To review the literature concerning mortality associated with general anaesthesia in horses and to assess whether there is evidence for a reduction in mortality over the 20 years since the ...Confidential Enquiry into Perioperative Equine Fatalities (CEPEF).
PubMed, Scopus, Google Scholar. Search terms used: horse; pony; equine; anaesthesia; anesthesia; recovery; morbidity, and mortality.
The most recent studies, in which isoflurane and sevoflurane have been more commonly used for anaesthesia maintenance, report fewer intraoperative cardiac arrests than older studies in which halothane was favoured. Catastrophic fractures, however, have become the greatest cause of recovery-associated mortality.
Several tests have been advocated for diagnosis of insulin dysregulation (ID). Tests using simple sugars may not reflect the response to naturally ingested carbohydrates. This study aimed to evaluate ...agreement between the oral glucose test (OGT), the oral sugar test (OST), a novel oral test using a proprietary cereal (WEET), the IV combined glucose-insulin tolerance test (CGIT) and fasted basal insulin (FI) for diagnosis of ID. Each of the five tests above was performed on a group of six normal and six insulin dysregulated mixed-breed ponies in a randomised crossover study. Area under the curve (AUC) and maximum concentration of insulin from OGT, OST and WEET showed strong to very strong bivariate correlations (r = 0.85–0.94, and r = 0.87–0.92, respectively; P ≤ 0.001) and were significantly different between tests (associated with dose of carbohydrate) and between CGIT-positive and -negative ponies. Dichotomous results showed substantial agreement between OST and both WEET (κ = 0.65; P = 0.02) and OGT (κ = 0.67; P = 0.01) and between CGIT and both OST (κ = 0.63; P = 0.03) and OGT (κ = 0.67; P = 0.01), and no agreement between FI, which had low sensitivity, and all other tests (κ = 0.15 – 0.31; P > 0. 05). Palatability of WEET was variable, resulting in one pony being excluded for analysis of WEET data. Further work on development of an oral test using a more palatable feedstuff and appropriate cut-offs or diagnostic thresholds for tests of ID is warranted.
•A novel oral carbohydrate test showed good dichotomous agreement with other tests.•Insulinaemic responses to three oral carbohydrate tests were strongly correlated.•Insulin resistant ponies had a greater insulinaemic response to oral carbohydrate.•Fasting basal insulin lacked sensitivity for diagnosis of insulin dysregulation.
Assessment of the severity of pain in colic cases is subjective. The Equine Acute Abdominal Pain Scale (EAAPS), previously validated using film clips of horses with colic, was tested for feasibility ...and revalidated in both medical and surgical colic cases in Israel and the UK. Feasibility qualities evaluated were quickness and ease-of-use. Pain in 231 horses, presented for colic, was assessed by 35 participants; 26 in the UK and 9 in Israel. Without prior training, participants assessed the severity of pain using two scales; the EAAPS and a visual analogue scale (VAS). Convergent validity comparing the EAAPS to the VAS was substantial, discriminant validity was good, and predictive validity for surgical treatment was similar to the VAS, but for mortality, the VAS was significantly better. No participants reported the EAAPS to be "very slow" or "very difficult" to use. The mode reported was "quick"/"very quick" and "easy"/"very easy" to use, though in less than 10% of cases, it was reported to be a little less quick or easy. More experienced first-time users found it significantly quicker to use than less experienced participants. In conclusion, the EAAPS is the only equine pain assessment scale that has been tested and found to demonstrate good feasibility for use in the referral hospital setting.
Reasons for performing study: Evaluation of equine body fat content is important for nutritional and clinical purposes. However, our understanding of total body fat and its regional distribution in ...the body is sparse. Currently, body fat evaluation relies on the subjective assessment of body condition score (BCS), which has never been validated against ‘gold standard’ chemical analysis or dissection measurements in ponies. Objectives: To define the relationships between subjective (BCS), objective (morphometric) indices of body fat and ‘gold standard’ measurements of actual body composition. Hypotheses: BCS and morphometry offer valid, noninvasive methods for determination of body fat in equids. Methods: Seven mature (mean ± s.e. 13 ± 3 years, 212 ± 14 kg, BCS 1.25–7/9), Welsh Mountain pony mares, destined for euthanasia (for nonresearch purposes), were used. For all ponies, body mass (BM), BCS and various morphometric measurements were recorded. Following euthanasia, all ponies were systematically dissected. Discrete white adipose tissue (WAT) depots were independently described. Gross, body chemical composition was determined by proximate analyses. Results: Total somatic soft tissues increased linearly (r²= 1.00), whereas body WAT content (1–26% live BM) increased exponentially (r²= 0.96), with BCS. WAT was equally distributed between internal and external sites in all animals irrespective of BCS. Nuchal fat was a poor predictor of total WAT (r²= 0.66). Periorbital WAT did not alter with BCS (r²= 0.01). Heart girth:withers height and ultrasonic retroperitoneal fat depth were closely associated with total, chemically‐extracted lipid which comprised 1–29% live BM (r²= 0.91 and 0.88, respectively). Conclusions and potential relevance: The exponential relationship between BCS and total body WAT/lipid suggests that BCS is unlikely to be a sensitive index of body fat for animals in moderate‐obese states. Morphometric measurements (body girths and retroperitonel fat depth) may be useful to augment subjective BCS systems.
To determine the mortality rates associated with equine anaesthesia for elective and emergency (colic and non-colic) cases in one equine, university teaching hospital and to investigate the effect of ...several horse- and anaesthetic-related variables on anaesthetic recovery quality.
Retrospective data analysis.
In total, 1416 horses undergoing anaesthesia between May 2010 and December 2013.
Patient information and details of the anaesthetic, recovery period and immediate complications were extracted from an archiving database. Statistical evaluation of factors affecting mortality included chi-squared tests and binary logistic regression. Factors affecting recovery quality were investigated using univariable and multivariable ordinal logistic regression. Statistical significance was set at p < 0.05.
Anaesthesia/recovery-related mortality was 1.1% for all cases, 0.9% for elective cases, 1.6% for colics and 0% for non-colic emergencies. Fractures and dislocations accounted for the majority (71.4%) of deaths. No intra-operative deaths occurred during the study period. Risk factors for mortality included increasing age and American Society of Anesthesiologist's (ASA) status but these and other factors were confounded by ‘colic’. Non-fatal complications in the immediate recovery period included postanaesthetic myopathy/neuropathy and postanaesthetic respiratory obstruction. Recovery quality was associated with body mass (p = 0.016), ASA status 3 and 4 (p = 0.020 and 0.002, respectively), duration of anaesthesia (p < 0.001) and out-of-hours anaesthesia (p = 0.013). Although recovery quality was also influenced by age and breed-type, these factors were removed from the final model as age was highly associated with both ASA status (p < 0.001) and colic surgery (p < 0.001), and breed-type was a determinant of body mass.
Anaesthetic/recovery-associated mortality was comparable to previously reported figures except intra-operative deaths were not reported. Fractures remained responsible for the largest proportion of recovery-associated deaths. Improvements to the recovery process that can reduce fracture occurrence are still required.
Glucagon-like peptide-1 (GLP-1), the principal incretin in horses, may play a role in the pathophysiology of insulin dysregulation (ID). This study aimed to describe its concentration in response to ...three preserved forages and four dynamic tests for ID in ponies. Twelve adult ponies of mixed ID status were given a meal of hay, soaked hay or haylage, an in-feed oral glucose test (OGT), oral sugar test (OST), an oral test using a proprietary breakfast cereal (WEET) or a combined glucose-insulin tolerance test (CGIT) weekly in a randomised cross-over study. Glucose, insulin and GLP-1 concentrations were measured before and following each intervention. Ponies were designated ID or non-ID and insulin resistant (IR) or non-IR according to OGT and CGIT results, respectively.
All interventions apart from the CGIT provoked a GLP-1 response within 30 min. The OGT and WEET interventions, (containing the greatest dose of non-structural carbohydrate, 1.06 and 1 g/kg BW, respectively), resulted in a greater area under the curve (AUC) for GLP-1 compared to all other interventions (P < 0.001). No difference in GLP-1 response was detected according to ID or IR status, despite there being strong positive correlations (rs 95 % CI) between GLP-1 and insulin concentrations measured at individual time points (0.67 0.62 – 0.71; P < 0.001) and as AUC (0.66 0.49–0.79, P < 0.001). These data do not support of the use of GLP-1 as an adjunctive diagnostic test for ID or IR, as defined by conventional intravenous or oral dynamic tests.
•Glucagon-like peptide-1 (GLP-1) was detected within 30 min of oral carbohydrates.•GLP-1 response was associated with dose of non-structural carbohydrate.•Soaking hay resulted in a decreased GLP-1 response.•GLP-1 and insulin responses were correlated.•Insulin dysregulation status did not affect GLP-1 response.
•The insulinaemic and glycaemic responses of ponies to soaked hay, dry hay and haylage were compared.•Soaked hay produced the lowest insulinaemic and glycaemic responses to feeding, whilst haylage ...produced the highest responses.•Insulin-dysregulated ponies had a higher insulinaemic response to all forages than ponies without insulin dysregulation.•The insulinaemic response to feeding hay was reduced after soaking the hay.•Feeding haylage can result in a pronounced insulinaemic response.
Reduction of the hyperinsulinaemic response to feeding is central to the management of insulin dysregulation (ID). The aim of this study was to compare insulinaemic and glycaemic responses to soaked hay, dry hay and haylage in ponies. Twelve ponies of mixed breeds were maintained under identical management conditions. A randomised four-way crossover trial was conducted, in which fasted animals were fed a meal of 0.25% body weight as dry matter intake soaked hay, dry hay or haylage, or administered an oral glucose test (OGT). Blood glucose and serum insulin concentrations were measured before and at 2h following OGT, and regularly for 5h following forage meals. Median and interquartile range (IQR) area under the curve (AUC) for insulin (AUCi) was greater for haylage (median 6495; IQR 17352) vs. dry hay (2932; IQR 5937; P=0.019) and soaked hay (1066; IQR 1753; P=0.002), and greater for dry hay vs. soaked hay (P=0.002). The AUC for glucose (AUCg) was lower for soaked hay (1021; IQR 99) vs. dry hay (1075; IQR 105; P=0.002) and haylage (1107; IQR 221; P=0.003). Six ponies were classified as having ID based on the OGT. AUCi was greater in ID vs. non-ID ponies after all forages. In contrast, there was no detectable effect of ID status on AUCg. On an equivalent dry matter basis, soaked hay produced the lowest insulinaemic and glycaemic responses to feeding, while haylage produced the highest responses. The insulinaemic effects of all forages were greater in ponies with ID. These data support the practice of soaking hay with water to reduce postprandial insulinaemic responses in ponies.
Evidence-based, weight loss management advice is required to address equine obesity. Changes in body mass (BM), body condition score (BCS), heart (HG) and belly circumference (BG), direct ...(ultrasonographic) and indirect (D2O dilution, bioelectrical impedance analysis BIA) measures of body fat as well as indices of insulin resistance (IR) were monitored in 12 overweight (BCS⩾7/9) horses and ponies of mixed breed and gender for 16weeks. Animals were randomly assigned to two groups (Group 1, n=6, BCS 7.6/9±0.6, 489±184.6kg; Group 2, n=6, BCS 8.1/9±0.6, 479±191.5kg). Daily dry matter intake (DMI) was restricted to 1.25% BM as one of two, near-isocaloric (DE ∼0.115MJ/kgBM/day), forage-based diets (Group 1, 0.8% BM chaff-based feed: 0.45% BM hay; Group 2, 1.15% BM hay: 0.1% BM nutrient-balancer).
Statistical modelling revealed considerable between-animal heterogeneity in proportional weight losses (0.16–0.55% of Week 1 BM weekly). The magnitude of weight loss resistance (WLR) or sensitivity to dietary restriction was independent of diet or any measured outset variable and was largely (65%) attributed to animal identity. Predicted rates of weight loss decreased over time. BCS and BIA were poor estimates of D2O-derived body fat%. Reciprocal changes in depths of retroperitoneal and subcutaneous adipose tissues were evident. Changes in BG were associated with losses in retroperitoneal fat and BM (r2, 0.67 and 0.79). Indices of IR improved for 9/12 animals by Week 16. For obese animals, weight loss should be initiated by restricting forage DMI to 1.25% BM. Subsequent restriction to 1% BM may be warranted for WLR animals.
Summary
Reasons for performing study: Increased prevalence of obesity among UK horses and ponies demands evidence‐based advice to promote weight loss.
Hypothesis: Restriction of dry matter intake ...(DMI) to 1% of body mass (BM, 6% of predicted maintenance digestible energy DE requirements) would promote weight loss without compromise to health.
Methods: Five mature (mean ± s.e. 10 ± 2 years), overweight/obese pony mares (BM, 257 ± 20 kg: body condition score BCS 6.8/9 ± 0.5) were studied over 12 weeks. Animals were individually housed. Daily provision of a chaff‐based, complete diet (measured DE, 8.5 MJ/kg DM) was restricted to 1% of actual BM as DMI daily. BCS, girth measurements and ultrasound‐derived measures of subcutaneous fat depth overlying the gluteal region and 12th intercostal space (rib‐eye) were recorded weekly. Body fat content was estimated at the beginning and end of the study by deuterium oxide dilution methods. Clinical biochemistry was monitored weekly. Behaviour was observed (24 h, 3/5 ponies) on 3 occasions.
Results: BM decreased by 4.3 ± 1.1% during the first week and thereafter by 0.7 ± 0.1% of BM at end of Week 1 each week. BCS remained constant. Heart and belly girths, rump width and subcutaneous fat depth at rib‐eye decreased significantly with time and BM. Fat comprised 45 ± 19% of BM loss. Fatter animals lost relatively more fat. With decreased feeding activity, time spent in ‘play’ and rest increased by 36 ± 11% and 438 ± 95%, respectively.
Conclusions: This plane of nutrition resulted in an overall rate of weight loss of 1% of outset BM weekly. BCS was not a useful index of early weight loss but heart and belly girths and subcutaneous rib‐eye fat were identified as alternative markers.
Potential relevance: This study provides an evidence‐base for the management of weight loss in obese animals, especially those for which exercise may be contra‐indicated.
Body condition scoring systems were originally developed to quantify flesh cover in food animals and are commonly used to evaluate body fat in Equidae. The relationship between concurrent estimates ...of body fat content (eTBF%, deuterium oxide dilution; range, 2.7–35.6%) and subjective appraisals of body ‘fatness’ (body condition score, BCS; range, 1.25–9/9), was investigated in 77 mature horses and ponies. Univariate (UVM, r2=0.79) and multivariable (MVM, r2=0.86) linear regression models described the association, where BCS and eTBF% were explanatory and outcome variables, respectively. Other measures (age, sex, breed, body mass, ultrasound-generated subcutaneous and abdominal retroperitoneal fat depths, withers height, heart and belly circumferences) were considered as potential confounders but only height, belly circumference and retroperitoneal fat depth remained in the final MVM.
The association between BCS and eTBF% was logarithmic. Appraisal of the transformed regression (UVM), actual eTBF% values and 95%CIs of the model forecast, suggested that the power of log-transformed BCS as a predictor of eTBF% decreased as BCS increased. The receiver operating characteristic curve for the prediction of horses with an eTBF% of >20%, suggested that the UVM correctly classified 76% of horses using a ‘cut-off’ of BCS 6.83/9 (sensitivity, 82.5%; specificity, 70.8%). Negative values for eTBF% were obtained for two thin ponies which were excluded from analyses, and caution is advised in the application of deuterium dilution methodologies where perturbed tissue hydration could be predicted. The data suggest that BCS descriptors may warrant further consideration/refinement to establish more clinically-useful, sub-classifications for overweight/obese animals.
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