Reindeer, wild and semi-domesticated (caribou in North America), reside in northern latitudes across the world and have been the focus of substantial research, including aspects of health and disease as well as their management by a variety of ethnic groups (Tryland and Kutz 2019; Horstkotte et al. 2022; Tryland et al. 2022; Tryland 2022).

In the United Kingdom, in 1952, Mikel Utsi and Ethel Lindgren established a reindeer herd in the Cairngorm Mountains with a habitat similar to the arctic conditions reindeer experience in FennoScandia (Smith 2018). Reindeer have been kept in zoological collections in the United Kingdom for some time. In recent years, reindeer have been imported from northern Europe and kept by smallholders and used in various commercial settings, often associated with the Christmas season. The number of reindeer in the UK is likely to be small. The identification of a form of Chronic Wasting Disease in wild reindeer in Norway in 2016 led to an import ban of reindeer into the United Kingdom. Historically, there have been concerns about the health and welfare of reindeer kept in the United Kingdom, in part given that they may be owned by inexperienced owners (FAWC 2013). Disease surveillance has shown that reindeer are susceptible to a variety of diseases that affect other deer species and livestock (Foster and Wight 2022). Prospective new reindeer owners and their attending veterinary surgeons should carefully consider the high levels of stockmanship required in order for them to thrive.

A distinctive feature of reindeer is that males and females grow antlers; furthermore, they have a particular condition associated with hyperplastic changes to antler velvet, which is discussed in Chapter 10. Skin diseases are discussed in Chapter 26. Reindeer are susceptible to malignant catarrhal fever and should not be kept with sheep or goats (see Chapter 17; Figures 31.1 and 31.2a,b).

Reindeer in the United Kingdom are rarely considered separately to other cervid species from a legal perspective. The only specific reference to reindeer is in the Dangerous Wild Animals Act (1976) which includes reindeer as a dangerous wild animal; however, specifically excludes domestic reindeer. Outside of zoological collections, all reindeer in the United Kingdom are considered domestic.

Primary legislation that is likely to affect reindeer in the United Kingdom is also likely to affect other domestic livestock, though in the majority of situations they may be considered pets or exhibition animals. As domestic livestock, they are required to be identified by ear tag or tattoo and to be kept on land with a designated county parish holding (CPH) number or temporary land association with a CPH. Both individual identification and registration for a CPH are not always undertaken by reindeer owners in the United Kingdom, primarily out of ignorance of the law. Reindeer movements are covered by the general movement licence and are tracked by the Livestock Information Service through the mandatory submission of a LIS-2 form by the transporter. To comply with the general licence, reindeer must be identified by ear tag.

All statutory requirements for the testing of other deer for Mycobacterium bovis apply to reindeer. This means that private testing for M. bovis may be conducted; however, permissions must be sought from the Animal and Plant Health Agency (APHA) prior to testing and the results of that testing must be reported. The APHA is also able to impose statutory testing on reindeer herds.

Under the Veterinary Surgeons Act (1966), the removal of antler in velvet is an act of veterinary surgery other than for relief of suffering or saving life. As the majority of male reindeer in the United Kingdom are castrated, their antler cycle is disrupted by the lack of testosterone. Castrated male reindeer, therefore, are inconsistent in their cleaning of velvet, necessitating manual removal, as otherwise abnormal and erratic antler growth occurs. If the antler is not clean by the time casting usually occurs, then manual removal must therefore be performed by a veterinary surgeon under local anaesthetic. The Welfare of Livestock (Prohibited Operations) Regulations (1982) also prohibits the ‘removal of any part of the antlers of a deer before the velvet of antlers is frayed and the greater part of it has been shed’. For further information about the removal of antlers in velvet, please refer to Chapter 4.

Nutritionally related illnesses include malaise, weight loss, diarrhoea, sudden death, gastrointestinal problems and rumen acidosis.

For wild and semi-domesticated reindeer, their nutritional requirements can vary substantially with the seasons. They are selective feeders – rather than grazers (that digest large amounts of fibrous grass), such as sheep or cattle, or concentrate selectors (that select dietary items with high digestibility) such as roe deer. They are similar, to some extent, to fallow and red deer. They are intermediate feeders, meaning they feed on a variety of different items. While they are known to graze, they are also renowned for eating lichen material in the winter months and browsing on several different species of leaves and shrubs during the summer months. Lichens are rich in carbohydrates while low in protein, nitrogen and macrominerals; consequently, they need other food sources during the winter period to survive. They can lose 10–20% of their body weight during this period (Åhman and White 2019).

During spring and summer, reindeer tend to eat food that is considerably higher in nutritional value. During this time, they gather fat reserves for winter and grow their antlers; this is clearly demonstrated with a distinctive increase in body condition (Hyvärinen et al. 1975). Antler growth can be an incredibly demanding process on the body. Cervids possess the ability to utilise the calcium from within their bones to produce antlers, which is then later replenished by the calcium obtained from their diet. Calcium and magnesium are crucial to antler growth; both iodine and zinc have also been linked to antler growth in certain species (Banks et al. 1968).

Changes in diet for captive reindeer should be made with care because the gut has to adapt to new dietary items. Gut microbiota is a complex and dynamically balanced ecological network; it maintains both the gut and overall health of the host. Numerous studies have demonstrated that gut microbial structure abnormalities can be associated with mental disorders, intestinal, metabolic and other diseases (Jiang et al. 2022). Sudden exposure to rich, lush pasture should be avoided. A stress response may follow a sudden change of diet, such as access to concentrated feeds, and may lead to gut changes, including inflammation, acidosis and even death. Any changes to reindeer diets should be a phased introduction so that the rumen microbiota have time to react and transition to the new diet. Immediate diet changes are harmful to any ruminant; everything must be done in moderation and should be transitioned over slowly, even if it is considered to be a dietary improvement.

Stress responses may also be observed with transport and mixing of groups; this may be manifested as weight loss and/or diarrhoea. Sufficient fibre should be provided in the diet to avoid scouring. Poor body weight is a routinely reported problem in reindeer, often further exacerbated by endoparasite burdens (McSloy 2014). In the United Kingdom, reindeer often lose body condition over winter as they tend to have restricted or no access to sufficient grazing. If the grazing throughout winter is going to be considerably different from the warmer months, ad-libitum supplementary forage should be provided, as this can affect rumen function (Nilsson et al. 2006). It is common that when reindeer lose body condition, handlers may panic and continuously increase their concentrated feed as a first course of action. Feeding a diet that is high in concentrates can be detrimental and result in rumen acidosis, which is a dangerous cycle if a reindeer is already scouring. Rumen acidosis can be reversed if it is in the primary stages, but once they enter chronic acidosis, they will get abomasal ulcers, resulting in death. The focus should be on providing good quality forage, not the concentrated feed, as this only forms a small part of their diet (ideally <25%).

It is clear that there is a lack of understanding regarding the requirements for the supplementary feeding of reindeer. In the United Kingdom, collections tend to supplementary feed all year round. There is an array of supplementary forages that are fed to reindeer, such as Alfa-A Original (based on alfalfa), reindeer lichen, silage, hay, chopped grass, barley straw and dried browse. A variety of supplementary forages should be provided to reflect their natural diet. There are numerous commercial reindeer concentrates to supplement their needs, although an ordinary grazer pellet (for cattle and sheep, preferably calf pellets) will suffice. Salt licks should also be provided on an ad-libitum basis.