Fletcher 1 vet issues in UK/Europe
Deer Veterinary Issues in the United Kingdom and Europe
John Fletcher
Abstract. A background to European deer farming is provided emphasising regional differences in management, species farmed, methods of slaughter and venison marketing. The small size of European deer farming is demonstrated especially in comparison to the wild venison sector.Specific issues are considered together with their relevance for the veterinary profession:deer slaughter and venison handling, the use of tranquillisers to handle deer and ensuing residue issues, legislation prohibiting the removal of growing antlers, disease in both wild and farmed deer, surveillance for transmissible spongiform encephalopathies and the prevalence of paratuberculosis. The large subsidies provided to conventional livestock producers but denied to deer farmers have limited European deer farming but substantial reforms to the Common Agricultural Policy, to be implemented in 2005, will redress this. This may stimulate entrants into deer farming attracted by the growing realisation of the health benefits of venison at a time when obesity and its related diseases are recognised as the major health risk of the 21st century.
Introduction.
Chardonnet (2002) estimates the European farmed deer population, red and fallow, including the central European nations, at 410,000 and the Scandinavian reindeer at 900,000. This contrasts with the total European wild deer population estimated by Gill (1995) at just over 1 million red deer, 5.5 million roe, 125,000 fallow, 0.5 million moose,50,000 reindeer . A consideration of veterinary issues relating to European deer cannot therefore disregard wild deer although since the opportunity for intervention is limited, the role of the veterinarian is mostly one of disease surveillance. As the problems of increasing wild deer numbers become more widely recognised (see Session 4) then this veterinary role grows. The status of wildlife health monitoring in the United Kingdom was examined by Sainsbury (2001) who described the ‘fragmented’ situation in the UK dependant ‘on a small number of limited statutory schemes of restricted scope’and a number of ad hoc schemes with limited funding, and he compared it unfavourably with the national surveillance system in France in which organised groups of hunters play a fundamental role.
The importance of wild animals as reservoirs of infectious disease has been discussed by Simpson (2002) who concluded that ‘the UK would benefit from a more positive approach to the study of wildlife and the infections they harbour’. The public health risks associated with the farming of game mammals was reviewed by Fletcher (1997).
Veterinarians have been active in the national debate on the ethics of hunting deer with hounds, and more recently research on the accuracy of rifle shooting of deer in Scotland by analysis of permanent wound tracts was carried out by a veterinarian (Urquhart 2003). Recent discussion of the welfare implications of catching wild Scottish red deer for slaughter also involved veterinarians, as has a recent discussion in England as to how best to deal with deer injured in road traffic accidents. The use of firearms may be unsafe or distressing to onlookers whilst the use of drugs raises the question of carcase disposal.
In preparing this paper representatives of the Federation of European Deer Farmers’ Associations (FEDFA) were each asked what issues they considered important and also asked to answer some questions as to how farmed deer were slaughtered in their country.
European deer farming
Responses were received from FEDFA representatives and others in Austria,Benelux, Czech Republic, Denmark, France, Norway, Poland, Switzerland. Farm sizes are very small indeed with a clear predominance of ‘hobby’ farmers. Thus Norway has 38 red deer and 13 fallow farmers farming anational total of 500 red deer and 150 fallow; Benelux has 1500 farms farming a total of 1,200 red deer and 1,200 fallow; Switzerland has 485 deer farms carrying 8389 deer; the Czech Republic has around 200 farms carrying between 5,000 and 8,000 deer; Denmark has 142 farms carrying about 20,000 deer and Poland 60 farms with 4,000 fallow, 700 red and 200 sika.Britain has 311 deer farms carrying 32,500 deer. Only the UK and Denmark send any deer to abattoirs for slaughter and, even in those two countries, abattoir slaughter is probably a minority compared to slaughter in the field. Some deer farmers in most countries kill deer in their handling system but the strong majority kill in the field with a rifle after ante-mortem inspection by a veterinarian.
All deer farmers can legally kill for 12 months of the year although there may be some variation in France between the different departements and the situation in Germany is not clear. In some countries it is legal to cut velvet antlers but none do as they fear this would jeopardise their venison market by playing into the hands of their detractors, usually hunters, nor do they have sufficient volume of velvet to make marketingworthwhile. All have a requirement for meat inspection usually involving a vet which contrasts with wild venison which in many countries has no veterinary inspection. Whilst in most countries some deer farmers remove the hard antlers from their stags to avoid injury to other deer usually using a crush, many leave the antlers on their stags. Indeed, for many, interest in the antlers is often the chief reason for keeping the deer.
With the exception of Norway where deer farmers receive similar support to sheep farmers, and Poland where 50% support up to 10,600 euros is available to new entrants, and preferential interest rates, less than 3% compared to commercial rates of around 15%, are offered to deer farmers, there is virtually no support paid.
As can be imagined so small are many units that the venison can easily be consumed by the farmer and his friends however among the serious farmers the establishment of the market is the principal concern. In the central European countries and in countries quite new to deer farming such as Norway farmed deer numbers are growing, farmers are optimistic, and there is concern to make farms profitable.
This small survey has large gaps:Chardonnet (2002) cites Germany as having 103,660, Sweden 25,800; and Italy 24,000farmed fallow with Ireland 61,000 and Spain 4,000 enclosed red deer. In Germany, Sweden and Italy the fallow deer are usually on small farms often with a trophy interest and the venison is probably not often sold. In Spain the enclosures are generally large parks maintained for trophy hunting and the sale of live deer to hunters, however in Ireland the red deer are usually abattoir killed and are managed in ways quite similar to those in New Zealand. This Irish venison is currently being sold in UK supermarkets.
From the veterinary viewpoint most European deer farmers stated that ante mortem inspection (by a veterinarian) was a requirement and that the meat was subsequently treated as red meat whereas wild venison is not subject to the same controls. Within Britain and also in some other member states there are many deer parks carrying deer in semi-wild conditions where they are rarely if ever handled and are kept usually for historical and amenity purposes. Munro (2002) gives annual culls of British park deer as 2276 red and 5588 fallow suggesting that park red deer may number about 7000 and fallow about 17,000. These seem very conservative figures.With the changes to the Common Agricultural Policy there is a steady increase in the numbers of British deer parks as conventional agriculture has become less profitable, and as large country houses become fashionable private residences and deer parks attractive assets. These parks are restricted by the hunting seasons and sell much of their venison into the game trade.Although where deer are ante mortem inspected, killed and bled on a farm or park they are permitted to enter a red meat abattoir within a specified time interval, two hours at ambient temperature or slightly longer if refrigerated. They may then be skinned and eviscerated and given a red meat stamp. Such premises are, of course, overseen by a veterinary surgeon. In practice this is a grey area and many park carcases are probably being sold illicitly as farmed. Since within Britain at least, the premium for farmed venison over wild is around 800% (£3.20/kg for farmed compared to £ 0.40/kg for wild) the incentives are clear.
.The European trophy industry.
Trophies remain a vital part of the European deer industry attracting wealthy enthusiasts from all over the world. Although roe deer are not easily kept in parks and the best trophies for this species come from wild animals, for fallow, red and sika the superior trophies are likely to be obtained within deer parks and these park deer are usually shot by trophy hunters for a fee. There is also a trade between farms and parks for trophy stags that have outlived their usefulness on the farm or are being reared specifically for sale to hunting enclosures. These antlered adults, cannot easily be captured and transported without the use of drugs and are normally darted with a tranquilliser rifle using a variety of cocktails but which usually have Immobilon (etorphine hydrochloride 2.45 mg/ml and acetyl promazine 10 mg/ml) as a key ingredient. Much of this darting is done by lay people who may obtain the drugs from vets provided the vet can state that the animals are ‘under his care’. Since the distributors of Immobilon have found that their major market is for use in equines and since these are not deemed in Britain to enter the human food chain and since the use of Immobilon in cattle is very small no MRL’s have been established which means that the drug cannot be used in animals which may enter the human food chain. This has recently created a significant food scare in Britain when a Scottish estate was found to have supplied the carcases of trophy stags which had been tranquillised with Immobilon to a game dealer. The Food Standards Agency issued a press release naming the game dealer and all those to whom he had supplied venison during a given time period. The game trade claims this cost them around £250,000 sterling (350,000 €) in lost sales.
Disease:
Wild deer are increasingly recognised as potential agents in the spread of zoonoses and livestock diseases (Simpson,2002). The rapid increase in deer numbers seen through much of Europe is creating, in many areas, an increase in deer densities. Where deer are causing damage to crops and forests then the fencing off of those areas exacerbates the increasing population density of deer and the consequence is a heightened risk of deer disease which may in turn spread to domestic animals and even man. The winter feeding of wild red deer in Scotland has been going on for 150 years but is now being frowned on as creating dense aggregations of deer and an increased risk of disease in already over-crowded populations. In some areas the practice may become illegal. Such parasites as Dictyocaulus, Fasciola, Ostertagia, and ticks are all favoured and clinical problems may emerge. Spring deaths due to Ostertagia have already been reported in wild red deer stags in Scotland (Munro pers comm). Paratuberculosis has been reported in wild red deer and sika in Belgium, in wild red deer in the Italian alps and is certainly present elsewhere in both wild and farmed deer. The incrimination of rabbits as likely factors in the spread of Johne’s disease to cattle and sheep in Scotland has increased interest in the possibility of other species of wild animals also being involved (Greig,1997). A herd of dairy cattle certified free of paratuberculosis on an island off the Dutch coast experienced a breakdown of status which it was thought could have been due to infection from roe deer. On investigation it was found that the deer are infected with paratuberculosis although not the strain infecting the cattle. Five roe deer had been introduced to the island in 1992 and the deer now number around 200. It is thought that some of the five might have been infected at a rehabilitation centre by being fed raw infected cow’s milk as fawns (van Weering in press). Although the zoonotic risk of a link to Crone’s disease remains controversial, paratuberculosis causes significant losses on deer farms throughout Europe.In the absence of any strategy to eliminate the disease, efforts are aimed at minimising losses by monitoring of deer for early clinical signs and subsequent culling and avoiding overgrazing.
Cryptosporidiosis remains a problem amongst red deer at calving time on some farms and following a number of cases in which public water supplies have been contaminated by human strains of cryptosporidia there must be concern that wildlife grazing beside reservoirs could prove a problem.
The reduced severity of European winters has fuelled concerns that diseases may appear where they have not been recognised before. One such disease is bluetongue which before 1998 had only occasionally occurred in Spain, Portugal and certain Greek islands but has now been recognised throughout Mediterranean Europe in five serotypes and has caused the loss of 300,000 sheep. The usual vector, Culicoides imicola, although spreading north, rarely exists beyond 40o north, whereas recent outbreaks of bluetongue have occurred as far north as 44o 30’, this suggests other species of culicoides may be involved and these have ranges taking them as far north as Britain (Mellor, 2003).
Global warming, if it continues, is likely also to benefit the tick, Ixodes ricinus, and the diseases carried by ticks may become more prevalent. Although Lyme disease is inseparably linked with deer in the public consciousness it is now recognised that deer are not competent reservoirs for Borrelia burgdorferi although they may be vital as the only host large enough to provide adult ticks of Ixodes ricinus with a feed. This also has implications in the epidemiology of louping ill virus which is responsible for high mortality in the red grouse (Lagopus scoticus), valued by hunters who pay large sums of money to shoot these birds. Tick populations can be reduced if sheep are removed from grouse moors and mountain hare populations are reduced or eliminated. However this strategy is unsuccessful unless the deer are also removed. Research into the use of self medicating applicators to dose wild red deerwith acaricides is being carried out by the Game Conservancy in Scotland. The virus causing the serious human disease, tick borne encephalitis, in Austria and other countries is also spread by Ixodes ricinus and the role of deer in the tick’s life cycle is likely to be relevant in this condition. Although red deer experimentally infected with the bacteria, Ehrlichia phagocytophila, developed a persistent infection, roe deer are probably the natural host. This bacteria causes tick borne fever in European sheep as well as the emerging disease of man, horse and dog, granulocytic ehrlichiosis, in the USA and Europe (Alberdi 2000; Stuen 2001). Babesia can cause the death of naïve deer transported into infected areas and it has been suggested that climate change could exacerbate this condition by extending the range and density of tick populations.
Among the zoonoses with which deer could be implicated is verocytotoxigenic Escherichia coli O157. This has caused serious food poisoning and human fatalities where pastures contaminated by livestock have been used as camp and picnic sites; although deer have not yet been blamed in any such outbreak, the pathogenic O157 strain has been isolated from red deer and muntjac (Pritchard et al., 2001).
Following concern in the USA over the apparent spread of CWD, a European decision was made to implement surveillance of deer for TSE’s. Despite this decision very few brains have actually been examined. Munro (2002) analysed the UK deer industry and made recommendations as to how brains could be surveyed for TSE’s (Munro,2002) and,during 2002 and 2003, 320 deer brains, predominantly of roe deer killed in road traffic accidents, were examined by immunohistochemistry; the more rapid ELISA (Biorad) is quicker but has not yet been validated for deer. In 2004 the target is 500 brains of which it would be preferred if these could be from deer found dead or sick; to date 300 have been tested of which 1110 were wild shot mostly roe and the balance of red and fallow from parks(pers comm Mathews). In Denmark TSE surveillance was run briefly but by January 1st 2004 it had been abandoned, in Switzerland a programme to screen a minimum of 200 brains per annum for at least two years was instituted in January 2003 but so far less than 100 brains have been tested.
A project to assess the susceptibility of red deer to BSE has been undertaken in Scotland. !8 red deer calves genotyped and confirmed homozygous for methionine at codon 132 were fed with brain from BSE affected cattle of which 6 calves will be killed 6 months after feeding and a further 6 calves will be killed at 12 months; the remaining 6 will be killed 5 years post infection. If no infection is established by feeding infected material, deer will be inoculated intra-cerebrally. The objective of this trial is to establish the clinical and pathological signs of BSE in deer. A knowledge of the pathological picture will be helpful in surveillance of deer brains for evidence of TSE.