Colic after swimming exercise in racehorses: an investigation of incidence, management, surgical findings and outcome

The incidence of colic following swimming exercise (SC) in a racehorse population examined over 3 years was 0.08%. Following 167,977 swims, 136 cases were reported. Colic resolved spontaneously in 2 horses, medically in 129 or surgically in 5. In a separate study, 21 horses were subject to exploratory laparotomy for SC. Findings included non-strangulating displacements in 7 horses, strangulating displacements in 7, a combination of non-strangulating and strangulating displacements in 1, prominent gaseous intestinal distension in 5 and no abnormalities in 1 horse. A poor response to analgesia prompted surgery in all cases. Rectal palpation and/or abdominal ultrasound was performed in 16 of 21 cases and abnormalities were found in 14 of these. Of the 21 surgical cases, 20 (95.2%) survived to discharge and 18 (90%) raced postoperatively.     

Arterial supply to the rat colon

Rats are often used as animal models in studies such as on intestinal transplantation and anastomosis healing, which require colectomy. Although detailed information regarding arterial supply is important to establish accurate and reproducible experimental procedures, this has not been studied in the rat colon. Therefore, we analysed the detailed arterial distribution pattern and its individual variations in the colon of 34 rats. The rat colon received colic branches of the ileocolic artery, and the right, middle and left colic arteries. The single left colic artery constantly arose from the caudal mesenteric artery and was distributed to the descending colon, whereas the others showed variations in number and distribution. The ileocolic artery gave rise to one (12%) or two (88%) colic branches supplying the proximal ascending colon, and these branches formed rich, mesh-like anastomoses along the initial portion of the ascending colon. One (74%) or two (26%) right colic arteries originated from the cranial mesenteric artery and supplied the ascending colon and right colic flexure. Moreover, one (38%), two (56%) or three (6%) middle colic arteries emerged from the cranial mesenteric artery and were distributed to the transverse colon, left colic flexure and proximal descending colon. In total, we categorized the individual variations in arterial branching and anastomosis into 11 patterns. Arterial supply to the rat colon showed a specific pattern and frequent individual variations. These findings thus provide essential information for establishing reproducible models of rat colic surgery.     

Clinical pathology and ultrasonographic findings from a Warmblood gelding with primary,severe, acute pancreatitis

A 24-year-old Warmblood gelding presented with a 6-hour history of recurrent colic signs of increasing severity. Upon presentation, he was mildly painful, tachycardic and tachypnoeic and had decreased borborygmi. Nasogastric intubation resulted in no net reflux and rectal palpation revealed an ascending colon impaction. Percutaneous abdominal ultrasonography revealed dilated, thickened and hypomotile loops of small intestine. Complete blood count revealed leucopenia with neutropenia and an increased packed cell volume. Serum biochemistry revealed hyperproteinaemia, hyperglycaemia, hypocalcaemia, hyperbilirubinaemia, hypercholesterolaemia and elevated liver enzymes. Despite sedation and fluid resuscitation, the gelding became severely colicky. A repeat ultrasound was performed, revealing a moderate amount of free fluid and a mass effect between the liver and right dorsal colon. Abdominocentesis yielded a yellow, turbid fluid containing free-floating white debris with an increased total protein and lactate concentration. Cytology of the fluid revealed necrotic mesothelial cells. The gelding was humanely euthanised due to poor prognosis. Necropsy revealed acute, severe pancreatitis and duodenitis. The mass effect on ultrasonography was retrospectively identified as the pancreas exhibiting a similar architecture to that seen in cases of acute pancreatitis in small animals.     

Trends in the management of horses referred for evaluation of colic: 2004–2017

The financial crisis of 2008 had effects on veterinary practice, with falling turnovers associated with reluctance of owners to spend money on veterinary care. There were anecdotal reports that fewer horses were undergoing colic surgery. The aims of this study were to document the numbers of horses with colic being referred to, and undergoing surgery and/or euthanasia, at two equine hospitals (a university based equine hospital in the United States [NC State] and a private equine hospital in the UK [Bell Equine]) over a 14-year period (2004–2017). There was a trend of declining total yearly equine accessions at NC State starting in 2009, followed by an increase starting in 2012. At Bell Equine, total accessions showed an increasing trend from 2004 to 2015, followed by a slight decline in 2016 and 2017. The proportion of equine accessions that were colics varied from around 15% to 20% at both hospitals and did not show any notable variations over the time period studied. Both practices showed a trend of decreasing colic admissions undergoing and recovering from surgery starting from 2007 to 2008. The numbers and percentages of colic admissions that were subjected to euthanasia increased from 2004/2005 to 2014/2015 in both hospitals; there was a greater increase in numbers being subjected to euthanasia at surgery at NC State, compared to a greater increase in numbers being subjected to euthanasia without surgery at Bell Equine. At both hospitals, there was a trend of increasing mean invoice totals over the study period. The results show that there has been a trend of decreasing numbers of horses undergoing surgical treatment for colic since 2004/2005. This is likely to be, at least partly, due to the financial crisis of 2008, although other factors, including the high costs of surgery and the ageing equine population may also be important.     

Equine tapeworm infections: Disease,diagnosis and control

Equine tapeworm infection has gained increasing attention over the past few decades and a number of research studies have already been published. These focus primarily on the most common of the 3 tapeworm species, Anoplocephala perfoliata, although some new information has also been generated for the other two species, Anoplocephala magna and Anoplocephaloides mamillana. The preponderance of research studies have focused on development and validation of diagnostic techniques for tapeworm detection and the role of these parasites in equine gastrointestinal disease. Several diagnostic techniques have been found useful for diagnosis of A. perfoliata but each has its strengths and weaknesses. Egg counting techniques have been modified to achieve acceptable to good diagnostic performance but the trade‐off is often a more time‐consuming method. Validation studies indicate that these methods can reliably detect tapeworm burdens above 10 worms. Several enzyme‐linked immunosorbent assays (ELISAs) have been developed and made commercially available. These can generate useful information about tapeworm exposure on the herd level but are less reliable for individual diagnosis. Unfortunately, none of the available diagnostic techniques are useful for evaluating anthelmintic treatment efficacy. Coproantigen testing may find use as a future diagnostic modality but further characterisation is required. The large body of scientific evidence supports an association between A. perfoliata infection and certain types of equine colic, although some discrepancy exists between studies. Tapeworm surveillance and control should be considered as part of the overall parasite control strategy. When properly used, the currently available diagnostic tools can guide the veterinarian to make strategic decisions regarding tapeworm control.     

Correlation of epiploic foramen length to height,weight, breed,gender and age in horses

Epiploic foramen entrapment (EFE) is one of the most common causes of small intestinal strangulation in horses. Cribbing and previous episodes of colic are suggested as risk factors for its occurrence. The aim of this study was to correlate the height, weight, breed, gender and age to the epiploic foramen (EF) length. Forty-three horses were submitted to post-mortem measurement of epiploic foramen with abdominal and thoracic organs positioned in situ. After data collection, linear regression between EF length and the explanatory variables was performed. None of the post-mortem physical variables was associated with EF length, supporting the hypothesis that there is no association between EF length and age, and that increased intra-abdominal pressure is the most important factor predisposing to EFE recurrence.     

Evaluation of Fecal Sand Clearance in Horses With Naturally Acquired Colonic Sand Accumulation With a Product Containing Probiotics,Prebiotics, and Psyllium

Consumption of sand and dirt in horses can cause chronic diarrhea and colic because of irritation and obstruction of the gastrointestinal tract of horses. Prevention has primarily focused on changes in management to reduce the intake of sand and feeding of psyllium products. The purpose of this study was to evaluate the efficacy of a product containing probiotics, prebiotics, and psyllium in the clearance of colonic sand in horses with naturally acquired sand accumulation using a randomized, placebo-controlled, blinded clinical trial format. After identification of 10 horses with sand accumulation as determined by both auscultation and abdominal radiography, quantitative assessment of changes in colonic sand content in response to management changes combined with treatment with the probiotic/psyllium product or no treatment was assessed by blinded observers. Fecal sand output was monitored in both groups via sand sedimentation analysis of fecal samples every 3 days for 35 days and with pre- and post-treatment abdominal radiography. There was a significant reduction in sand accumulation in both treatment and control groups, but there were no significant differences between treatment and control groups in clearance of colonic sand as measured by both fecal sand sedimentation and quantitative radiography.     

Equine duodenal motility,assessed by ultrasonography,as a predictor of reflux and survival following colic surgery

Intestinal dysmotility following equine colic surgery contributes negatively to financial and prognostic outcomes. This study assessed duodenal contractility as a predictor of post-operative reflux and survival to discharge in horses following colic surgery. Duodenal contractility was assessed using daily transabdominal ultrasound examinations in 49 horses for up to 7 days (Day 1 scan performed between 6 and 36 h post-surgery and sequential daily scans performed between 08.00 and 20.00 h) following colic surgery (September 2014–April 2017). The duodenum was visualised ventral to the right kidney, and duodenal contractions were measured over 2 min. The signalment of each horse and surgical findings were noted. Outcomes were defined as horses that refluxed (>5 L/24 h beyond 24 h) or did not reflux post-operatively and those that were survivors or were nonsurvivors. A significant difference in duodenal contractions at Day 1 post-operatively was identified between horses that refluxed (n = 8) and those who did not reflux (n = 32; P = 0.013) but not between those who were nonsurvivors (n = 7) and survivors (n = 32; P = 0.113). Horses in the reflux group had reduced duodenal contractility comparatively. There were no significant differences in duodenal contractions in the sequential days after the Day 1 scan or between duodenal contractions and surgical findings. A significant association was identified between duodenal contractions and survivors (P = 0.039; odds ratio 1.88). The main study limitations were the single centre design with consequent small numbers of horses included. The study did not account for other factors that may contribute to alterations in motility such as drug administration or stages of re-feeding. This preliminary study indicates that Day 1 (6–36 h post-operatively) duodenal contractions may predict reflux (>5 L/24 h beyond 24 h) and that increased duodenal contractions are associated with survival. However, there was no clear distinction or cut-off between groups. Future studies with greater numbers of horses yielding better statistical power are required.     

Are horses that undergo an exploratory laparotomy for correction of a right dorsal displacement of the large colon predisposed to post operative colic,compared to other forms of large colon displacement?

Reason for performing study: It is a clinical impression that horses diagnosed with a right dorsal displacement (RDD) of the large colon, are more likely to suffer from recurrent episodes of colic post operatively, compared to other forms of nonstrangulating large colon displacement. Objectives: To investigate whether the type of nonstrangulating large colon displacement identified at exploratory laparotomy would influence long‐term outcome. Hypothesis: Horses identified with a RDD of the large colon at exploratory laparotomy would be more likely to experience recurrent episodes of post operative colic than other types of displacement. Materials and methods: Medical records for horses undergoing an exploratory laparotomy, from 2000–2008, for a nonstrangulating large colon displacement were reviewed. Data retrieved included: subject details, previous medical history, details of current episodes of colic, results of preoperative examination, surgical findings and procedures, post operative management and complications. Follow‐up information was obtained by reference to computerised clinical records and by telephone questionnaire administered to the horse's owner or carer, and included details of any colic episodes exhibited by the horse after discharge and whether a repeat celiotomy had been required to resolve the colic episodes. Results: There were 165 surgeries identified, in 154 horses. It was found that those horses with RDD were significantly more likely to experience recurrent episodes of colic requiring veterinary intervention post operatively compared to other types of displacement. Clinical relevance: Long‐term prognosis and likelihood of post operative complications is an important consideration for both owners and veterinarians.     

Small intestinal segmental volvulus in horses after gastroscopy: Four cases (2011–2012)

Gastroscopy is the most common technique used in veterinary medicine to evaluate the stomach in horses and to date, no complications have been described associated with the procedure. This paper reports 4 cases developing a nonstrangulating segmental volvulus of the small intestine after gastroscopy at 3 referral institutions over a 2 year period. After performing diagnostic gastroscopy, all horses developed acute and severe clinical signs of colic unresponsive to medical management. Time range between gastroscopy and onset of colic signs varied from 10 min to 3 h. An exploratory laparotomy revealed a nonstrangulating segmental volvulus of the small intestine that was manually corrected without need for resection in all horses. In all cases, affected small intestine was severely gas distended. Three of those horses survived to discharge and were alive at follow‐up. One horse was subjected to euthanasia 2 days after surgery due to diffuse intestinal lymphoma.     

Demographic,preoperative and anaesthesia-related risk factors for unsatisfactory recovery quality in horses undergoing emergency abdominal surgery

ObjectiveTo determine demographic, preoperative and anaesthesia-related variables that may be associated with unsatisfactory recovery quality in horses undergoing emergency abdominal surgery (colic) in an equine teaching hospital.Study designRetrospective case series.AnimalsA total of 313 horses.MethodsThe anaesthetic records of horses admitted for surgical treatment of colic between 2005 and 2018 were examined. Overall quality of recovery was assessed as dangerous, poor, fair, good or excellent. The following categories were constructed as a dichotomic variable: unsatisfactory recovery (poor and dangerous recoveries) and satisfactory recovery (excellent, good and fair recoveries). Univariable and multivariable analyses were performed to evaluate the association between all studied variables and recovery.ResultsAll recoveries were unassisted. Unsatisfactory recovery quality totalled 17.2% (3.5% and 13.7% were dangerous and poor recoveries, respectively), whereas satisfactory recoveries totalled 82.8% (26.2%, 40.9% and 15.7% were fair, good and excellent recoveries, respectively). Univariable analysis showed that unsatisfactory recoveries were associated with high preoperative packed cell volume, pain behaviour, poor premedication and induction quality, high intraoperative mean heart rate, low mean arterial blood pressure, dobutamine dose ≥1.5 μg kg^–1 minute^–1, non-administration of romifidine, long anaesthesia time and prolonged time to stand. The multivariable model showed that factors strongly associated with unsatisfactory recovery quality were dobutamine dose ≥1.5 μg kg^–1 minute^–1 [adjusted odds ratio (AOR) = 6.60; 95% confidence interval (CI), 2.91–14.96], poor premedication quality (AOR=4.60; 95% CI, 1.73–12.23) and a time to stand > 70 minutes (AOR=2.59; 95% CI, 1.13–5.91).Conclusions and clinical relevanceOur study shows that high dobutamine requirements, poor premedication quality and a prolonged time to stand are risk factors for unsatisfactory recovery quality in horses undergoing anaesthesia for colic surgery. Addressing these factors may enable clinicians to improve the quality of recovery phase.     

Congenital hypoplasia of the dorsal colon in a Quarter Horse filly with chronic,intermittent colic

Congenital colonic anomalies are rare in the horse and, to the authors' knowledge, no cases have been reported that include measurements of each segment of the large colon to confirm which section is abnormal. This case report describes chronic, intermittent colic in a Quarter Horse filly that had been attributed to chronic idiopathic hepatitis prior to an exploratory laparotomy. A colonic anomaly discovered at surgery became the primary differential for aetiology of the intermittent colic. Euthanasia of the filly and necropsy allowed further examination of the anomaly, where it was determined that the dorsal colon was short compared to the ventral large colon. In addition, the diagnosis of chronic idiopathic hepatitis was confirmed.     

Caecal duplication in a 13‐year‐old Thoroughbred

A 13‐year‐old Thoroughbred gelding was presented for evaluation of recurrent colic of 4 weeks duration. These colic episodes were mild and responsive to medical therapy. Episodes of colic became more frequent and more painful. Exploratory laparotomy revealed a large intestine duplication with a cystic structure located at the caecocolic junction that was unable to be exteriorized and therefore not amenable to surgical correction. Thirty‐six hours following surgery, the horse became acutely painful, sweaty, and febrile suggesting gastrointestinal rupture. Post mortem examination showed a 0.6 × 1 m duplication and a 0.5 × 0.6 m cystic dilation that was probably associated with the caecum. There was a 10 × 30 cm area of rupture located within the duplication. Histological evaluation confirmed the presence of a true duplication.     

Surgical management of foreign body obstruction of the small and large colons in 29 equids (2004–2016)

The objectives of the study were to describe the clinical presentation, surgical findings, complications and outcome of a case series of small and large colon obstruction by foreign bodies (FBs) in horses. The study is a retrospective case series which included 29 equids (28 horses and one donkey). Medical records of cases diagnosed with FB obstruction of the large or small colon between the years 2004 and 2016 that underwent surgery were reviewed. Data regarding signalment, clinical signs, surgical findings and post-operative variables were recorded. Short- (survival to hospital discharge) and long- (1 year after surgery) term survival rates were obtained. Cases had a mean age of 4.2 years, with both females and Arabian horses being overrepresented. Abdominal distention was the most common observation on presentation and the FB could be palpated in 20% of the cases during rectal examination. The most common reason to go into surgery was severe pain with abdominal distention. Significantly more FBs were found in the small colon during surgery (P<0.0001) and most were removed by small colon enterotomy. Complications rate post-operatively was relatively high (41%) with fever and diarrhoea being most common. Twenty-three cases (79%) were released from the hospital and all cases that were available for long-term follow-up were alive and returned to previous activity. No correlation between the chosen method of surgical removal of the FB and survival or complications post-operatively was noted. These data reflect favourable prognosis for surgical removal of colonic FBs. Few techniques are available to improve the safety of removal and the preferred method depends on the FB location, appearance and mobility. As FB obstruction resembles ‘noncomplicated’ colonic impaction, it is essential to try and recognise FB cases since deterioration can be rapid and surgery is the only sufficient treatment.     

An update on equine post‐operative ileus: Definitions,pathophysiology and management

Post‐operative ileus (POI) is a serious condition which any horse undergoing abdominal surgery is at risk of developing, leading to increased hospitalisation time and resulting costs. Advances in the understanding of the development of equine POI are mainly based on human and rodent literature, where manipulation‐induced inflammation has been identified as a trigger, with activation of resident muscularis externa macrophages playing a crucial role in the pathophysiology. Despite many pharmacological trials in all species, there is no single completely successful treatment for POI, highlighting that the condition is multifactorial in cause and requires a multimodal approach to minimise its incidence.     

Isocupressic acid,an abortifacient component of Cupressus macrocarpa

Anecdotal reports suggest that abortion occurs in New Zealand cattle after ingestion of macrocarpa (Cupressus macrocarpa). The clinical signs observed are similar to those seen in abortions caused by ponderosa pine (Pinus ponderosa Laws). Isocupressic acid has been identified as an abortifacient component of the needles of ponderosa pine. Macrocarpa collected from the Palmerston North area contained 0.89% and 1.24% isocupressic acid, compared to 1.70% isocupressic acid in Ponderosa pine needles from Oregon in the United States as analysed by the USDA-ARS Poisonous Plant Research Laboratory. These findings support observations that macrocarpa causes abortion in late gestation cattle in New Zealand and suggest the causal agent is probably isocupressic acid.