134


EQUINE VETERINARY EDUCATION / AE / MARCH 2016


Original Article


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


F. A. Burden†*, E. Hazell-Smith†, G. Mulugeta†, V. Patrick†, R. Trawford† and H. W. Brooks Brownlie‡


†The Donkey Sanctuary, Sidmouth, Devon, UK; and ‡School of Veterinary Sciences, University of Bristol, Langford, UK. *Corresponding author email: faith.burden@thedonkeysanctuary.org.uk Keywords: horse; donkey; biochemistry; haematology


Summary 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.


Background


The domestic donkey (Equus asinus) is kept predominantly as a companion in the UK, Europe and North America, but is frequently used as a working animal in developing countries worldwide. Domestic donkeys are a unique equine species descended from wild asses evolved to live in inhospitable, mountainous and arid desert environments (Epstein 1984). Their popularity as companions belies the relative dearth of


physiological or scientific data on the species compared with other commonly encountered domestic species and veterinarians encountering donkeys may find it difficult to obtain relevant reference intervals for biochemical and haematological blood parameters. Reference intervals for haematology and blood biochemistry parameters were previously established for domestic donkeys in the UK by French and Patrick (1995) using results from the resident population of a large specialised sanctuary (The Donkey Sanctuary). Other studies have focused on particular donkey breeds or presented data for specific cohorts, often involving relatively small study populations and mixed aged groups, or which are pertinent to certain environmental conditions (Folch et al. 1997; Jordana et al. 1998; Mori et al. 2003, 2004; Caldin et al. 2005). Periodic review of reference intervals (RIs) is recommended


in order to account for changes in laboratory methods and technologies (Anonymous 2011a). In addition, a marked increase in understanding specific nutritional requirements of donkeys in recent years has led to changes in management practices (Cox et al. 2009; Burden et al. 2013), which could alter physiological parameters. This study is thus a timely revision of commonly used biochemical and haematological parameters for clinically healthy, mature donkeys.


Materials and methods


Study animals This study assessed the haematological and biochemical blood profiles of 138 mature donkeys between the ages of 4 and 24 years. The donkeys were all owned and cared for by The Donkey Sanctuary and lived on farms in the South West of England. All donkeys were considered clinically healthy at the time of blood sampling, which was undertaken as part of assessment of suitability for rehoming of the animals to private homes. They were sampled in Autumn (n = 41), Spring (n = 32), Summer (n = 35) and Winter (n = 30) between February 2008 and June 2011. The study group consisted of 29 female and 111 gelding donkeys. The donkeys were fed ad libitum straw with restricted quantities of haylage and grazing according to body condition and prevailing weather conditions; donkeys also had access to an equine specific mineral block. None of the donkeys were working (draught or riding).


Sampling and clinical assessment Blood samples were drawn from the jugular vein into 10 ml plain and EDTA-containing evacuated blood collection tubes (BD Vacutainer)1. Complete blood counts and biochemical


© 2015 The Donkey Sanctuary. Equine Veterinary Education published by John Wiley & Sons Ltd. on behalf of EVJ Ltd. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88