donkey

Resistance to currently available anthelmintics is a serious phenomenon which is prevalent globally. Cyathostomins are one of the major parasites, and are of primary concern in donkeys. There have been reports of emerging resistance to pyrantel, but the status of pyrantel resistance in donkey populations in the UK is largely unknown. This report investigates pyrantel resistance in two geographically isolated donkey herds in the South West of England. The first herd had suspected pyrantel resistance, with already established resistance to other anthelmintics. In the second herd the efficacy of pyrantel was not suspected at the time the study took place. Faecal Egg Count Reduction Test (FECRT) was carried out, revealing large scale resistance. Eighty one percent of the first herd and 73% of the second herd had a FEC of less than 95% after treatment, and anthelmintic resistance was confirmed using the World Association for the Advancement of Veterinary Parasitology guidelines. These findings indicate that anthelmintic resistance to pyrantel exists in both tested donkey populations and illustrate the continuing development of resistance through different classes of chemotherapeutics.

A 36-year-old donkey developed dyspnoea, pyrexia, hypoalbuminaemia and oedema. Following continued clinical deterioration the donkey was humanely destroyed. Grossly, there were numerous nodules (5-10mm) scattered throughout the lung. Microscopically, the lung was infiltrated by an angiocentric and bronchocentric to diffuse mixed population of small mature and atypical lymphocytes, histiocytes, plasma cells and fewer eosinophils. The infiltrate was composed of numerous small mature and fewer atypical CD3(+) T lymphocytes. Low numbers of CD20(+) and CD79a(+) B cells, some atypical, accompanied the T cells. These infiltrates were consistent with an angiocentric lymphoma and resembled lymphomatoid granulomatosis, an Epstein-Barr virus (EBV)-associated human tumour. Immunohistochemistry for EBV latent membrane protein and polymerase chain reaction analysis for equine gamma herpesvirus DNA were negative. To the authors' knowledge this is the first case of angiocentric lymphoma reported in a donkey and the first case of lymphomatoid granulomatosis-type disease in an animal in which possible concurrent infection with a gamma herpesvirus has been investigated.

Donkeys have evolved to thrive on highly fibrous, poor quality foodstuffs and have evolved as browsers as well as grazers. As such, they have different nutrient requirements with significantly lower energy and protein needs when compared with horses. Dietary management of donkeys is essential when kept in a temperate climate as they are prone to obesity and related disorders. A diet based on fibrous forages and limited grazing is usually sufficient for the majority of donkeys and mules. Specialist feeding is discussed in this article.

Reason for study

Dental disorders have recently been recognised as having major clinical and welfare implications in donkeys. However, no investigation appears to have examined the association of dental disorders with managemental factors and any intercurrent illness.

Objectives

To determine the association of dental disorders observed in a post mortem study with age group, body condition score, time since last dental treatment, feeding and the illness that necessitated euthanasia or caused death.

Methods

A prospective study documented the type and prevalence of dental disorders in 349 mainly aged donkeys (median estimated age of 31 years) that were subjected to euthanasia over an 18 month period in 2005-2006. The estimated age, body condition score, supplemental feed status, time since last dental treatment and nature of the intercurrent disease that necessitated euthanasia or caused death were also recorded. Multivariable analysis was performed to examine associations of these factors with specific dental disorders and between specific dental disorders.

Results

There was a high prevalence (93.4%) of significant dental disease. Age group was significantly associated with the presence of dental disorders and an older age range was a high risk factor for the presence of cheek teeth (CT) diastemata. There was a significant association between the presence of CT diastemata and the concurrent presence of displaced, missing and worn CT. There was also a significant association between the presence of diastemata and colic.

Conclusions and potential relevance

Aged donkeys have a high prevalence of dental disorders especially of CT diastemata. Dental disorders and, in particular, the presence of CT diastemata were significantly associated with colic. Routine, prophylactic dental treatments should be performed, especially in aged donkeys.

Reason for study

Donkey dental disorders are being recognised with increased frequency worldwide and have important welfare implications; however, no detailed investigations of dental disorders in donkeys appear to have been published.

Objectives

To determine the prevalence of specified dental disorders in donkeys by performing a prospective post mortem study on donkeys that were subjected to euthanasia or died for other reasons at The Donkey Sanctuary, UK.

Methods

Post mortem examinations were performed on 349 donkeys over an 18 month period, 2005-2006. The presence and extent of specified dental disorders were recorded and these data analysed to determine their prevalence and common locations.

Results

A high prevalence (93%) of disorders was noted in the population with a median age of 31 years. In particular, cheek teeth diastemata (85% prevalence) were very common, often associated with advanced periodontal disease. Other disorders observed included missing teeth (in 55.6% of donkeys), displaced teeth (43%), worn teeth (34%), local overgrowths (15%), focal sharp overgrowths (3%) and dental-related soft tissue injuries (8%).

Conclusions and potential relevance

Aged donkeys have a high prevalence of significant dental disease, especially cheek teeth diastemata. These findings highlight the importance of routine dental examinations and prophylactic dental treatments to improve the dental health and welfare of donkeys.

Polyodontia is defined as the presence of teeth in excess of the normal dental formula. In equids, supernumerary teeth are uncommon but, when present, are usually located mainly in the caudal aspects of the cheek teeth rows (distomolars), also being found adjacent to normal cheek teeth or even in an ectopic location. It is believed that this disorder is a result of an inappropriate differentiation of dental germinal tissue during gestational development, with external trauma also acting as an initiating factor, when teeth germs are affected. The presence of these abnormal teeth can lead to axial displacement, dental overgrowths, dental-related soft tissue damage, diastemata formation, periodontal disease and development of secondary sinusitis. A large prospective, cross-sectional study was performed in 800 donkeys, with the aim to investigate the prevalence and aetiopathogenesis of clinically diagnosed oral and dental disorders. Polyodontia was recorded in 2.25% of the donkeys, presenting 36 supernumerary teeth, with 2.80% being incisors and 97.20% cheek teeth, with prevalence increasing with age. The caudal aspects of the maxillary cheek teeth rows were the most common locations for supernumerary teeth development (distomolars). The mandible was far less commonly affected than the maxilla. Although polyodontia is uncommon in donkeys, it should be considered in the differential diagnosis of dental disease. A methodical oral examination and a complete radiographic survey of the entire dental arcades are crucial for a correct early diagnosis and treatment plan implementation. The increasing prevalence of fully erupted supernumerary teeth recorded in older groups suggested a late onset eruption process, and therefore, in donkeys undergoing regular dental prophylaxis, the presence of previously unnoticed supernumerary teeth should always be sought.

Salivary duct lithiasis is a condition characterized by the partial or total obstruction of a salivary gland or its excretory duct due to the formation of sialoliths. A 9-year-old female donkey, belonging to the unique and endangered indigenous breed of donkey in Portugal, was diagnosed with a sialolith in the rostral portion of the right parotid duct based on clinical, oral, dental, and radiographic examination results. Surgical removal of the sialolith was done through a percutaneous approach.

Most donkey and local horse breeds are vulnerable to extinction as mechanization of agriculture progress throughout the world. The present study analyzed the pedigree and herd records of the donkey Asinina de Miranda breed (RAM), identifying genealogical and human factors that may affect the breed genetic diversity in the future and suggesting suitable strategies to breed preservation, early on the conservation program. The breeding rate was very low, with a ratio of foaling/live animals of 0.23 (178/760). The estimated number of founders and ancestors contributing to the reference population was 128 and 121. The number of founder herds in the reference population was 64, with an effective number of founder herds for the reference population of 7.6. The mean age of herd owners was 65.50±0.884 years, with a negative association among the herd size and owner’s age (P<0.001). In contrast, the size of the herd and the ownership of a male were both positively associated (P<0.001) with the herd number of in-born foals. Both the owners’ age and the herd location (RAM home region v. dispersal region) were negatively associated with the foaling number (P<0.001). The main identified risk factors were: low breeding rates; low number of males and their unequal contribution to the genetic pool; unequal contribution of the herds to genetic pool; and advanced age of herd owners.

Post-mortem examination of 16 donkey cheek teeth (CT) with caries (both peripheral and infundibular) and pulpar exposure were performed using computerised axial tomography (CAT), histology and scanning electron microscopy. CAT imaging was found to be useful to assess the presence and extent of caries and pulp exposure in individual donkey CT. Histology identified the loss of occlusal secondary dentine, and showed pulp necrosis in teeth with pulpar exposure. Viable pulp was present more apically in one exposed pulp horn, with its occlusal aspect sealed off from the exposed aspect of the pulp horn by a false pulp stone. Scanning electron microscopy showed the amelo-cemental junction to be a possible route of bacterial infection in infundibular cemental caries. The basic pathogenesis of dental caries in donkeys appears very similar to its description in other species.

Background

Gastrointestinal nematode infections constitute a threat to the health and welfare of donkeys worldwide. Their primary means of control is via anthelmintic treatments; however, use of these drugs has constraints in developing countries, including cost, limited availability, access to cheaper generic forms of variable quality and potential anthelmintic resistance. As an alternative, bioactive plants have been proposed as an option to treat and control gastrointestinal helminths in donkeys. This study aimed to use participatory methodology to explore donkey owner knowledge, attitudes and beliefs relating to the use of plant-based treatments for gastrointestinal parasites of donkeys in Ethiopia.

Results

In focus groups, 22/29 groups stated they knew of plants used for the treatment of gastrointestinal parasites in donkeys. All groups volunteered plants that were used in cattle and/or small ruminants. In total, 21 plants were named by participants. ‘Koso’ (Hagenia abyssinica) ‘Grawa’ (Vernonia amygdalina) and a mixed roots and leaves preparation were the most frequently named plant preparations. ‘Enkoko’ (Embelia shimperi) and ‘a mixture of roots and leaves’ were ranked highly for effectiveness in donkeys. However, ‘Grawa’ and ‘Koso’ were the highest ranked when taking into account both the rank position and the number of groups ranking the plant.

Thematic analysis of participants’ current attitudes and beliefs surrounding traditional plant-based remedies for gastrointestinal parasites revealed that anthelmintics obtained from clinics were generally favoured due to their ease of administration and perceived higher effectiveness. There was doubt surrounding the effectiveness of some plant-based treatments, but there were also perceived advantages including their low cost, ease of cultivation and availability. However, plant-based treatments were considered a “past trend” and people favoured “modern” medicine, particularly among the younger generation.

Conclusions

There was extensive knowledge of plant-based treatments for gastrointestinal parasites in livestock in Ethiopia. In donkeys, Koso (Hagenia abyssinica), Grawa (Vernonia amygdalina), Enkoko (Embelia shimperi) and ‘mixed roots and leaves’ were the most frequently named and/or highest ranked plants with reported efficacy against gastrointestinal parasites. Further in vitro and in vivo investigation of these plants is now required to determine viable alternatives for the treatment and control of gastrointestinal parasites in Ethiopia.