The Netherlands

Assessment of chronic pain is very important for monitoring and improving welfare and quality of life in donkeys. Freedom from disease and pain is one of the ‘five freedoms’ underlying animal welfare. The aim of the current study was to develop a pain scale for assessment of chronic pain in donkeys (Donkey Chronic Pain Scale; DCPS), including behavioural and facial expression-related parameters. The scale was applied to 77 donkeys (38 donkeys diagnosed with chronic health problems by means of clinical examination and additional diagnostic procedures and 39 healthy control animals). Animals were assessed twice daily for three consecutive days by two observers that were not masked to the condition of the animals but were unaware of the analgesic treatment regimens. Both composite, facial expression-based and combined DCPS pain scales showed excellent inter-observer reliability (Cronbach’s alpha = 0.98, 0.96 and 0.98 respectively; P < 0.001). Individual composite and facial expression-based pain scores and the resulting combined DCPS showed significant differences between donkeys with chronic conditions and control donkeys at all time points (P < 0.001). A DCPS cut-off of 6 showed good sensitivity and specificity (92% and 82.5% respectively) for presence of a chronic painful condition. Facial expression-related parameters separately showed low sensitivity. In conclusion, it is possible to use a composite pain scale for assessment of chronic pain in donkeys, based on behavioural and facial expression-based parameters. Further studies are needed to validate this pain scale before it can be used in veterinary practice.

Background

Equine gut microbiology studies to date have primarily focused on horses and ponies, which represent only one of the eight extant equine species. This is despite asses and mules comprising almost half of the world’s domesticated equines, and donkeys being superior to horses/ponies in their ability to degrade dietary fiber. Limited attention has also been given to commensal anaerobic fungi and archaea even though anaerobic fungi are potent fiber degrading organisms, the activity of which is enhanced by methanogenic archaea. Therefore, the objective of this study was to broaden the current knowledge of bacterial, anaerobic fungal and archaeal diversity of the equine fecal microbiota to multiple species of equines. Core taxa shared by all the equine fecal samples (n = 70) were determined and an overview given of the microbiota across different equine types (horse, donkey, horse × donkey and zebra).

Results

Equine type was associated with differences in both fecal microbial concentrations and community composition. Donkey was generally most distinct from the other equine types, with horse and zebra not differing. Despite this, a common bacterial core of eight OTUs (out of 2070) and 16 genus level groupings (out of 231) was found in all the fecal samples. This bacterial core represented a much larger proportion of the equine fecal microbiota than previously reported, primarily due to the detection of predominant core taxa belonging to the phyla Kiritimatiellaeota (formerly Verrucomicrobia subdivision 5) and Spirochaetes. The majority of the core bacterial taxa lack cultured representation. Archaea and anaerobic fungi were present in all animals, however, no core taxon was detected for either despite several taxa being prevalent and predominant.

Conclusions

Whilst differences were observed between equine types, a core fecal microbiota existed across all the equines. This core was composed primarily of a few predominant bacterial taxa, the majority of which are novel and lack cultured representation. The lack of microbial cultures representing the predominant taxa needs to be addressed, as their availability is essential to gain fundamental knowledge of the microbial functions that underpin the equine hindgut ecosystem.