This chapter focuses on clinical disorders affecting donkeys. For a more in-depth view of the subject, the reader should refer to the on-line paper by Thiemann and Bell entitled "The Peculiarities of Donkey Respiratory Disease" (2002).
In spite of the importance of mules and donkeys to the economies of many developing countries, knoweldge of their reproductive pattern remains fragmentary. The attitude that all equines are similar, which prevailed for a long time, is false. In addition, some of the well known breeds of donkeys such as the Poitou, Catalonian and Zamorano-Leones breeds are in danger of extinction (Tibary and Bakkoury, 1994; Dare et al, 1998; Folch et al, 1998; Jordana et al, 1999; Serres et al, 2002; Tibary et al, 2006).
The objective of this chapter is to review current knowledge in donkey reproduction as well as their use for mule production. The chapter describes:
In popular and scientific literature the female donkey is often referred to as 'the donkey mare', 'jenny' or 'jennet'. The male donkey is referred to as the 'donkey stallion', 'jack' or 'jackass'. There is some confusion on the use of the term jenny and jennet, as some may use them for the female mule (a cross between a horse stallion and a donkey mare). For the sake of consistency, the terms 'jack' and 'jenny' will be used throughout this chapter to refer to the male donkey and the female donkey respectively, while the term 'mare' and 'stallion' will be reserved for the horse genders.
The domestic donkey is a descendent of the African wild ass and was first domesticated in approximately 3000 BC (Rossel et al., 2008). Current estimates of the worldwide donkey population are approximately 44 million (Starkey and Starkey, 2004) with the majority of donkeys providing transport and draught power in developing countries. Donkeys are tractable animals that come in a variety of sizes, with breeds ranging from miniatures of less than 91cm to mammoth jacks and andalucian donkeys reaching over 1.6 meters (Svendsen, 2009). The donkey evolved in desert areas and has adapted to eating poor quality fibrous plant material (Izraely et al. 1989). The donkey and its hybrid offspring the mule and hinny are renowned for their stoic natures and ability to survive in tough environments on poor quality food making them the work animals of choice in inhospitable areas of the world (Svendsen, 2009, Starkey and Starkey 2004).
Donkeys and mules are also used for leisure and competition in developed countries and are popular as children’s ride and drive animals or as mounts for trail riding. Keeping donkeys and mules in temperate environments as leisure animals can, however, put them at risk of diseases associated with obesity or inappropriate management. They therefore require careful feeding to help to prevent conditions such as laminitis, hyperlipaemia and gastric ulceration.
Donkeys, for many reasons, should not be considered as if they were small horses, studies have shown physiological (Hill et al. 2001, Liberatore et al. 2001) as well as pharmacological and pharmacokinetic differences between donkeys and horses (Lizarraga et al. 2004). Unfortunately, however, little specific detailed information about the nutritional needs of donkeys and mules is available and although some fundamental research has been carried out it is still far behind the field of horse nutrition. Much of the information in this chapter draws on scientific research but also the extensive experience of the authors in managing herds of both working and non-working donkeys as well as mules.
Few veterinary products have market authorisation for use in the donkey. Although preparations designed for horses and ponies are often used for donkeys, there are recorded differences between these species in the pharmacokinetics of certain drugs. An understanding of these differences can enable the practitioner to make appropriate therapeutic decisions to achieve maximum efficacy of medication and reduce the risk of toxicity.
Medicines are included in this chapter only where it has been recorded that there is a notable difference between donkeys and the horse and pony.
Clinicians are advised that they must consult current equine formularies and datasheets. Owners should be informed accordingly and it is imperative that the appropriate national legislation is adhered to.
While we have made every effort to ensure that the content of this chapter is currently accurate, we accept no liability for any loss, damage or expenses arising as a result of relying solely on the information contained within the formulary in this book.
It can be difficult to estimate the weight of a donkey and therefore determine effective dosing regimes. A donkey specific nomogram or a donkey specific weigh tape should be used to estimate weight.
This chapter will aim to guide the clinician through the techniques necessary to maximise the accuracy of diagnosis for the common conditions encountered in the donkey. First, facilities, equipment and sample-taking are outlined, and then the procedure for performing a donkey post-mortem is described.
Perhaps one of the biggest challenges when managing parasites in donkeys is that of clinical assessment. Donkeys with significant endoparasite burdens may appear healthy and it is rare to observe the type of clinical signs (diarrhoea, weight loss, colic or poor condition) that are more common in horses and ponies.
Although donkeys can be infected by the same parasites as horses and ponies there are some notable differences in parasite dynamics and treatment regimes, the most important being the lack of anthelmintic products licensed for use in donkeys.
Donkeys have evolved to thrive on highly fibrous, poor quality foodstuffs and have evolved as browsers as well as grazers. As a result they have different nutrient requirements, with significantly lower energy and protein needs than horses and ponies. Dietary management of the donkey is essential to avoid health issues and should be seen as the foundation of a healthy animal.
Donkeys requiring hospitalisation can be managed in a similar way to small ponies, although differences in temperament, behaviour and conformation must be taken into consideration.
Donkeys form strong bonds with companions and should be help together. Stress should be kept to a minimum, as hyperlipaemia is a common complication of any management change or illness. Nurses and grooms should be sensitive to subtle behavioural changes, which are often early indicatorsof illness. Donkeys are stoical by nature and often do not exhibit dramatic symptoms. Any donkey described as dull, head held low, generally disinterested and with reduced appetite, should be investigated.
In this chapter, nursing care aspects will be described.
Specific, validated information on the epidemiology and manifestation of infectious diseases in donkeys and mules is frequently limited or lacking. Donkey specific differences are discussed where they are supported by evidence or experience both in the notifiable infectious diseases, as included in the OIE's (World Organisation for Animal Health) 2018 list of diseases, and in other infectious diseases. Where a disease is not included, reference should be made to general equine texts and information.
Prevention is an important consideration for infectious diseases in any species and revolves around sound biosecurity principles, early detection and vaccination where available.