Estimate of the national incidence of and operation-level risk factors for colic among horses in the United States, spring 1998 to spring 1999

Musculoskeletal Injury and Illness Patterns in British Eventing Horses: A Descriptive Study

There has been little investigation into the health patterns of the eventing horse population outside veterinary clinics. To target health problems in the eventing horse population, it is important to determine the relative impact of different health problems. The objectives were to describe the prevalence and patterns of lameness/illness in registered British eventing horses. An online survey was released for all horses registered with British eventing in 2018. Data were collated and descriptive analyses undertaken. A total of 1677 surveys were completed, among which 49.4% reported a previous lameness/musculoskeletal problem, 26% being in the previous six months. The most frequently reported musculoskeletal problems were in the foot (421), joints (382), wounds (340), back (333), ligament (205), tendon (213), bones (140) and muscles (135). The most frequent non-musculoskeletal problems related to the skin (183), gastric ulceration (173), colic (145) and infection (88). Injuries to the hoof sole/muscles/tendons were most frequently sustained in competition, suspensory ligament/splint bone/stifle/tarsal injuries were more frequently sustained in training and abscess/foot penetration at rest. DDFT injuries were most frequently out of training for >12 months, SDFT/stifle/suspensory ligament for <12 months, tendon sheath/splint bone for <3 months and tarsal/sole bruising/abscess for <2 weeks. A greater understanding of injuries/illnesses frequently sustained could be useful for veterinarians working with event horses.

Early recognition of pain: improving colic outcomes in horses in Senegal

Background

Limited knowledge exists on recognition and treatment of equine abdominal pain in low- and middle-income countries. This study aimed at finding indicators for recognizing abdominal pain, evaluating responses to clinical and behavioral changes, and assessing the impact of timely referral on colic outcomes in a suburban region of Senegal. The final goal was to identify factors that may be leveraged to improve the outcome of horses presented for abdominal pain in Senegal.

Study design

Retrospective, observational cohort study.

Methods

Data from 26 foals and 40 adult horses referred for acute abdomen between 2013 and 2014 and the first semester of 2023 were reviewed. Signs of abdominal pain were grouped into behavioral, posture modification and animal interactions with the environment. Time to referral was defined as the time between the recognition of abdominal pain and referral. The association of time to referral and the outcome was calculated for each subpopulation and compared using logistic regression analysis as appropriate.

Results

A significant proportion of owners (47%) and veterinarians (77.8%) relied on behavioral changes to detect abdominal pain in foals. Most owners referred foals within 24 h, while veterinarians referred within 12 h. Mortality in foals exceeded 50% when referral was delayed by 12 h or more. In adult horses, groomers often were the first noticing behavioral changes (79%), and they referred the horse within three hours, whereas owners typically delayed referral for 24 h or longer, leading to increased hospitalization expenses.

Limitations

The study considered a limited cohort in an suburban area of Senegal. Sourcing complete data was challenging. Additionally, accurately assessing owner experience was difficult due to the participant group's heterogeneity. Absence of a reliable system to measure daily horse-owner interaction time and logistical challenges in the abdominal pain symptom alert chain were also limiting factors.

Conclusions

Early detection is critical for positive colic outcomes in both foals and adult horses. Therefore, raising awareness and providing training to horse owners for prompt recognition of symptoms and referral is essential. This proactive approach aims to improve overall outcomes and reduce the financial burden of equine hospitalization in Senegal.

Dry matter concentration, particle size distribution and sand presence in faeces from horses with and without colic

A study comprising 74 colic and 74 control horses admitted to an animal hospital was performed. Faecal samples were collected and analysed for dry matter concentration, particle size distribution using wet-sieving, and sand presence through a sand sedimentation test. Data on horse breed, age, gender and basic feeding variables was collected and analysed using χ2-tests. Faecal dry matter concentration, particle size distribution and sand score was compared between colic and non-colic horses, and between horses with different colic types, using one-way ANOVA. Results showed that colic and non-colic horse groups were similar in breed, age, gender and basic feeding variables. Faecal dry matter concentration, particle size distribution and sand score were similar among colic and non-colic horses. Horses diagnosed with "unknown colic cause" had higher proportion of particles >0.5 <1.0 mm size compared to horses with colic due to impactions in caecum or colon, torsion or gas accumulation (P<0.05), but this difference was very small and most likely not of biological importance. Faecal dry matter concentration and sand score were similar among horses with different types of colic. Increased knowledge of the composition of particles of different size in equine faeces may enhance our understanding of digesta passage rate in colic and non-colic horses, which is needed to develop preventative measures of certain types of colic.

Comparison of Xylazine and Lidocaine Infusion versus Medetomidine Continuous Rate Infusion during General Anesthesia with Isoflurane in Horses Undergoing Emergency Laparotomy

(1) The main goals of general anesthesia include pain management and a safe anesthetic protocol for smooth recovery. In this retrospective study, we compared two anesthetic protocols for general anesthesia with isoflurane during emergency laparotomy: sedation with xylazine and the intraoperative infusion of lidocaine (X group) versus medetomidine as a preoperative sedation and intraoperative infusion (M group). (2) The medical records of horses who underwent emergency laparotomies between 2016 and 2023 were reviewed. According to the anesthetic protocol, patients were allocated to the X or M groups. Data about the horse, signalment, history, and anesthetic variables were analyzed. (3) Group X had a significantly higher heart rate (HR), lower respiratory rate (RR) and mean and diastolic arterial pressure (MAP/DAP). A progressive increase in HR and RR was observed in both groups. Group X underwent a decrease in RR and an increase in DAP. In Group M, a decrease in MAP and DAP was observed. Group M exhibited a longer recovery time with similar recovery scores. Both protocols provided safe anesthesia for emergency laparotomy, with minor cardiovascular and respiratory depression. Minor respiratory depression was detected when xylazine was used, while recovery was longer with medetomidine.

Antibiotic prophylaxis and hospitalization of horses subjected to median laparotomy: gut microbiota trajectories and abundance increase of Escherichia

Introduction

Horse clinics are hotspots for the accumulation and spread of clinically relevant and zoonotic multidrug-resistant bacteria, including extended-spectrum β-lactamase producing (ESBL) Enterobacterales. Although median laparotomy in cases of acute equine colic is a frequently performed surgical intervention, knowledge about the effects of peri-operative antibiotic prophylaxis (PAP) based on a combination of penicillin and gentamicin on the gut microbiota is limited.

Methods

We collected fecal samples of horses from a non-hospitalized control group (CG) and from horses receiving either a pre-surgical single-shot (SSG) or a peri-operative 5-day (5DG) course of PAP. To assess differences between the two PAP regimens and the CG, all samples obtained at hospital admission (t0), on days three (t1) and 10 (t2) after surgery, were screened for ESBL-producing Enterobacterales and subjected to 16S rRNA V1-V2 gene sequencing.

Results

We included 48 samples in the SSG (n = 16 horses), 45 in the 5DG (n = 15), and 20 in the CG (for t0 and t1, n = 10). Two samples of equine patients receiving antibiotic prophylaxis (6.5%) were positive for ESBL-producing Enterobacterales at t0, while this rate increased to 67% at t1 and decreased only slightly at t2 (61%). Shannon diversity index (SDI) was used to evaluate alpha-diversity changes, revealing there was no significant difference between horses suffering from acute colic (5DG, SDImean of 5.90, SSG, SDImean of 6.17) when compared to the CG (SDImean of 6.53) at t0. Alpha-diversity decreased significantly in both PAP groups at t1, while at t2 the onset of microbiome recovery was noticed. Although we did not identify a significant SDImean difference with respect to PAP duration, the community structure (beta-diversity) was considerably restricted in samples of the 5DG at t1, most likely due to the ongoing administration of antibiotics. An increased abundance of Enterobacteriaceae, especially Escherichia, was noted for both study groups at t1.

Conclusion

Colic surgery and PAP drive the equine gut microbiome towards dysbiosis and reduced biodiversity that is accompanied by an increase of samples positive for ESBL-producing Enterobacterales. Further studies are needed to reveal important factors promoting the increase and residency of ESBL-producing Enterobacterales among hospitalized horses.

Sales and race performance of juvenile Thoroughbreds with surgically corrected large colon displacements

BACKGROUND

Juvenile Thoroughbreds can be expensive to raise and train to race. Part of the economic return in these juveniles are the weanling, yearling and 2-year-old in training sales at which major surgeries must be declared.

OBJECTIVES

To determine if surgically corrected large colon displacements were associated with a reduction of sales price and racing performance. We hypothesised that the surgery would be associated with a reduced sales price but would not be associated with a reduction in race earnings or starts.

STUDY DESIGN

Retrospective cohort study.

METHODS

The medical, sales and racing records of horses less than 2 years old that had a surgical diagnosis of large colon displacement were examined (n = 110). Surgical cases were compared with a control group (n = 299) whose sales and racing data were evaluated.

RESULTS

There was no significant difference in median sale price overall between the two groups. Horses undergoing surgery had a reduced number of starts in the 2-year-old year (1 start; p < 0.001) when compared with control horses (2.32 starts), but no significant difference over the 2- to 4-year-old period. There was no significant association with surgery on earnings within the 2- to 4-year-old period of racing when compared with controls.

MAIN LIMITATIONS

The main limitations for this study were the retrospective design, relatively small number of horses and covering only the 2- to 4-year-old period of the horses' racing career.

CONCLUSIONS

Overall, the results of this study suggest that if the juvenile Thoroughbred requires surgery for a large colon displacement, there is minimal association with sales price or race performance compared with their siblings. With this information, it will be easier to make informed decisions to take young horses to surgery.

A cross-sectional study of colic and rate of return to racing in Thoroughbreds at Seoul Racecourse in Korea between 2010 and 2020

BACKGROUND

The incidence of colic and the outcomes of colic surgery have not been surveyed in racetracks in Korea.

OBJECTIVES

This study examined the incidence, mortality, and case fatality of colic and investigated the effects of age and sex after an exploratory celiotomy on the long-term survival rate (return to racing), subsequent racing performance, and career longevity.

METHODS

The incidence, mortality, and case fatalities of colic were examined over an 11-year period. The records of 40 horses that had undergone a celiotomy, after participating in at least one race and 75 race-matched control horses were analyzed. The racing performance and career length of the horses that returned to racing post-surgery were compared with a control group.

RESULTS

The annual incidence, fatality rate of colic, and annual mortality rate at Seoul Racecourse were 6.5, 2.8 per 100 horse-years, and 0.2 deaths cases per 100 horse-years, respectively. Of the 40 horses that underwent colic surgery, 26 (65%) returned to racing. The likelihood of returning to racing decreased with increasing age of the horses, and geldings had a lower probability of returning. While the performance in the five preoperative races between the two groups was not significantly different, a significant decrease in racing performance was observed after the surgery date (p < 0.01). Horses that underwent colic surgery did not show a significant decrease in career length.

CONCLUSIONS

Surgical treatment for colic at the age of three and four years had a negative impact on the racing performance. On the other hand, there was no significant difference in career longevity between the two groups.

Epidemiology of Colic: Current Knowledge and Future Directions

Epidemiologic studies are essential for the generation of evidence-based, preventive health care strategies. This includes ways to minimize colic risk and assist informed decision making concerning diagnosis, treatment, and likely outcomes. It is important to consider that colic is not a simple "disease" but is a syndrome of abdominal pain that encompasses multiple different disease processes, and which is multifactorial in nature. This review focuses on prevention and diagnosis of colic, including specific forms of colic, communications with owners/carers concerning colic risk and management, and areas of future research.

Retrospective Study on Risk Factors and Short-Term Outcome of Horses Referred for Colic from 2016 to 2022

Simple Summary

Colic syndrome is the most common out-of-hours call for equine practitioners. In most cases, medical treatment at home is effective for the resolution of the disorders. In 20% of cases, hospital intensive care is required. Several factors have been addressed as predisposing to the disorder. Cardiovascular and hemodynamic variables are the most reliable indicators of the severity of the condition and, thus, are important prognostic factors. The aim of the study was to highlight the predisposing factors and best prognostic clinical signs for discharge in a cohort of horses referred for colic syndrome. Medical records from 2016 to 2022 were examined. One hundred and fifty-seven horses were included in the study. Month and time of admission were the main predisposing factors. Cardiovascular variables (heart rate on admission and after 3–6 h, packed cell volume, capillary refill time, and mucosal membranes) and the presence of gastric reflux were negatively associated with discharge as well as time to standing after surgery. The results from this retrospective study may help the clinician in evaluating prognosis, deciding on the best treatment, and adequately informing the owner of the rates of success.

Abstract

(1) Background: colic syndrome is a multifactorial life-threatening condition in equids. Awareness of predisposing and prognostic indicators is useful to adequately inform the owner of the outcome and plan the best treatment. The aim of the study was to identify the variables associated with short-term survival in a cohort of horses referred for colic to a veterinary teaching hospital; (2) Methods: medical records of horses referred for colic from 2016 to 2022 were retrospectively reviewed. Univariate and multivariate regression models were built to assess the odds ratios of discharge from the hospital, both on the whole sample and in those patients undergoing surgery; (3) Conclusions: Month, time of admission, cardiovascular variables (heart rate on admission and after 3–6 h, packed cell volume, capillary refill time, and mucosal membranes), and presence of gastric reflux were significantly associated with discharge in the univariate regression in all horses and in those surgically treated. In the multivariate regression model, heart rate, packed cell volume, and capillary refill time showed significant association with the outcome in the whole sample. Although comparison between this study and previous studies is difficult due to the number and type of variables included, cardiovascular variables and markers of hypovolemia were also shown to be associated with outcome.

Predictive Models for Equine Emergency Exploratory Laparotomy in Spain: Pre-, Intra-, and Post-Operative-Mortality-Associated Factors

The extrinsic and intrinsic characteristics of an equine population may influence the onset of gastrointestinal lesions and affect the survival rate of patients. The equine population in Spain has been the focus of a small number of studies, none of which have involved more than one surgical center. In this retrospective cohort study, we aimed to analyze the survival rate, identify the variables that influenced death, and generate multivariate models using clinical variables. Data were collected from the clinical records of two surgical referral centers in the same region, and a total of 566 horses met the inclusion criteria. The statistical analysis was divided into three parts: The first and second included logistic analysis, in order to identify the variables most closely associated with survival. The third part assessed all previous variables in terms of survival and hospitalization time, using a COX survival analysis. The main risk factors associated with intra-operative mortality were related to seasonality (winter and summer), patient age (older than 9 years), distance from the hospital, the presence of a strangulating lesion, and the bowel segment affected (small intestine). Furthermore, the main factors associated with mortality during hospitalization were the characteristics of the lesions (strangulating) and the differences between surgical centers. The models generated in this study have good predictive value and use only reliable and easily obtainable variables. The most reliable characteristics are those related to the type of colic and the location of the lesion.

Short-term survival rates of 1397 horses referred for colic from 2010 to 2018

Background

Up-to-date and hospital-specific knowledge of prognoses for horses with various forms of colic is essential for helping to guide owners’ decisions on costly treatments, and for assessing the continuous development of standards of care in the hospital. This study aimed to determine the short-term survival rates of horses admitted with colic to the University Hospital for Large Animals (UHLA), University of Copenhagen, Denmark, from 2010 to 2018, and to compare these to a previous local study as well as recent, comparable international studies.

Short-term survival rates were calculated for horses grouped by treatment (surgical, medical) and diseases. Results were compared to the selected studies using Chi-square tests.

Results

A total of 1752 horses were admitted with colic during the period, of which 355 were excluded for reasons such as economic restrictions or immediate euthanasia. Short-term survival of the remaining 1397 cases was significantly higher (83.0% (95% CI 81.1–85.0%)) than a previous local study (76%) and a recent Dutch study (80%). Medical treatment was carried out in 77.1% of cases, and surgery in 22.9% of the cases. Short-term survival for medically (89.7%) and surgically (60.6%) treated horses was significantly higher in the present study compared to the previous study (87% and 42%, respectively), but was similar to that found in the Dutch study. Significantly fewer horses were euthanised during surgery than in the previous study (17.2 vs. 40%), and significantly more horses recovered from surgery (79.1 vs. 56%). Short-term survival rate of surgically treated horses (60.6%) did not differ from other European studies (55–62%).

Conclusions

Short-term survival rates have increased since the previous study at UHLA, mainly due to a decrease in intraoperative euthanasia. Survival rates in this study are similar to those found in recent comparable colic studies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13028-022-00631-4.

How to perform a percutaneous cecal or colonic trocarization in horses with severe abdominal tympany

BACKGROUND

Cecal or colonic gas tympany of any cause may result in increased intraabdominal pressure, causing a significant decrease in venous return and cardiac output. Trocarization of the large colon or cecum in the event of large intestinal tympany may resolve gas distension and accompanying increased intraabdominal pressures sufficiently enough to promote resolution of a displaced large colon. Furthermore, trocarization of the medical colic may decrease morbidity and mortality associated with severe intraabdominal hypertension.

DESCRIPTION

This how-to description details the technique of transcutaneous trocarization of the large colon and cecum in the standing horse using a 14-gauge catheter.

SUMMARY

Trocarization is not a substitute for surgery in the severely gas-distended painful horse exhibiting signs of colic that require surgery; however, it is a viable medical therapy with minimal risk that alleviates gas distention and may assist with correction of a colonic displacement in the horse.

KEY POINTS

The majority of colic episodes involving the large colon can be managed medically without surgical intervention. Auscultation and percussion of the paralumbar fossa area will solicit an audible "ping" (gas/fluid interface), thus targeting the appropriate site for trocarization. Percutaneous trocarization allows for rapid controlled decompression of colonic or cecal tympany, permitting improvement of both ventilation and perfusion. In situations where a displacement or primary colonic or cecal tympany is suspected, trocarisation is deemed successful if the horse has resolution of colic signs and the physical examination parameters return to normal. Trocarization may be clinically advantageous by requiring less pain medication, decreased time in the hospital, decreased costs, and avoidance of surgical intervention; yet, this therapy should not take place of surgical intervention if deemed necessary.

[Evaluation of clinical examination parameters and a scoring system in equine colic as well as the assessment of their prognostic value]

SUBJECT AND AIM

In horses, colic is associated with relatively high mortality rates. Identification of parameters associated with poor outcome may aid in providing a more accurate prognosis. This study aimed to assess the early prognostic value towards survival of the horse based on parameters of the clinical examination.

MATERIAL AND METHODS

In a retrospective study (2013-2017), results of the clinical examination of horses with colic were analyzed. Obtained parameters were categorized from physiologic up to different pathophysiologic manifestations. The risk of death was calculated as odds ratios in comparison to normal values of these parameters. Individual score points were obtained and related to the respective outcome. Cut-off values for prognosis and treatment were calculated to distinguish between outcome and treatment group.

RESULTS

A total of 492 colic horses were analyzed, presenting 433 survivors (88 %). Overall, medical treatment was selected in 346 (70.3 %) horses (with 96 % survivors) and surgical treatment (laparotomy) was performed in 146 (29.7 %) horses (69.2 % survivors). An increased likelihood of the outcome "death" was found in horses aged over 20 years (OR = 5.498, p < 0.0005), with colic signs of > 6 hours duration (OR = 3.590, p = 0.035) and, also, for breeds of draft horses (OR = 8.364, p < 0.0005). Horses with significant increases in heart and respiratory rates (OR = 24.294, p < 0.0005 and OR = 20.375, p < 0.0005, respectively) and increased blood lactate concentrations (> 90 mg/dl: OR = 26.390, p < 0.0005) were more likely to succumb to the disease. However, a scoring system failed to show an association between high score points and poor prognosis.

CONCLUSION AND CLINICAL RELEVANCE

Parameters of the clinical examination as well as the history of the patient may be indicative for the patient's outcome. However, no clear-cut distinction of the evaluated parameters towards survival and treatment options was obtained. A careful investigation of the patient remains mandatory for selection of treatment and a proper assessment of prognosis.

Management of Colic in the Field

Colic is one of the most frequent emergencies necessitating veterinary attention. Referral is not an option in many cases; therefore, the ability to diagnose and treat colic in an ambulatory setting is paramount. Portable imaging and point-of-care testing has improved the ability to identify lesions and assess the patient's status. In cases when field management is the only option, practitioners should be aware of the various treatment options available.

The effects of signalment, diet, geographic location, season, and colitis associated with antimicrobial use or Salmonella infection on the fecal microbiome of horses

BACKGROUND

The fecal microbiome of healthy horses may be influenced by signalment, diet, environmental factors, and disease.

OBJECTIVES

To assess the effects of age, breed, sex, geographic location, season, diet, and colitis caused by antibiotic use (antimicrobial-associated diarrhea [AAD]) and Salmonella infection on fecal microbiota.

ANIMALS

Healthy horses (n = 80) were sampled from nonhospital environments across multiple geographical locations in the United States. Horses with AAD (n = 14) were defined as those that developed diarrhea secondary to antimicrobial use. Horses with Salmonella infection (n = 12) were presented with spontaneous onset of colitis and subsequently tested positive on Salmonella quantitative polymerase chain reaction. All horses were >1 year of age and stratified by a dietary scale that included forages (pasture and hay) and concentrates grouped by percentage of fiber and amount.

METHODS

Illumina sequencing of 16S rRNA genes was performed on fecal DNA.

RESULTS

Healthy horses fed higher amounts of grain clustered separately from those fed lower amounts of grain (analysis of similarities [ANOSIM], R = 0.356-0.385, Q = 0.002). Horses with AAD and Salmonella had decreased richness and evenness compared to healthy horses (P < .05). Univariable analysis of the 3 groups identified increases in Bacteroidetes (Q = 0.002) and Protebacteria (Q = 0.001) and decreases in Verrucomicrobia (Q = 0.001) in AAD horses whereas Salmonella horses had less Firmicutes (Q = 0.001) when compared to healthy horses.

CONCLUSIONS AND CLINICAL IMPORTANCE

Although the amount of grain in the diet had some impact on the fecal microbiome, colitis had a significantly larger influence. Horses with ADD have a more severe dysbiosis than do horses with Salmonella.

How Can Nutrition Help with Gastrointestinal Tract-Based Issues?

Many horses are fed differently than their wild ancestors. They often have limited access to pasture and are fed conserved forage and concentrates rich in starch and sugars, in only 2 meals per day. Feeding practices in contrast to natural feeding behavior can lead to gastrointestinal issues. Standard nutritional evaluation is warranted because of its important role in prevention and in treatment and management of diseases. When medical and nutritional treatments are combined, success rates are higher. New techniques to characterize equine microbiota have been used, allowing for microbiota manipulation to prevent and treat intestinal diseases.

A Pilot Randomised Clinical Trial Comparing a Short-Term Perioperative Prophylaxis Regimen to a Long-Term Standard Protocol in Equine Colic Surgery

Background: For surgical interventions classified as clean or clean-contaminated, including laparotomy, guidelines in human and veterinary medicine recommend a short-term perioperative antibiotic prophylaxis (PAP). In equine colic surgery, however, PAP commonly exceeds 24 h. Objectives: The aim of this study was to compare a single-shot to a 5-day lasting PAP considering surgical site infections (SSI) and other adverse effects probably associated with the particular antimicrobial regimen. Study design: The study was designed as a randomised non-inferiority pilot study including horses subjected to colic surgery while receiving one of two distinct PAP regimens. Methods: All horses (n = 67) included in the study received the standard physical examination before and after surgery. Colic surgery was performed according to the current standard of the clinic. Horses were randomly assigned to two groups, receiving either the “single-shot” or the “5-day lasting” antibiotic prophylaxis. The “single-shot” group (n = 30) received penicillin and gentamicin only once before and, if needed, during surgery, whereas the “5-day lasting” group (n = 37) received antibiotics for five days. In addition to the standard laboratory examinations, serum amyloid A and fibrinogen were determined preoperatively and during five days after surgery. SSI, postoperative colitis and haemolytic anaemia were classified as postoperative complications potentially related to antibiotic use. Results: The outcome of this preliminary non-inferiority clinical trial showed that the occurrence of postoperative adverse events (i.e., SSI, postoperative colitis and haemolytic anaemia) lacked significant differences between the study groups. Main limitations: The main limitations of this study are the limited group sizes and our inability to blind the study. Conclusions: Single-shot PAP seems to be an alternative approach considering the 5-day lasting protocol commonly used in equine abdominal surgery. However, a proper hygiene management together with a close clinical and laboratory monitoring of the equine patient is indispensable.

Lack of Association Between Barometric Pressure and Incidence of Colic in Equine Academic Ambulatory Practice

Anecdotal accounts correlate equine colic onset to changing weather conditions; however, atmospheric effects on colic have not been studied extensively. We hypothesized that changes in barometric pressure would increase the likelihood of a colic diagnosis compared with other noncolic sick events. Multivariable logistic regression analysis was used to look for associations between colic diagnosis and barometric pressure. The University of Pennsylvania Field Service electronic medical records were searched by identifiable examination type via billing procedure codes collecting 3,108 emergent and nonemergent medical events along with corresponding weather data from the National Weather Service from January 1, 2005, through January 1, 2017. Barometric pressure values and changes were not found to be statistically associated with a diagnosis of colic (P = .1). Horses that did not survive were almost 12 times more likely to have a diagnosis of colic (odds ratio [OR]: 11.97; P < .0001). Horses with disease recurrence were 30% more likely to have a diagnosis of colic (OR: 1.29; P = .006). The likelihood of colic diagnosis increased with increasing latitude (OR: 2.43; P = .04). Horses were more likely to be diagnosed with colic in the fall (OR: 1.72; P < .0001), spring (OR: 1.29; P = .04), and summer (OR: 1.85; P < .0001), compared with winter. Stallions were 48% less likely to colic compared with mares (OR: 0.52; P = .016) and Quarter Horses were 32% less likely to colic compared with Thoroughbreds and Arabians (OR: 0.68; P = .047). This study provided evidence that changes in barometric pressure were not a contributing risk factor for colic, although seasons with changing weather and latitude may play a role.

Changes in the faecal bacterial microbiota during hospitalisation of horses with colic and the effect of different causes of colic

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 < .05), and a lower species richness (P = .005) and Shannon diversity (P = .02) in horses with colic ≥60 h compared to <60 h. Based on PCoA and PERMANOVA, there was a significant difference in bacterial community composition for horses with different colic duration (P = .001) and lesion location (P = .006). Several differences in bacterial phyla and genera were observed at different time points and with different types of colic.

MAIN LIMITATIONS

Relatively low numbers and a diverse population of horses.

CONCLUSIONS

The microbiota change from hospital admission to day 3/discharge in horses with colic and horses with colic ≥60 h and large colon lesions have a distinct bacterial population compared to horses with colic <60 h and small intestinal lesions.

Mixed methods investigation of the use of telephone triage within UK veterinary practices for horses with abdominal pain: A Participatory action research study

BACKGROUND

Telephone triage is an integral part of modern patient care systems in human medicine, and a key component of veterinary practice care systems. There is currently no published research on telephone triage within the veterinary profession.

OBJECTIVE

To investigate current approaches to telephone triage of horses with abdominal pain (colic) in veterinary practice and develop new resources to support decision-making.

STUDY DESIGN

Participatory action research using mixed-methods approach.

METHODS

An online survey assessed current approaches to telephone triage of horses with colic in UK veterinary practices. Structured group and individual interviews were conducted with four equine client care (reception) teams on their experiences around telephone triage of colic. Evidence-based resources, including an information pack, decision flow chart and recording form, were developed and implemented within the practices. Participant feedback was obtained through interviews six months after implementation of the resources.

RESULTS

There were 116 participants in the online survey. Management and client care staff (53/116) felt less confident giving owner advice (p<0.01) and recognising critical indicators (p = 0.03) compared to veterinary surgeons and nurses (63/116). Thirteen themes were identified in the survey relating to owner advice; exercise and owner safety were most frequently mentioned, but conflicting guidance was often given. Fourteen client care staff were interviewed. They were confident recognising colic during a telephone conversation with an owner and identified the most common signs of critical cases as sweating and recumbency. The new resources received positive feedback; the decision flow chart and information on critical indicators were identified as most useful. After resource implementation, there was an increase in confidence in recognising critical cases and giving owners advice.

MAIN LIMITATIONS

Limited sample population.

CONCLUSIONS

This study described existing approaches to telephone triage, identified variations in advice given, and worked with client care teams to develop new resources to aid decision-making.

Protective effects of dexmedetomidine on small intestinal ischaemia-reperfusion injury in horses

BACKGROUND

Strangulating small intestinal lesions in the horse have increased morbidity and mortality compared to nonstrangulating obstructions due to mucosal barrier disruption and subsequent endotoxaemia.

OBJECTIVES

To investigate protective effects of dexmedetomidine on small intestinal ischaemia-reperfusion injury in the horse.

STUDY DESIGN

Randomised, controlled, experimental study.

METHODS

Eighteen systemically healthy horses were randomly assigned to three groups: control, preconditioning, and post-conditioning. During isoflurane anaesthesia, complete ischaemia was induced in a 1-m segment of jejunum for 90 minutes. Horses in the preconditioning and post-conditioning groups received dexmedetomidine (3.5 µg/kg followed by 7 µg/kg/h) before (preconditioning) or after beginning ischaemia (post-conditioning), and during reperfusion. Jejunal biopsies were collected before ischaemia (baseline-1), at the end of the ischaemic period (ischaemia), and 30 minutes after reperfusion (reperfusion-1). Additional biopsies were taken 24 hours after reperfusion from ischaemia-reperfusion-injured jejunum (reperfusion-2). Epithelial injury was scored histologically, and morphometric analyses were used to calculate villus surface area (VSA) denuded of epithelium. Data were analysed using analysis of variance, Kruskal-Wallis and Wilcoxon two-sample tests.

RESULTS

In the control group, epithelial injury scores and percentage of VSA denudation for ischaemia-reperfusion-injured jejunum were higher compared to baseline-1 at all time points. The ischaemia and both reperfusion samples from the pre- and post-conditioning groups had lower epithelial injury scores and percentage of VSA epithelial denudation compared to the control group, with no difference from baseline-1 at any time point for the preconditioning group.

MAIN LIMITATIONS

Preconditioning has limited application in the clinical setting with naturally occurring strangulating small intestinal lesions.

CONCLUSIONS

Dexmedetomidine was protective for small intestinal ischaemia-reperfusion injury in the horse when administered before or during ischaemia.

Association Between Disease Severity, Heart Rate Variability (HRV) and Serum Cortisol Concentrations in Horses with Acute Abdominal Pain

Simple Summary

Acute abdominal pain is a major cause for emergency treatment in horses and associated with a high stress level leading to an increased serum cortisol concentration. Stress can also be assessed by analyzing the heart rate variability (HRV). We investigated whether the stress level was different between horses with different causes of abdominal pain and, therefore, demanding a different treatment strategy. Heart rate, its variability in the time domain analyses, and cortisol level indicated a decrease in the stress level the day after admission and the day of discharge from the hospital in comparison to admission for both conservatively and surgically treated patients. However, such changes, over time, were not seen in horses that were euthanized during the hospitalization. Furthermore, the difference in the parameters measured between horses that were eventually euthanized and those that survived was best visible the day after admission. Therefore, we concluded that HRV can give further important information on the stress level in horses with colic and might be helpful in assessing possible outcome. However, further studies are required to assess the validity of HRV analyses in horses with colic.

Abstract

Heart rate variability (HRV) is a noninvasive technique to detect changes in the autonomous nervous system. It has rarely been investigated in horses with colic. Therefore, the objective was to assess the evolution of HRV parameters and cortisol concentrations in horses with colic. The 43 horses included in this study were categorized into three groups according to the treatment (1, surgical; 2, conservative; 3, euthanized). The HRV and laboratory variables were measured at admission (T1), the day after admission (T2), and at discharge (T3) and compared between groups and over time with an ANOVA with Bonferroni correction. Relationships between the HRV parameters themselves and the laboratory variables was assessed by Pearson correlation coefficients. Evolution of the heart rate (HR) over time, mean normal to normal R intervals (meanNN) and cortisol concentrations indicate a decreased sympathetic stimulation over time in group 1 and 2, in contrast to group 3. For group 3, the meanNN and HR differed significantly to group 2 at T1 and to group 1 and 2 at T2. Treatment induced a change in the HRV and cortisol response in horses managed conservatively or surgically but not in horses that required euthanasia. However, further studies are required to assess the validity of HRV analyses in horses with colic.

Indicators of 'critical' outcomes in 941 horses seen 'out-of-hours' for colic

BACKGROUND

This study aimed to describe the presentation and outcomes of horses with signs of colic (abdominal pain) seen 'out-of-hours' in equine practice.

METHODS

This was a retrospective study of horses seen 'out-of-hours' with colic by two equine veterinary practices between 2011 and 2013. Case outcomes were categorised as 'critical' or 'not critical'. A critical outcome was defined as requiring medical or surgical hospital treatment, or resulting in euthanasia or death. A non-critical outcome was defined as resolving with simple medical treatment. A hierarchical generalised linear model was used to identify 'red flag' parameters (aspects of signalment, history and presenting clinical signs) associated with critical outcomes.

RESULTS

Data were retrieved from 941 cases that presented with colic; 23.9 per cent (n=225/941) were critical. Variables significantly associated with the likelihood of a critical outcome in the final multivariable model were increased heart rate (P<0.001), age of the horse (P=0.013) and abnormal mucous membrane colour (P<0.001). Overall 18 per cent (n=168/941) of cases were euthanased.

CONCLUSIONS

This study highlights the mortality associated with colic. The 'red flag' parameters identified should be considered an essential component of the primary assessment of horses with colic.

Effect of the p38 MAPK inhibitor doramapimod on the systemic inflammatory response to intravenous lipopolysaccharide in horses

Background

Doramapimod, a p38 MAPK inhibitor, is a potent anti‐inflammatory drug that decreases inflammatory cytokine production in equine whole blood in vitro. It may have benefits for treating systemic inflammation in horses.

Objective

To determine whether doramapimod is well tolerated when administered IV to horses, and whether it has anti‐inflammatory effects in horses in a low‐dose endotoxemia model.

Animals

Six Standardbred horses.

Methods

Tolerability study, followed by a blinded, randomized, placebo‐controlled cross‐over study. Horses were given doramapimod, and clinical and clinicopathological variables were monitored for 24 hours. Horses then were treated with doramapimod or placebo, followed by a low dose infusion of lipopolysaccharide (LPS). Clinical variables (heart rate, rectal temperature, noninvasive blood pressure), leukocyte count and tumor necrosis factor alpha (TNF‐α) and interleukin‐1 beta (IL‐1β) concentrations were measured at multiple time points until 6 hours post‐LPS infusion.

Results

No adverse effects or clinicopathological changes were seen in the safety study. When treated with doramapimod as compared to placebo, horses had significantly lower heart rates (P = .03), rectal temperatures (P = .03), and cytokine concentrations (P = .03 for TNF‐α and IL‐1β), and a significantly higher white blood cell count (P = .03) after LPS infusion.

Conclusions and Clinical Importance

Doramapimod has clinically relevant anti‐inflammatory effects in horses, likely mediated by a decrease in leukocyte activation and decrease in the release of pro‐inflammatory cytokines. To evaluate its potential as a novel treatment for systemic inflammatory response syndrome in horses, clinical trials will be necessary to determine its efficacy in naturally occurring disease.

The cecal and fecal microbiomes and metabolomes of horses before and after metronidazole administration

Antibiotic administration can be a cause of gastrointestinal disease in horses, creating a disruption in the normal population and function of bacteria found in the hindgut. The objective of this study was to describe the changes in the cecal and fecal microbiomes and metabolomes of clinically healthy horses before and after metronidazole administration. Metronidazole (15 mg/kg BID PO) was given to five horses with cecal cannulas. The study was suspended on Day 3 due to adverse gastrointestinal effects. Cecal and fecal samples were obtained before (Days minus52, m28, m14, and 0) and after (Days 7, 14, 28, and 52) metronidazole administration. DNA was extracted from the cecal and fecal samples, and 16S rRNA genes were sequenced. Richness and evenness indices were significantly decreased by metronidazole administration in both cecal and fecal samples, but the overall composition was only significantly changed in fecal samples on Day 3 (ANOSIM, p = 0.008). The most dominant phyla were Bacteroidetes and Firmicutes in all groups examined. In fecal samples, significant changes of the phyla Actinobacteria, Spirochaetes, Lentisphaerae, and Verrucomicrobia occurred on Day 3, which correlated with clinical signs of gastrointestinal disease. The metabolome was characterized by mass spectrometry-based methods and only named metabolites were included in the analysis. Fecal, but not cecal, metabolites were significantly affected by metronidazole. The fecal metabolites affected represent diverse metabolic pathways, such as the metabolism of amino acids, carbohydrates, lipids, nucleic acids and cofactors and vitamins. Metronidazole administration has potential to cause adverse effects in horses, alters the bacterial composition of the horse’s cecal and fecal content, and the metabolome of fecal samples.

Non-invasive evaluation of the equine gastrointestinal mucosal transcriptome

Evaluating the health and function of the gastrointestinal tract can be challenging in all species, but is especially difficult in horses due to their size and length of the gastrointestinal (GI) tract. Isolation of mRNA of cells exfoliated from the GI mucosa into feces (i.e., the exfoliome) offers a novel means of non-invasively examining the gene expression profile of the GI mucosa. This approach has been utilized in people with colorectal cancer. Moreover, we have utilized this approach in a murine model of GI inflammation and demonstrated that the exfoliome reflects the tissue transcriptome. The ability of the equine exfoliome to provide non-invasive information regarding the health and function of the GI tract is not known. The objective of this study was to characterize the gene expression profile found in exfoliated intestinal epithelial cells from normal horses and compare the exfoliome data with the tissue mucosal transcriptome. Mucosal samples were collected from standardized locations along the GI tract (i.e. ileum, cecum, right dorsal colon, and rectum) from four healthy horses immediately following euthanasia. Voided feces were also collected. RNA isolation, library preparation, and RNA sequencing was performed on fecal and intestinal mucosal samples. Comparison of gene expression profiles from the tissue and exfoliome revealed correlation of gene expression. Moreover, the exfoliome contained reads representing the diverse array of cell types found in the GI mucosa suggesting the equine exfoliome serves as a non-invasive means of examining the global gene expression pattern of the equine GI tract.

Differential Defecation of Solid and Liquid Phases in Horses-A Descriptive Survey

Simple Summary

Free faecal liquid is a condition in horses where faeces are voided in one solid and one liquid phase. The presence of free faecal liquid may cause management problems in equine husbandry and is potentially contributing to impaired equine welfare. Causes of free faecal liquid are not known, but nutritional factors such as the feeding of specific forages have been suggested to be of importance. Characterization of horses showing free faecal liquid and their feeding and management was, therefore, performed via an internet-based survey in order to map the condition further. Results showed that horses with free faecal liquid included a large variety of different breeds, ages, disciplines, coat colours, housing systems and feeding strategies, meaning that almost any type of horse could be affected. Horses that were reported to show free faecal liquid did so with all types of feeding strategies, but changes from wrapped forage to hay, to pasture, or to another batch of wrapped forage often resulted in diminished signs of free faecal liquid. Horses were also reported to have a comparably high incidence of colic in relation to published data for other horse populations. The results indicated that more detailed studies are required for a further understanding of the underlying cause of free faecal liquid.

Abstract

Free faecal liquid (FFL) is a condition in horses where faeces are voided in one solid and one liquid phase. The liquid phase contaminates the tail, hindlegs and area around the anus of the horse, resulting in management problems and potentially contributing to impaired equine welfare. The underlying causes are not known, but anecdotal suggestions include feeding wrapped forages or other feed- or management-related factors. Individual horse factors may also be associated with the presence of FFL. This study, therefore, aimed to characterize horses showing FFL particularly when fed wrapped forages, and to map the management and feeding strategies of these horses. Data were retrieved by a web-based survey, including 339 horses with FFL. A large variety of different breeds, ages, disciplines, coat colours, housing systems and feeding strategies were represented among the horses in the study, meaning that any type of horse could be affected. Respondents were asked to indicate if their horse had diminished signs of FFL with different changes in forage feeding. Fifty-eight percent (n = 197) of the horse owners reported diminished signs of FFL in their horses when changing from wrapped forages to hay; 46 (n = 156) of the horse owners reported diminished signs of FFL in their horses when changing from wrapped forages to pasture; 17% (n = 58) reported diminished signs of FFL when changing from any type of forage batch to any other forage. This indicated that feeding strategy may be of importance, but cannot solely explain the presence of FFL. The results also showed that the horses in this study had a comparably high incidence of previous colic (23%, n = 78) compared to published data from other horse populations. In conclusion, the results showed that FFL may affect a large variety of horse types and that further studies should include detailed data on individual horse factors including gastrointestinal diseases as well as feeding strategies, in order to increase the chance of finding causes of FFL.

Genetics, Evolution, and Physiology of Donkeys and Mules

The genus Equus is made up of donkeys, horses, and zebras. Despite significant variation in chromosome number across these species, interspecies breeding results in healthy, although infertile, hybrid offspring. Most notable among these are the horse-donkey hybrids, the mule and hinny. Donkeys presently are used for everything from companion animals to beasts of burden. Although closely related from an evolutionary standpoint, differences in anatomy and physiology preclude the assumption that they can be treated identically to the domestic horse. Veterinarians should be aware of these differences and adjust their practice accordingly.

Risk factors for acute abdominal pain (colic) in the adult horse: A scoping review of risk factors, and a systematic review of the effect of management-related changes

Acute abdominal pain (colic) is the most common reason for emergency veterinary treatment in the horse. Consolidation of data through a systematic review is important to inform evidence-based medicine and clinical guidelines, but there are currently no published systematic reviews on colic in the horse. The aim of this study was to identify, categorize and appraise the evidence on factors associated with increased risk of developing abdominal pain (colic) due to gastrointestinal disease in the adult horse. A scoping review was performed to identify and categorize evidence on all risk factors for colic. A systematic review of management-related risk factors was then performed following PRISMA guidelines. Both searches were conducted in Medline, CAB Abstracts and Web of Science databases, and publications were assessed against inclusion and exclusion criteria. For the scoping review, study and participant characteristics of included publications and key results were extracted and tabulated. For the systematic review, cohort, case-control or cross-sectional studies investigating acute abdominal pain in horses within two weeks of management changes were assessed. Study characteristics, participant characteristics and study results of included publications for the systematic review were extracted and tabulated. Included publications were appraised using the Joanna Briggs Institute Critical Appraisal Tools for cohort, case-control and cross-sectional studies. The scoping review search identified 3,756 publications. Fifty eight studies met final inclusion criteria, and 22 categories of risk factors were identified. These were grouped into three broad areas: horse-related factors, management-related factors and environment-related factors. The largest body of evidence related to management change. The systematic review of management change identified 410 publications: 14 met inclusion criteria for analysis. These consisted of one cohort, eight case-control and five cross-sectional studies. The studies were conducted between 1990-2008, and the majority of studies were located in the USA (8/14) or UK (3/14). The risk factors related to management change that were assessed were feed, carer, exercise, pasture, water and housing. The largest bodies of evidence for increased risk of colic associated with management change were changes in feed (5/14 publications) and recent change in housing (3/14). Most studies (8/14) did not meet the JBI criterion on confounding factors. There was marked heterogeneity of study methodologies and measures. This is the first study to use a combined scoping and systematic review to analyse evidence for modifiable risk factors for a common condition in the horse. It provides a comprehensive review that will be a key resource for researchers, veterinary practitioners and horse owners. It identified modifiable risk factors associated with an increased risk of colic which should be a key target for preventative health programmes. The findings from the critical appraisal were used to develop recommendations for future research to improve the quality of evidence-based veterinary medicine.

Preliminary results on the association with feeding and recovery length in equine colic patients after laparotomy

Colic is a serious disease for horses and the nutritional management of postoperative colic patients is an extremely important field. The aim of this retrospective study was to analyse the different factors, especially related to nutritional management, that may be associated with recovery length during hospitalization after a surgical intervention for colic, using a multivariate model. Data were collected from the records of horses presented to two hospitals and undergoing surgery for colic. The length (days) of recovery was the outcome of interest and was taken into account as a reference parameter (short, medium, long). The parameters collected (patient details, preoperative clinical and laboratory examinations, postoperative parameters and post-surgery nutritional parameters) were subjected to multivariate analysis (MCA and PCoA). A ranking class dataset was used to calculate Kendall's tau correlation of the length of recovery with respect to other parameters. Descriptive statistic to identify differences in the recovery length among groups (Kruskal-Wallis and Dunn's Multiple Comparison Test) was also performed. p value was set at < 0.05. Groups were not different in preoperative clinical parameters (BCS, PCV, total protein), postoperative parameters (time to 1st defecation, time to the end of IV fluid therapy and time to first water drinking, anaesthesia) and patient details (age). The comparison among groups revealed differences on the post-surgical nutritional parameters. Horses with short recovery consumed higher % of DM as forages in the 24 hr compared with the horses that have a long recovery and reach the minimum DM intake in a shorter period. Both Kendall and MCA analysis confirmed that the time to first feeding had a positive association with the length of recovery. Only 37 horses undergoing colic surgery were included in the study. From a clinical standpoint, this study has shown which nutritional parameters are associated with short recovery.

Colic Prevention to Avoid Colic Surgery: A Surgeon's Perspective

Management factors associated with colic, particularly related to stall confinement and nutrition, have been linked to alterations in gastrointestinal mucosal transport, motility, and microbiome, which in turn creates conditions that induce colic. In particular, meal feeding creates large changes in water movement in and out of the colon and alters the microbiome. These conditions may in turn result in colic conditions such as large colon impaction or large colon volvulus. In addition, a range of management and nutritional factors have been found to place horses at risk of select colic conditions such as ileal impaction. Other specific colic conditions, such as strangulating lipomas, may be related to fat metabolism in geldings and ponies, although the association with nutrition and the endocrine system are less well defined. It has long been understood that parasites are associated with colic, and with the advent of highly effective anthelmintics, parasite-induced colic has been markedly reduced. Nonetheless, equine mangers and veterinarians have to be aware of changes in parasite resistance or patterns of activity, such as the resurgence of large strongyles with surveillance-based management of parasites. Overall, understanding management risk factors can lead to recommendations that prevent colic in horses. Additional study of these factors may ultimately lead to reductions in the prevalence of colic by suggesting optimal management practices.

Clinical and intestinal histologic features of horses treated for recurrent colic: 66 cases (2006-2015)

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.

Exploratory Celiotomy in the Horse Secondary to Acute Colic: A Review of Indications and Success Rates

To review indications and risk factors for exploratory celiotomy secondary to acute colic in the horse; decision making for and during surgery; and prognosis for return to function after exploratory celiotomy for the practicing veterinarian. Data sources included scientific reviews and original research publications from veterinary sources, as well as clinical data specifically in regard to underlying disease and survival rates from a tertiary referral hospital where exploratory celiotomy is commonly performed. There is a high positive predictive value of specific clinical preoperative parameters of the equine acute abdomen, many of which rely on techniques available to field practitioners, relative to the need for surgical intervention. Decision making regarding surgical procedure or even intraoperative euthanasia depends on owner expectations. Survival rates following exploratory celiotomy range from fair to excellent (60%-100%) depending on underlying lesion and return to athleticism following celiotomy is good to excellent (76%-90%). A knowledge base of indications for and rates of survival from colic requiring exploratory celiotomy in the horse is of paramount importance to the equine practitioner. Preconceived notions of poor survival rates are rampant among horse owners, and owners rely on their primary veterinarian's advice for continuation to referral center and in further treatment including exploratory celiotomy.

Colic in the British military working horse population: a retrospective analysis

Colic is a common and potentially life-threatening condition of horses. Multiple risk factors have been previously identified and it is known that a careful management routine can help reduce colic rates. The British military working horse population represents a unique cohort of horses that are intensively managed with a strict regimen. This retrospective study examined the incidence and mortality rate of colic within this population, as well as the signalment of affected horses, and compared these with the general population. Data for 717 horses over a five-year period (2008-2012) were analysed. Of these, 163 horses (22.7 per cent) experienced 267 colic episodes and 13 horses (1.8 per cent) died because of colic. Recurrent colic was experienced by 35 per cent (57/163) of horses. The incidence of colic was 11.1 episodes per 100 horse-years and of colic-related death was 0.5 deaths per 100 horse-years. Horses purchased from mainland Europe were more likely to suffer from colic (OR 4.6; P<0.001) and from recurrent colic (OR 6.0; P=0.005) than horses purchased from Ireland. Only 3 per cent (8/267) of colic episodes were treated surgically. It was concluded that the incidences of colic and colic-related deaths within the British military working horse population are similar to those of the general horse population.

Anthelmintic efficacy against equine strongyles in the United States

Equine strongyle parasites are ubiquitous in grazing equids across the world. Anthelmintic resistance is widely developed in cyathostomin populations, but very few surveys have evaluated anthelmintic efficacy in equine populations in the United States, and most of these are over 15 years old. The present study was carried out as part of the National Animal Health Monitoring Systems (NAHMS) Equine 2015-2016 study. The aims were to investigate anthelmintic treatment efficacy by means of the fecal egg count reduction test (FECRT) and identify parameters associated with decreased efficacy. Data were collected from equine operations in 28 states via questionnaires and fecal samples submitted for fecal egg count analysis. Participants were instructed to collect samples from six equids at the day of anthelmintic treatments and 14 days later, and they were asked to include an empty syringe with a legible label of the anthelmintic product used in the shipment. Overall, dewormer treatment was effective for 76.3% of operations (84.6% of animals). Macrocyclic lactone use was effective for 88.7% of operations (95.0% of animals) while pyrimidine/benzimidazole use was effective for 21.4% of operations (43.5% of animals). Univariate analysis revealed that overall, macrocyclic lactones exhibited significantly higher efficacy than the pyrimidine and benzimidazole drug classes (p < 0.0001). There were no statistically significant differences observed between geographic regions (West, South Central, North East, and Southeast). Body weight (p = 0.0355), amount of anthelmintic administered (p = 0.0119), and operation size (p = 0.0162) were statistically associated with anthelmintic efficacy, while anthelmintic treatment frequency in the previous 12 months was not (p = 0.7081). Multiple, mixed-effect logistic regression revealed that anthelmintic drug class (p < 0.0001) was the most impactful factor in predicting anthelmintic efficacy, after accounting for operation size, region and clustering of equids at the operation level. Pasture rotation (p = 0.0129) also demonstrated a significant effect using this model. These data document widespread occurrence of reduced anthelmintic efficacy of benzimidazole and pyrimidine products against strongyle infections in equids in the United States. Anthelmintic efficacy patterns were relatively uniform between the four studied regions, and some epidemiological factors were identified to be associated with anthelmintic efficacy against strongyle infections. This information can be useful in devising sustainable parasite control strategies in the future.

Plasma and peritoneal fluid concentrations of ceftriaxone after intravenous and intraperitoneal administration in horses

Intraperitoneal (IP) use of antimicrobial agents may lead to therapeutic effects with better clinical results than intravenous (IV) administration. The aim of this study was to compare plasma and peritoneal fluid concentrations of ceftriaxone after IP and IV administration in horses, and to evaluate possible adverse effects. One group of five horses received 25mg/kg ceftriaxone diluted in 1L saline solution by IP catheter once daily for 5 days, while a second group of five horses received 25mg/kg ceftriaxone diluted in 250mL saline solution by IV injection once daily for 5days and 1L saline solution by IP catheter once daily for 5 days. Peritoneal fluid and plasma were collected to determine ceftriaxone concentrations after the first and fifth administration. IP administration of ceftriaxone resulted in concentrations above a minimum inhibitory concentration (MIC) of 1μg/mL for 24h in peritoneal fluid and for 12h in plasma, while IV administration of ceftriaxone resulted in lower peritoneal fluid concentrations, which remained above a MIC of 1μg/mL for 12h in peritoneal fluid and 10h in plasma. No adverse effects were observed. Comparisons of ceftriaxone concentrations, time of occurrence of the maximum (T_max) and minimum (T_min) concentrations, and the mean residence time (MRT), between the two groups showed that IP administration provided greater availability of cephalosporin in peritoneal fluid. The IP use of ceftriaxone (25mg/kg diluted in 1L saline solution once daily) may be useful for the prophylaxis and/or treatment of peritonitis in horses.

Occurrence, treatment protocols, and outcomes of colic in horses within Nairobi County, Kenya

Aim:

The aim of this study was to determine the treatments and their outcomes in horses with colic in Nairobi County, Kenya.

Materials and Methods:

This is a retrospective study to determine the occurrence, treatments, pain management, and outcomes of colic in horses in Nairobi County. Association between pain management protocols and the outcomes of colic with regard to recovery or death was also determined. Data collected from four equine practitioners were organized manually and given numerical codes as appropriate to facilitate entry into the computer. The coded data were entered into Microsoft Excel 2010 and exported to StatPlus pro 5.9.8 statistical package for analysis. Simple association tests were done between various factors and occurrence of colic.

Results:

The incidence of colic for the 11 years was 3.1%, which constituted 68.0% spasmodic colic, 27.8% impaction colic, and 4.2% displacement colic. Flunixin meglumine as a nonsteroidal anti-inflammatory drug (NSAID) was used as the only pain management treatment in 85.3% of the cases, flunixin meglumine and butorphanol as NSAID-OPIOD combination in 6.4% of the cases, while buscopan as an antispasmodic was recorded in 5.9% of the cases mainly in spasmodic colic. Univariate analysis revealed simple association between various factors and the type of colic a horse was having. There was an association between the type of colic and the decision-making on the pain management protocol to use, whether single analgesic protocol (χ²=22.5, p<0.001) or use of analgesic combinations (χ²=18.3, p<0.001). The type of colic strongly influenced the decision for performing nasogastric intubation (χ²=265, p<0.001), but performing nasogastric intubation was weakly (χ²=4.9, p=0.03) associated with horse recovery from colic. Type of colic also strongly influenced the need for the use of metabolic stimulants, particularly vitamin B-complex (χ²=99.3, p<0.001). Recovery or death of the horse from colic was strongly associated with the type of colic (χ²=250, p<0.001). The possibility of recurrence of colic was weakly (χ²=4.6, p=0.04) determined by the type of colic, a horse had. Multivariate logistic regression revealed that the main cause of death was intestinal displacement and the majority of the horses with intestinal displacement died (β-estimate 2.7, odds ratio=0.07, p=0.007) compared to horses that had impaction colic.

Conclusion:

The incidence of colic is 3.1%, and the most common type of colic is spasmodic followed by impaction. The most common pain management protocol for colic is NSAIDs, mainly flunixin meglumine, followed by flunixin-butorphanol combination. Surgery for horses with colic in Nairobi County is not commonly done due to impeding poor prognoses. The horse owners tend to prefer euthanasia for such cases.

Equine Intestinal Mucosal Pathobiology

The equine intestinal mucosa is intimately involved in maintaining homeostasis both on a systemic level by controlling extracellular fluid movement and at the local level to maintain barrier function. Horses are particularly susceptible to the clinical syndrome of colic, with the most severe cases involving strangulating obstruction that induces ischemia. Because of the mucosal vascular architecture, the mucosal epithelium is particularly susceptible to ischemic injury. The potential for reperfusion injury has been investigated and found to play a minimal role. However, inflammation does affect mucosal repair. Mechanisms of repair, including villus contraction, epithelial restitution, and tight junction closure, are critical to reforming the mucosal barrier. Nonsteroidal anti-inflammatory drugs have an impact on this repair, particularly at the level of the tight junctions. Completion of mucosal regeneration requires proliferation, which is now being actively studied in equine enteroids. All of these aspects of equine mucosal pathobiology are reviewed in depth.

Equine colic: clinical epidemiology and associated risk factors in and around Debre Zeit

A prospective study was conducted to describe clinical epidemiology of equine colic in the Society for Protection of Animal Abroad and Donkey Sanctuary Project Clinic, at Debre Zeit, Ethiopia, from November 2014 to April 2015. The objectives were to describe clinical epidemiology of equine colic, to characterize the main types of equine colic, and to determine the major risk factors associated with equine colic. The method which was used in the study was attending clinical case of equine and assessing physiological parameters, fecal egg count, abdominal sounds, and rectal examination as well as questioner interviewing of the owners. The data were collected and analyzed using Statistical Package for Social Science. The incidence of colic was 10.3% in the study period. Colicky were typed as unknown, flatulent, impaction, spasmodic, and enterolithiasis. The proportion of case incidence were 63.1 (41/65), 33.8 (22/65), and 3.1% (2/65), in donkey, horse, and mule, respectively. The total mean (±SD) of temperature 37.80 ± 1.003, heart rate 57.54 ± 10.098, fecal egg count 236.922 ± 67.990, respiratory rate 30.92 ± 7.315, and packed cell volume 41.40 ± 10.221 were recorded. The case fatality rate of equine colic was 15.38% (10/65). There were statistically highly significant (p < 0.01) differences in impaction colic in relation to species. Interview with 183 equine owners revealed incidence of equine colic as the sixth major disease condition affecting equine. A long-term epidemiological study of the true representative population should be carried out to determine the incidence rate and associated risk factors of equine colic in the study area.

Interval prevalence of and factors associated with colic in horses hospitalized for ocular or orthopedic disease

OBJECTIVE To determine interval (1-year) prevalence of and factors associated with colic in horses hospitalized for ocular or orthopedic disease. DESIGN Cross-sectional study. ANIMALS 105 horses with ocular disease and 197 horses with orthopedic disease admitted to a veterinary teaching hospital between July 1, 2011, and June 30, 2012. PROCEDURES Medical records were reviewed to determine whether colic (abnormal behavior prompting abdominal palpation per rectum or nasogastric intubation) was observed during hospitalization. Data were collected on putative risk factors for colic, including reason for admission, signalment, and medical or surgical interventions received. RESULTS No significant difference in interval prevalence of colic was identified between horses with ocular disease (8/105 [8%]) or orthopedic disease (9/197 [5%]). However, horses with ocular disease differed significantly from other horses in median age (10 vs 3 years, respectively); proportions of sexually intact males (3% vs 30%), Thoroughbreds (28% vs 62%), and those receiving general anesthesia (65% vs 80%); and median duration of hospitalization (3 vs 2 days). For every 1 mg/kg increase in daily NSAID dose, the odds of colic increased by 98%. No difference between groups was identified in median duration of colic (1 day), hospitalization (7 vs 3 days), or systemic NSAID administration (7 vs 5 days). Colic in both groups resolved with medical management for all but 1 horse with ocular disease. CONCLUSIONS AND CLINICAL RELEVANCE Horses hospitalized for ocular disease were at no greater odds for colic than were horses hospitalized for orthopedic disease. Medical management of colic appeared adequate for most horses.

A Microbiological Map of the Healthy Equine Gastrointestinal Tract

Horses are exquisitely sensitive to non-specific gastrointestinal disturbances as well as systemic and extraintestinal conditions related to gut health, yet minimal data are available regarding the composition of the microbiota present in the equine stomach, small intestine, and cecum and their relation to fecal microbiota. Moreover, there is minimal information regarding the concordance of the luminal and mucosal microbial communities throughout the equine gut. Illumina-based 16S rRNA gene amplicon sequencing of the luminal and mucosal microbiota present in seven regions of the gastrointestinal tract of nine healthy adult horses revealed a distinct compositional divide between the small and large intestines. This disparity in composition was more pronounced within the luminal contents, but was also detected within mucosal populations. Moreover, the uniformity of the gut microbiota was much higher in the cecum and colon relative to that in the stomach, jejunum and ileum, despite a significantly higher number of unique sequences detected in the colon. Collectively, the current data suggest that while colonic samples (a proxy for feces) may provide a reasonable profile of the luminal contents of the healthy equine large intestine, they are not informative with regard to the contents of the stomach or small intestine. In contrast to the distinct difference between the highly variable upper gastrointestinal tract microbiota and relatively uniform large bowel microbiota present within the lumen, these data also demonstrate a regional continuity present in mucosal microbial communities throughout the length of the equine gut.

Colic in a working horse population in Egypt: Prevalence and risk factors

REASONS FOR PERFORMING STUDY

Colic is an important health problem in managed horse populations. Currently, there is limited information about colic prevalence and risk factors for colic in working horse populations.

OBJECTIVES

To determine the prevalence of, and risk factors for, colic in a working horse population in Egypt and to describe management practices in this working horse population.

STUDY DESIGN

Cross-sectional survey.

METHODS

Owners of 350 working horses were interviewed. Data about their horses, management and colic episodes in the preceding 12 months were collected. Dental examination was conducted on 342 horses and blood samples (n = 100) were collected for immunodiagnosis of tapeworm (Anoplocephala perfoliata) infection. Multivariable logistic regression analysis was used to identify risk factors for a history of colic in the preceding 12 months.

RESULTS

The 12-month prevalence of colic was 54.6%. Severe and moderate tapeworm infection intensity was identified in 3% and 26% of horses tested, respectively. Horses that had severe dental disease (odds ratio [OR] 6.8, 95% confidence interval [CI] 1.9-24.3, P<0.001), that displayed stereotypic behaviour (OR 2.0, 95% CI 1.15-3.5, P = 0.013), were fed ground corn during the 'dry season' (OR 1.65, 95% CI 1.03-2.6, P = 0.035) or that had received an anthelmintic in the previous 6 months (OR 2.1, 95% CI 1.3-3.3, P = 0.003) were more likely to have a history of colic in the preceding 12 months. Horses fed on rice bran during the 'green season' (OR 0.47, 95% CI 0.26-0.9, P = 0.015) and that displayed geophagia/coprophagia (OR 0.19, 95% CI 0.05-0.73, P = 0.001) were less likely to have a history of colic.

CONCLUSIONS

Colic is common in this working horse population and this study has identified factors associated with altered likelihood of colic. The study provides important information that may be used to inform future prospective studies investigating colic in working horse populations and to assist development of preventive healthcare strategies. The Summary is available in Chinese - see Supporting information.

Prospective study of the primary evaluation of 1016 horses with clinical signs of abdominal pain by veterinary practitioners, and the differentiation of critical and non-critical cases

BACKGROUND

The majority of research on the evaluation of horses with colic is focused on referral hospital populations. Early identification of critical cases is important to optimise outcome and welfare. The aim of this prospective study was to survey the primary evaluation of horses with clinical signs of abdominal pain by veterinary practitioners, and compare the initial presentation of critical and non-critical cases.

RESULTS

Data from 1016 primary evaluations of horses presenting with clinical signs of colic were submitted by 167 veterinary practitioners across the United Kingdom over a 13 month period. The mean age of the study population was 13.5 years (median 12.0, range 0-42). Mean heart rate on primary presentation was 47 beats/min (median 44, range 18-125), mean respiratory rate was 20 breaths/min (median 16, range 6-100), and median gastrointestinal auscultation score (0-12, minimum-maximum) was 5 (range 0-12). Clinical signs assessed using a behavioural severity score (0-17, minimum-maximum), were between 0 and 6 in 70.4 % of cases, and 7-12 for 29.6 % of cases. Rectal examination was performed in 73.8 % of cases. Cases that responded positively to simple medical treatment were categorised retrospectively as 'non-critical'; cases that required intensive medical treatment, surgical intervention, died or were euthanased were categorised as 'critical'. Eight-hundred-and-twenty-two cases met these criteria; 76.4 % were 'non-critical' and 23.6 % were 'critical'. Multivariable logistic regression was used to identify features of the clinical presentation associated with critical cases. Five variables were retained in the final multivariable model: combined pain score: (OR 1.19, P < 0.001, 95 % CI 1.09-1.30), heart rate (OR 1.06, P < 0.001, 95 % CI 1.04-1.08), capillary refill time >2.5 s (OR 3.21, P = 0.046, 95 % CI 1.023-10.09), weak pulse character (OR 2.90, P = 0.004, 95 % CI 1.39-5.99) and absence of gut sounds in ≥1 quadrant (OR 3.65, P < 0.001, 95 % CI 2.08-6.41).

CONCLUSIONS

This is the first study comparing the primary presentation of critical and non-critical cases of abdominal pain. Pain, heart rate, gastrointestinal borborygmi and simple indicators of hypovolaemia were significant indicators of critical cases, even at the primary veterinary examination, and should be considered essential components of the initial assessment and triage of horses presenting with colic.