Evaluation of peritoneal l-lactate concentration in horses in the early post-partum period.

BACKGROUND: Peritoneal fluid lactate concentration is an important diagnostic tool in horses with abdominal pain. Information on peritoneal lactate concentrations is lacking following parturition in the mare. OBJECTIVES: To compare blood and peritoneal lactate concentrations in a population of mares within 36 h post-partum, report a normal reference range and identify any impact of retained foetal membranes (RFMs). METHODS: This is a retrospective study evaluating healthy mares from which blood and peritoneal samples had been obtained within 36 h of parturition. Exclusion criteria included signs of abdominal pain within this period. Data was interrogated for normality using a Shapiro-Wilk test. Wilcoxon signed-rank test and Bland-Altman analysis were used to compare blood and peritoneal lactate concentrations. Linear regression was used to compare age and breed data with peritoneal lactate concentrations. Significance was defined as p < 0.05. RESULTS: Forty mares met the inclusion criteria. Mean age was 12.6 ± 4.1 years, and most mares were multiparous (65%). Peritoneal lactate ((1.2 (IQR = 0.9-1.6) mmol/L) was increased compared to blood lactate concentration (0.7 (IQR = 0-1.1)mmol/L; p < 0.001). Plasma total protein (TP) concentrations were 68 (IQR = 64-74) g/L and peritoneal protein concentrations 8 (IQR = 4-9.7) g/L. Six mares developed RFM. The median fold-increase in peritoneal lactate concentration compared to blood lactate concentration was 0.9 (IQR: 0.01-1.7; range: 0-2.5). The reference range for peritoneal fluid lactate concentration was 0-2.5 mmol/L. CONCLUSION: Peritoneal lactate concentrations in healthy post-partum mares remained within the normal reference range and were not influenced by RFM or parturition. Increased peritoneal lactate in this group warrants further investigation.

Factors associated with development of post-operative reflux in horses with large colon volvulus and association with complications and outcomes.

BACKGROUND: Post-operative reflux (POR) is rare following large colon volvulus (LCV) but does occur despite the absence of a small intestinal lesion. The prevalence, risk factors and association with survival of POR after LCV are currently unknown. OBJECTIVES: To determine the prevalence of POR in horses with an LCV and its association with survival. A further objective was to assess factors which may predict POR. The hypothesis was that horses with POR following LCV surgery have a worse outcome for survival compared to those without POR. STUDY DESIGN: A retrospective cross-sectional study. METHODS: Clinical data of client owned horses which underwent colic surgery at a single UK referral hospital between 2008 and 2021, where LCV was the primary finding, were retrieved from hospital records. Statistical analyses included chi-squared, t-tests and odds ratios (ORs). Horses with concurrent lesions, and those that did not survive past anaesthetic recovery, were excluded from analysis. POR was defined as ≥2 L of gastric reflux on at least one occasion. RESULTS: A total of 128 horses were included in the study, 23 of which had POR (18%). Overall survival to hospital discharge was 86%, 95% in the non-POR and 44% in the POR group. Horses with POR were less likely to survive to discharge than those without (OR = 26, 95% confidence interval [CI] [7.68-88.0], p < 0.001), and less likely to be alive 3 years after surgery (OR = 13.4, 95% CI [2.78-64.8], p < 0.001). MAIN LIMITATIONS: Due to the retrospective study design, full data sets were not available for every case because clinical records were incomplete or, at that time, certain tests were not performed or clinical variables were not measured. CONCLUSIONS: POR in LCV cases is a negative prognostic indicator for survival.

Current Topics in Medical Colic.

The list of medical causes of acute or chronic colic in horses is extensive. The purpose of this article is to review 4 medical causes of equine colic with a focus on newer trends in treatment. The 4 topics selected include gastric impaction, gastric glandular disease, colon displacement, and inflammatory bowel disease.

Assessment of the microvascular perfusion using sidestream dark-field imaging in healthy newborn foals.

BACKGROUND: Different methods to measure tissue perfusion are available in equine neonatology, but they are not representative of microvascular derangements. OBJECTIVE: To evaluate the feasibility of the sidestream dark-field (SDF) capillaroscopy to visualize the capillary microvasculature in conscious newborn foals, the differences between two imaging sites and times of measurements, and the measurements' reproducibility. METHODS: Seventeen healthy newborn foals were enrolled. Three sites at the upper and lower lip mucosa were assessed by SDF, using a hand-held capiscope, at 24 h and at 4-5 days after birth. Videos were assessed independently by two observers for quality and for semiquantitative calculation of microvascular parameters, including vascular density (VD), microvascular flow index (MFI), proportion of perfused vessels (PPV), and functional capillary density (FCD). Data were analyzed using unpaired and paired Student's T-tests to assess differences between sites and time-points. Bland-Altman plots and intraclass correlation coefficient (ICC) were used to assess measurement reproducibility. RESULTS: Differences were found between the upper and the lower lip for VD at both 24 h and 4-5 days, and for FCD at 24 h, and between the two time-points for PPV at the lower lip. ICC for measurement reproducibility was good for all parameters (0.64-0.79) for the lower lip, and was good for VD and FCD (0,76-0,79) and fair to moderate for MFI and PPV (0.31-0.41) for the upper lip. CONCLUSIONS: Measurement of the capillary microvasculature is feasible in the conscious newborn foal. The lower lip has the best measurement reproducibility. Further investigations are warranted in cardiovascularly compromised cases, particularly in septic foals.

An objective study into the effects of an incline on naturally occurring lameness in horses.

BACKGROUND: The clinical examination of lame horses in real world settings often requires the use of sloped surfaces. OBJECTIVES: This pilot study aimed to evaluate the effects of uphill and downhill locomotion on asymmetry in horses with naturally occurring lameness affecting forelimbs and hindlimbs. METHODS: Ten horses (8-19 years) with forelimb lameness and eight horses (7-16 years) with hindlimb lameness were fitted with inertial sensors at the poll, withers, sacrum and both tuber coxae. Data were collected whilst the horses were trotted in hand on a level surface (<0.7%), as well as up and down a minor slope of 2.4%. Data were collected for a minimum of 25 strides at each incline type. Effect of incline was compared using a repeated measures ANOVA and, where significant, a subsequent Bonferroni's multiple comparisons. RESULTS: Of the horses with hindlimb lameness, there were reductions in asymmetry seen during downhill locomotion when compared with trotting on the flat (flat: 6.6 ± 4.4 mm to downhill: 1.9 ± 2.9 mm; p = 0.015) and when compared with uphill locomotion (8.4 ± 4.3 mm; p = 0.007). Horses with forelimb lameness showed no significant difference in asymmetry. However, there were considerable changes in poll asymmetry (>20 mm) among conditions in individual horses. Two horses with hindlimb lameness and two horses with forelimb lameness switched asymmetry between left and right by changing incline. CONCLUSIONS: These results confirm that incline can be an influential factor in the assessment of lame horses. Further work is justified to elucidate the types of pathology associated with the most relevant changes in asymmetry which would allow the use of an incline to prioritise a list of differential diagnoses.

Assessment of agreement using the equine glandular gastric disease grading system in 84 cases.

INTRODUCTION: Equine glandular gastric disease (EGGD) is a common condition causing signs of gastric pain although lesions are highly variable in their appearance. The only definitive method to diagnose EGGD ante-mortem is gastroscopy. The current recommended method for describing these lesions is the European College of Equine Internal Medicine (ECEIM) guidelines; however, repeatability between users is variable. This study aimed to validate the reliability of lesion descriptions using ECEIM consensus guidelines, using four blinded equine internal medicine diplomates. METHODS: Ninety-two horses with EGGD with pre- and post-treatment gastroscopy images were identified using the electronic record at a UK equine hospital between 2012 and 2019. Eight horses were excluded due to non-diagnostic images. Four blinded observers used the recommended grading system to describe images and outcomes. Intraclass correlation coefficients and Krippendorff's alpha were used to determine reliability and agreement, respectively. RESULTS: Intraclass correlation coefficient for severity was 0.782 (95% confidence interval [CI] 0.722-0.832), for distribution was 0.671 (95% CI 0.540-0.763), for the descriptor raised was 0.635 (95% CI 0.479-0.741), fibrinosuppurative was 0.745 (95% CI 0.651-0.812), haemorrhagic was 0.648 (95% CI 0.513-0.744), hyperaemic was 0.389 (95% CI 0.232-0.522) and for outcome was 0.677 (95% CI 0.559-0.770). Krippendorff's alpha for severity was 0.466 (95% CI 0.466-0.418), for distribution was 0.304 (95% CI 0.234-0.374), for the descriptor raised was 0.268 (95% CI 0.207-0.329), fibrinosuppurative was 0.406 (95% CI 0.347-0.463), haemorrhagic was 0.287 (95% CI 0.229-0.344), hyperaemic was 0.112 (95% CI 0.034-0.188) and for outcome was 0.315 (95% CI 0.218-0.408). There was moderate reliability determined between observers using intra-class correlation coefficients and unacceptable agreement determined between observers using Krippendorff's alpha. DISCUSSION: These results suggest that the current grading system is not comparable between observers, indicating the need to review the grading system or define more robust criteria.

Evaluation of the treatment of equine glandular gastric disease with either long-acting-injectable or oral omeprazole.

BACKGROUND: Equine glandular gastric disease (EGGD) is common in domesticated horses and can be challenging to treat. Oral omeprazole (ORLO) is used widely but the clinical response is frequently poor. OBJECTIVES: To compare rates of EGGD healing and improvement between ORLO and a long-acting injectable omeprazole preparation (LAIO). STUDY DESIGN: Retrospective clinical study. METHODS: The case records and gastroscopy images of horses presenting to masked for peer review over a 12-month period were reviewed, with images blindly assessed by one of the authors. Treatment responses to 4 mg/kg LAIO administered every 7 days for 2 and 4 weeks were compared with ORLO 4 mg/kg PO q24hrs for 4 weeks. Data were compared using a Mann-Whitney U test with post-hoc Dunn's test, Chi-squared test and a Fisher's exact test. RESULTS: Thirty-three horses that received LAIO and 12 that received ORLO were identified. Nine horses in the LAIO had received other treatments previously. The groups were comparable in signalment and EGGD lesion severity. Long-acting injectable omeprazole was found to be non-inferior to ORLO. LAIO was associated with better healing rates than ORLO at 4 weeks (LAIO-80%; ORLO-42%; p = 0.02), and reduction in lesion severity at 2 and 4 weeks in the LAIO group but not in the ORLO group at 4 weeks. Eighteen percent of horses in the LAIO group and 50% in the ORLO group did not heal at 4 weeks. There was no association between rate of healing or improvement and resolution or improvement of clinical signs. Six localised and self-limiting injection site reactions were identified in 4 horses treated with LAIO (6.7%). MAIN LIMITATIONS: Retrospective design, small numbers and the use of other treatments prior to use of LAIO. CONCLUSIONS: LAIO was found to be non-inferior to oral omeprazole for EGGD. Larger blinded randomised clinical trials are justified.

Transabdominal ultrasonographic measurement of caudal vena cava to aorta derived ratios in clinically healthy neonatal foals.

BACKGROUND: Ultrasonographic measurement of the vena cava and aorta (Ao) diameters and their ratios have been suggested to be a reliable way of quantifying hypovolemia. OBJECTIVE: To evaluate the feasibility and reliability of an ultrasonographic technique for measurement of Ao and caudal vena cava (CVC) and derived ratios using three different acoustic windows in a population of healthy neonatal foals. Correlation between Ao and CVC measurements and ratios and foals' age or bodyweight were also investigated. METHODS: In 14 healthy foals aged less than 7 days, the diameters of the Ao and of the CVC in long and short axis were measured by two observers from images obtained using three different ultrasonographic imaging planes (left dorsal, left ventral and right views). The Ao and CVC cross-sectional area and the CVC/Ao diameter and area ratios were calculated. Image quality was subjectively assessed. Intraobserver and interobserver reliabilities for image quality scores and measurements were evaluated between the two observers. Simple linear regression models were used to identify correlations between the CVC/Ao measurements and ratios and the age and bodyweight of the foals. RESULTS: The left ventral view showed the highest reliability. A correlation between bodyweight and the short axis measurement of the CVC was found (R2  = 0.385; p = 0.018). Age was positively correlated with the long axis of measurement of the CVC (R2  = 0.426; p = 0.011) and CVC/Ao diameter ratio (R2  = 0.625; p = 0.001). CONCLUSIONS: The left ventral view allows the Ao and CVC cross sections to be easily visualized and measured in neonatal foals in right lateral recumbency.

Use of aminoglycoside antibiotics in equine clinical practice; a questionnaire-based study of current use.

Veterinary use of the aminoglycoside antibiotics is under increasing scrutiny. This questionnaire-based study aimed to document the use of aminoglycosides with a particular focus on gentamicin. An online questionnaire was delivered to generalist equine veterinary surgeons and specialists in internal medicine to determine the perceived importance, frequency of use and routes of administration of the aminoglycoside antibiotics. A series of hypothetical scenarios were also evaluated regarding gentamicin. Data were compared to evaluate the impact of the level of specialisation on prescribing practices for different antibiotics using Chi-squared and Fischer's exact tests. Data were analysed from 111 responses. Gentamicin was commonly used empirically without culture and susceptibility testing. Generalists were more likely to use gentamicin only after susceptibility testing than specialists in a variety of clinical presentations including respiratory diseases, septic peritonitis, acute febrile diarrhoea, cellulitis and contaminated limb wounds (p < 0.01). Intravenous administration of gentamicin was most common, although inhaled and regional administration of gentamicin and amikacin were also described. Amikacin was most commonly used by intra-articular administration. Gentamicin was more likely to be used in high-risk procedures or contaminated surgeries (86% and 74%, respectively) compared with clean surgery (32%; p < 0.0001). Gentamicin was often used perioperatively in horses undergoing exploratory celiotomy and more commonly used in horses undergoing an enterotomy (90%) than without and enterotomy (79%; p = 0.04). Most respondents (86%) used gentamicin at a dose of 6.6 mg/kg in adults, with few changing their dosing strategies based on the presence of sepsis, although higher doses were more reported in foals (7-15 mg/kg) irrespective of the presence of sepsis. Aminoglycosides are widely used in equine practice and use outside current EU marketing authorisations is common. Stewardship of the aminoglycoside antibiotics could be enhanced in both generalists and specialists through the more frequent use of susceptibility testing, regional administration and dose adjustment, especially in foals.

Real-time three-dimensional (3D) echocardiographic characterisation of an atrial septal defect in a horse.

Atrial septal defects have been well reported in humans and dogs and the principles of intervention have been well established. In contrast, there is very little information published about these congenital anomalies in horses. True ASDs are regarded as rare and little is known about the clinical significance of these defects in horses. An 11-year-old Thoroughbred gelding with a history of poor performance was diagnosed with an atrial septal defect, measuring approximately 2 cm in diameter, on 2D transthoracic echocardiography. Real-time three-dimensional (3D) echocardiography was used to map the structure of the defect and was useful in fully characterising the ASD in this case.

A study investigating the treatment of equine squamous gastric disease with long-acting injectable or oral omeprazole.

BACKGROUND: Equine squamous gastric disease (ESGD) is a highly prevalent disease in horses, particularly in elite athletes. Some horses respond slowly, or fail to respond, to the licensed treatment, oral omeprazole (ORLO). OBJECTIVES: To compare rates of ESGD healing and improvement between ORLO and a long-acting injectable omeprazole preparation (LAIO). STUDY DESIGN: Retrospective clinical study. METHODS: The case records and gastroscopy images of horses presenting to Rainbow Equine Hospital over a 12-month period were reviewed, with images being reviewed blind by one of the authors (David Rendle). Treatment responses were compared between horses that received 2 or 4 injections of 4 mg/kg LAIO at weekly intervals, and horses that received ORLO at 4 mg/kg PO SID for 4 weeks. Data were compared using a Mann-Whitney test with post hoc Dunn's test, chi-squared test or Fisher's exact test. RESULTS: Fifty-six horses met the inclusion criteria: 29 received LAIO and 27 received ORLO. Treatment groups were comparable in terms of signalment and ESGD lesions. There was a difference in rate of healing when LAIO and ORLO treatment groups were compared at 28 days (LAIO-97%; ORLO-67%; p = .005; OR = 14(1.8-158)), but no difference between LAIO at 14 days and ORLO at 28 days (LAIO-86%; ORLO-67%; p = .12; OR = 3.1 (0.9-10)). Five localised and self-limiting injection site reactions were identified in 3 horses out of 98 injections (5.1%). MAIN LIMITATIONS: The study was limited by its retrospective nature, absence of randomisation and limited numbers. CONCLUSIONS: Four weeks of treatment with LAIO resulted in better rates of ESGD healing than 4 weeks of ORLO. Larger more robust studies of LAIO are warranted.

Hydroxyethyl starches in equine medicine.

OBJECTIVE: To review and discuss the use of hydroxyethyl starches (HES) in equine veterinary medicine, and to provide recommendations for its use. DATA SOURCES: Veterinary and human peer-reviewed medical literature including scientific reviews, meta-analyses, and original research articles. HUMAN DATA SYNTHESIS: Increasing evidences on adverse effects after HES use and decreasing support for beneficial effects with regards to volume expansion and colloid osmotic pressure (COP) support in critically ill subjects have led to a recent guideline to limit the use of HES in critically ill people. EQUINE VETERINARY DATA SYNTHESIS: The rationale for HES use in horses is mainly extrapolated from human medicine, and very limited studies in horses are available. There is limited evidence suggesting a superiority of volume expansion effects of HES over crystalloids. The potential for HES to increase and maintain COP is well supported, but there is no evidence that maintaining or increasing plasma COP influences outcome, tissue edema formation, or rates of complications that potentially relate to edema formation. HES induce dose-dependent changes in coagulopathic parameters, but there is no evidence that HES causes clinical coagulopathies. Insufficient data are available on other adverse effects such as acute kidney injury, or mortality in horses. The use of HES should be restricted in septic patients, but may still have some use in cases of hemorrhagic shock resuscitation, hypoalbuminemia, or perioperative fluid replacement. CONCLUSION: The evidence supporting the use of HES in horses is weak due to lack of species-specific investigations. Acknowledging species differences, the use of HES should be judicious, yet with some recognition of its benefits in particular cases. More research is necessary to improve knowledge on use of HES in horses and to establish better future recommendations.

Management factors and clinical implications of glandular and squamous gastric disease in horses.

BACKGROUND: To date, risk factors for equine glandular gastric disease (EGGD) have not been described in Thoroughbred racehorses. OBJECTIVES: To determine management factors associated with EGGD, identify clinical signs in affected horses, and compare these to equine squamous gastric disease (ESGD). ANIMALS: The study was carried out on 109 Thoroughbred racehorses from 8 training yards (3 in the United Kingdom and 5 in Australia). METHODS: Gastroscopic examination alongside a questionnaire regarding management, feeding, exercise, and health. RESULTS: Management factors and clinical signs were different for EGGD versus ESGD. Exercising ≥5 days per week was associated with a 10.4 times (95% CI [confidence interval]: 1.34-26.9) increased risk of EGGD. Horses racing below expectation were 3.7 times (95% CI: 1.1-16.7) more likely to have EGGD. Trainer was also identified as a risk factor for EGGD. Time in work ≤6 weeks was associated with a decreased risk of ESGD (odds ratio [OR] 0.3; 95% CI: 0.1-0.99). Horses aggressive to humans were less likely to have ESGD (OR 0.12; 95% CI: 0.03-0.54). Horses with stereotypies were more likely to have ESGD (OR 5.0; 95% CI: 1.6-15.9). CONCLUSIONS AND CLINICAL IMPORTANCE: The findings of our study further support the notion that EGGD should be considered as a distinct disease entity to ESGD. Exercising ≤4 days per week could reduce the risk of EGGD. Horses with EGGD are more likely to perform below expectation and, as such, EGGD might be performance limiting in some affected individuals. Stress minimization could reduce the risk of EGGD.

Diagnostic accuracy of blood sucrose as a screening test for equine gastric ulcer syndrome (EGUS) in weanling foals.

BACKGROUND: Equine gastric ulcer syndrome is an important cause of morbidity in weanling foals. Many foals are asymptomatic, and the development of an inexpensive screening test to ensure an early diagnosis is desirable. The objective of this study was to determine the diagnostic accuracy of blood sucrose for diagnosis of EGUS in weanling foals. RESULTS: 45 foals were studied 7 days before and 14 days after weaning. The diagnostic accuracy of blood sucrose for diagnosis of gastric lesions (GL); glandular lesions (GDL); squamous lesions (SQL) and clinically significant gastric lesions (CSL) at 45 and 90 min after administration of 1 g/kg of sucrose via nasogastric intubation was assessed using ROC curves and calculating the AUC. For each lesion type, sucrose concentration in blood was compared to gastroscopy; and sensitivities (Se) and specificities (Sp) were calculated across a range of sucrose concentrations. Cut-off values were selected manually to optimize Se. Because of concerns over the validity of the gold standard, additional Se, Sp, and lesion prevalence data were subsequently estimated and compared using Bayesian latent class analysis. Using the frequentist approach, the prevalence of GL; GDL; SQL and CSL before weaning was 21; 9; 7 and 8% respectively; and increased to 98; 59; 97 and 82% respectively after weaning. At the selected cut-off, Se ranged from 84 to 95% and Sp ranged from 47 to 71%, depending upon the lesion type and time of sampling. In comparison, estimates of Se and Sp were consistently higher when using a Bayesian approach, with Se ranging from 81 to 97%; and Sp ranging from 77 to 97%, depending upon the lesion type and time of sampling. CONCLUSIONS: Blood sucrose is a sensitive test for detecting EGUS in weanling foals. Due to its poor specificity, it is not expected that the sucrose blood test will replace gastroscopy, however it may represent a clinically useful screening test to identify foals that may benefit from gastroscopy. Bayesian latent class analysis represents an alternative method to evaluate the diagnostic accuracy of the blood sucrose test in an attempt to avoid bias associated with the assumption that gastroscopy is a perfect test.

Diagnostic accuracy of blood sucrose as a screening test for equine gastric ulcer syndrome (EGUS) in adult horses.

BACKGROUND: Equine gastric ulcer syndrome (EGUS) is common in adult horses, particularly those involved in performance disciplines. Currently, detection of EGUS by gastroscopy is the only reliable ante mortem method for definitive diagnosis; however it is unsuitable as a screening test because it is expensive, time consuming, and is not readily available to most veterinarians. Sucrose permeability testing represents a simple, economical alternative to gastroscopy for screening purposes, and the feasibility of this approach in the horse has been previously reported. The aim of this study was to determine the diagnostic accuracy of blood sucrose as a screening test for EGUS in a large group of adult horses with and without naturally occurring gastric disease. RESULTS: One hundred and one adult horses with or without naturally occurring gastric ulceration were studied. The diagnostic accuracy of blood sucrose for diagnosis of gastric lesions (GL), glandular lesions (GDL), squamous lesions (SQL), and clinically significant lesions (CSL) at 45 and 90 min after administration of 1 g/kg of sucrose via nasogastric intubation was assessed using receiver operator characteristics (ROC) curves and calculating the area under the curve (AUC). For each lesion type, sucrose concentration in blood was compared to gastroscopy, as the gold standard, and sensitivities (Se) and specificities (Sp) were calculated across a range of sucrose concentrations. Ulcer grading was performed blindly by one observer; and the results were validated by comparing them with that of two other observers, and calculating the level of agreement. Cut-off values were selected manually to optimize Se. The prevalence of GL, GDL, SQL, and CSL was 83, 70, 53 and 58% respectively. At the selected cut-offs, Se ranged from 51 to 79% and Sp ranged from 43 to 72%, depending upon the lesion type and time of sampling. CONCLUSIONS: Blood sucrose is neither a sensitive or specific test for detecting EGUS in this population of adult horses with naturally occurring gastric ulceration. Further studies aimed at evaluating the performance characteristics of the test in different study populations are warranted. Given the limitations of endoscopy, due consideration should also be given to alternative methods for comparison of blood sucrose with a gold standard.

Validation of a novel translumbar ultrasound technique for measuring renal dimensions in horses.

A reliable method for obtaining renal ultrasonographic measurements in the horse is important for diagnosis and monitoring of clinical renal disease. The aims of this prospective study were to develop and validate a novel translumbar ultrasound technique for measuring renal dimensions in horses. Six Thoroughbred or Thoroughbred part bred horses were recruited. All horses were scheduled for euthanasia due to reasons unrelated to the kidneys. Two observers recorded renal length, width, and depth; and dimensions of the cortex, medulla, pyramids, and pelvis for both kidneys in each horse using novel translumbar and conventional transabdominal ultrasound methods. The same measurements were recorded from post-mortem renal specimens. Both kidneys were consistently identified by both methods in the 15-17th intercostal spaces and paralumbar fossa. Using the translumbar technique, maximal dimensions were obtained for the left kidney in the 16th intercostal space (length 16.2 ± 2.0 cm, width 11.8 ± 0.5 cm, depth 6.4 ± 0.9 cm) and for the right kidney in the 15th intercostal space (length 16.1 ± 1.2 cm, width 13.4 ± 1.2 cm, depth 6.7 ± 0.7 cm). Renal dimensions obtained by transabdominal and translumbar projections did not differ (P > 0.05). Good correlations were found between overall renal dimensions and post-mortem measurements for both ultrasound techniques (r(2) > 0.8), but were better for the translumbar method (mean r(2) = 0.92 cf. 0.88). Good-to-excellent reliability was found for all translumbar ultrasound measurements except for the renal cortex. Reproducibility was better for the larger (overall length, width, and depth) than the smaller (cortex, medulla, and pyramids) structures. Findings indicated that translumbar ultrasonography is a valid method for measuring renal dimensions in horses.

Administration of trimethoprim-sulphadimidine does not improve healing of glandular gastric ulceration in horses receiving omeprazole: a randomised, blinded, clinical study.

BACKGROUND: Interest in Equine Gastric Ulcer Syndrome (EGUS) has recently increased in part due to a growing awareness of the differences between squamous and glandular disease. The pathophysiology and epidemiology of squamous and glandular disease are different and recently it has been shown that the response of glandular gastric ulceration to monotherapy with omeprazole is poor. Given these differences it has been recommended that specific treatment guidelines be formulated for equine glandular disease and that adjunctive therapies be investigated. Along these lines it has been suggested that the addition of antimicrobials may enhance healing. The objective of this study was to investigate whether the addition of trimethoprim-sulphadimidine to omeprazole therapy would result in superior healing of naturally occurring equine glandular ulceration compared with omeprazole monotherapy. RESULTS: Combination therapy of omeprazole plus trimethoprim-sulphadimidine could not be demonstrated to be superior to omeprazole monotherapy. Healing of the glandular mucosa was observed in 7/15 (47%; 95% CI 24 to 71%) and 3/13 (23%; 95% CI 7% to 50%) of horses in the TMPS and OMEP groups, respectively (OR = 1.8; 95% CI 0.32 to 10.0; p = 0.67). Improvement of the glandular mucosa was observed in 12/15 (80%; 95% CI 56 to 94%) and 9/13 (69%; 95% CI 42 to 89%) of horses in the TMPS and OMEP groups, respectively (OR = 2.9; 95% CI 0.6 to 15.0; p = 0.25). CONCLUSIONS: The results of the present study do not support the addition of trimethoprim-sulphadimidine to therapeutic protocols for equine glandular ulceration. Several limitations were present in the study and the use of antimicrobials as an adjunctive treatment warrants further investigation. However, given the potential deleterious consequences associated with the indiscriminate use of antimicrobials, the inclusion of antimicrobials in treatment regimes for EGUS is not justified until their efficacy is further validated.

Reliability and identification of aortic valve prolapse in the horse.

BACKGROUND: The objectives were to determine and assess the reliability of criteria for identification of aortic valve prolapse (AVP) using echocardiography in the horse. RESULTS: Opinion of equine cardiologists indicated that a long-axis view of the aortic valve (AoV) was most commonly used for identification of AVP (46%; n=13). There was consensus that AVP could be mimicked by ultrasound probe malignment. This was confirmed in 7 healthy horses, where the appearance of AVP could be induced by malalignment. In a study of a further 8 healthy horses (5 with AVP) examined daily for 5 days, by two echocardiographers standardized imaging guidelines gave good to excellent agreement for the assessment of AVP (kappa>0.80) and good agreement between days and observers (kappa >0.6). The technique allowed for assessment of the degree of prolapse and measurement of the prolapse distance that provided excellent agreement between echocardiographers, days and observers (kappa/ICC>0.8). Assessments made using real-time zoomed images provided similar measurements to the standard views (ICC=0.9), with agreement for the identification of AVP (kappa>0.8). Short axis views of the AoV were used for identification of AVP by fewer respondents (23%), however provided less agreement for the identification of AVP (kappa>0.6) and only adequate agreement with observations made in long axis (kappa>0.5), with AVP being identified more often in short axis (92%) compared to long axis (76%). Orthogonal views were used by 31% of respondents to identify the presence of AVP, and 85% to identify cusp. Its identification on both views on 4 days was used to categorise horses as having AVP, providing a positive predictive value of 79% and negative predictive value of 18%. Only the non-coronary cusp (NCC) of the AoV was observed to prolapse in these studies. Prolapse of the NCC was confirmed during the optimisation study using four-dimensional echocardiography, which concurred with the findings of two-dimensional echocardiography. CONCLUSIONS: This study has demonstrated reliable diagnostic criteria for the identification and assessment of AVP that can be used for longitudinal research studies to better define the prevalence and natural history of this condition.