Equine Veterinary Journal最新文献

Background: Orotracheal intubation is commonly performed for inhalation anaesthesia in horses to ensure safe and reliable administration of volatile anaesthetics and to secure the airways. In human and equine medicine, the occurrence of intubation-associated complications has been described, which can range from mild mucosal irritation to severe necrosis. However, there are only sparse descriptions of mucosal alterations and the course of healing after elective surgery in horses.

Objective: To investigate the prevalence and severity of tracheal lesions following endotracheal intubation associated with general anaesthesia in equine patients.

Study design: Prospective, clinical study.

Methods: Forty adult Warmblood horses, weighing 400-600 kg, presented for elective surgery under general anaesthesia were included. For orotracheal intubation, a silicone tube was used and inflated until a cuff pressure of 40 cmH₂O was confirmed. In all horses, endoscopic examination of the trachea with video documentation was performed prior to intubation and immediately after extubation, as well as 1, 3, 5 and 7 days after general anaesthesia. The type (redness, secretion, bleeding, erosions) and degree (0 = non-existent to 4 = severe) of corresponding lesions were assessed and scored. The occurrences of clinical signs were recorded. Statistical evaluation was performed using Friedman's test and Pearson correlation.

Results: The median score immediately after recovery from anaesthesia was 6 (2-12) and increased significantly to 11 (4-15) after 1 day (p = 0.021). At day 7, the median score was 0 (0-2) with only four horses showing signs of mild tracheitis, and clinical signs were not observed throughout this time period. The duration of intubation correlated with the degree of tracheal damage (r² = 0.67, p < 0.001).

Main limitations: Clinical, non-randomised study without a control group.

Conclusion: Although orotracheal intubation was accompanied by focal inflammation of the trachea, in the present study no horses showed clinical signs and lesions healed within a week.

Background: Due to the high frequency of laminitis reported for both conditions, the relationship between pituitary pars intermedia dysfunction (PPID) and insulin dysregulation (ID), and the potential role of dopamine in modifying insulin secretion, requires further investigation.

Objectives: To evaluate the effect of pergolide mesylate on insulin sensitivity and postprandial insulin and glucose responses in horses and ponies with ID, both with or without concurrent PPID.

Study design: Randomised crossover study.

Methods: Sixteen horses and ponies, comprising eight matched pairs (PPID+ID or ID-only), were given pergolide mesylate at a dose of 2 μg/kg bwt orally once daily for 4 weeks (plus a 4-week non-treatment control period, with a 4-week washout between phases). A combined glucose and insulin tolerance test (CGIT) and a standard meal test (SMT; containing 1.1 g/kg bwt of starch and 0.1 g/kg bwt of free sugars), were performed before and after each treatment period to determine insulin sensitivity and postprandial insulin and glucose responses, respectively. Variables derived from the CGIT and SMT were analysed using linear mixed models.

Results: Pergolide treatment did not alter any of the variables derived from the CGIT in either the PPID+ID or ID-only groups (all p > 0.05). For the SMT, insulin responses were reduced by pergolide treatment for the PPID+ID group, with Δ change values for the total area under the curve for insulin over 300 mins (estimated marginal mean [95% confidence interval]) being -25.4 (-39.9 to -7.3) min∙mIU/mL (p = 0.03) and Δ change values for peak insulin concentration being -100 (-167 to -29) μIU/mL (p = 0.04). No effect of pergolide treatment was detected for the ID-only group.

Main limitations: Number of animals and heterogeneity among groups.

Conclusions: Pergolide had no effect on tissue insulin sensitivity. However, the results suggest that postprandial hyperinsulinaemia may be limited by this dopamine receptor agonist in animals with PPID plus ID.

Background: Post-mortem studies have shown that fractures involving the metacarpophalangeal/metatarsophalangeal or fetlock joint are associated with focal areas of microdamage. Identification of computed tomography (CT) features consistent with microdamage and their association with fracture may aid in identification of horses at risk of fracture.

Objectives: To identify CT features associated with fracture of the metacarpophalangeal/metatarsophalangeal joint.

Study design: Retrospective cohort study.

Methods: Post-mortem CT images of 367 limbs from 157 Thoroughbred racehorses were graded for CT features. Multivariable logistic regression models were generated. Intraclass correlation coefficients of key CT features to assess intra and inter-rater reliability were calculated.

Results: The presence of lysis within the subchondral/trabecular bone underlying the lateral and, or, medial parasagittal groove (PSG) of the distal third metacarpus/tarsus (odds ratio [OR] 9.6; 95% confidence interval [CI] 4.3-21.3; p < 0.001) and sclerosis of the palmar subchondral and trabecular bone underlying the lateral and medial PSG that projected proximoaxially (OR 4.6; 95% CI 1.1-19.02; p = 0.03) were associated with condylar fracture. The presence of a proximal sesamoid bone (PSB) lytic lesion (OR 5.3; 95% CI 1.2-23.6; p = 0.03) and increasing medial PSB density (OR 1.02; 95% CI 1.00-1.03; p < 0.001) were associated with PSB fracture. Palmar osteochondral disease grade was not associated with condylar (p = 0.8) or PSB fracture (p = 0.09). Inter rater reliability was moderate for the presence of PSG lysis (ICC 0.7; 95% CI 0.6-0.8) and shape of sclerosis in the lateral condyle (ICC 0.6; 95% CI 0.5-0.8).

Main limitations: The extent of lysis within the PSG and the volume of the PSB could not be as accurately obtained in limbs with multiple fracture fragments.

Conclusions: CT examination of fetlock joints post-mortem identified changes associated with both metacarpal condylar fracture and PSB fracture in racehorses. These findings show that pre-race CT screening has the potential to reduce fracture rates.

Background: Conservative and surgical management of left dorsal displacement and nephrosplenic ligament entrapment of the large colon (NSLE) is well described in horses. Whilst breed factors predispose the development of NSLE, it is unknown if breed affects the likelihood for surgical intervention.

Objectives: To compare the incidence of surgical intervention and differences in pre-operative parameters between Thoroughbred and non-Thoroughbred horses. The authors hypothesise a higher proportion of Thoroughbreds require surgical intervention.

Study design: Retrospective cross-sectional study.

Methods: Case records at a single equine referral hospital were searched between January 2007 and September 2022 for horses with suspected or confirmed NSLE on transrectal palpation, transabdominal ultrasonography or exploratory laparotomy. Horses were classified into Thoroughbred and non-Thoroughbred groups. Unpaired T-tests, Mann-Whitney U tests, Chi-squared tests and multivariable analysis were used to compare groups. A mixed effects multivariable logistic regression model compared surgery or conservative management as outcome variables.

Results: A total of 179 NSLEs in 169 horses were included (100 Thoroughbreds). Forty-eight horses (26.8%) underwent surgery, including 34 Thoroughbreds (70.8%). A total of 131 NSLEs in 125 horses were treated conservatively (73.2%), including 66 Thoroughbreds (50.4%). Univariable analysis showed Thoroughbreds were more likely to require surgical intervention compared with non-Thoroughbred breeds (odds ratio [OR] = 2.5; 95% confidence interval [CI] 1.03-6.18; p = 0.04). Thoroughbreds requiring surgical intervention were significantly younger than those treated conservatively (surgical group median = 2 years [interquartile range, IQR = 1], conservative group median = 4.5 years [IQR = 7], 95% CI 1.66-5.27 years; p ≤ 0.0001). Multivariable analysis, however, showed decreasing age alone was associated with an increased likelihood of surgical intervention (OR = 0.9; 95% CI 0.81-0.99; p = 0.03).

Main limitations: Definitive diagnosis of NSLE is not possible in conservatively managed cases.

Conclusions: For this hospital population, Thoroughbreds were more likely to require surgical correction of NSLE, most likely due to the significantly increased likelihood of surgical intervention in young horses.

Background: Pain assessment based on facial expressions has been described in foals.

Objectives: To extend previous pilot findings of the Equine Utrecht University Scale for Facial Assessment of Pain in Foals (EQUUS-FAP FOAL).

Study design: Prospective blinded case-control study (known groups analysis).

Methods: Video recordings (30-60 s) of n = 100 foals (38 patients and 62 controls) were collected. Videos were randomised and scored by two observers, blinded for the condition of the animals. Inter- and intra-observer agreement was tested by Intra Class Correlation (ICC) analysis. Differences between patients and controls were tested using Mann-Whitney U test, differences before and after analgesic treatment were tested with Wilcoxon signed rank test. Multilevel binomial logistic regression was performed for statistical weighting of each pain scale item. Receiver operating characteristic (ROC) analysis was performed to determine sensitivity, specificity and cut-off values.

Results: EQUUS-FAP FOAL showed good inter- and intra-observer reliability (ICC coefficient of 0.85 and 0.90 respectively, p < 0.001). Patients had significantly higher pain scores (median score 7, IQR 5.3-7.5) compared with controls (median score 2.5, IQR 1-3, p < 0.001) and the patient pain scores decreased after analgesic treatment (median score 6.5, IQR 5-8 vs. median score 4.5, IQR 3.5-6.5, p < 0.05). Multilevel binomial logistic regression showed the relative importance of the individual scale items. Using the original scale, sensitivity and specificity were 88.2% (95% CI 76%-96%) and 87.9% (81%-98%) respectively, with an area under the ROC curve of 94.9% (92%-98%), based on a cut-off value of ≥4. These values remained similar with the weighted scale based on logistic regression output.

Main limitations: Videos of included patients were short and acquired by a person in front of the stable.

Conclusions: The current study shows that EQUUS-FAP FOAL can be effectively used to assess acute pain in young foals.

Background: Adequate vitamin availability is vital for cellular and immune function and for normal growth. Available data on age-related changes in serum concentrations of vitamins in foals are limited. In addition, associations between circulating vitamin concentrations and the development of bronchopneumonia in foals are not described.

Objectives: (1) To quantify circulating concentrations of vitamins C, D and E from birth to weaning in foals; (2) to determine associations between vitamin concentrations and the development of bronchopneumonia during this period.

Study design: Prospective cohort study.

Methods: Blood samples were serially collected from 100 initially healthy Warmblood foals from birth to 5 months of age. Health status was evaluated weekly, and the development of subclinical and clinical bronchopneumonia was recorded. After weaning, foals were allocated to healthy, subclinical and clinical pneumonia groups, and samples from 15 foals/group were randomly selected for vitamin C, D and E quantification via ELISA and HPLC. Data were analysed with linear mixed models (p < 0.05).

Results: Circulating concentrations of vitamins C, D and E did not differ between healthy foals and foals with subclinical or clinical pneumonia. Foal age significantly impacted vitamin concentrations (p < 0.001) in a vitamin-specific manner. Vitamins C and E concentrations increased during the first week of life and then decreased until weaning. Vitamin C concentrations were higher at pneumonia diagnosis in foals with pneumonia diagnosed at or before 8 weeks of age than in healthy foals. Vitamin D concentrations were lowest on Day 7 and then increased steadily until weaning.

Main limitations: A small number of foals was included, and results may be specific to this study population due to environmental and farm management factors.

Conclusions: Circulating concentrations of vitamins C, D and E vary with age in foals, but do not appear to be related to the development of bronchopneumonia.

Background: Fungi are ubiquitous in horses' environment. Their contribution to the pathophysiology of severe asthma (SA) is acknowledged, while controversies remain for mild-moderate asthma (MA).

Objectives: We hypothesised that fungi are a risk factor for asthma. Our objective was to compare different combinations of analytical methods (cytology, culture) and sampling sites (tracheal wash (TW), bronchoalveolar lavage fluid (BALF)) in relation to clinical status (control, MA, SA).

Study design: Prospective cross-sectional study.

Methods: The study population included asymptomatic racing horses in the field and horses referred to the hospital for respiratory investigations. Fungi were detected by cytology and identified by mycology on TW and pooled BALF. Chi-square tests and multivariable logistic regressions were used for prevalence comparison between groups and association with clinical investigations.

Results: In total 155 horses (85 MA, 35 SA and 35 controls) were included in the study. The overall proportions of fungal detection in TW ranged from 45.7% to 89.4% among groups. The prevalence of fungal detection in BALF was significantly lower by cytology for SA (5.7%) than MA horses (23.6%) and significantly higher by culture for MA horses (31.8%) than controls (8.6%). Fungal detection by culture in BALF was significantly associated with high tracheal mucus score, high neutrophil proportions in BALF and diagnosis of MA.

Main limitations: Mycology was only performed in pooled BALF, and environment was not sampled.

Conclusions: Fungi were significantly more prevalent in the airways of MA horses than SA and/or controls. Fungal detection on TW, either by cytology or culture, was uninformative in a clinical context. Fungal detection by culture, but not cytology in BALF was associated with MA.

Background: Sycamore tree-derived hypoglycin A (HGA) toxin causes atypical myopathy (AM), an acute, equine pasture-associated rhabdomyolysis but incidence fluctuates.

Objectives: Investigate whether tree or environmental factors influence HGA concentration in sycamore material and are associated with AM relative risk.

Study design: Retrospective and experimental prospective study.

Methods: UK sycamore population, seed production and AM incidence data were obtained. HGA concentration was measured in seeds from trees from 10 different central UK locations. The effect of tar spot infection, seed maturity, tree trunk girth, location (urban/countryside), AM cases within 130 m, soil type, facing direction of seeds on the tree and year on seed HGA concentration was examined. HGA concentration was compared in whole and homogenated seeds stored in different ways.

Results: HGA concentration in sycamore seeds was not associated with tree tar spot infection, location, trunk girth, seed weight or branch-facing direction but HGA concentration in sycamore seeds varied significantly and in parallel year on year in the same trees. Trees in the same vicinity tended to have similar HGA concentrations in their seeds when compared with those from farther afield. Seed production estimates were positively correlated with regional AM case incidence (τb = 0.3; p = 0.007). HGA sycamore seed concentration remained stable as seeds matured, but HGA declined in leaves as they wilted in autumn. Warmer and wet storage resulted in higher HGA concentrations in seed homogenates but not in whole seeds. HGA was detected in water containing sycamore seeds for 48 h.

Main limitations: Lack of accurate weather data; sampling restricted to central England.

Conclusions: Tree factors that were investigated did not affect HGA concentration in sycamore seeds but HGA concentrations varied year on year. AM incidence is related to seed production; conditions that mimic browsing and ingestion increased seed HGA concentration. HGA toxicity could occur from contaminated water sources.