Donkey Flashcards
A reassortant G3P[12] rotavirus A strain associated with severe enteritis in donkeys
• A severe outbreak of acute enteritis occurred in two intensive donkey breeding farms in Shandong Province, China (2019), affecting 119 of 206 donkey foals.
• The morbidity rate was highest in foals aged 30–59 days (77%), with a mortality rate of 29.5% in this age group. Fatality rates peaked in foals aged 0–29 days (45.5%).
• A novel Group A Rotavirus (RVA) strain, designated RVA/Donkey-wt/CHN/Don01/2019/G3P[12], was identified in 89.9% of symptomatic foals.
Detection of Hepatitis E Virus Genotypes 3 and 4 in Donkeys in Northern China
•12.22% of donkeys were seropositive for anti-HEV antibodies, and 4.24% were RNA-positive, indicating active infection.
• The HEV RNA isolated belonged to genotypes 3b, 4b, and 4h, which are prevalent in domestic pigs in China. These findings support the hypothesis of cross-species transmission from pigs to donkeys.
•Younger donkeys (0.5–1 year) had higher RNA positivity rates (8.02%) compared to older age groups (declined to 0% by 1.5–2 years).
•Older donkeys (1.5–2 years) exhibited higher antibody levels, suggesting successful immune responses after prior exposure.
•HEV is zoonotic, and donkeys may pose a risk of transmission through meat products or direct contact, especially as intensive farming practices expand in China.
•While primarily transmitted via the fecal-oral route, other routes (e.g., vertical transmission, contaminated dairy products, blood transfusion) are documented in other species and may apply to donkeys.
Comparative anti-inflammatory effects of insulin and dexamethasone on cardiovascular biomarkers and antioxidants in miniature donkeys subjected to induced carbohydrate overload
• heart rate, respiratory rate and rectal temperature increased in miniature donkeys subjected to carbohydrate engorgement.
• Heart rate, respiratory rate and rectal temperature decreased 12 h after intravenous treatment by insulin (3 IU/kg bwt) and dexamethasone (2 mg/kg bwt) in miniature donkeys subjected to carbohydrate engorgement.
• There was no difference between insulin (3 IU/kg bwt) and dexamethasone (2 mg/kg bwt) in changes in clinical variables during carbohydrate engorgement in miniature donkeys.
Comparative Effects of Insulin and Dexamethasone
• Both drugs showed similar anti-inflammatory effects in reducing HR, RR, RT, and improving antioxidant levels.
• Insulin’s effects on cardiovascular biomarkers (cTnI, Hcy) were comparable to dexamethasone.
• No significant superiority of one drug over the other was observed for any measured parameter.
Dental health and management practices of donkeys in the UK: What should we be considering?
• Dental disease severity increases with age.
• Significant deterioration in dental health typically begins between 10–15 years
• Poor dental health (grades 4–5) often correlated with underweight donkeys (low BCS), suggesting compromised mastication affecting dietary intake.
• overweight donkeys also showed significant dental pathologies,
• Pathological grades (3–5) were more common among donkeys with restricted grazing.
• Use of chopped forage feed was higher in donkeys with acceptable dental grades
• No significant differences between dental grades and bedding types.
• 71% of donkeys had no history of prior dental examinations.
• Weak agreement (k = 0.270) between dental grades assessed at PAM and AM, suggesting underestimation of dental disease at pre-admission.
• Pathological grades were more frequently identified during AM examinations.
Comparative evaluation of the sedative and physiological effects of dexmedetomidine alone and in combination with methadone, morphine, tramadol or pethidine in miniature donkeys
• Dexmedetomidine combined with opioids (morphine, methadone, tramadol, or pethidine) provided superior sedation compared to dexmedetomidine alone, particularly 15–30 minutes post-administration.
• No significant differences in sedation scores were observed among the various opioid combinations. -> flexibility in choice
• The duration of sedation ranged from 5 to 60 minutes across all treatments.
•Dexmedetomidine/opioid combinations exhibited greater suppression of intestinal motility than dexmedetomidine alone, particularly at 75–90 minutes.
Characterisation of the oral glucose and sugar tolerance tests and the enteroinsular axis response in healthy adult donkeys
Oral Glucose Tolerance Test (OGTT):
• Plasma glucose and insulin peaked at 180 minutes, later than previously reported for donkeys (150 minutes).
• Glucose-dependent insulinotropic polypeptide (GIP) and active glucagon-like peptide-1 (aGLP-1) concentrations increased significantly, with aGLP-1 peaking at 240 minutes.
• OGTT elicited a stronger and more prolonged enteroinsular axis response than OSTT.
Oral Sugar Tolerance Test (OSTT):
• Plasma glucose peaked at 300 minutes, and insulin at 150 minutes.
• GIP showed a slower and delayed increase, peaking at 360 minutes, while aGLP-1 peaked at 120 minutes and returned to baseline by 180 minutes.
• Glucose and insulin curves were right-shifted compared to horses and ponies, with slower return to baseline.
• OGTT resulted in higher and more sustained glucose and incretin responses compared to OSTT.
• The area under the curve (AUC) for GIP and aGLP-1 was larger in OGTT, indicating stronger incretin stimulation by intragastric glucose.
• Insulin concentrations in donkeys were lower than cut-off values for insulin dysregulation (ID) diagnosis in horses and ponies, underscoring the need for species-specific diagnostic parameters.
• The aGLP-1 curve mirrored the insulin curve better than the GIP curve, suggesting aGLP-1 as the dominant incretin in donkeys.
Evaluation of the combined glucose-insulin and intravenous glucose tolerance tests for insulin dysregulation diagnosis in donkeys
Combined Glucose-Insulin Test (CGIT):
• Identified 2/6 donkeys as insulin dysregulation (ID)-positive using positive phase duration (PPD >45 min) and 3/6 using insulin concentration (≥100 μIU/mL at 45 min).
• Fewer ID-positive results compared to IVGTT, indicating lower sensitivity.
Intravenous Glucose Tolerance Test (IVGTT):
• Identified 5/6 donkeys as ID-positive using glucose and insulin parameters.
• Classified a higher number of donkeys with ID compared to CGIT.
• Glucose-positive phase duration was longer (PPD >120 min for horses, PPD >150 min for donkeys).
• Proxies like glucose/insulin ratio (<4), MIRG (>10), and RISQI (<0.22) were proposed as potential ID diagnostic tools, differing from those in horses.
• Insulin dysregulation altered proxy values significantly compared to healthy donkeys.
• CGIT and IVGTT thresholds for donkeys differed significantly from those used in horses.
• Delayed glucose and insulin clearance in donkeys compared to horses
• CGIT evaluates tissue insulin sensitivity but has low repeatability and sensitivity.
• IVGTT assesses both β-cell sensitivity and glucose disposal, making it more comprehensive but time-intensive.
• IVGTT is recommended for donkeys with suspected mild ID due to its higher sensitivity.
Cross-sectional study to identify the prevalence of and factors associated with laminitis in UK donkeys
• Period prevalence of laminitis in UK donkeys was 48.5% over 42 months, significantly higher than annual figures reported for horses and ponies (0.5%–34%).
• Laminitis was frequently recurrent, with 41.7% of donkeys experiencing multiple episodes during the study.
• Acute laminitis accounted for 35% of episodes, characterized by clinical signs such as pain and increased digital pulses but without radiographic changes.
• Chronic laminitis was more common (65%) and involved radiographic changes consistent with chronicity.
• Laminitis episodes occurred predominantly in January, February, October, and November, contrasting with spring and summer peaks typically reported in horses.
• Seasonal changes, including diet transitions (pasture to haylage), increased time spent on hard surfaces, and routine anthelmintic treatments, likely influenced these patterns.
Risk Factors
• Compared with control animals, the laminitic outcome groups were significantly (P < .05) more likely to be:
- younger (first episode),
- less likely to get extra feed (all four groups)
- to have an additional medical problem (first episode)
-less likely to have undergone dental work, movement, imaging (all four groups) or surgery (first; all laminitis, chronic episodes) in the month preceding the episode.
Body Condition and Endocrinopathies:
• Contrary to horses, being overweight/obese and body condition score (BCS) were not significantly associated with laminitis in donkeys.
• Endocrinopathies (PPID and basal hyperinsulinaemia) were surprisingly not linked to increased laminitis odds, despite a recognized association in other equids.
Energy hormone response to fasting-induced dyslipidemia in obese and non-obese donkeys
• Obese donkeys showed earlier lipid mobilization, with significant increases in total triglycerides (TTG) and total cholesterol (TC) observed at 42–48 hours of fasting.
• Non-obese donkeys displayed delayed increases in TTG and TC, beginning at 60 hours.
• Plasma glucose concentrations decreased significantly in obese donkeys by 24 hours, whereas no significant changes were observed in non-obese donkeys.
• Insulin levels decreased by 12 hours and remained low throughout fasting, promoting lipid mobilization by reducing the inhibition of hormone-sensitive lipase. Was not significantly different between groups
• Glucagon concentrations increased significantly after 60 hours in obese donkeys but remained stable in non-obese donkeys.
• The IGR decreased consistently in both groups during fasting, while the glucagon-to-insulin ratio (GIR) increased, particularly in obese donkeys.
• Leptin concentrations were higher in obese donkeys at baseline and decreased significantly after 60 hours of fasting.
• No significant changes were observed in adiponectin concentrations, although a decreasing trend was noted in obese donkeys.
• Insulin-like growth factor-1 (IGF-1) decreased significantly in obese donkeys but not in non-obese donkeys, reflecting greater energy demands in the former.
• Ghrelin levels remained unchanged, suggesting other regulatory mechanisms for hunger and energy balance in donkeys.
Morphine in donkeys: Antinociceptive effect and preliminary pharmacokinetics
• Morphine at 0.5 mg/kg IV provided significant mechanical antinociception, lasting up to 5 hours.
• The lower dose (0.1 mg/kg) also increased nociceptive thresholds but for a shorter duration (~1 hour).
• Dose-dependent effects were observed, with the higher dose producing greater and longer-lasting effects.
• Morphine was rapidly cleared, with a terminal half-life of 51 minutes and a volume of distribution of 2.07 L/kg.
• Metabolites included morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G), with M3G being the predominant metabolite.
• M3G concentrations consistently exceeded morphine and M6G levels, reflecting rapid glucuronidation.
• No significant adverse effects on heart rate, respiratory rate, or rectal temperature.
• Minimal neuroexcitation (e.g., mild ataxia) observed in a few cases, resolving within 30 minutes.
• No signs of gastrointestinal disturbances, although objective measures of motility were not assessed.
Differences Between Donkeys and Horses:
• Morphine had a shorter half-life and higher clearance in donkeys compared to horses, indicating faster metabolism.
• Despite higher M3G levels, donkeys exhibited minimal neuroexcitation compared to horses, suggesting species-specific responses.
Pharmacokinetic properties of pergolide mesylate following single and multiple-dose administration in donkeys
• Pergolide was rapidly absorbed after both intragastric and oral administration, with plasma concentrations detectable within 15 minutes.
• Following a single intragastric dose, the maximum concentration (Cmax) was lower (0.16 ± 0.16 ng/mL) compared to multiple oral doses (3.74 ± 2.26 ng/mL).
• Time to maximum concentration (Tmax) was significantly faster after oral administration (0.40 ± 0.20 h) compared to intragastric dosing (4.54 ± 3.38 h).
• The elimination half-life (t½) was significantly longer after multiple oral doses (16.35 ± 5.21 h) compared to a single intragastric dose (9.74 ± 1.35 h).
• Progressive increases in trough concentrations over time suggested potential accumulation or changes in metabolism with repeated dosing.
• Jugular vein samples consistently showed higher pergolide concentrations compared to cephalic vein samples, indicating possible oral transmucosal absorption.
• Pergolide administration (2 µg/kg) was well tolerated in all donkeys, with no observed changes in physical exam parameters, appetite, or behavior.
Donkeys vs. Horses:
• Pergolide’s pharmacokinetics in donkeys showed higher plasma concentrations and longer Tmax compared to horses
• Donkeys demonstrated a longer half-life after multiple doses, suggesting potential nonlinear pharmacokinetics or alterations in metabolic pathways with repeated administration.
PPID Treatment:
• Pergolide administered orally at 2 µg/kg appears suitable for treating pituitary pars intermedia dysfunction (PPID) in donkeys, achieving therapeutic plasma concentrations similar to or higher than those reported in horses.
• The longer half-life after multiple doses supports once-daily administration.
• Although pergolide was well tolerated, long-term safety and efficacy in donkeys with clinical PPID remain unknown.
The prevalence of uveitis in a population of donkeys in the UK
• Uveitis was observed in 2.9% of donkeys examined (6/207 donkeys).
• Comparable prevalence to that reported for horses in the UK, despite limited existing data for donkeys.
• Uveitis was distributed equally between eyes, with bilateral involvement in two donkeys.
Clinical Signs:
• Active uveitis: Keratic precipitates, aqueous flare, low intraocular pressure (IOP), miosis, and corneal edema.
• Post-inflammatory uveitis: Iris rests, synechiae formation, cataracts, peripapillary scarring, and vitreal opacities.
• Cataract formation was present in 100% of uveitis-affected donkeys, higher than rates in horses (~50%).
• Three of the eight uveitic eyes (37.5%) were blinded due to pathology, as determined by a negative menace response.
Risk Factors:
• Age: Increasing age was associated with a higher risk of uveitis (odds ratio 1.11 per year; P = 0.046).
Pathophysiology
• Inflammation disrupts the blood-ocular barrier, leading to vascular congestion and protein leakage into adjacent tissues.
• Manifestations include miosis, aqueous flare, corneal edema, and reduced aqueous humor production.
Chronic Phase:
• Prolonged inflammation results in synechiae, cataracts, vitreal degeneration, and peripapillary scarring.
• Structural damage to the choriocapillaris and retina disrupts oxygen and nutrient supply, impairing photoreceptor function.
Outcome following emergency laparotomy in 33 UK donkeys: A retrospective multicentre study
Presentation and Indications for Surgery:
• Clinical Signs: 46.9% of donkeys exhibited non-specific signs (e.g., dullness, anorexia, weight loss), while 37.5% showed severe colic signs. Only 15.6% presented with mild colic signs.
• Timing: 30% were referred after >72 hours of clinical signs, indicating delayed recognition or intervention compared to horses.
• Indications for Surgery: Pain and diagnostic findings were the main reasons for proceeding with laparotomy.
Most common primary lesions:
• Small Intestine (SI): 42.4%, including strangulating lesions (volvulus, deep adhesion bands) and obstructions (enteroliths, ileal impaction).
• Large Colon: 39.3%, including displacements, torsions, and obstructions (e.g., pelvic flexure impaction).
• Gastric and caecal lesions accounted for 6.1% each, including firm gastric impactions and caecal rupture.
Survival Outcomes:
• Overall survival to discharge was 54.5%.
• Intraoperative Euthanasia: 15.2% of donkeys were euthanized during surgery due to poor prognosis.
• Postoperative Mortality: 35.7% of donkeys that recovered from anesthesia did not survive to discharge.
• Repeat Laparotomy: Required in 21.4% of cases, with 66.7% of these surviving to discharge.
Postoperative Complications:
Complications occurred in 82.1% of cases, including:
• Hyperlipaemia: 42.9%
• Ileus: 21.4%
• Persistent colic: 17.9%
• Incisional complications: 21.4%
Donkeys vs. Horses:
• Donkeys showed a higher prevalence of non-specific signs (dullness, anorexia) compared to overt colic signs common in horses.
• Postoperative hyperlipaemia (42.9%) was significantly more frequent in donkeys than in horses (<1%), reflecting species-specific metabolic differences.
• Repeat laparotomy rates (21.4%) and survival after a second surgery (66.7%) were higher than in horses (<11% repeat laparotomy, ~44.8%-48.2% survival).
• Donkeys may have a higher pain threshold or exhibit less demonstrative pain behavior, complicating clinical assessments and delaying referrals.
Risk Factors and Prognostic Indicators
• Age: Increasing age was the only significant predictor of mortality; older donkeys had higher in-hospital death rates (OR 1.18 per year; p = 0.02).
• Severity of Signs: Unlike horses, severity or duration of clinical signs before referral did not predict survival, possibly due to smaller sample size or species-specific differences.
• Gastric and caecal pathologies were associated with poor outcomes, with no survivors in these categories.
• Donkeys with gastric lesions were less likely to show severe colic signs compared to those with small intestinal lesions (p = 0.05).
• Repeat laparotomy should be considered when indicated, as it does not appear to significantly worsen prognosis.
Gastroscopic characterisation and prevalence of gastric ulcer syndrome in working mules in Colombia
• The prevalence of mule gastric ulcer syndrome (MGUS) in the study was 42%.
-Most lesions were located in the squamous region (27%), particularly in the margo plicatus, while glandular lesions accounted for 20%, primarily in the fundus and pyloric antrum.
-Multifocal lesions were more common (28%) than focal lesions (16%), with the majority being superficial (99%).
• Clinically relevant lesions (grade ≥2) were present in both squamous and glandular regions, but severe lesions (grades 3–4) were rare.
• Only one deep lesion (1%) was identified, indicating a low frequency of severe ulcerative disease.
• Work regimen (days worked per week) was the only variable significantly associated with MGUS (OR: 1.98; 95% CI: 0.49–0.96). More intense workloads increased the likelihood of ulcers.
Novel equid papillomavirus from domestic donkey
• A novel papillomavirus, designated as Equus asinus papillomavirus type 3 (EaPV3), was identified in oral swab samples from donkeys in the Gansu province of China.
• This virus expands the known diversity of equine papillomaviruses, being the third identified in donkeys (after EaPV1 and EaPV2).
