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.     

The creation of an international audit and database of equine colic surgery: survey of attitudes of surgeons

REASONS FOR PERFORMING STUDY: Currently, there is a lack of available evidence-based data concerning the optimum treatments for horses affected by different types of colic and this precludes the application of clinical audit in this area. In order to accumulate such data, a large-scale, multicentre database of the outcomes of colic surgery is proposed. The attitudes of surgeons is an important consideration in determining the feasibility of developing this database. OBJECTIVES: To assess attitudes and opinions of equine surgeons concerning clinical audit and to assess the perceived advantages and problems of setting up a large-scale international audit/database of colic surgery. METHODS: Interviews were conducted with 30 equine surgeons (large animal/equine surgeons who are diplomates of either the American College of Veterinary Surgeons or the European College of Veterinary Surgeons). Questionnaires were sent by e-mail to 98 equine surgeons. RESULTS: Face to face interviews were conducted (n = 30) and 43/98 completed questionnaires received (44%). The results of the 2 techniques were very similar. There was generally a high level of interest in the development of a large scale database of colic surgery, but perceived problems included time to collect and submit data, and confidentiality issues. A minority of surgeons reported that they were undertaking any form of specific monitoring of the results of colic surgery within their hospitals. CONCLUSIONS: There is a good level of interest among equine surgeons to develop a large scale database of colic surgery and most would be willing to contribute data from their own hospitals provided that data collection is quick and easy, and that confidentiality is maintained.     

Antimicrobial drug use and resistance in dogs

Fifteen years (1984-1998) of records from a Veterinary Teaching Hospital were analyzed to determine whether antimicrobial drug resistance in coagulase-positive Staphylococcus spp. (S. aureus, S. intermedius) isolated from clinical infections in dogs has increased, and whether there has been a change in the species of bacteria isolated from urinary tract infections in dogs. In coagulase-positive Staphylococcus spp., a complex pattern showing both increases and decreases of resistance to different classes of antimicrobial drugs was observed, reflecting the changing use of different antimicrobial drug classes in the hospital over a similar period (1990-1999). In canine urinary tract infections identified from 1984 to 1998, an increase in the incidence of multiresistant Enterococcus spp. was apparent, with marginal increases also in incidence in Enterobacter spp. and in Pseudomonas aeruginosa, both of which, like Enterococcus spp., are innately antimicrobial-resistant bacteria. A survey of directors of veterinary teaching hospitals in Canada and the United States identified only 3 hospitals that had any policy on use of "last resort" antimicrobial drugs (amikacin, imipenem, vancomycin). Evidence is briefly reviewed that owners may be at risk when dogs are treated with antimicrobial drugs, as well as evidence that some resistant bacteria may be acquired by dogs as a result of antimicrobial drug use in agriculture. Based in part on gaps in our knowledge, recommendations are made on prudent use of antimicrobial drugs in companion animals, as well as on the need to develop science-based infection control programs in veterinary hospitals.     

Factors associated with Salmonella shedding among equine colic patients at a veterinary teaching hospital

OBJECTIVE: To evaluate factors potentially associated with fecal Salmonella shedding among equine patients hospitalized for colic at a veterinary teaching hospital and to determine the effects of probiotic treatment on fecal Salmonella shedding and clinical signs. DESIGN: Longitudinal study and controlled trial. ANIMALS: 246 equine colic patients. PROCEDURE: History and medical information were obtained from patient records. Fecal and environmental samples were submitted for aerobic bacterial culture for Salmonella enterica. Fifty-one patients were treated with a commercially available probiotic; 46 were treated with a placebo. Logistic regression was used to evaluate data. RESULTS: Salmonella organisms were detected in feces from 23 (9%) patients at least once during hospitalization. Patients were more likely to shed Salmonella organisms if diarrhea was evident < or = 6 hours after hospitalization and duration of hospitalization exceeded 8 days (odds ratio [OR], 20.3), laminitis developed during hospitalization (OR, 12.0), results of nasogastric intubation were abnormal (OR, 4.9), leukopenia was evident < or =6 hours after hospitalization (OR, 4.6), or travel time to the teaching hospital exceeded 1 hour (OR, 3.5). Horses treated with the probiotic did not differ from control horses in regard to likelihood of fecal Salmonella shedding (OR, 1.5) or prevalence of clinical signs. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that certain risk factors are associated with fecal shedding of S enterica among equine patients hospitalized at a veterinary teaching hospital because of colic and that pathogen monitoring in patients and the hospital environment and use of barrier nursing precautions for equine colic patients are beneficial.     

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

OBJECTIVE: To estimate the national incidence of, operation-level risk factors for, and annual economic impact of colic among horses in the United States during 1998 and 1999. DESIGN: Epidemiologic survey. ANIMALS: 21,820 horses on 1,026 horse operations in 28 states. PROCEDURES: Horses were monitored for colic for 1 year, and results were recorded in a log that was collected quarterly. Operation-level data were collected via 4 on-site personal interviews. Associations between colic and independent variables adjusted for size of operation were determined. RESULTS: Annual national incidence of colic in the US horse population was estimated to be 4.2 colic events/100 horses per year. Case fatality rate was 11%, and 1.4% of colic events resulted in surgery. Annual cost of colic in the United States was estimated to be $115,300,000. CONCLUSIONS AND CLINICAL RELEVANCE: The national impact of equine colic is substantial because of the high case fatality rate.     

Evolution of equine infection control programs.

The science of control of infectious diseases in hospitals was born in 1847 when Semmelweis, a physician, ordered his medical students to scrub their hands in chlorinated lime water between patients and demonstrated that this simple procedure resulted ina dramatic decline in patient morbidity and mortality. In the late nineteenth century came huge breakthroughs in the understanding that microorganisms cause many disorders, and methods to eliminate and control these microorganisms were attempted. By 1910, sterile instruments, gowns, masks, and gloves had become standard for surgical procedures in large university human hospitals, and isolation of human and veterinary patients with contagious diseases became standard. With the advent of vaccines, many epidemic viral diseases could be controlled, and antimicrobial drugs allowed many previously devastating bacterial diseases to be treated effectively. Before long, however, bacterial resistance became an important issue and remains so today, particularly for Salmonella and Staphylococcus aureus in horses. Vaccination has decreased the number of animals susceptible to equine influenza and equine herpesvirus 1, yet these contagious diseases still pose a serious issue in large equine veterinary hospitals. The development of equine isolation facilities and improved methods of barn cleaning; mandatory application of procedures, such as handwashing or use of disinfectant hand wipes, to prevent the spread of infectious diseases; and monitoring of antimicrobial resistance and use of restricted antimicrobial drugs were driven by recognition and necessity and have given rise to current equine infection control programs.     

Clustering of reported cases of leptospirosis among dogs in the United States and Canada

A retrospective study was conducted to determine whether cases of leptospirosis diagnosed among dogs in the United States and Canada were clustered in time, space, or time-and-space. The study population was estimated--based on first examination of each dog--to consist of 1,035,366 dogs examined at 22 veterinary teaching hospitals between 1983 and 1998. The veterinary medicine database was searched for records of dogs in which a diagnosis of leptospirosis was made during the study period. The scan statistic (Poisson model) was used to examine for clustering of cases, using recorded date of diagnosis and the location of the veterinary teaching hospital at which the diagnosis was made. Three-hundred and forty dogs diagnosed with leptospirosis were identified. Cases were clustered in the period of 1992-1998. A cluster of dogs diagnosed at three veterinary teaching hospitals located in the midwest of the United States was identified. The composition of this spatial cluster was influenced by the age and gender distribution of the population at-risk. A cluster of cases involving 143 dogs diagnosed with leptospirosis between 9 April 1993 and 14 December 1998 at six veterinary teaching hospitals located in the midwest of the United States was identified. This time-space cluster was not influenced by the age, gender or breed distribution of the population of dogs presented at veterinary teaching hospitals during the study period. Leptospirosis was clustered during the 1990s in the midwest of the United States. Dog risk factors (age, gender, breed) do not explain the clustering that was observed. Leptospira serovar or environmental factors might be responsible for the clustering of canine leptospirosis in the United States and Canada.     

Survival and complication rates in 300 horses undergoing surgical treatment of colic. Part 1: Short-term survival following a single laparotomy

REASONS FOR PERFORMING STUDY: A minority of equine colic cases prove fatal unless treated surgically; however, few studies have considered long-term survival and complication rates, and few have attempted to identify factors that might affect outcomes. Such information is required for owners and veterinary surgeons to make informed decisions about the most appropriate treatment for individual cases. OBJECTIVES: To document short-term survival rates of 300 horses undergoing colic surgery and analyse factors that might have predisposed to short-term death. METHODS: History, clinical and surgical findings, treatments and outcomes of 300 surgical colic cases (1994-2001) were reviewed. Comparisons among groups of discrete data were made using chi-squared or Student's t tests as appropriate. Significance was set at P < 0.05, and 95% confidence intervals were calculated for percentages. RESULTS: The short-term survival rate (to discharge) was 70.3% for all horses and 83.1% for those recovering from anaesthesia; for horses that had a single laparotomy it was 87.2%. The most common reasons for death/euthanasia in the post operative period after a single laparotomy were persistent pain/colic, post operative ileus and grass sickness. Horses with lesions involving the small intestine and caecum had lower survival rates (75.2 and 66.7%, respectively) than those with large colon or small colon lesions (89.9 and 100%, respectively). The survival rate for ischaemic/strangulating lesions (68.9%) was lower than for simple obstructions (90.5%). CONCLUSIONS: Short-term survival of horses undergoing exploratory laparotomy for acute colic is dependent on many factors, including the nature of the underlying disease, cardiovascular status and post operative complications. POTENTIAL RELEVANCE: These retrospective studies may be used as a basis for prospective studies assessing treatments that could ultimately improve survival and decrease complication rates.     

Prevalence and risk factors associated with outcome of surgical removal of pedunculated lipomas in horses: 102 cases (1987-2002)

OBJECTIVE: To determine the prevalence of pedunculated lipomas and identify risk factors affecting postoperative complications and survival in horses at a veterinary teaching hospital undergoing surgery for colic caused by pedunculated lipomas. DESIGN: Retrospective study. ANIMALS: 102 horses with a diagnosis of pedunculated lipoma. PROCEDURE: Age, breed, weight, and sex of horses with pedunculated lipomas were compared with the total equine hospital population and the population of horses admitted for abdominal surgery during the same period. Follow-up information was obtained by reevaluation or contact with owners via telephone or written request. RESULTS: Prevalence of pedunculated lipomas as a reason for abdominal surgery in horses, compared with the population of horses with and without lipomas admitted for abdominal surgery, was 10%. Castrated male Saddlebred and Arabian horses > 14 years old were identified as being at risk for developing pedunculated lipomas. Postoperative complications were detected in 72% of horses with pedunculated lipomas. Variables associated with low survival rates included surgery before 1992, heart rate > 80 beats/min, abnormal color of abdominal fluid, pale mucous membranes, surgery requiring intestinal resection, and inability to attain a mean arterial pressure > or = 100 mm Hg. Horses undergoing surgery from 1992 to 1996, weighing < 409 kg (900 lb), or requiring jejunojejunal anastomosis had a high survival rate. CONCLUSIONS AND CLINICAL RELEVANCE: Although many of the variables reflected the health of the horse at the time of surgery, results may help veterinarians recognize risk factors associated with development of pedunculated lipomas and better predict the outcome of horses undergoing surgery for colic caused by pedunculated lipomas.     

Post operative infection, pyrexia and perioperative antimicrobial drug use in surgical colic patients

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

Effect of perioperative prophylactic antimicrobial treatment in dogs undergoing elective orthopedic surgery.

OBJECTIVE: To determine whether perioperative antimicrobial prophylaxis would reduce incidence of postoperative infection among dogs undergoing elective orthopedic procedures. DESIGN: Randomized, controlled, blinded, intention clinical trial. ANIMALS: Dogs of any breed, sex, or age undergoing elective orthopedic surgery at a veterinary teaching hospital. PROCEDURES: Dogs were randomly assigned to 1 of 3 groups: treatment with saline solution, treatment with potassium penicillin G, and treatment with cefazolin. Treatments were intended to be administered within 30 minutes prior to surgery; a second dose was administered if surgery lasted > 90 minutes. Dogs were monitored for 10 to 14 days after surgery for evidence of infection. RESULTS: After the first 112 dogs were enrolled in the study, it was found that infection rate for control dogs (5/32 dogs) was significantly higher than the rate for dogs treated with antimicrobials (3/80 dogs). Therefore, no more dogs were enrolled in the study. A total of 126 dogs completed the study. Monte Carlo simulations indicated that compared with dogs that received antimicrobials prophylactically, dogs that received saline solution developed infections significantly more frequently. Difference in efficacy, however, was not observed between the 2 antimicrobial drugs used. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that perioperative antimicrobial prophylaxis decreased postoperative infection rate in dogs undergoing elective orthopedic surgery, compared with infection rate in control dogs. Cefazolin was not more efficacious than potassium penicillin G in these dogs.     

Trends in the frequency of calcium oxalate uroliths in the upper urinary tract of cats

Medical records from cats diagnosed with uroliths at nine United States veterinary teaching hospitals from 1980 to 1999, and records of cats with uroliths submitted for analyses to the Minnesota Urolith Center from 1981 to 2000, were evaluated. A 10-fold increase in frequency of upper tract uroliths occurred in cats during the 20-year interval at the nine veterinary teaching hospitals. Calcium oxalate emerged as the predominant mineral type in upper tract uroliths, having increased more than 50-fold during the study period. These results emphasize the need for increased awareness of the occurrence of upper urinary tract uroliths in cats.     

Investigating the opinions of donkey owners and veterinary surgeons towards pain and analgesia in donkeys

The aim of this questionnaire‐based study was to identify which analgesics are currently prescribed to donkeys in clinical practice and to collect opinions from veterinary surgeons and donkey owners on the importance of different pain‐related behaviours in donkeys. Questionnaires were completed by 143 veterinary surgeons and 93 donkey owners. Phenylbutazone, flunixin, detomidine and butorphanol were reported as the most frequently used analgesics in donkeys. Most veterinary surgeons reported administering these drugs at the horse dose rate and dosing interval, which may be inappropriate in the donkey. Four pain‐related behaviours were identified as very important by veterinary surgeons and owners: dullness for colic‐associated pain, keeping the foot lifted, and lameness for foot and limb pain and inability to chew properly for head and dental pain. This is a more limited behavioural repertoire than has recently been identified to be associated with pain in the donkey and suggests that the respondents were reporting perceived wisdom as to what people think are the behavioural signs associated with pain or were not interpreting pain‐related behaviours correctly.     

Prevalence of and risk factors for leptospirosis among dogs in the United States and Canada: 677 cases (1970-1998)

OBJECTIVE: To determine whether there was a temporal trend in prevalence of leptospirosis among dogs in the United States and Canada and to determine whether age, sex, and breed were risk factors for the disease. DESIGN: Retrospective study. ANIMALS: 1,819,792 dogs examined at 22 veterinary teaching hospitals between 1970 and 1998. PROCEDURES: The Veterinary Medical Data Base was searched for records of dogs in which a diagnosis of leptospirosis was made, and hospital prevalence was calculated. Logistic regression was used to examine the association between leptospirosis and age, sex, and breed. RESULTS: 677 dogs with leptospirosis were identified. Thus, hospital prevalence was 37 cases/100,000 dogs examined. A significant increase in leptospirosis prevalence between 1983 and 1998 was identified. Male dogs were at significantly greater risk of leptospirosis than were female dogs; dogs between 4 and 6.9 years old and between 7 and 10 years old were at significantly greater risk than dogs < 1 year old; and herding dogs, hounds, working dogs, and mixed-breed dogs were at significantly greater risk than companion dogs. CONCLUSIONS AND CLINICAL RELEVANCE: The prevalence of leptospirosis among dogs examined at veterinary teaching hospitals in the United States and Canada has increased significantly since 1983. Male dogs of working and herding breeds were at greater risk.     

Pre-operative and anaesthesia-related risk factors for mortality in equine colic cases

Mortality rates for horses that have undergone emergency abdominal surgery are higher than for other procedures. Here, multivariable modelling of data from 774 surgical colic cases is used to identify pre-operative and anaesthesia-related variables associated with intra- and post-operative mortality. Intra-operative mortality was significantly (P<0.05), and positively associated with heart rate and packed cell volume (PCV) at admission, and negatively associated with the severity of pain. Post-operative mortality increased with increasing age and PCV at admission. Draught horses, Thoroughbreds and Thoroughbred-cross horses carried a significantly worse prognosis. We detected a small but significant variability in the risk of intra-operative death amongst referring veterinary surgeons. Different anaesthetic induction agents, inhalation maintenance agents and the use, or not, of intermittent positive pressure ventilation had no significant effect on risk of death. We conclude that cardiovascular compromise, level of pain, age, and breed are all associated with the risk of mortality in equine surgical colic cases.     

Outcome and long‐term follow‐up of 20 horses undergoing surgery for caecal impaction: A retrospective study (2000–2008)

Reasons for performing study: If untreated, caecal impaction may progress to rupture of the caecum and reports of long‐term outcome for horses undergoing surgery for caecal impaction are required. Objectives: To describe short‐ and long‐term complication rates for horses undergoing surgery for caecal impaction in an otherwise life‐threatening gastrointestinal condition. Methods: Case records were reviewed for horses undergoing surgery for caecal impaction. Horses were included in the study if an abnormally large, fluid‐distended or feed‐impacted caecum was the primary diagnosis at surgery and excluded if the caecum had already ruptured upon opening the abdomen, necessitating euthanasia. Short‐term follow‐up data were obtained from clinical records; and included complications, repeat celiotomy and survival to discharge. Long‐term survival was defined as survival for >1 year post operatively. Long‐term follow‐up data were obtained through telephone interviews with owners and referring veterinary surgeons. Survival, occurrence of post operative colic and subsequent use of the horse were recorded. Results: Twenty horses underwent surgery for caecal impaction: 16 horses underwent caecal bypass (typhlotomy and removal of caecal contents, ileal transection followed by ileocolostomy); 3 underwent typhlotomy alone; and one horse underwent typhlotomy followed by a second procedure where caecal bypass was performed. Five horses (25%) were admitted for colic evaluation with primary caecal impactions, in 10/20 (50%) of cases the impaction was secondary to previous orthopaedic surgery and in 5/20 (25%) caecal impaction was identified at repeat celiotomy following a previous colic surgery. Sixty‐five percent (13/20) of horses survived to discharge; 11/13 (85%) of horses discharged survived long term; 100% (3/3) horses that received typhlotomy alone were discharged and survived long term. Conclusions: The prognosis following caecal impaction surgery is fair, if the horse survives to discharge then prognosis for long‐term survival is good. Potential relevance: Surgery for caecal impaction carries a fair prognosis for a potentially life threatening disease, in particular where caecal dysfunction is suspected.     

Overview of issues pertaining to the manufacture, distribution, and use of antimicrobials in animals and other information relevant to animal antimicrobial use data collection in the United States

This paper provides condensed literature review and contextual information concerning antimicrobial use in animals and antimicrobial use data collection techniques. Information is summarized into the following topics: (I) antimicrobial use for animal growth promotion; (II) regulatory framework for approval of veterinary antimicrobials and feed additives in the United States; (III) animal health product manufacturing and distribution networks; (IV) existing estimates of animal antimicrobial use in the United States; (V) additional sources for animal use data in the United States; (VI) recommendations from international expert groups; (VII) animal antimicrobial use surveillance systems in other nations and (VIII) human use data collection systems in the United States.     

The usability of peritoneal lactate concentration as a prognostic marker in horses with severe colic admitted to a veterinary teaching hospital

Colic can be a life‐threatening condition in horses and there is a need for parameters that can help determine the prognosis and need for surgery. The aim of the study was to investigate whether peritoneal fluid (PF) lactate concentration is useful for this purpose in horses with severe colic presented to a veterinary hospital. During a 16 month period, the peritoneal fluid (PF) lactate concentration was measured in 74 of 760 colic horses admitted to the Utrecht University equine clinic using a portable analyser. When comparing survivors and nonsurvivors, heart rate, PF and blood lactate concentrations and blood glucose concentration were significantly higher in horses that did not survive. No horse with a PF lactate concentration >9.4 mmol/l survived. The presence of a strangulating lesion was also significantly associated with nonsurvival, as was PF colour: no horse with red PF survived in the present series. In horses with yellow PF, the blood glucose concentration was correlated with the presence of a strangulating intestinal lesion. Peritoneal lactate concentrations can be easily and rapidly measured using a portable analyser and may be useful in assessing the prognosis and/or need for surgery in equine colic cases.     

Dosing equine antimicrobials: Ensuring clinical success and avoiding antimicrobial resistance

Underdosing of equine antimicrobials is a global issue and may be contributing to antimicrobial resistance in horses. Recent research in Australia has identified that most antimicrobial use in peer-reviewed literature is at a higher dose than that currently on the label for many common equine antimicrobials in the United States, the UK and Australia. These dosing regimens used are now considered the most appropriate doses to be using in horses and veterinarians treating equine patients should be aware of the contemporary dosing regimens.