138


EQUINE VETERINARY EDUCATION / AE / MARCH 2016


Girardi et al. 2013) which may not reflect the general donkey population especially when study populations are small; the reference values of Al-Busadah and Homeida (2005) for example were garnered from 13 individuals. In the study by Courouc


population is intended to reflect the majority of the general UK pet/companion donkey population. This discussion underlines the importance of using relevant and recent reference intervals for clinical assessment of veterinary cases.


e-Malblanc et al. (2008) the majority of animals


sampled were lactating or heavily pregnant females thus representing a physiologically specific cohort. The transference of the RIs reported here would undoubtedly be inappropriate to these populations and the establishment of RIs relevant to specific populations as those mentioned is beneficial to veterinarians working within the local context; however, such RIs have limited applicability to other populations. Despite the proverbial longevity of donkeys, especially


when kept as pets or companions, previous study of age- related effects on their physiology is relatively limited (Zinkl et al. 1990; Mot et al. 2011). Changes in physiological parameters according to age are sometimes discussed in published work but the relative longevity of global donkey populations varies and what constitutes ‘young’, ‘adult’ and ‘aged’ donkeys in such study populations are too inconsistent for valid comparisons to be made (Zinkl et al. 1990; Dinev et al. 2009; Mot et al. 2011). In countries where donkeys are working hard, lifespan tends to be shorter than in animals kept as pets and the complex influences of diet, genetics, environment and socioeconomic factors, as well as physical effects (work) on ‘ageing’ mean that it is unlikely to be legitimate to extrapolate age-related effects between populations. Thus studies establishing reference intervals for such populations are not relevant to a broad range of ages. Conversely, the study by French and Patrick (1995) included companion donkeys from the full age range of animal available for study (0–49 years old) to reflect the pet donkey population in the UK. Although age did not appear to be a significant factor in that study the inclusion of immature/ juvenile donkeys with adult/aged animals could be questioned and the current study therefore concentrates on mature adults 4–24 years old. In view of the longevity of the pet donkey further elucidation of age-appropriate reference intervals throughout their typical lifespan would be of value to veterinarians and is currently being pursued. The Donkey Sanctuary promotes the mantra “donkeys are


different” and these unique animals should in no way be considered merely as small horses. Notwithstanding variations in sample handling and analysis, in common with previous studies in donkeys (Zinkl et al. 1990; French and Patrick 1995; de Aluja et al. 2006; Lemma and Moges 2009; Getachew et al. 2010; Etana et al. 2011) the reference intervals established in the current study appear to be significantly different to those recently generated for non-Thoroughbred, adult horses (Anonymous 2011a). When RI transference validation was undertaken with these RIs and those of horses (Anonymous 2011a) only 4 of 20 biochemical analyte RIs and 0 of 16 haematological analyte RIs were transferrable. Notable biochemical differences included significantly lower RIs for TBil and Creat and higher RIs for bile acids in the donkey test population compared with those of the sampled non-Thoroughbred horses. Haematological characteristics were markedly different in comparison to the horse reference values, with no RIs established in this study indicating transference with horse RI values. By the inclusion of a large group of mature donkeys (n = 138) of no specific breed or physiological demands and of varied sizes, the current study


Conclusions


This study establishes reviewed reference intervals for haematological and biochemical parameters for donkeys. The reference intervals in this study are appropriate for use in nonworking, mature donkeys kept in temperate climates and are now used by the diagnostic laboratories of The Donkey Sanctuary, UK to aid clinical decision-making in their resident animals. These reviewed reference intervals also underpin comments appended to results of blood samples from privately owned donkeys submitted by veterinarians to the diagnostic laboratory at the Donkey Sanctuary. These reference intervals may not be relevant to other donkey populations such as working donkeys in tropical regions. Their extrapolation to animals of extremes of age or in specific physiological states should also be undertaken with caution. The lack of transferability noted between study parameters in donkeys and horses highlights the importance of using species-appropriate reference intervals for clinical assessment of veterinary cases.


Authors’ declaration of interests No conflicts of interest have been declared.


Ethical animal research


The study was ethically reviewed and approved by the directors of The Donkey Sanctuary. All animals involved in the study are owned by The Donkey Sanctuary, no client owned animals were involved.


Source of funding This study was funded by The Donkey Sanctuary.


Acknowledgements


This study was funded and supported by The Donkey Sanctuary. The authors wish to thank the veterinary team who carried out the clinical examinations and research and pathology team who helped collate the raw data for this study.


Authorship


F. Burden conceived, designed and coordinated the study and drafted the manuscript, G. Mulugeta assisted with design of the study and helped to draft the manuscript, E. Hazell- Smith participated in the study design and carried out the statistical analysis, R. Trawford and V. Patrick carried out the blood analysis, collated data and helped to draft the manuscript and H. Brooks Brownlie assisted with design and coordination of the study and helped to draft the manuscript.


Manufacturers' addresses 1Pre-Analytical Solutions, BD, Franklin Lake, New Jersey, USA.


© 2015 The Donkey Sanctuary. Equine Veterinary Education published by John Wiley & Sons Ltd. on behalf of EVJ Ltd.


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