laminitis

EMS and PPID in donkeys

Citation

Alexandra K. Thiemann. 9 May 2019. EMS and PPID in donkeys. Presented at Schweizerische Tierarztetage. (8 May - 10 May 2019). Fribourg, Switzerland.

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Presentation details
Date presented: 
Thursday 9 May 2019
Abstract

Equine Metabolic Syndrome is defined as a “Clinical syndrome associated with an increased risk of laminitis that includes insulin dysregulation and any combination of increased generalised or regional adiposity, weight loss resistance, and altered adipokine concentrations.” https://sites.tufts.edu/edu/equineendogroup.
Donkeys are prone to Equine Metabolic Syndrome due to their physiological adaptations to survive in resource poor environments. The donkey has a lower nutritional requirement than a pony of the same size, but is often exposed to excess feed with high non- structural carbohydrate levels. In addition, they are generally given little exercise.
Donkeys and many small pony breeds are considered to be relatively insulin resistant- which has a survival advantage, but also leads to, and is linked with both hyperinsulinemia and obesity.
As well as clinical symptoms we need to test for insulin dysregulation. Resting insulin levels have very low sensitivity /high specificity and should not be relied upon as a sole test. At the Donkey Sanctuary we use an oral carbohydrate challenge using Karol Light (corn syrup). As donkeys are at increased risk of hyperlipaemia we do not starve patients before testing , but have a standard protocol that involves the donkey only having access to straw for at least 6 hours prior to testing.
We then give 45ml/100kg of syrup and obtain baseline blood samples. A second sample is taken 60-90 minutes later to measure serum insulin, which should be below 60mU/L.
At present adipokine testing is not validated for donkeys
There will be cases of EMS that do not demonstrate obesity and cases that also suffer from concurrent PPID, so in some cases further diagnostics will be warranted.
In many cases management of EMS relies on improving the dietary management of the donkey, and initiating a controlled weight loss programme. Ideally, the exercise is increased, but this will be dictated by whether there is any underlying lameness. To prevent boredom in cases of dietary restriction there are several ways to modify and enrich the stable environment.
Medical treatments exist: metformin can be used to reduce glucose absorption enterically and help in transitioning a donkey to pasture; a thyroxine derivative may be useful to increase the metabolic rate.
Pituitary Pars Intermedia Dysfunction (PPID) is seen in donkeys and, as many are kept until they are geriatric it is seen relatively frequently. The condition is known to be associated with an increased risk of immunosuppression and laminitis. Affected cases may have obvious clinical signs such as hirsutism, muscle wastage and polydipsia.
However we rely upon testing suspect donkeys for elevations in ACTH to detect cases before such signs are reached.
PPID results in hyperinsulinemia, which is a risk factor for laminitis. We also find these cases may have higher faecal egg counts, higher ectoparasites burdens and delayed wound healing.
Treatment of the underlying disorder relied upon the use of pergolide- Prascend at 2µg/kg. As the drug can suppress appetite donkeys need careful monitoring when on the drug and may need to start at lower doses. Testing In autumn when the levels are at their highest is considered the best time to discriminate for positive cases.

Donkey hoof disorders and their treatment

Citation

Alexandra K. Thiemann, Karen Rickards. March 2013. Donkey hoof disorders and their treatment. In Practice. 35. 135-140.

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Publication details
Publication date: 
1 March 2013
Journal: 
In Practice
Volume: 
35
Page numbers: 
135-140
DOI number: 
doi:10.1136/inp.f1074
Abstract

Disorders of the hoof have important health and welfare implications in donkeys. Clinical conditions that affect the donkey hoof include laminitis, which is one of the most common causes of lameness in donkeys in the UK, as well as white line disease/abscess, and chronic conditions such as overlong hooves. This article reviews the normal anatomy and function of the donkey’s foot, before discussing in more detail the diseases that can arise and their treatment.

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Development of a quantitative multivariable radiographic method to evaluate anatomic changes associated with laminitis in the forefeet of donkeys

Citation

Simon N. Collins, Sue J. Dyson, Rachel C. Murray, Richard Newton, Faith A. Burden, Andrew F. Trawford. August 2012. Development of a quantitative multivariable radiographic method to evaluate anatomic changes associated with laminitis in the forefeet of donkeys. American Journal of Veterinary Research. 73:8. 1207-1218.

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Publication details
Publication date: 
8 August 2012
Volume: 
73
Issue: 
8
Page numbers: 
1207-1218
DOI number: 
10.2460/ajvr.73.8.1207
Abstract

Objective—To establish and validate an objective method of radiographic diagnosis of anatomic changes in laminitic forefeet of donkeys on the basis of data from a comprehensive series of radiographic measurements.

Animals—85 donkeys with and 85 without forelimb laminitis for baseline data determination; a cohort of 44 donkeys with and 18 without forelimb laminitis was used for validation analyses.

Procedures—For each donkey, lateromedial radiographic views of 1 weight-bearing forelimb were obtained; images from 11 laminitic and 2 nonlaminitic donkeys were excluded (motion artifact) from baseline data determination. Data from an a priori selection of 19 measurements of anatomic features of laminitic and nonlaminitic donkey feet were analyzed by use of a novel application of multivariate statistical techniques. The resultant diagnostic models were validated in a blinded manner with data from the separate cohort of laminitic and nonlaminitic donkeys.

Results—Data were modeled, and robust statistical rules were established for the diagnosis of anatomic changes within laminitic donkey forefeet. Component 1 scores ≤ −3.5 were indicative of extreme anatomic change, and scores from −2.0 to 0.0 denoted modest change. Nonlaminitic donkeys with a score from 0.5 to 1.0 should be considered as at risk for laminitis.

Conclusions and Clinical Relevance—Results indicated that the radiographic procedures evaluated can be used for the identification, assessment, and monitoring of anatomic changes associated with laminitis. Screening assessments by use of this method may enable early detection of mild anatomic change and identification of at-risk donkeys.

Online references

Radiological anatomy of the donkey's foot: Objective characterisation of the normal and laminitic donkey foot

Citation

Simon N. Collins, Sue J. Dyson, M. C. Murray, Faith A. Burden, Andrew F. Trawford. July 2011. Radiological anatomy of the donkey's foot: Objective characterisation of the normal and laminitic donkey foot. Equine Veterinary Journal. 43:4. 478-86.

Authors
Publication details
Publication date: 
1 July 2011
Volume: 
43
Issue: 
4
Page numbers: 
478-86
DOI number: 
10.1111/j.2042-3306.2010.00312.x
Abstract

Reasons for performing study

Anatomical change within a laminitic foot is of diagnostic and prognostic importance. A lateromedial radiograph represents the current 'gold standard' by which these changes are identified. Detection of anatomical change is dependent upon a priori knowledge of normality and subjective assessment alone may not identify modest change. Normal baseline data is, therefore, needed against which objective comparisons can be made. There is little information regarding the radiological anatomy of the donkey foot, hence an equine model has been widely adopted. However, descriptive accounts suggest fundamental anatomical differences between these 2 species.

Objectives

To characterise objectively the radiological anatomy of normal donkey feet and define the nature and extent of anatomical change associated with laminitis.

Methods

The anatomy of the forefoot was quantified from lateromedial radiographs of 83 normal and 74 laminitic donkeys, using a computer based imaging system. Data were analysed using univariate and bivariate statistical methods. Results: Baseline data were established that define the radiological characteristics of the anatomy of normal donkey feet. The key hoof, bone and weightbearing stance parameters of lateromedial radiographs have been evaluated. Laminitis was associated with significant rotation and distal displacement of the distal phalanx, increases in integument depth and morphometric change to the distal phalanx (P<0.05).

Conclusions

This study challenges the validity of applying an equine model to the radiological anatomy of donkey feet. Hence, the diagnosis of anatomical change cannot be based on baseline data previously given for the horse and guidelines should be revised accordingly for the donkey. Potential relevance: This study provides an objective basis for the identification of anatomical change associated with laminitis in donkey feet.

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