donkey

Background: Objective recognition of pain in horses has been studied extensively, however studies on objective pain assessment in donkeys are limited, and the available scales are not validated. Objectives: This study describes scale construction and clinical applicability of a Composite Pain Scale (do-CPS) and a Facial Assessment of Pain scale (do-FAP) for acute pain in donkeys. Study design: observational. Methods: The study included 159 adult donkeys (n = 44 patients, n = 115 control donkeys) which were directly observed at The Donkey Sanctuary. Patients were presented with lameness (24), colic (7), head related pain (7) or post-operative pain (6). Based on equine scales specific potential elements and scores for donkeys were developed in a pilot study. The observers were not involved in donkeys’ clinical management. For each animal, the score of each element in both scales was assessed by two groups of independent observers. When applicable the patients were followed over time, once or twice daily. Patients and control groups were compared by Mann Whitney-U-tests. Results: The inter-observer reliability was strong for do-CPS (R2 = 0.95, p<0.001) and good for do-FAP (R2 = 0.77, p<0.001). Patients had significantly higher pain scores, compared to control donkeys (p<0.001 for both do-FAP and do-CPS). Sensitivity overall for the do-CPS (73%), do-FAP (68%), and specificity do-CPS (99%), do-FAP (75%) were good. Sensitivity and specificity for “lameness” were strong in do-CPS (92% and 100%, respectively). Sensitivity and specificity for “colic” were strong for both do-CPS (71% and 100%, respectively), do-FAP (95% and 79%, respectively). Main limitations: Observers could not be masked to the patients’ condition. More patients are needed with painful conditions other than lameness. These scales will be validated in a planned follow-up research. Conclusions: Objective pain assessment in donkeys is possible and may support objective evaluation of treatment of donkeys with acute pain.

This study examined normal donkey teeth using gross anatomical inspection, computed axial tomography (CAT), radiography, scanning electron microscopy (SEM) and, decalcified and undecalcified histology to determine their normal gross anatomy, histology and ultrastructure. CAT findings have shown donkey endodontic anatomy and the density (in Hounslow units) of donkey calcified dental tissues, i.e. enamel, dentine and cementum to be similar to values recorded in horses. Decalcified and undecalcified histology has identified donkey cheek teeth to have a similar histological appearance to that which has been described in the horse. SEM of donkey dental tissue has demonstrated minor differences to normal horse dental ultrastructure. Now that normal donkey dental anatomy has been clearly defined, pathological changes can be identified in diseased teeth and supporting structures and will allow a better understanding of the pathophysiology of common donkey dental disorders. Ultimately the results of this project will enable better dental care specifically developed for donkeys, promoting welfare in the donkey.

Although donkeys are considered to be more resistant to trypanosomes, they are often seen causing severe clinical disease, particularly anaemia, lethargy and boor body condition, in immuno-compromised animals due to stress from overwork, poor management practices and low quality diets. Studies made by The Donkey Sanctuary in Kenya showed a high prevalence of both tsetse and none tsetse transmitted trypanosomes. T. congolense and T. brucei sp are the most highly prevalent tsetse transmitted trypanosomes while T. vivax is the second most prevalent, next to T. congolense. Infection prevalence of T. vivax as high as 30% were diagnosed in Kenya and Ethiopia using parasitological techniques. These prevalences could have been higher had they been diagnosed using molecular techniques, as it was shown by the study made in Gambia, in which they found an infection prevalence of 87% using PCR.

Dourine is mostly diagnosed in horses from the highland regions in Ethiopia. Recent serological study made in Ethiopia, however, revealed not only in donkeys but across all agro-ecological zones. However, as the CFT does not differentiate between the infection of Dourine and Surra, it is difficult to know the true epidemiology of these diseases among equids where they both exist. Although Surra is reported in donkeys from different countries, it is not reported in donkeys in Ethiopia. However, Surra is endemic in camels in the arid and semi-arid regions of Ethiopia. The recent migration of camels to the mid-lowland areas during the dry season in search of feed might spread the disease among equids in the area.

A recent study made in Gambia by Glasgow University, funded by The Donkey Sanctuary, showed a fatal neurological syndrome among donkeys and horses caused by trypanosomosis. The aetiological agent of this emerging neurological syndrome has been established based on the presence of trypanosomes in the brain of affected animals. However, given the genetic homology between T. evansi, T. brucei brucei and T. equiperdum, it was not possible to confirm which one of these is causing this devastating condition. To solve this mystery and identify the species of trypanosome involved, study on further molecular characterization of cerebral trypanosomosis is underway in Gambia, a project funded by The Donkey Sanctuary.

The infection of trypanosomes in donkeys raises certain questions that need to be addressed. Given the high infection prevalence in the donkey population and associated diseases:

• Are they really carriers/resistant to trypanosomosis?
• The welfare implication of trypanosomosis in donkeys.
• What would be the role of donkeys in the epidemiology of trypanosomosis?
• The impact of exclusion of donkeys in the control of animal trypanosomosis?

Introduction

Mycobacterial infections are rare in equines. Mycobacterium bovis (M. bovis) is an important zoonotic pathogen causing disease in a wide range of animal species. Infection with M. bovis has not been documented previously in the donkey.

Materials and Methods

A 29-year-old donkey gelding presented with depression, pyrexia, tachycardia, tachypnoea and generalised wheezes and crackles on thoracic auscultation. Haematologic examination identified neutrophilic leukocytosis. Response to treatment with antimicrobials and non-steroidal anti-inflammatories was poor and the donkey was euthanased.

Results

On gross postmortem examination the lungs were diffusely consolidated with an irregular nodular appearance of the surface and multiple coalescing, firm, pale masses diffusely distributed throughout the parenchyma. Multiple, variably sized, firm, pale nodular masses were also identified within the mediastinum, epicardium, omentum, kidneys, liver, spleen and diaphragm. Histopathological examination of lung showed prominent interstitial fibrosis and diffuse granulomatous inflammation in which acidfast bacilli were occasionally identified. The additional nodular masses represented foci of chronic granulomatous inflammation. Culture of lung yielded a heavy growth of mycobacteria confirmed to be M. bovis by molecular techniques (GenoType MTBC).

Conclusion

Although rare in equines, disease caused by M. bovis should be considered as a possible differential diagnosis in donkeys presenting with signs of respiratory disease and respiratory or generalised granulomatous inflammation.

Traditional herd health monitoring is based on veterinary morbidity/ mortality figures using historical data from computerised records. The Donkey Sanctuary has responsibility for a large number of rescue and rehomed donkeys on farms whose welfare is high priority. The Donkey Sanctuary has introduced a validated welfare assessment tool to be used four times a year, to monitor animal and resource based measures of welfare (AWIN). This allows information to captured in real time rather than retrospectively and adverse welfare can be identified. Using this tool allows evidence based management changes to be made.

The Donkey Sanctuary is an equine charity whose mission is to “transform the quality of life for donkeys, mules and the people that depend upon them worldwide”. In the UK, The Donkey Sanctuary cares for over 2000 donkeys on a number of farms varying in size from 250-580 animals. The farms aim to rehome up to 10% of their herd annually to guardian (private) homes or donkey assisted therapy centres. The farms also provide a show case for our work to visiting professionals and the public. Welfare of the donkeys on farms is critical to the credibility of The Donkey Sanctuary. Using welfare-based criteria alongside health records has enabled the teams to pro-actively monitor donkey welfare, refine management practices, re-direct budgets and track progress. Since 2017, The Donkey Sanctuary has been using the stage 1 AWIN (Animal Welfare Indicators), which are animal and resource based measures. AWIN is used on a quarterly basis on all farms to evaluate the following AWIN criteria: Appropriate nutrition (body condition score BCS), Absence of injuries (lameness, joint swelling, skin change, prolapse), Absence of disease (hair coat, faecal staining, ocular/nasal discharge, abnormal breathing, cheek teeth palpation), Absence of Pain (hoof neglect, lameness, hot branding), and Human-Animal Relationship (avoidance behaviours, tail tuck). The donkeys chosen are a random 10% at each visit using a named list of donkeys. This data is evaluated alongside information collected from a computer based Animal Management System, where vets input clinical conditions in pre-determined categories to monitor physical health - the main ones aligned are BCS, lameness, colic, hyperlipaemia, sarcoid, eye disease, and mortality rate. Over 1 year at 1 farm with 580 donkeys: AWIN showed (i) loss of weight control over summer with total animals BCS >4 (scale 1-5) increasing from 13% in January to 31% in September, (ii) lameness peaking on turnout (from 6-15% herd), (iii) skin disease (relating to lice burden) decreasing from 32% (winter) to 7 % summer, (iv) hoof neglect (thrush, abscesses) remaining high all year at >50%, (v) avoidance behaviours constant at about 12%- relating to new animals arriving and calm animals leaving. Data is recorded in Excel, and presented graphically and by written documentation. Quarterly meetings with the farm manager and staff enable timely feedback.

Welfare can be benchmarked across farms and improvements aimed for. AWIN is validated and straightforward to use.

We compared spatial problem solving abilities in the mule (Equus asinus x Equus caballus) with that of its parent species to assess the effects of hybridization on cognition. In a detour task the animals(N=48) were required to make a detour through a gap at one end of a straight barrier in order to reach a visible target. After one, two, three or four repeats (A trials), the gap was moved to the opposite end of the barrier (B trials) and deviations from the straight line and the latency to crossing the barrier were recorded. Mules performed significantly above chance level on their first detour, unlike the other two species. We discuss our results with reference to hybrid vigour and to the flexibility of problem solving strategies with regards to species differences.