Race performance following epiglottic entrapment surgery in Thoroughbred yearlings.

BACKGROUND: Epiglottic entrapment can occur in yearling Thoroughbreds (TB); however, race performance following surgical correction is unknown. OBJECTIVES: To determine the race performance of horses treated surgically for epiglottic entrapment as yearlings as compared to an untreated cohort. A second objective was to identify risk factors for treated horses not racing post-operatively. STUDY DESIGN: Retrospective cohort and case-control studies. METHODS: Medical (1989-2014) and race records of 66 treated TB racehorses were reviewed. Observed abnormalities on pre- and post-operative endoscopic images and surgical method were recorded. Race records (EquineLine) were recorded. Racing performance of treated yearling TBs and two of their maternal half-siblings, which were used as the untreated cohort, was evaluated in a cohort study. A case-control study was used to investigate risk factors for not racing post-operatively among treated horses. Quarterly starts and earnings were compared to an untreated cohort. Survival analysis was used to assess career longevity. Rates of racing and earnings were compared between groups using Poisson and negative binomial regression respectively. Associations between clinical variables and not racing post-surgery were evaluated using logistic regression. RESULTS: Sixty-six treated horses were identified, 65 of which had at least one half-sibling. Proportions of horses that raced were similar for treated and maternal cohorts (70.0 vs. 70.8%, P = 0.9). Treated horses performed similarly to untreated horses. In treated horses, epiglottic entrapment with abnormal right arytenoid movement was associated with never racing (OR 15.40, 95% CI 1.64-144.23, P = 0.02). More females were affected by epiglottic entrapment than males (47/66 vs. 19/66 respectively, P<0.001). MAIN LIMITATIONS: The retrospective design over a prolonged period of time with cases obtained from a single hospital population. Low case numbers likely influenced the outcome of the multivariable analysis. CONCLUSIONS: Thoroughbred racehorses treated in their yearling year for epiglottic entrapment had no differences in performance variables compared to their untreated cohort. Epiglottic entrapment with abnormal right arytenoid movement might decrease odds of racing post-operatively.

Prevalence of complications associated with use of the Henderson equine castrating instrument.

BACKGROUND: Castration is one of the most common surgical procedures performed in the horse. Complication rate and types of complications associated with use of the Henderson equine castrating instrument have not been determined. OBJECTIVE: To determine the complication rate and type of complications encountered when using the Henderson equine castrating instrument in equine ambulatory practice. STUDY DESIGN: Retrospective case series. METHODS: Medical records of horses undergoing routine castration using the Henderson drill were identified and evaluated for the occurrence of complications. The relationship between potential risk factors and complications was examined using basic descriptive statistics and quantified by means of logistic regression. RESULTS: Of 252 horses in the study population, 27 (10.7%) developed a complication after surgery; 25 of which were nonlife-threatening and responded to medical management. Two complications, one each of wound botulism and evisceration, resulted in euthanasia. Age at the time of castration was significantly associated with the occurrence of (P = 0.005, Wilcoxon rank sum test) complications. Compared to younger horses, the odds of having a complication were significantly greater (OR 2.99, 95% CI 1.27-7.0; P = 0.01) for horses of 4 years of age or more. MAIN LIMITATIONS: The retrospective nature of this study. There is also a lack of direct comparison between different castration methods. CONCLUSIONS: The Henderson equine castrating instrument is an acceptable alternative to traditional emasculators. Its use is associated with a low rate of complications (8.3%) in young horses (≤3 years of age) compared to older horses (21.3%) and a very low rate of serious complications (0.8%) in all ages of horses.

Are horse age and incision length associated with surgical site infection following equine colic surgery?

It is our clinical impression that age and incision length are more strongly associated with surgical site infection (SSI) following colic surgery than skin closure or wound protection method. Therefore, the objective of this observational clinical cohort study was to identify the risks for SSI in horses undergoing colic surgery. Data collection included pre-, intra-, and postoperative variables. Variables with P < 0.2 following univariable analysis were used in a logistic regression multivariable model. Variables with P <0.05 were included in the final model. Odds ratios (OR; 95% confidence intervals, 95% CI) were determined. The area under the curve (AUC) for the receiver-operator characteristic was calculated. The final multivariable model included breed (P = 0.008), incision length (P = 0.004), surgical procedure classification (P <0.001), and postoperative (PO) colic (P = 0.037; overall model P <0.001, and AUC was 0.81 [excellent discrimination between SSI vs. no SSI]). Warmbloods (OR 12.0; 95% CI 2.7-74.8), American breeds (OR 6.4; 95% CI 1.2-43.0), and Thoroughbreds (4.5; 95% CI 1.1-25.5) more commonly had SSI than other breeds (ponies/miniature horses, Draft breeds, Standardbreds, Arabians, and Crossbreeds [referent]). A higher SSI rate was associated with incision lengths >27 cm (3.7; 95% CI 1.5-9.9), heavily contaminated procedures (12.0; 95% CI 3.3-49.9), and horses with PO colic (2.7; 95% CI 1.1-6.8). SSI appeared to be more common after heavily contaminated procedures and in horses with PO colic, which probably resulted in more incisional contamination and trauma. Some breeds appeared to have higher odds of SSI. Age was not associated with SSI. The risk of developing SSI was higher for horses with an incision >27 cm; therefore, surgeons are encouraged to use the minimum incision length required to accomplish the necessary abdominal exploration and bowel manipulation in the safest manner possible.

Retrospective Evaluation of Horses Diagnosed with Neuroborreliosis on Postmortem Examination: 16 Cases (2004-2015).

BACKGROUND: Equine neuroborreliosis (NB), Lyme disease, is difficult to diagnose and has limited description in the literature. OBJECTIVE: Provide a detailed description of clinical signs, diagnostic, and pathologic findings of horses with NB. ANIMALS: Sixteen horses with histologically confirmed NB. METHODS: Retrospective review of medical records at the University of Pennsylvania and via an ACVIM listserv query with inclusion criteria requiring possible exposure to Borrelia burgdorferi and histologic findings consistent with previous reports of NB without evidence of other disease. RESULTS: Sixteen horses were identified, 12 of which had additional evidence of NB. Clinical signs were variable including muscle atrophy or weight loss (12), cranial nerve deficits (11), ataxia (10), changes in behavior (9), dysphagia (7), fasciculations (6), neck stiffness (6), episodic respiratory distress (5), uveitis (5), fever (2), joint effusion (2), and cardiac arrhythmias (1). Serologic analysis was positive for B. burgdorferi infection in 6/13 cases tested. CSF abnormalities were present in 8/13 cases tested, including xanthochromia (4/13), increased total protein (5/13; median: 91 mg/dL, range: 25-219 mg/dL), and a neutrophilic (6/13) or lymphocytic (2/13) pleocytosis (median: 25 nucleated cells/µL, range: 0-922 nucleated cells/µL). PCR on CSF for B. burgdorferi was negative in the 7 cases that were tested. CONCLUSION AND CLINICAL IMPORTANCE: Diagnosis of equine NB is challenging due to variable clinical presentation and lack of sensitive and specific diagnostic tests. Negative serology and normal CSF analysis do not exclude the diagnosis of NB.

Accuracy of a Mouse Bioassay for the Diagnosis of Botulism in Horses.

BACKGROUND: The laboratory diagnosis of botulism in horses traditionally has relied upon the mouse bioassay (MBA). The accuracy of this test for the diagnosis of botulism in horses is unknown. HYPOTHESIS/OBJECTIVES: Our goal was to determine the sensitivity, specificity, positive predictive value, and negative predictive value of the MBA on laboratory-processed fecal and gastrointestinal samples for foals and adult horses. ANIMALS: Cases included all horses with a final clinical diagnosis of botulism that were admitted between 1986 and 2011 and had MBA testing performed. Controls included horses without botulism that were admitted during the same time period and had MBA testing performed. METHODS: Retrospective study. Horses suspected of having botulism had fecal or (less commonly) gastrointestinal content samples tested using MBA. For every hospitalized botulism suspect, control samples were obtained from ≥1 additional hospitalized horses not suspected to have botulism. RESULTS: One hundred and twenty-nine adult horses and 253 adult controls were identified. Overall sensitivity of the MBA was only 32% but specificity was 97%. Forty-three foal cases and 21 foal controls were evaluated; sensitivity of the MBA was 53% and specificity was 100%. Positive predictive value was substantially higher (100% for foals and 89% for adults) than negative predictive value (51% for foals and 67% for adults). CONCLUSIONS AND CLINICAL IMPORTANCE: Mouse bioassay has low sensitivity but high specificity for the diagnosis of botulism in horses. Positive results are highly suggestive of botulism but negative results do not exclude the diagnosis. Unaffected horses and foals rarely shed C. botulinum in their feces.

Streptococcus equi Detection Polymerase Chain Reaction Assay for Equine Nasopharyngeal and Guttural Pouch Wash Samples.

BACKGROUND: Bacterial culture and polymerase chain reaction (PCR) assays for the detection of Streptococcus equi in nasopharyngeal washes (NPW) and guttural pouch lavage (GPL) samples have low sensitivity. In human diagnostics, processing of samples with flocked swabs has improved recovery rates of bacterial agents because of improved surface area and elution factors. HYPOTHESIS: For S. equi subsp. equi (S. equi) detection in NPW and GPL samples we hypothesized that: direct-PCR would be more reliable than flocked swab culture (FS culture); flocked swab PCR (FS-PCR) would be equivalent to direct-PCR; and FS culture would be more reliable than traditional culture. SAMPLES: A total of 193 samples (134 NPW and 59 GPL) from 113 horses with either suspected S. equi infection, convalescing from a known S. equi infection, or asymptomatic horses screened for S. equi. METHODS: Prospective study. Samples were submitted for S. equi direct-PCR. Using logistic regression, direct-PCR (gold standard) was compared to FS culture, traditional culture, and FS-PCR also performed. RESULTS: Direct-PCR was statistically more sensitive than FS-PCR, FS culture, and traditional culture (P < .001). All methods had sensitivities <70% relative to the direct-PCR. FS culture had a similar sensitivity relative to traditional culture. The odds of GPL samples being positive on direct-PCR (P = .030) and FS-PCR were greater than those for NPW samples (P = .021). CONCLUSIONS AND CLINICAL IMPORTANCE: Use of flocked swabs during laboratory preprocessing did not improve detection of S. equi via either PCR or bacterial culture from samples. Direct-PCR is the preferred method of detection of S. equi.

Efficacy of major anthelmintics for reduction of fecal shedding of strongyle-type eggs in horses in the Mid-Atlantic region of the United States.

In the last decade there have been numerous reports of anthelmintic resistant cyathostomins in many parts of the world. The objective of the present study was to evaluate the efficacy of the commercially available anthelmintics against cyathostomin egg shedding in the Mid-Atlantic region of the United States. A total of 989 horses from 67 different farms located in southeastern Pennsylvania, northern Delaware, and northeastern Maryland were treated with fenbendazole, oxibendazole, pyrantel pamoate, ivermectin, or moxidectin at their recommended dosages. Fecal egg count reduction testing was used to determine the efficacy of each anthelmintic on those horses with fecal egg counts of ≥ 200 eggs per gram on the day of treatment (272 horses). Decreased efficacy (reduction of strongyle-type fecal egg counts by less than 90%) was found for fenbendazole, oxibendazole, and pyrantel pamoate, with only 6%, 21% and 43% of horses showing reductions of greater than 90%, respectively. The macrocyclic lactones showed high efficacy in all horses sampled in this study. The decreased anthelmintic efficacy detected in this study adds further evidence for the existence of resistant cyathostomins throughout much of the eastern United States. Findings from this study can be used to create a more sustainable approach for parasite control programs.

Outcome of adult horses with botulism treated at a veterinary hospital: 92 cases (1989-2013).

BACKGROUND: There are no studies evaluating a large population of adult horses treated for botulism. Reported survival rates in outbreak situations are low; however, many horses in outbreaks do not receive treatment. HYPOTHESIS/OBJECTIVES: That adult horses treated at a veterinary hospital would have improved survival compared to outbreak situations. Additional aims included identification of predictors of nonsurvival. ANIMALS: All horses greater than 6 months of age with a final diagnosis of botulism admitted to a veterinary teaching hospital between 1989 and 2013 were included. METHODS: Retrospective study. Historical, admission, and hospitalization data were retrieved from medical records and associations between variables and nonsurvival were identified using logistic regression. Two multivariable models were developed pertaining to (1) information available at admission and (2) clinical findings during hospitalization. RESULTS: Ninety-two records met inclusion criteria. Retained variables for the two models indicated that higher rectal temperature (OR, 1.94; CI, 1.19-3.17) and dysphagia (OR, 4.04; CI, 1.01-16.17) observed at admission increased the odds of survival, as did treatment with antitoxin (OR, 121.30; CI, 9.94-1,480.65). Horses with abnormal respiratory effort or inability to stand had decreased odds of survival. Overall survival was 48% but was significantly higher (67%, P = .011) for horses that arrived standing, and even higher (95%, P < .001) for horses that remained able to stand throughout hospitalization. Complications occurred in 62% of horses but were not associated with nonsurvival. CONCLUSIONS AND CLINICAL IMPORTANCE: Horses that lose the ability to stand have a poor chance of survival. Complications are common in treated horses but do not reduce survival.

Comparison of short- and long-term complications and survival following jejunojejunostomy, jejunoileostomy and jejunocaecostomy in 112 horses: 2005-2010.

REASONS FOR PERFORMING THE STUDY: There is disagreement among surgeons over whether jejunoileostomy (JI) or jejunocaecostomy (JC) is the better method of anastomosis following proximal ileal resection. OBJECTIVE: To compare short- and long-term complications and outcome in horses undergoing jejunojejunostomy (JJ), JI and JC and to test the hypotheses that a higher proportion of horses undergoing JI would have short-term complications and mortality compared with horses undergoing JC or JJ and that JC would be associated with a higher long-term mortality and occurrence of colic. STUDY DESIGN: Retrospective cross-sectional study. METHODS: Medical records of horses undergoing celiotomy for a small intestinal obstruction and JJ, JI or JC from 2005 to 2010 were reviewed. Post operative complications were recorded. Short-term outcome was alive vs. dead at hospital discharge and was analysed using a Chi-squared test. Long-term follow-up was obtained and a Kaplan-Meier estimate of the survivor function was performed. RESULTS: There were 112 horses included. A higher proportion of JI horses had a repeat celiotomy during hospitalisation compared with horses undergoing JC. The number of horses alive at hospital discharge was not different between groups: JJ 79% (95% confidence interval [CI] 68-90%), JI 78% (95% CI 61-96%), JC 83% (95% CI 71-96%). Among horses discharged with long-term follow-up, more horses had colic after JC compared with JJ or JI. Long-term post discharge survival based on the Kaplan-Meier survivor function was lower for horses undergoing JC than JJ or JI (P = 0.04). CONCLUSION: While there was no difference in short-term outcome between groups, more horses with JI underwent a repeat celiotomy during hospitalisation. Horses with a JC were more likely to have long-term complications with colic. Horses that were subjected to euthanasia because of colic within 12 months of hospital discharge either had a JC or repeat celiotomy. The results suggest that, when possible, a JI may be the preferred method of anastomosis based on more favourable survival and lower occurrence of colic long term.

Syndromic surveillance for evaluating the occurrence of healthcare-associated infections in equine hospitals.

REASONS FOR PERFORMING STUDY: Methods that can be used to estimate rates of healthcare-associated infections and other nosocomial events have not been well established for use in equine hospitals. Traditional laboratory-based surveillance is expensive and cannot be applied in all of these settings. OBJECTIVES: To evaluate the use of a syndromic surveillance system for estimating rates of occurrence of healthcare-associated infections among hospitalised equine cases. STUDY DESIGN: Multicentre, prospective longitudinal study. METHODS: This study included weaned equids (n = 297) that were admitted for gastrointestinal disorders at one of 5 participating veterinary referral hospitals during a 12-week period in 2006. A survey form was completed by the primary clinician to summarise basic case information, procedures and treatments the horse received, and whether one or more of 7 predefined nosocomial syndromes were recognised at any point during hospitalisation. Adjusted rates of nosocomial events were estimated using Poisson regression. Risk factors associated with the risk of developing a nosocomial event were analysed using multivariable logistic regression. RESULTS: Among the study population, 95 nosocomial events were reported to have occurred in 65 horses. Controlling for differences among hospitals, 19.7% (95% confidence interval, 14.5-26.7) of the study population was reported to have had at least one nosocomial event recognised during hospitalisation. The most commonly reported nosocomial syndromes that were unrelated to the reason for hospitalisation were surgical site inflammation and i.v. catheter site inflammation. CONCLUSIONS: Syndromic surveillance systems can be standardised successfully for use across multiple hospitals without interfering with established organisational structures, in order to provide useful estimates of rates related to healthcare-associated infections.

Using syndromic surveillance to estimate baseline rates for healthcare-associated infections in critical care units of small animal referral hospitals.

BACKGROUND: Expected rates of healthcare-associated infections (HCAI) have not been established in veterinary hospitals. Baseline rates are critically needed as benchmarks for quality animal care. OBJECTIVE: To estimate the occurrence of events related to HCAI identified using a standardized syndromic surveillance system in small animals in critical care cases at referral hospitals. ANIMALS: Weaned dogs and cats (n = 1,951) that were hospitalized in the critical care unit of referral teaching hospitals during a 12-week period. METHODS: Multicenter, prospective longitudinal study. A survey was completed for all enrolled animals to record basic demographics, information about procedures and treatments that animals received, and to document the occurrence of defined nosocomial syndromes. Data were analyzed to identify risk factors associated with the occurrence of these nosocomial syndromes. RESULTS: Controlling for hospital of admission, 16.3% of dogs (95% confidence intervals [CI], 14.3-18.5) and 12% of cats (95% CI, 9.3-15.5) were reported to have had ≥ 1 nosocomial syndrome occur during hospitalization. Risk factors found to have a positive association with the development of a nosocomial syndrome were longer hospital stays, placement of a urinary catheter, surgical procedures being performed, and the administration of antiulcer medications and antimicrobial drugs excluding those given perioperatively. CONCLUSIONS AND CLINICAL IMPORTANCE: Syndromic surveillance systems can be successfully standardized for use across multiple hospitals to effectively collect data pertinent to HCAI rates and risk factors for occurrence.

Short communication: Survey of animal-borne pathogens in the farm environment of 13 dairy operations.

A survey was conducted on 13 dairies to determine the occurrence of 5 animal-borne pathogens (Salmonella enterica, Escherichia coli O157:H7, Campylobacter jejuni, Mycobacterium avium ssp. paratuberculosis, and Cryptosporidium parvum) and their distributions across farm elements (feces, bedding, milk filters, stored manure, field soil, and stream water). Presence of C. parvum was measured only in feces and stored manure. All but one farm were positive for at least one pathogen species, and 5 farms were positive for 3 species. Escherichia coli O157:H7 was detected on 6 farms and in all farm elements, including milk filters. Mycobacterium avium ssp. paratuberculosis was detected on 10 of 13 farms and in all farm elements except for milk filters. Salmonella enterica and C. jejuni were detected at lower frequencies and were not identified in soil, stream water, or milk filters on any of the 13 farms. Cryptosporidium parvum was detected in feces but not in stored manure. Stored manure had the highest occurrence of pathogens (73%), followed by feces (50%), milk filters, bedding, soil, and water (range from 23 to 31%). Association of pathogen presence with farm management factors was examined by t-test; however, the small number of study farms and samples may limit the scope of inference of the associations. Pathogens had a higher prevalence in maternity pen bedding than in calf bedding, but total pathogen occurrence did not differ in calf compared with lactating cow feces or in soils with or without manure incorporation. Herd size and animal density did not appear to have a consistent effect on pathogen occurrence. The extent of pathogen prevalence and distribution on the farms indicates considerable public health risks associated with not only milk and meat consumption and direct animal contact, but also potential dissemination of the pathogens into the agroecosystem.

Treatment of idiopathic headshaking in horses with pulsed high-dose dexamethasone.

BACKGROUND: Treatment of idiopathic headshaking in horses is complicated by an incomplete understanding of underlying pathophysiology and partially effective treatments. If an inflammatory etiology exists, corticosteroids could be beneficial. HYPOTHESIS: An anti-inflammatory dose of dexamethasone reduces the signs of idiopathic headshaking in a field setting. ANIMALS: Convenience sample of 20 adult horses with idiopathic headshaking syndrome. Cases were recruited from the general population and diagnosed by attending veterinarians. METHODS: Prospective, blinded clinical trial. Pulsed dosing was with oral dexamethasone (60 mg PO Q24h × 4 days, q3 weeks for 4 months) or placebo (inert paste). Owners were blinded and asked to score the headshaking from 0 to 4 (4 = most severe) 3 days per week. The change in headshaking scores (HS) over each treatment pulse was compared between groups by ordinal logistic regression. RESULTS: Twelve horses completed the trial. There was no significant difference between treated or placebo horses (P = .987). Sun (P ≤ .001), wind (P = .028), and exercise (P ≤ .045) significantly increased HS. CONCLUSIONS AND CLINICAL IMPORTANCE: No benefit of dexamethasone treatment was detected for idiopathic headshaking. The results confirmed previous reports of common triggers for headshaking behavior

Antimicrobial use in horses undergoing colic surgery.

BACKGROUND: Recommendations for antimicrobial prophylaxis for surgery are well-described in human medicine, but information is limited for veterinary practice. OBJECTIVE: To characterize antimicrobial use in horses undergoing emergency colic surgery. ANIMALS: A total of 761 horses undergoing emergency colic surgery (2001-2007). METHODS: Retrospective case review. Antimicrobial dose and timing, surgical description, and duration of treatment were collected from medical records. Associations between antimicrobial use and the occurrence of fever, incisional inflammation or infection, catheter-associated complications, or Salmonella shedding during hospitalization were analyzed using rank-sum methods and logistic regression. RESULTS: A total of 511 (67.2%) horses received an inappropriate amount of drug preoperatively. Median time from preoperative dose to incision was 70 (IQR 55-90) minutes; median total surgery time was 110 (IQR 80-160) minutes. Seventy-three horses were euthanized under anesthesia because of poor prognosis. Of 688 horses, 438 should have been redosed intraoperatively based on the duration of surgery. Only 8 (1.8%) horses were redosed correctly. Horses remained on perioperative antimicrobials a median of 3 (IQR 2-4.5) days. Antimicrobial therapy was reinstituted in 193 (28.9%) horses, and median days of total treatment were 3.8 (IQR 2-6). Signs that led to reinstituting therapy were fever (OR 3.13, P = .001) and incisional inflammation/infection (OR 2.95, P = .001). Horses in which treatment was reinstituted had 2.3 greater odds of shedding Salmonella (P = .003). Increased surgical time was associated with longer duration of antimicrobial therapy (OR 1.02, P = .001). CONCLUSIONS AND CLINICAL RELEVANCE: Despite published recommendations regarding antimicrobial prophylaxis, compliance is poor; improvement might reduce postoperative complications.

Identification of predictors of Salmonella shedding in adult horses presented for acute colic.

BACKGROUND: Colic has been associated with shedding of Salmonella. Horses with salmonellosis typically develop diarrhea, fever, and leukopenia. Overlooking additional predictors may result in failure to detect shedding horses and increase environmental contamination. OBJECTIVES: Evaluate associations between signalment and clinicopathologic data during early hospitalization and Salmonella shedding in horses treated for acute colic. ANIMALS: Horses with acute colic admitted to a referral hospital. A total of 59 horses shedding Salmonella compared to 108 Salmonella-negative horses. METHODS: Retrospective case-control study evaluating patient and Salmonella culture data. Associations between variables and Salmonella shedding were identified using logistic regression. Two multivariable models were developed pertaining to (1) information available within 24 hours of admission and (2) clinical findings that developed later during hospitalization. RESULTS: Variables retained for multivariable model 1 indicated that Warmbloods and Arabians had increased odds for shedding Salmonella, as did horses requiring surgery (OR, 2.52; 95% CI, 1.10-5.75) or having more severe gastrointestinal disease (OR, 2.59; 95% CI, 1.08-6.20). Retained variables for model 2 demonstrated that horses that were treated surgically (OR, 1.60; 95% CI, 0.70-3.62), developed fever >103°F (OR, 2.70; 95% CI, 0.92-7.87), had abnormal leukocyte count (OR, 1.38; 95% CI, 0.61-3.09), or became inappetent and lethargic (OR, 16.69; 95% CI, 4.08-68.24) had increased odds for shedding Salmonella. CONCLUSIONS AND CLINICAL IMPORTANCE: In horses with acute colic that present without signs of diarrhea, fever, or leukopenia, additional predictors associated with shedding Salmonella could be used to more promptly identify horses likely to shed organisms.

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.

Survival characteristics of Salmonella enterica serovar Newport in the dairy farm environment.

Multi-drug resistant (MDR) Salmonella enterica serovar Newport (S. Newport) has established a reservoir in dairy cattle. Infected herds suffer significant mortality in both adult and young animals, posing a considerable economic loss to producers. Land application of manure from infected animals may further spread the pathogen into the agroecosystem, causing public health concerns. Previous work by our group demonstrated that the organism persisted in manure and manured soil for 6 to 10 mo under laboratory conditions. In the present study, we determined the survival characteristics of MDR S. Newport in a dairy lagoon, compost pile, and soil of a grass field under natural conditions using environmental sentinel chambers with an initial concentration of S. Newport around 7 log(10) per gram. In the static compost pile at 64 °C, S. Newport was eliminated within 18 h. In the dairy effluent lagoon, the pathogen survived for >137 d, whereas in the field soil, the organisms persisted for over 276 d. The survival of MDR S. Newport in both the lagoon and field soil followed a pattern of (1) an increase or plateau for a few days, (2) log-linear decline for 6 to 13 wk, and (3) a long tailing phase at low and variable concentration for 4 to 9 mo. Log reduction times (days required for 90% decrease in concentration) based on the log-linear decline phase were 7 d in the lagoon and 14 to 20 d in the soil. Conditions leading to faster inactivation during the initial phase do not necessarily translate into a quicker elimination of the pathogen. Regression models of the log-linear phase may be inaccurate for estimating complete pathogen elimination.

A multicenter retrospective study of 151 renal biopsies in horses.

BACKGROUND: Renal biopsies are uncommonly performed in horses and little is known about their diagnostic utility and associated complication rate. OBJECTIVE: To describe the techniques, the complication rate, risk factors, and histopathology results; as well as evaluate the safety and diagnostic utility of renal biopsy in the horse. ANIMALS: One hundred and forty-six horses from which 151 renal biopsies were obtained. Animals ranged in age from 48 hours to 30 years. METHODS: Multicenter retrospective study, with participation of 14 institutions (1983-2009). RESULTS: Renal biopsy in horses was associated with a similar rate of complications (11.3%) to that occurring in humans and companion animals. Complications were generally associated with hemorrhage or signs of colic, and required treatment in 3% of cases. Fatality rate was low (1/151; 0.7%). Biopsy specimens yielded sufficient tissue for a histopathologic diagnosis in most cases (94%) but diagnoses had only fair (72%) agreement with postmortem findings. Risk factors for complications included biopsy specimens of the left kidney (P = .030), a diagnosis of neoplasia (P = .004), and low urine specific gravity (P = .030). No association with complications was found for age, sex, breed, institution, presenting complaint, other initial clinicopathologic data, biopsy instrument, needle size, or use of ultrasonographic guidance. CONCLUSIONS AND CLINICAL IMPORTANCE: Renal biopsy in horses has low morbidity and results in a morphological histopathologic diagnosis in 94% of cases. However, this procedure might result in serious complications and should only be used when information obtained would be likely to impact decisions regarding patient management and prognosis.