Pack wounds of donkeys and mules in the Northern High Atlas and lowlands of Morocco

Reasons for performing study: Wounds are one of the primary welfare concerns of working equids and are often related to harness or load‐bearing packs. Objectives: To identify and quantify factors associated with the presence of pack wounds in donkeys and mules working in the wood trade in the Midelt (Northern High Atlas) region of Morocco, and to compare wounds of these donkeys and mules to those working in other trades. Methods: The study population comprised equids working in the Midelt region involved in the wood trade. Comparison populations were comprised of equids working in other trades, in the same region and in Khemmiset region (lowlands of Central Morocco). Wounds were numbered and scored according to their severity. Questionnaires were used to gather data from owners, and objective data regarding the animal, berdaa (back‐pack) and load were collected. Data were analysed using multilevel uniand multivariable regression models to allow for clustering of wound sites within an equid. Results: Analysis showed an overall pack wound prevalence of 54% (n = 80/147). The most common site was the withers. Equids working in the wood trade were at increased risk of suffering pack wounds. Equids in the lowland study population were at increased risk of developing pack wounds, and donkeys were at increased risk of suffering pack wounds compared to mules both overall and within the wood trade. Other factors affecting the prevalence of wounds included the cleanliness of the berdaa and the frequency and distances of work imposed on the equid. Conclusion: Pack wounds in donkeys and mules are common in the 2 study regions of Morocco and appear to be associated with work factors including the trade the equids work in, the frequency and distances of work imposed and cleanliness of the pack. Donkeys are more susceptible than mules to developing pack wounds. Potential relevance: These results allow recommendations to be made to owners of equids that may decrease the prevalence of wounds and, therefore, improve welfare and working capability of these equids. Research is required to identify reasons for regional difference in prevalence of pack wounds in equids not working in the wood trade.     

Pharmacology and therapeutics in donkeys

Therapeutics are often administered to donkeys based on dosage and intervals recommended for horses because very few drugs have donkey‐specific label indications. Yet differences between donkeys and horses in drug distribution, metabolism and elimination have been noted for most therapeutic agents studied. These differences can be partially explained by the donkey's unique physiology. Since their ancestors evolved in a desert environment, the modern donkey exhibits qualities that allow them to tolerate dehydration better than the horse and recover more quickly from its effects. Fluid balance and body water compartment partitioning differ from the horse and may have implications regarding drug distribution. Since donkeys are preferential browsers, differences in diet may have influenced evolutionary differences in metabolic disposition of drugs. It is important to acknowledge these differences when designing dose regimes for donkeys based on horse protocols in order to avoid either lack of efficacy or toxicity.     

Idiopathic typhlocolitis in 40 aged donkeys

Typhlocolitis was diagnosed in 40 aged donkeys at routine post mortem examinations subjected to euthanasia for colic‐related clinical signs at The Donkey Sanctuary. Gross pathological changes included oedema, ulceration and haemorrhage involving the caecum and ventral colon. Histopathology indicated endoparasite and bacterial associated inflammation in 20 and 11 cases, respectively. Bacterial culture in 18 cases did not yield a definite aetiological agent. Other management and stress related factors were looked at to identify obvious risk factors. This report describes the clinical, biochemical and haematological parameters and pathological changes observed in 40 donkeys diagnosed with typhlocolitis.     

Polyodontia in 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.     

Reference intervals for biochemical and haematological parameters in mature domestic donkeys (Equus asinus) in the UK

Reference intervals (RIs) for haematology and serum biochemistry for donkeys in a temperate climate have been previously published using blood sample results from the resident population of a large donkey shelter in the UK. Periodic review of reference intervals is recommended to ensure their applicability to the patient population and changes in laboratory methods and technologies. The current study aimed to revise the previously published haematology and serum biochemistry values for the adult domestic donkey (Equus asinus) in the UK in the light of a change in analytical equipment at the Donkey Sanctuary laboratory, but also to refine the demography of the sample population with respect to age, physiology and clinical history. Clinical pathology results from 138 clinically healthy mature (4–24 years inclusive) female and castrated male donkeys selected from the resident population of the Donkey Sanctuary, were analysed retrospectively. The animals were blood sampled during the period February 2008 to June 2011 as part of a routine health screen prior to rehoming. Results for a total of 38 biochemical and haematological parameters were analysed including 3 previously unreferenced parameters in addition to those assessed in the previous study. The new reference intervals and median values show very poor transferability with recently derived reference intervals for non‐Thoroughbred horses and only limited transferability with reference intervals previously published for donkeys in the UK. Of particular note is a marked reduction in the upper reference limit for triglycerides of 2.8 mmol/l (from 4.3 mmol/l) since this parameter is used to decide when donkeys are at risk of developing hyperlipaemia. This study demonstrates the value of intermittent review of reference intervals and refinement of study populations. Notwithstanding the caution with which reference interval data from different laboratories should be compared, the lack of transferability of results between donkeys and horses highlights the importance of use of species‐appropriate reference intervals for clinical decision‐making.     

Common helminth infections of donkeys and their control in temperate regions

Roundworms and flatworms that affect donkeys can cause disease. All common helminth parasites that affect horses also infect donkeys, so animals that co‐graze can act as a source of infection for either species. Of the gastrointestinal nematodes, those belonging to the cyathostomin (small strongyle) group are the most problematic in UK donkeys. Most grazing animals are exposed to these parasites and some animals will be infected all of their lives. Control is threatened by anthelmintic resistance: resistance to all 3 available anthelmintic classes has now been recorded in UK donkeys. The lungworm, Dictyocaulus arnfieldi, is also problematical, particularly when donkeys co‐graze with horses. Mature horses are not permissive hosts to the full life cycle of this parasite, but develop clinical signs on infection. In contrast, donkeys are permissive hosts without displaying overt clinical signs and act as a source of infection to co‐grazing horses. Donkeys are also susceptible to the fluke, Fasciola hepatica. This flatworm can be transmitted, via snails and the environment, from ruminants. As with cyathostomins, anthelmintic resistance is increasing in fluke populations in the UK. A number of the anthelmintic products available for horses do not have a licence for use in donkeys, and this complicates the design of parasite control programmes. As no new equine anthelmintic classes appear to be near market, it is important that the efficacy of currently effective drugs is maintained. It is important that strategies are used that attempt to preserve anthelmintic efficacy. These strategies should be based on the concept that the proportion of worms in a population not exposed to anthelmintic at each treatment act as a source of ‘refugia’. The latter is an important factor in the rate at which resistance develops. Thus, it is imperative that parasite control programmes take into account the need to balance therapy to control helminth‐associated disease with the requirement to preserve anthelmintic effectiveness.     

Metabolic acidosis in healthy mules under general anaesthesia with halothane

ObjectiveTo report the severe metabolic acidosis identified in a group of 11 healthy mules anaesthetized with halothane for castration.Study designData generated from a prospective study.AnimalsEleven mules aged 2.5–8 years, weighing 230–315 kg and 11 horses aged 1.5–3.5 years, weighing 315–480 kg.MethodsAnimals were anaesthetized for castration as part of an electroencephalographic study. Preanaesthetic medication was acepromazine (0.03 mg kg^?1) administered through a preplaced jugular venous catheter. Anaesthesia was induced 30–90 minutes later with intravenous thiopental (10 mg kg^?1). After orotracheal intubation, anaesthesia was maintained with halothane vaporised in oxygen. The animals’ lungs were ventilated to maintain the end-tidal CO₂ concentration between 3.9 and 4.5 kPa (29–34 mmHg). Anaesthetic monitoring included invasive blood pressure measurement via the auricular artery (mules) and submandibular branch of the facial artery (horses). Arterial blood gas samples were drawn from these catheters at three time points during surgery and pH, PaCO₂, base excess (ecf) and HCO₃^? were measured. Values were compared between groups using a Mann–Whitney test. p was taken as <0.05. Results are reported as median (range).ResultsPaCO₂ did not differ between groups but pH was significantly lower in mules [7.178 (7.00–7.29)] compared to horses [7.367 (7.24–7.43)] (p = 0.0002). HCO₃^? values were significantly lower in the mules [16.6 (13.0–22.3) mM] compared to horses [23.7 (20.9–23.7) mM] (p = 0.0001), whilst base excess (ecf) was significantly more negative in the mules [?11.4 (?1.27 to ?16) mM] compared to horses [?1.3 (?5.8 to +2.4) mM] (p = 0.0004).Conclusion and clinical relevanceThis study demonstrated severe metabolic acidosis in healthy mules, which may have prompted intervention with drug therapies in a clinical arena. It is probable that the acidosis existed prior to anaesthesia and caused by diet, but other possible causes are considered.     

Thyroid hormone concentrations differ between donkeys and horses

Reasons for performing study: Reference intervals for thyroid hormones (TH) concentrations have not been previously established for donkeys, leading to potential misdiagnosis of thyroid disease. Objectives: To determine the normal values of TH in healthy adult donkeys and compare them to TH values from healthy adult horses. Methods: Thirty‐eight healthy Andalusian donkeys and 19 healthy Andalusian horses from 2 different farms were used. Donkeys were divided into 3 age groups: <5, 5–10 and >11 years and into 2 gender groups. Serum concentrations of fT3, tT3, rT3, fT4 and tT4 were quantified by radioimmunoassay. All blood samples were collected the same day in the morning. None of the animals had received any treatment for 30 days prior to sampling or had any history of disease. Both farms were in close proximity and under similar management. Differences between groups were determined using a one‐way ANOVA analysis followed by Fisher's LSD test. P<0.05 was considered significant. Results: Serum TH concentrations were higher in donkeys than in horses (P<0.01). Donkeys <5 years had higher serum rT3, fT4 and tT4 concentrations than donkeys >5 years (P<0.05). Furthermore, older donkeys (>11 years) had lower serum fT3 and tT3 concentrations than younger donkeys’ groups (<5 and 5–10 years, P<0.05). TH concentrations were not different between genders (fT3: P = 0.06; tT3: P = 0.08; rT3: P = 0.15; fT4: P = 0.89; and tT4: P = 0.19). Conclusions: Thyroid hormone concentrations are different between healthy adult donkeys and horses. Potential relevance: Establishing species‐specific TH reference ranges is important when evaluating clinicopathologic data in equids in order to avoid the misdiagnosis of thyroid gland dysfunction. Further studies to elucidate the physiological mechanisms leading to these differences are warranted.     

Investigating the opinions of donkey owners and veterinary surgeons towards pain and analgesia in donkeys

The aim of this questionnaire‐based study was to identify which analgesics are currently prescribed to donkeys in clinical practice and to collect opinions from veterinary surgeons and donkey owners on the importance of different pain‐related behaviours in donkeys. Questionnaires were completed by 143 veterinary surgeons and 93 donkey owners. Phenylbutazone, flunixin, detomidine and butorphanol were reported as the most frequently used analgesics in donkeys. Most veterinary surgeons reported administering these drugs at the horse dose rate and dosing interval, which may be inappropriate in the donkey. Four pain‐related behaviours were identified as very important by veterinary surgeons and owners: dullness for colic‐associated pain, keeping the foot lifted, and lameness for foot and limb pain and inability to chew properly for head and dental pain. This is a more limited behavioural repertoire than has recently been identified to be associated with pain in the donkey and suggests that the respondents were reporting perceived wisdom as to what people think are the behavioural signs associated with pain or were not interpreting pain‐related behaviours correctly.     

Seminal parameters and field fertility of cryopreserved donkey jack semen after insemination of horse mares

Reasons for performing study: As mule production is often concentrated in remote areas of the world, a simplified semen cryopreservation protocol is required. Aim: To compare the seminal parameters of cryopreserved donkey semen in lactose‐EDTA and lactose‐yolk extenders and the fertility rates on horse mares. Methods: Trial 1: Sperm total and progressive motility, vigour (scale 0–5), morphology (major and minor defects) and plasma membrane integrity (HOST) were evaluated in 25 ejaculates from 5 donkey jacks immediately after collection (raw), after chilling to 5°C (chilled) and after freezing/thawing. The semen was mixed with skimmed‐milk extender, centrifuged, and then re‐suspended in lactose‐EDTA or lactose‐yolk extender. Semen was loaded into 0.5 ml straws and chilled to 5°C for 1 h, after which samples were either evaluated (chilled semen) or placed above liquid nitrogen for 20 min prior to immersion. Seminal parameters were evaluated by ANOVA and Tukey's test. Trial 2: Cryopreserved semen from 3 males was used to inseminate 53 mares at 60 oestrous cycles randomly assigned to lactose‐yolk (n = 30 cycles) or lactose‐EDTA (n = 30 cycles) extenders. Pregnancy diagnosis was performed 15 and 25 days post ovulation. The pregnancy rates were compared using Chi‐squared tests. Results: Trial 1: No significant differences were evident in any seminal parameters between extenders after either chilling or cryopreservation. Total and progressive motility were significantly (P<0.05) lower in cryopreserved semen than raw and chilled semen for both extenders. Trial 2: Pregnancy rates did not significantly differ between extenders (lactose‐EDTA extender 53.33 and 43.33%; lactose‐yolk 50.0 and 46.66% for Days 15 and 25 post ovulation, respectively). Conclusions: Cryopreservation of donkey semen using the simplified lactose‐yolk extender resulted in similar seminal parameters and fertility rates when compared to lactose‐EDTA extender. Potential relevance: Lactose‐yolk extender may be advocated as a simple, easy to prepare extender, for use in geographically isolated enterprises producing mules throughout the world.     

Serum cortisol in mules intended for agricultural work

Cortisol is a hormone secreted by the adrenal glands that is stimulated by physiological and pathological factors and has been studied widely in equids, but not in mules. The objectives of this study were to obtain a reference value for serum cortisol in mules destined for agricultural activities and to identify age- and gender-related differences in the value. The concentration was obtained in blood samples using a commercial sandwich ELISA specific for cortisol. The concentration was 96.3 ± 40.6 ng/ml and similar between age groups and genders.     

Abdominal wall herniation in working Moroccan equids: 14 cases (2016–2017)

Hernia of the abdominal musculature was seen in 14 working equids (1% of total admissions) during the 14-month period between October 2016 and December 2017. Animals with hernias of less than 2 months’ duration (six animals) were treated conservatively with compressive abdominal bandaging whereas those with hernias of more than 2 months’ duration (five animals) were treated surgically with a primary closure of the defect. Surgical repair was not possible in three individuals due to the large size of the defect, location and lack of availability of prosthetic mesh. Of the 11 equidae treated, all showed complete resolution of the hernia by the time of discharge, and follow-up with owners, between 5 and 16 months post-treatment, revealed that no recurrence of the ruptures.