in several low abundance bacterial taxa were detected and also some evidence of interhorse variation in response.The volatile faecal metabolome of Thoroughbred racehorses is dominated by organic acids, alcohols and ketones; this study demonstrates that dietary supplementation with amylase-rich malt extract may significantly alter the profile of VOCs. The faecal microbiome is highly diverse, dominated by Firmicutes and Bacteroidetes. Small but significant changes in microbial community structure were detected following dietary supplementation. This study describes the faecal metabolome and microbiome of healthy Thoroughbred racehorses against which future studies of disease and dietary intervention can be benchmarked.

Risk factors for large colon volvulus (LCV) in the horse have not been previously reported. Knowledge of these risk factors may allow the introduction of measures that could be taken to minimise the incidence of LCV.To investigate risk factors for LCV in the horse.A prospective, multicentre, unmatched case-control study was conducted over a 24 month period in the UK. Data on 69 cases and 204 control horses, from 4 veterinary hospitals, were obtained via telephone questionnaires. Multivariable logistic regression was used to identify associations between horse and management-level variables and the likelihood of LCV.Increasing height, multiple colic episodes in the previous 12 months and mares, with a greater odds ratio in mares that had previously foaled, were associated with increased risk of LCV. Receiving medication (excluding anthelmintic treatment) in the previous 7 days and quidding behaviour were also associated with increased risk. Management-level variables associated with greater risk of LCV were an increase in the hours of stabling in the previous 14 days, an increasing number of horses on the premises, and 3 or more people involved in the horse's care. Variables related to nutrition associated with increased risk of LCV were being fed hay, being fed sugar-beet, a change in pasture in the previous 28 days, and an alteration in the amount of forage fed in the last 7 days.This study has identified factors that may assist in the recognition of horses with increased risk of LCV and factors that might be altered to minimise the incidence of LCV.Clinicians can use this information to identify horses at risk of LCV and to provide evidence-based advice to owners of these horses.

The pattern of long-term survival and specific factors associated with long-term survival have not previously been evaluated in horses with a strangulating large colon volvulus (LCV).To provide data on the long-term survival of horses with LCV and to identify pre-, intra- and post operative variables associated with survival.Clinical data and long-term follow-up information were obtained from 116 horses with a strangulating LCV (≥360°) undergoing general anaesthesia. Two multivariable Cox proportional hazards models for post operative survival time were developed: Model 1 included all horses and evaluated preoperative variables and Model 2 included horses that survived anaesthesia and evaluated pre-, intra- and post operative variables.The study population comprised 116 horses. Eighty-nine (76.7%) survived general anaesthesia. Of these, the percentage that survived until discharge, to one year and to 2 years was 70.7%, 48.3% and 33.7%, respectively. Median survival time for horses that survived general anaesthesia was 365 days. In Model 1 increased preoperative packed cell volume (PCV) was significantly associated with reduced post operative survival (hazard ratio [HR] 1.08, 95% confidence interval [CI] 1.05-1.11). However, this effect changed over time. In Model 2 abnormal serosal colour intraoperatively (HR 3.61, 95% CI 1.55-8.44), increased heart rate at 48 h post surgery (HR 1.04, 95% CI 1.02-1.06), and colic during post operative hospitalisation (HR 2.63, 95% CI 1.00-6.95), were all significantly associated with reduced post operative survival.Survival time in horses with a LCV was associated with preoperative PCV, serosal colour, heart rate at 48 h post operatively and colic during post operative hospitalisation.This study provides evidence-based information on the long-term survival of horses with LCV and identifies parameters that may assist decision-making by clinicians and owners.

There is limited information about risk factors and survival associated with disorders of the small colon requiring surgical management.1) To document the types of surgical lesion in horses where pathology of the small (descending) colon was the primary cause of abdominal pain, 2) to describe the short- and long-term survival of these cases and identify factors associated with survival and 3) to identify preoperative variables associated with localisation of a lesion to the small colon.Clinical data and long-term follow-up were obtained for horses that underwent exploratory laparotomy over a 10-year period. Descriptive data were generated for short- and long-term survival and survival analysis performed to identify factors associated with reduced survival. Univariable and multivariable relationships were explored using a Cox proportional hazards model. Preoperative factors associated with increased likelihood of a small colon lesion were explored, using controls randomly selected from horses undergoing exploratory laparotomy for treatment of colic unrelated to the small colon.The study population included 84 horses. Of horses with small colon lesions recovered from anaesthesia, the percentage that survived until discharge, one year and 2 years following surgery, was 91.0, 81.0 and 73.5%, respectively. Median survival time for horses in which a resection had been performed was 1029 vs. 3072 days in the nonresection group. Small colon cases were more likely to have shown a longer duration of colic signs prior to admission (P0.001) and to develop post operative diarrhoea (P = 0.001) when compared with surgical controls.Lesions of the small colon carry a good prognosis for survival following surgery. Resection and anastomosis was the only factor associated with reduced long-term survival.This study provides information about lesion types and post operative survival that may be used to assist informed decision-making when managing these cases.

Adipose tissue is an important source of inflammatory cytokines (adipokines) and adiposity has been identified as having a significant effect on human morbidity and mortality. Obesity is also an emerging welfare problem in the UK horse population, but the role that it plays in secondary diseases is unclear.To examine the expression of inflammation-related adipokine genes in retroperitoneal adipose tissue of horses undergoing emergency abdominal surgery and to explore associations with adiposity and post operative survival.Retroperitoneal adipose tissue samples were obtained from 76 horses undergoing emergency abdominal surgery. Real-time PCR was used to measure gene expression for leptin, adiponectin, tumour necrosis factor-alpha, macrophage chemoattractant protein-1, macrophage inhibitory factor, serum amyloid A, haptoglobin and interleukin-1. Multivariate patterns of adipokine expression were explored with principal component analysis (PCA), whilst univariable associations with post operative survival were tested in a Cox proportional hazards model.Leptin gene expression was higher in overweight and obese horses than in lean animals. Expression of mRNA encoding adiponectin mRNA in visceral adipose tissue was positively associated with increased post operative mortality (hazard ratio 1.31, 95% CI 1.05-1.65). However, PCA did not demonstrate multivariable patterns of adipokine gene expression from visceral adipose tissue associated with body mass index or with survival.In horses presented with acute intestinal disease, increased adiponectin gene expression from retroperitoneal adipose tissue is associated with an increased risk of mortality. Obesity assessed by BMI had no association with increased post operative mortality in horses with primary gastrointestinal disease.Further study is warranted on the expression and effects of adipokines, particularly adiponectin, and correlation with postoperative outcome.

The frequency of recurrent colic in the UK equine general practice population is previously unreported. Elucidating risk factors for recurrent colic could provide a basis for clinical decision making and interventions.To determine the incidence rate of and risk factors for recurrent colic.Horse management, prophylactic health care and innate behaviour contribute to the risk of recurrent colic.A cohort of 127 horses was enrolled at the point of a veterinary-diagnosed medical colic episode. Participating owners completed a baseline and 3 follow-up telephone questionnaires over one year. Clinical details of each colic episode were collected with data on management, behaviour and preventive healthcare. Incidence was calculated using time at risk data; non-time varying covariates were assessed for association with recurrent colic using multivariable logistic regression.The recurrence rate was 50 colic events/100 horse years at risk (HYAR). Including only veterinary attended recurrent colic episodes the incidence was 35 colic events per 100 HYAR. A multivariable logistic regression model was built to explore non-time varying risk factors for recurrence collected from baseline data. The model showed that horses that have a known dental problem (OR 5.5, 95% CI 1.3, 23.1) or crib-bite/windsuck (OR 12.1, 95% CI 1.4, 108.1) were at increased risk of recurrence during the year following a colic event.The incidence of recurrence in horses following a medical episode of colic is high in this population and represents a welfare concern. The incidence rate can be used to compare intervention efficacy in similar populations. Identified risk factors could provide the basis for management interventions or highlight at risk individuals.

Epiploic foramen entrapment (EFE) has been associated with reduced post operative survival compared to other types of colic but specific factors associated with reduced long-term survival of these cases have not been evaluated in a large number of horses using survival analysis.To describe post operative survival of EFE cases and to identify factors associated with long-term survival.A prospective, multicentre, international study was conducted using clinical data and long-term follow-up information for 126 horses diagnosed with EFE during exploratory laparotomy at 15 clinics in the UK, Ireland and USA. Descriptive data were generated and survival analysis performed to identify factors associated with reduced post operative survival.For the EFE cohort that recovered following anaesthesia, survival to hospital discharge was 78.5%. Survival to 1 and 2 years post operatively was 50.6 and 34.3%, respectively. The median survival time of EFE cases undergoing surgery was 397 days. Increased packed cell volume (PCV) and increased length of small intestine (SI) resected were significantly associated with increased likelihood of mortality when multivariable analysis of pre- and intraoperative variables were analysed. When all pre-, intra- and post operative variables were analysed separately, only horses that developed post operative ileus (POI) were shown to be at increased likelihood of mortality.Increased PCV, increased length of SI resected and POI are all associated with increased likelihood of mortality of EFE cases. This emphasises the importance of early diagnosis and treatment and the need for improved strategies in the management of POI in order to reduce post operative mortality in these cases.The present study provides evidence-based information to clinicians and owners of horses undergoing surgery for EFE about long-term survival. These results are applicable to university and large private clinics over a wide geographical area.

Equine grass sickness (EGS) remains a frequently fatal disease of equids in Great Britain (GB). The first nationwide surveillance scheme for EGS was developed to obtain information on the occurrence of EGS and to help facilitate future proposed intervention studies, such as vaccine trials.To collect both retrospective and prospective data on cases of EGS occurring in GB since 2000 and to assess potential risk factors for categories of EGS and survival after chronic EGS.Prospective data were collected using a nationwide surveillance scheme for EGS that was developed and initiated in 2007. Data were collected by means of postal and online questionnaires documenting both retrospective premises-level and prospective case-level information. Data on outcomes of EGS category and survival after chronic grass sickness (CGS) were analysed using univariable logistic regression.Descriptive data for 1410 EGS cases occurring in GB in the decade between the beginning of 2000 and the end of 2009 are presented. Univariable logistic regression analyses identified that CGS cases in Scotland were significantly more likely to survive than those occurring elsewhere in GB. There was no relationship between case details and the category of EGS or the outcome among CGS cases.EGS affected equids throughout England, Scotland and Wales. Although an overall average of 141 cases were reported to the nationwide surveillance scheme annually, this number of cases was not consistent between years. Around 50% of CGS cases survived, although regional differences in survival rates existed, probably due to variation in expertise of care and/or disease severity.This study provides information on the spatiotemporal occurrence of EGS in GB during the last decade. Data from the nationwide surveillance scheme can be used in developing protocols for future intervention studies such as Clostridium botulinum vaccine trials.

Endotoxaemia is frequently presumed on the basis of clinical signs in horses with colic.Measurements of plasma endotoxin (LPS) are rarely made in clinical cases and there is little information on the correlations between this variable, clinical variables and outcomes.To measure LPS levels in plasma of horses presented to the Philip Leverhulme Equine Hospital on admission and daily for up to 4 days and to relate LPS levels to selected clinical parameters, such as heart rate and packed cell volume, and outcomes.Blood samples were collected and stored at -20°C prior to assay of the plasma using a validated kinetic chromogenic Limulus amoebocyte lysate (LAL) assay. Clinical parameters and outcome variables were collected from hospital records. Associations were determined by Chi-squared test and logistic regression analysis.Daily blood samples were collected from 234 horses. LPS was detected in 26.5% of the study population and in 29% of those horses presented for colic. Horses providing samples with detectable LPS were more likely to die whilst in the hospital than those that did not (P = 0.045). Horses presenting with colic were more likely to have detectable LPS in their plasma than noncolic cases (P = 0.037), although LPS was detected in the plasma of 8 out of 42 noncolic horses. A horse that did not meet the study definition of clinical endotoxaemia was 10 times less likely to provide a positive LPS sample (OR 0.10, 95% CI: 0.05-0.22).The proportion of horses providing samples with detectable LPS was similar to other studies.LPS was detected in the minority of horses presented with colic. Increased levels of LPS positively correlated with packed cell volume and with risk of mortality in colic cases.

The clinical features of 71 cases in 70 horses in which part of the small intestine became entrapped in the epiploic foramen are described. The horses' sex, age and breed, the month during which they were affected, and whether they exhibited stereotypic behaviour were compared with the same variables in 1279 horses which suffered other types of surgical colic during the same period. Thoroughbred and thoroughbred cross horses were over-represented among the 70 affected horses. There was no age or sex predilection. Fifty-five (77.5 per cent) of the cases occurred between October and March and 15 (21.1 per cent) occurred in January. The cases were significantly more likely to have a history of crib-biting/windsucking than the control group (odds ratio 7.9, 95 per cent confidence interval 4.1 to 15.3). The condition had recurred in two of the horses. Fifty-eight (81.7 per cent) recovered from surgery and 49 (69 per cent) survived until they were discharged from hospital. The median survival time of 31 of the affected horses discharged from the hospital was 700 days, whereas 417 horses with other types of surgical colic had a median survival time in excess of 1931 days.

Equine grass sickness is a high mortality disease which, despite many years of investigation, is of unknown aetiology. Recent findings indicating that the disease is associated with Clostridium botulinum require support from an epidemiological study that recognises and controls for potential confounders, e.g. age, time of year and premises.EGS is associated with low antibody levels to C. botulinum antigens.A matched case-control study was conducted. Data were collected from 66 histologically confirmed cases of EGS and 132 premises-matched control horses. The probability of EGS in horses was modelled using conditional logistic regression.EGS was significantly associated (age-adjusted P0.005) with low antibody levels to each of 3 clostridial antigens; C. botulinum type C and C. novyi type A surface antigens and a C. botulinum type C toxin complex toxoid. These serological risk factors for EGS remained highly significant when entered into multivariable models. This study also identified new horse-level risk factors for EGS; feeding hay or haylage was associated with a decreased risk of disease, change of feed type or quantity during the 14 days prior to disease was associated with increased risk, and the use of an ivermectin anthelmintic at both the ultimate and penultimate treatments was also associated with a significantly increased risk of EGS.This study provides strong support for the role of C. botulinum in the aetiology of EGS and identifies managemental risk factors for the disease.Increasing anticlostridial antibody levels by vaccination and appropriate managemental interventions may decrease the risk of EGS occurring.