Evaluation of dietary and management risk factors for enterolithiasis among horses in California

Enteroliths are intestinal calculi that result in intestinal obstruction and colic in horses. Equine enterolithiasis occurs worldwide, but the disease is particularly prevalent in some geographic locations, including California. The objectives of this study were to evaluate dietary and environmental risk factors for the disease. This was accomplished through a case–control study by comparing horses with colic from enterolithiasis presenting to the University of California, Davis VMTH, to horses with colic of other causes. Data were collected on 61 horses with enterolithiasis and 75 controls via evaluation of patient records and questionnaires completed by owners at the time of admission. Following multiple logistic regression analysis, the following factors were found to be significantly associated with enterolithiasis: feeding ⩾50% of the diet as alfalfa; feeding <50% of the diet as oat hay; feeding <50% of the diet as grass hay; and lack of daily access to pasture grazing.     

Gastric rupture in horses: a review of 54 cases

The historical, clinical, laboratory, surgical and necropsy findings in 54 cases of gastric rupture in horses are described. Eleven per cent of the deaths of horses undergoing exploratory coeliotomy for colic during the period of the study were a result of gastric rupture. Comparison with all horses which had exploratory coeliotomies for colic over an eight year period did not show that horses with gastric rupture were different from these reference horses regarding age, breed or season. There were fewer stallions than expected in the gastric rupture group. Horses with histories of both acute and chronic (more than 36 h) colic were susceptible to gastric rupture. Primary and idiopathic causes of gastric dilation and rupture accounted for about one-third of the horses. All but one of these cases resulting from secondary causes fell into three aetiologically-related groups: obstructive, peritoneal and enteric, with approximately equal numbers of horses in each group. Most of the ruptures occurred along the greater curvature of the stomach. At least six horses ruptured their stomachs postoperatively in the presence of an indwelling nasogastric tube. The presence or absence of gastric reflux following nasogastric intubation was not a reliable indicator, on its own, of gastric dilation. Horses that later died from gastric rupture had markedly elevated heart rate, hypochloraemia, peritoneal exudative effusion (particularly with evidence of sepsis), pre- and/or postoperative gastric reflux and small or large intestinal disease. However, no distinctive feature of these horses was shown to place them at risk of gastric rupture.     

Post-mortem findings of gastric ulcers in Swedish horses up to one year of age: a retrospective study 1924-1996

Necropsy records from 702 horses, less than one year old, that were subjected to necropsy between 1924 and 1996 were used to estimate the prevalence of gastric ulceration in younger horses and to evaluate some potential risk factors that may contribute to the development of gastric ulceration. Information concerning breed, gender, age, season of death, clinical signs of colic, medical treatment, parasitism and documentation of diseases in different organs were recorded, as well as size, number and anatomical distribution of ulcers. Gastric ulcers were found in 96 of 702 young horses (14%) and gastritis in another 64 animals (9%). The cutaneous region adjacent to margo plicatus (51%), and the corpus region were commonly affected (46%). The investigation clearly demonstrates that gastric ulceration has affected young Swedish horses to a similar degree during most of the 20th century. A significant (p < or = 0.05) association between gastric ulcers and the signs of colic, parasitism and a concomitant intestinal, liver, and oesophageal involvement was found. No breed or sex predilection with gastric ulcers was obtained. The risk of gastric ulcers was highest during the fall (odds ratio 3.52) and lowest during the summer (odds ratio 0.45). The seasonal variation could not be explained by concomitant findings of Gasterophilus larvae. By using a multivariate logistic regression analysis, only season significantly influenced the risk of gastric ulceration.     

Feeding practices associated with colic in horses.

OBJECTIVE: To determine whether specific feeding practices were associated with development of colic in horses. DESIGN: Prospective matched case-control study. ANIMALS: 364 horses examined by veterinarians in private practice in Texas because of colic (cases; n = 182) or any other reason (controls; 182). PROCEDURE: Participating veterinarians were sent forms at the beginning of the study to collect information on signalment, feeding management practices, farm management practices, and preventive medical treatments. Case and control horses were compared by use of conditional logistic regression to identify factors associated with colic. RESULTS: Risk factors for colic were a recent change in batch of hay, decreased exposure to pasture, a recent change in type of grain or concentrate fed, feeding > 2.7 kg (6 lb) of oats/d, feeding hay from round bales, and Thoroughbred breed. Recent anthelmintic administration decreased the risk of colic. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that certain changes in diet (eg, change in batch of hay, change in type of grain or concentrate, feeding hay from round bales) and management (eg, decreased availability of pasture) increase the risk of colic in horses.     

Evaluation of dietary and management risk factors for enterolithiasis among horses in California

Enteroliths are intestinal calculi that result in intestinal obstruction and colic in horses. Equine enterolithiasis occurs worldwide, but the disease is particularly prevalent in some geographic locations, including California. The objectives of this study were to evaluate dietary and environmental risk factors for the disease. This was accomplished through a case–control study by comparing horses with colic from enterolithiasis presenting to the University of California, Davis VMTH, to horses with colic of other causes. Data were collected on 61 horses with enterolithiasis and 75 controls via evaluation of patient records and questionnaires completed by owners at the time of admission. Following multiple logistic regression analysis, the following factors were found to be significantly associated with enterolithiasis: feeding 50% of the diet as alfalfa; feeding <50% of the diet as oat hay; feeding <50% of the diet as grass hay; and lack of daily access to pasture grazing.     

Dietary and other management factors associated with colic in horses.

OBJECTIVE: To determine whether dietary and other management factors were associated with development of colic in horses. DESIGN: Prospective matched case-control study. POPULATION: 2,060 horses examined by veterinarians in private practice in Texas for colic and noncolic emergencies. PROCEDURE: Each month for 12 months, participating veterinarians were sent forms to collect information on 1 horse with colic and 1 horse that received emergency treatment for a condition other than colic, information collected included signalment, farm management and characteristics, diet, medical and preventive medical factors, transport, and activity or use. Case and control horses were compared by means of conditional logistic regression to identify factors associated with colic. RESULTS: Recent change in diet, recent change in type of hay, history of previous episode of colic, history of abdominal surgery for colic, recent change in weather conditions, recent change in housing, Arabian breed, administration of an anthelmintic during the 7-day period prior to examination, failure to receive regular deworming, age > 10 years, and regular exercise (vs pastured at all times) were associated with increased risk of colic. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that changes in diet (particularly in type of hay fed) contribute to increased risk of colic. A regular program for administration of anthelmintics may reduce the overall frequency at which colic develops, but recent administration of anthelmintics may predispose some horses to colic. Arabian horses may have an increased risk of colic, and horses at pasture may have a decreased risk of colic.     

Demographics and costs of colic in Swedish horses

BACKGROUND: Colic is an important cause of morbidity and mortality in horses. In Sweden, an insurance database with diagnostic medical information is maintained on >30% of the nation's horse population. HYPOTHESIS: The objective was to describe the occurrence of colic, defined by costly veterinary care and life claims, in horses at 1 insurance company during 1997-2002. HORSES: All horses (<21 years of age) with complete insurance for veterinary care and life during the period 1997-2002 were included. METHODS: Colic was defined as conditions where the main clinical sign was abdominal pain and the problem was related to the gastrointestinal system. The analyses included measures of incidence by sex, breed group, age categories, geographical location (urban/other), survival to and survival after colic, medical cost for colic, and multivariable modeling of risk factors related to the event of colic. RESULTS: In all, 116,288 horses contributed to 341,564 horse years at risk (HYAR). There were 3,100 horses with a colic diagnosis, of which 27% were settled for life insurance. The median gross cost for veterinary care was 4,729 Swedish Kronor (SEK). The overall occurrence and mortality rate of colic was 91 and 24 events per 10,000 HYAR. Survival after colic at 1 month was 76% (95% confidence interval: 75-78%). CONCLUSIONS AND CLINICAL IMPORTANCE: The occurrence of colic varied with breed group, age, and season. The mortality rates probably reflected the true mortality of colic. The veterinary care rates most likely underestimated of the risk colic because they represent relatively costly events.     

Postmortem findings of gastric ulcers in Swedish horses older than age one year: a retrospective study of 3715 horses (1924-1996)

The present study was performed to estimate retrospectively the prevalence of gastric ulceration in necropsied Swedish horses and to evaluate some potential risk factors. Horses (n = 3715) older than age one year and necropsied 1924-1996 were included. Information about breed, gender, age, season of death, clinical signs of colic, Gasterophilus larvae and documentation of diseases in different organs was recorded. Data on size, number and anatomical distribution of gastric ulcers were also obtained. The cold-blooded horses and the Standardbreds were the 2 most dominating breeds in our material. Gastric ulcers/erosions were seen in 633 (17%) of the horses. The highest prevalence was found in Thoroughbreds (19%) and Standardbreds (19%), whereas only 7% of the cold-blooded horses were affected. The cutaneous region along the margo plicatus was the most commonly affected area (52%). Multiple ulcers were seen in 62% of the horses with gastric ulcers and concurrent ulcers in the oesophagus were reported in 6%. In the bivariate analysis, significant associations were found between gastric ulcers and signs of colic (P<0.001) and gender (P<0.001), as well as between concomitant bowel (P<0.001), liver (P<0.05) and oesophageal (P<0.01) lesions. Using a multivariate logistic regression model, only year of necropsy and breed were found significantly to influence the risk of gastric ulceration by decreasing the Log Likelihood test value. The present study shows clearly that gastric ulceration has been present in Swedish horses throughout the 20th century, which also may be the situation worldwide.     

Risk factors for enterolithiasis among horses in Texas

OBJECTIVE: To identify risk factors for enterolithiasis in horses. DESIGN: Matched case-control study. ANIMALS: 26 horses with enteroliths, 104 horses with other causes of colic that underwent surgery (52 horses, surgical control group) or were treated medically (52 horses, nonsurgical control group). PROCEDURE: Medical records were reviewed for horses with enteroliths and control horses. Information collected included signalment, anamnesis, and findings on physical examination and clinicopathologic testing at admission. Horses with enteroliths and control horses were compared by means of conditional logistic regression to identify factors associated with enterolithiasis. RESULTS: Horses that were fed alfalfa hay, spent < or = 50% of time outdoors, or were Arabian or miniature breeds had an increased risk of developing enteroliths. Horses with enteroliths were more likely to have been hyperbilirubinemic and to have had clinical signs > 12 hours prior to admission. CONCLUSIONS AND CLINICAL RELEVANCE: Breed and diet appear to influence the risk of enterolithiasis; other management factors also may influence development of enteroliths. Duration of clinical signs may be longer and signs may be less severe among horses with enteroliths, compared with horses with other causes of colic.     

Prevalence of Gastric Ulcerations in Horses with Colic

The goal of this study was to determine the prevalence of gastric ulcers in horses with acute abdominal crisis (colic) and to examine the temporal effect of hospitalization on ulcer development in equine patients treated for colic. In addition, other factors that may be associated with gastric ulceration were also explored. The study design was a prospective original study incorporating 169 horses that presented to the George D. Widener Hospital for examination. One hundred and twelve horses presenting with the chief complaint of colic were included in the study group, and 57 horses that presented for non-colic or nonemergency complaints were evaluated and included as case controls. Gastroscopy was performed on equine patients presenting with the chief complaint of colic or horses presenting for reasons other than colic (control); mucosal changes were scored 0 to 3. Additionally, horses presenting for colic were gastroscopically evaluated twice during a 5-day period. Medical records were reviewed for history, clinical findings, laboratory results, and treatment. Seventy-six of 112 horses presenting with the chief complaint of colic had gastric ulceration compared with 41 of 57 horses in the control group. There was a significant association between age of the patient and chief complaint (ie, colic vs control) and between breed and chief complaint. There was no association between gastric ulcer score and chief complaint (colic vs control). Thirty-eight of the 112 horses presenting with colic deteriorated in ulcer score while hospitalized. Using a Pearson chi-squared test, there was no statistically significant association between gastric ulceration with age, breed, or sex. Horses with gastric ulceration in the colic group had lower packed cell volumes compared with horses presenting with colic without gastric ulcers, and this was statistically significant (P < .001). The high incidence of gastric ulceration in the study and control groups supports the reports of other investigators that gastric ulcers in horses, no matter the presenting complaint, are widespread. There was a significant association between breed and chief complaint (P = .005); however, breed and outcome of gastric ulceration were not related (Thoroughbreds were the least likely breed to present for colic). Although a trend in increasing gastric ulceration was seen in hospitalized colic patients, it was not statistically significant. This suggests that horses that are hospitalized may be at increased risk for developing gastric ulcers because of stress, feed deprivation, and administration of treatment. Thus, horses that present for colic should be gastroscopically evaluated if clinical signs raise the index of suspicion for gastric ulceration.     

Evaluation of low-molecular-weight heparin for the prevention of equine laminitis after colic surgery

Objectives – The aim of this study is to describe the prevalence of postoperative laminitis in colic cases and to determine if low-molecular-weight heparin (LMWH) is effective in preventing this complication.
Design – Retrospective clinical study.
Animals – Client-owned horses.
Interventions – SC administration of enoxaparin during the postoperative period.
Measurements and Main Results – Medical records of 360 horses undergoing surgery for colic and surviving at least 3 days were evaluated. Fifty-six horses admitted before 1995 did not receive LMWH (control group) and 304 admitted after 1995 received LMWH as a prophylaxis for laminitis (treatment group). Three grades of severity were defined for laminitis. Prevalence and severity of laminitis were compared between the 2 groups. Several parameters recorded on admission (sex, age, breed, site and nature of the disease, heart rate, PCV, gravity score, and shock score) and the administration of LMWH were tested as risk factors in the development of laminitis in a logistic regression procedure. Prevalence and grade of laminitis were significantly lower in the treatment group. Only the absence of LMWH was recognized as a significant risk factor in the logistic regression model.
Conclusions – The administration of LMWH appears to be effective in the prophylaxis of laminitis following colic surgery and may be useful in the postoperative management of these horses.     

Primary gastric rupture in 47 horses (1995–2011)

The purpose of this retrospective case-control study was to identify factors associated with primary gastric rupture and to investigate if there were differences between etiologies of primary gastric rupture. Compared to the general colic population, Quarter horses were under-represented and Friesians and draft breeds were over-represented in 47 cases of primary gastric ruptures. Horses with primary gastric rupture typically presented with severe clinical and clinicopathological derangements. There were 24 idiopathic gastric ruptures, 20 gastric impaction associated ruptures, and 3 perforating gastric ulcers. Thoroughbred horses were over-represented in the idiopathic gastric rupture group compared to other breeds and etiologies. This study suggests the presence of important breed predispositions for development of gastric rupture. Further study is necessary to identify if these predispositions are associated with management factors or breed-specific disorders.     

Risk factors of colic in horses in Austria

A hospital‐based case study was conducted at the University of Veterinary Medicine Vienna for a 1‐year period. The purpose of this study was to determine possible alterable and non‐alterable risk factors of equine colic in Austria. The investigated parameters were obtained from hospital medical records (individual factors, duty of the horse, deworming, change in diet and water intake), from questionnaires (feed intake, watering types, housing and pasture practices) and from http://www.orf.at (weather‐related factors). Moreover, 221 collected feed samples were investigated through hygienic quality sensory evaluation and mould, yeast and bacteria presumptive samples were confirmed by microbiological investigation. Variables that were observed from the hospital medical records and found to be significantly associated with colic in a univariate analysis were included in multivariate analysis and the only remaining risk factor was decreased water consumption (p < 0.001, OR = 5.025). Consequently, a total of 2743 horses and 366 cases of colic were observed during the study period. The risk factors for colic in Austria were identified for the first time in this study and these increased risk factors were decreased water consumption, high amount of concentrate intake (p = 0.037), low hygienic quality of hay (p = 0.027) and high temperature on the arrival date (p = 0.003). Results suggest that the occurence of colic may not stop, but may decrease with better feed management practices in Austria.     

Factors associated with development of ileal impaction in horses with surgical colic: 78 cases (1986-2000)

Deal impaction is prevalent in the south-eastern USA, where feeding of Coastal Bermuda hay has been implicated as a risk factor. Alternatively, infection with the tapeworm Anoplocephala perfoliata has been identified as a risk factor for ileal impaction in the UK. We hypothesised that feeding Coastal Bermuda hay and failure to administer routinely an anthelmintic with efficacy against tapeworms would place horses at risk of developing ileal impaction in the USA. Seventy-eight horses, with surgically confirmed ileal impaction and 100 horses admitted for colic that did not have an ileal impaction, were selected retrospectively for logistic regression analysis. Using odds ratios (OR) as an index of risk, feeding Coastal Bermuda hay (OR = 2.9) and failure to administer a pyrantel salt within 3 months of admission (OR = 3.1) placed horses at risk of development of ileal impaction. This study confirms the belief that feeding Coastal Bermuda hay places horses at risk of ileal impaction, although the quality of the hay may also play a role. Periodic administration of anthelmintics with efficacy against tapeworms should be considered to reduce risk of ileal impaction.     

Occurrence of Anoplocephala perfoliata infection in horses in Ontario, Canada and associations with colic and management practices

Infection with the tapeworm Anoplocephala perfoliata has been found to be associated with equine colic in horses in the United Kingdom. Using a matched case-control study design, data collected from 117 pairs of horses in Ontario were examined for evidence of associations between risk of colic and A. perfoliata infection, and between seropositivity to infection and management practices. Cases were horses in southern Ontario diagnosed with colic by local veterinarians, and control horses were from the same stables as cases and were matched by age, breed and gender where possible. Infection status was defined on the basis of positive results upon coprological examination, and/or seropositivity to a 12/13 kDa A. perfoliata secretory protein. Fifty-six percent of the 234 horses were seropositive for A. perfoliata, but eggs were found in samples from only 6% of horses. Horses dependent on pasture for a large part of their diet were significantly more likely to have ELISA optical density levels above 0.600 compared to other horses (odds ratio [OR]=6.38; p=0.029). This finding identified exposure to pasture as an important source of A. perfoliata infection in the horses used in the study. In a subset of 46 pairs of horses for which control horses had no known history of colic, a statistically significant negative association was found between the risk of colic and optical density (OD) levels >0.200-0.600, relative to OD levels < or = 0.090 (OR=0.08; p=0.017). There was no other statistical evidence of an association between the risk of colic and A. perfoliata infection.     

Effects of feeding large amounts of grain on colonic contents and feces in horses

OBJECTIVE: To assess changes in systemic hydration, concentrations of plasma electrolytes, hydration and physical properties of colonic contents and feces, and gastrointestinal transit in horses with access to large amounts of grain. ANIMALS: 6 horses with right dorsal colon (RDC) fistulas. PROCEDURE: In a crossover design, horses were alternately fed 1 of 3 diets: orchard grass hay ad libitum after being adapted to this diet for at least 5 days, orchard grass hay ad libitum and 4.55 kg of grain offered every 12 hours after being adapted to orchard grass hay ad libitum for at least 5 days, or orchard grass hay ad libitum and 4.55 kg of grain offered every 12 hours after being adapted to this diet for at least 5 days. Physical examinations were performed and samples of blood, colonic contents, and feces were collected every 6 hours during a 48-hour observation period. RESULTS: Grain ingestion had several effects, including changes in the concentrations of electrolytes in plasma; RDC contents became more homogenous, dehydrated, foamy, and less dense; RDC contents flowed spontaneously when the cannula was opened; RDC contents expanded when heated in an oven; and feces became fetid and less formed. Horses did not have any clinical signs of colic, endotoxemia, or laminitis. CONCLUSIONS AND CLINICAL RELEVANCE: Changes observed in the colonic contents and feces may be explained by the large amounts of hydrolyzable carbohydrates provided by grain. Access to large amounts of grain may increase the risk of tympany and displacement of the large intestine.     

Colic in geriatric compared to mature nongeriatric horses. Part 1: Retrospective review of clinical and laboratory data

Reason for performing study: It is the impression of some surgeons that geriatric horses have a lower survival rate compared to mature nongeriatric horses following colic surgery. One possible reason for this is that geriatric horses may be more critically ill at admission and have more severe disease than mature nongeriatric horses. Objective: To compare admission historical, physical examination and laboratory data for geriatric and mature nongeriatric horses referred for signs of colic. Methods: Medical records of horses admitted with a presenting complaint of colic between 2000 and 2006 were reviewed. Geriatric horses ≥16 years (n = 300) and mature nongeriatric horses 4–15 years (n = 300). Information obtained included duration of colic prior to admission, admission level of pain, heart rate, intestinal borborygmi, packed cell volume (PCV), plasma creatinine and blood lactate concentrations and peritoneal fluid total protein. Data were analysed using a Chi‐squared test or an analysis of variance. Level of significance was P<0.05. Results: There was no difference between geriatric and mature horses in the duration of colic prior to admission or in admission heart rate, PCV, or plasma creatinine or blood lactate concentrations. However, geriatric horses were more likely to be moderately painful and less likely to be bright and alert than mature horses; and less likely to have normal intestinal borborygmi than mature horses. Peritoneal fluid total protein concentration was higher in geriatric than mature horses. Conclusions and potential relevance: Geriatric horses presenting with signs of colic had a similar admission cardiovascular status based on heart rate, PCV, and plasma creatinine and blood lactate concentration to mature horses. Geriatric horses, however, may have different causes of colic, which may be more serious than mature horses based on pain, lack of intestinal borborygmi and peritoneal fluid total protein concentration.     

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.     

Survey of 79 referral colic cases

The clinical, surgical and/or necropsy diagnosis of 79 horses admitted to a referral clinic for evaluation of colic are reported. Twenty-one horses were presented with conditions amenable to medical treatment and all were subsequently discharged. Exploratory laparotomies were performed on 44 horses during the present study, in some cases as a diagnostic procedure preceding euthanasia. In general, in surgical cases the mortality rate was highest for problems involving the small intestine, followed by those affecting the large colon and then the small colon. Postoperative sequelae included peritonitis, infarction, visceral rupture and acute circulatory failure. Colitis, visceral rupture and thromboembolic infarction generally had a fatal result. The overall recovery rate (for 79 horses) was about 50 per cent.     

Risk factors associated with development of postoperative ileus in horses.

OBJECTIVE: To determine risk factors associated with development of postoperative ileus in horses undergoing surgery for colic. DESIGN: Case-control study. ANIMALS: 69 horses that developed ileus after surgery for colic and 307 horses that did not develop postoperative ileus. PROCEDURE: Signalment, history, clinicopathologic data, treatment, lesions, and outcome were obtained from medical records. RESULTS: Variables associated with increased risk of postoperative ileus included age > 10 years, Arabian breed, PCV > or = 45%, high serum concentrations of protein and albumin, anesthesia > 2.5 hours' duration, surgery > 2 hours' duration, resection and anastomosis, and lesions in the small intestine. Enterotomy reduced the risk of postoperative ileus. After multivariate logistic regression, the final model included the variables Arabian breed, PCV > or = 45%, lesion type, duration of surgery (> 2 hours vs < or = 2 hours), and pelvic flexure enterotomy. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that by evaluating certain factors, horses at increased risk of postoperative ileus may be recognized before the condition develops. Preventative treatment and early intervention may be instituted in these horses. Shortening surgery time and performing an enterotomy may decrease the probability of horses developing postoperative ileus.