CONTENT
1. HEALTH RISKS.
2. WELFARE AS PROJECT
FOR MANAGEMENT AND RESEARCH.
3. WAT
BETEKENT NATUURLIJKE BEGRAZING VOOR HET DIER? Bijlage: Onderzoekvoorstel
RANDVOORWAARDEN NATUURLIJKE BEGRAZING. (
4. ANIMAL WELFARE
AND ANIMAL HEALTH CARE.
5. VETERINARY AND
ANIMAL WELFARE ASPECTS OF LARGE MAMMALS IN NEAR NATURAL AREAS.
1. ASSESSMENT OF HEALTH RISKS OF LARGE SEMI-WILD HERBIVORES IN URBANIZED
AREAS.
(The original paper is published in the Vet.Quarterly
2000; 22:112-6).
G.J. VAN ESSEN AND J.M. VAN LEEUWEN Institute for Animal Science and Health (ID-Lelystad),
Department of Immunology, Pathobiology and
Epidemiology, PO Box 65, 8200 AB Lelystad.
ABSTRACT
The
health risks for both domestic animals and humans caused by large herbivores in
self-sustaining ecosystems are largely unknown. The aim of this article is to
make an inventory of these risks, to explore ways to manage them in practice,
and to make recommendations for the quantification of risks. Potential hazards
from herbivores in and around
Analysing
and managing risks enable decision-makers to formulate the conditions for the
development of nature reserves. In
INTRODUCTION
The
map of
Semi-wild large herbivores in the
|
The
A.To make
more room for 'naturalness'. Management is limited and directed towards
improving ecological processes. B.To
enhance 'semi-natural' nature. Management is similar to that of traditional agricultural methods and can be done by
nature managers and farmers. C. To enlarge interconnecting nature areas.
Farmers manage these areas. Semi-wild herbivores play a key role in the
ecosystem described in type A nature reserves. They prevent the dominant
growth of trees, thus providing habitat for other vegetation and animal
species such as wetland and aquatic birds (e.g. waders, herons, swans, greyleg geese, and ducks). There are three type A nature reserves in the
The 'Oostvaardersplassen'
in the
|
The
most intensive discussions about the health risks posed by dedomesticated
or semi-wild animals to domesticated animals concern these type A nature
reserves because
*of the fear that herbivores in these reserves will
be a source of infection to domesticated animals and that nature management
will distinguish between natural and husbandry diseases;
*there is a discrepancy in the handling of
carrion between nature reserves and farms. Carrion is ecologically important
for scavengers and insects, but farmers are legally obliged to destroy the
carcasses of dead animals by controlled rendering procedures;
*the (semi-) wild herbivores in type A nature
reserves are not identified whereas the identification and registration of
animals is compulsory on farms;
*there are also large differences in the need
for care between domesticated and dedomesticated
animals and this problem is compounded by the difficulty of catching wild
animals should they need treatment.
Because
these issues have a lot to do with official regulations for Animal Health and
Welfare, Zoonoses, Nature Protection, Transport,
Trade, etc., government needs advice on health risks in relation to semi-wild
large herbivores living in an agricultural and urbanized environment. The aim
of this article is to make an inventory of the health risks of large herbivores
to and from husbandry animals, to explore practical ways of managing these
risks and to make recommendations for the quantification of these risks. In another
article we will analyse the problems concerning the health and welfare of
ungulates.
INVENTORY OF HEALTH RISKS OF LARGE HERBIVORES
A
selection of some infectious diseases and susceptible species is given in Table
3. The data are registered in HandiSTATUS (9), a
computer application developed in collaboration with the Inter-American
Institute for Co-operation in Agriculture (IICA), Office International des
Epizooties (OIE), Food and Agricultural Organization (FAO), and World Health
Organization (WHO). The aim of establishing such a database is to facilitate
the exchange of animal health information between international organizations
and their member countries. All the data in the central OIE database on the
frequency of animal diseases and the control measures applied in member
countries are integrated into HandiSTATUS together
with the complete International Animal Health Code. Some of the Dutch data have
been supplemented by information from the Animal Health Service (1) and the
Institute for Animal Science and Health (4).
The OIE disease classification is as follows
(9):
List A diseases: Communicable diseases which
have the potential for very serious and rapid spread, irrespective of national
borders, which are of serious socio-economic or public health consequence, and
which are of major importance in the international trade of animals and animal
products. Reports are submitted to the OIE as often as necessary to comply with
the articles of the OIE International Zoo-Sanitary Code.
List B diseases: Communicable diseases which
are considered to be of socio-economic or public health importance within
countries and which are significant in the international trade of animals and
animal products. Reports are normally submitted once a year, although more
frequent reporting may in some cases be necessary to comply with the articles
of the OIE International Zoo-Sanitary Code.
List C diseases: Communicable diseases with
important socio-economic and/or sanitary influence at the local level.
The diseases and species mentioned in table 3
are examples selected for their relevance to this article. They were selected
on the basis of the following criteria:
(a) occurrence in and/or around
(b) occurrence in the
(c) existence of control or surveillance
measures in the
Most of the mentioned infectious diseases are
transmitted through contact with living animals and other commodities such as
animal products, animal genetic material, foodstuffs, biological products and
pathological material, but sometimes also by vectors such as insects (African
swine fever) or expired breath and air (foot and mouth disease virus).
The animals of the European Union are very
susceptible for infection with list A diseases because of the non-vaccination
policy of the EU. The intensive international trade in animals and animal
products and intensive tourism make it easy to import communicable diseases.
Therefore diseases that are prevalent in countries surrounding the EU, such as
RISK ASSESSMENT AND RISK MANAGEMENT
Risk assessment.
Several
contagious A and B diseases are present in and around
The
OIE has made guidelines for risk assessment to minimize import risks (9). Risk
assessment is also relevant when preparing guidelines to minimize the
transmission risks within a country. This is important when agricultural
organizations claim that obligatory vaccination and a stamping out policy (IBR,
BVD) are economically beneficial and when nature managers claim that these
diseases are natural diseases for cattle. Risk assessment requires the
collection of data for each disease to calculate the transmission ratio within
the feral population itself and from wild to domestic animals. A system for data
sampling and methods for analysing and modelling data have to be developed
before the risks can be quantified.
Data
on the transmission of bovine herpes virus-1 are available in general (5) but
have to be gathered in connection with the current IBR control campaign in the
Natural decomposition of carrion.
A
special issue is the need to allow natural processes, such as the decomposition
of cadavers in type A nature reserves. Dead animals form an indispensable
habitat for numerous necrophilic organisms (13), with
flies (Calliphoridae, Fannidae,
Sarcophagidae), beetles (e.g. Silphidae),
and mice (Muridae), being important for the
decomposition of the cadavers of large animals, such as boar, deer, cattle, and
horses.
Larger
scavengers in the
But
what are the risks of natural decomposition of carrion for animal and
human health? If contagious agents and diseases are involved such as Mycobacterium
bovis, Brucella
abortus, Rabies, BSE, foot- and mouth disease,
anthrax, and botulism, the risks can not be underestimated. If a large grazer
has died as a result of anthrax and the carcass is spread over a large area by
boars or other animals, there is a risk that the soil will become seriously
contaminated and that a large area will be lost for grazing. A special problem
may occur in the wetlands with C. botulinum.
The 'Oostvaardersplassen' have a documented history
of botulism in waterfowls. Large grazers are possibly healthy carriers of the Clostridium
bacteria and when the cadavers of these animals lie around for a while they may
constitute a big risk for the health status of other ruminants. Birds (e.g.
crows) may spread botulism by eating contaminated parts of the carcasses in the
same way as contaminated poultry litter spread disease among cattle (11,14).
Botulism types C and D in ruminants are common in dry areas with a low
phosphorus content in the soil such as in
Standard Monitoring.
A
standard method of health surveillance is necessary to record and manage the health
risks between domesticated and non-domesticated animal populations (10).
Because this is already normal practice in agriculture and mostly in the type
B- and C-nature reserves, it has formally to be introduced in the type A nature
reserves. This means regular clinical investigation should be carried out by a
veterinary clinician in cooperation with the nature manager. Periodical blood
sampling and autopsy of a number of animals that just died in the wild or were
slaughtered should be done by regional animal health services. If it is
impossible to catch the animals for sampling, a certain number of them have to
be shot or anaesthetized. Protocols for monitoring already exist or are being
developed. To some extent culling can be useful to prevent overcrowding. An
epidemiological sampling plan has to be made for monitoring the most important
infectious diseases in a certain country or area (6). The results for semi-
wild cattle in the type A areas in the
The
use made of test results depends on the desired health situation in the country
and on the actual or planned control and surveillance campaigns for certain
diseases in that country. To minimize the risks for transmission one has to
prevent the introduction of new animals of unknown disease status. Quarantine
procedures are needed and new animals should be assessed clinically. It is also
important to keep the (semi-) wild animals in a normal physical condition in
order to maintain resistance against diseases.
Future plans.
At
the moment the animal health regulations of the EU are highly oriented towards
husbandry animals. These regulations should be modified to include large
herbivores in type A nature reserves. It is also important to estimate the
health risks of herbivores in the larger nature reserves of the European Union
and the effect of animal transport between these areas.
Zoonotic
diseases are of special importance because more than 80 % of the infectious
agents causing diseases in humans also affect animals (12). More knowledge
about the magnitude of the risks of these diseases is necessary in order to be
able to handle these risks.
The
Veterinary Committee of Large Herbivores in Nature is a good forum to discuss
the health- and welfare-related activities of the Dutch government (8).
Participants are representatives of the Ministry of Agriculture, Nature
Management and Fisheries, Nature Management Institutions, Research, Animal
Health Services, Agricultural Organization, Animal Protection Organization,
etc. This commission has the task of evaluating the current situation and of
creating the conditions needed to give Nature more room. There is cooperation
with international groups such as the Large Herbivore or Carnivore Initiative.
CONCLUSIONS
*There are many risks for infection of large
herbivores in nature and agriculture as far as the OIE list of infectious
diseases is concerned. Many diseases are zoonotic.
*The importance of risks depends on the
position of a certain agent in the disease classification (A, B, C) and of the
disease status of the country where the large herbivores are living.
*A system of risk assessment is necessary to
learn more about the magnitude of the risks. This can be done at several
levels. The basal level for local practice is a yearly standard programme for
monitoring the animals in nature reserves and surroundings. A more advanced
level for (inter-) national purposes is an epidemiological study of the
transmission of agents in animal populations with and without interference of
management measures.
*Specific decisions based on the knowledge of
risk assessment can be made about the identification (or-not) of animals, the
biodegradation of cadavers in the field, the transport of animals, recreation,
the consumption of meat and whether animals in these areas should be vaccinated
or not.
*New EU veterinary policy should distinguish
between production and non-production animals in both small and larger natural
systems.
REFERENCES
1.Animal Health Service (Dutch) 1999; URL:
http://www.gd-dieren.nl/pages/frames/ frame1.htm
2.Bongers JH, and Tetenburg
GJ. Botulism in waterfowl. Proceedings Causes and risks of wild life diseases
in the Netherlands.Vet Quart 1996; 18: S156-7.
3.Statistics Netherlands, Voorburg/Heerlen. 1999; URL: http://www.cbs.nl/nl/ cijfers/kerncijfers/index.htm
4.Essen GJ van, and Leeuwen JM
van. Health aspects of large herbivores in natural areas. ID-DLO Report (Dutch).
1997: 1-110.
5.Hage JJ. Epidemiology of Bovine Herpes virus
1 infections. Thesis,
6.Hessels H. Standardized approach of possible infectious animal diseases with Heck cattle in the Oostvaardersplassen. Faculteit Diergeneeskunde Utrecht. Report (Dutch) 1997.
7.Kampf H. Grazing in Nature Reserves. Ministry
of Agriculture, Nature and Fisheries. 1998; Report (English) and URL:
http://www.minlnv.nl/grazers/
8. Kampf H. et.al.
Health and Welfare of Large Herbivores in Nature Areas. Report Veterinary
Committee of Large Herbivores in Nature (Dutch). 1996:1-110.
9.OIE, FAO, IICA, WHO. HandiSTATUS.
Help with world animal disease status. Version 1.39. 1997; URL:
http://www.oie.nl/software/A_handi.htm
10.Oosterbaan J, and Lumeij JT. Health and
welfare issues related to using (domestic) ungulates for the management of
nature parks in the
11.Ortolani EL, Brito
LA, Mori CS, Schalch U, Pacheco J, and Baldacci L.
Botulism outbreak associated with poultry litter consumption in three Brazilian
cattle herds. Vet. Hum. Toxicol. 1997; 39 (2): 89-92.
12.Osborn BI. Emerging diseases with a
worldwide impact and the consequences for veterinary curricula. Proceedings
Causes and risks of wild life diseases in the Netherlands.Vet.Quart.
1996; 18: S124-6.
13.Piek H. Observations on two carcasses of
Scottish Highland Cattle. Workshop of the Symposion
on Grazing of
14.Roumen M.P. Mortality of cattle by
contaminated poultry litter. Tijdschr Diergeneeskd 1998; 11: 618-9.
=====
2. MANAGING THE HEALTH AND
WELFARE OF UNGULATES IN LARGE, NEAR-NATURAL AREAS IN
*This document is written in 1999. The authors are grateful for setting
up important discussions with members of the national and local veterinary
committees about various aspects of managing health and welfare of ungulates.
The comments of dr.Patrick and dr. Alison Duncan (
*In december 1999 the Editorial Board of the
Veterinary Quarterly however wrote us: 'As you say the presence of large
predators and carrion eaters as an important condition for self control is
missing in the Oostvaardersplassen. However,
starvation, disease etc. to control populations of large animals such as
ungulates in these kind of areas is opposed by several groups of the community
as being unethical and a violation of the intrinsic value of the animals
concerned and of veterinary legislation. Moreover, in your manuscript there is
not enough scientific data nor results to justify the description of the
starvation of 71 and 91 animals during the winter period of three months. The
Editorial Board of the V.Q. has given your manuscript serious consideration but
has concluded that it is not suitable for publication in the V.Q'.
*Therefore the authors bring the paper on this webpage about large
herbivores to give readers the opportunity to discuss. The case about starvation
of animals is not written as a full fledged case report, but as introduction or
step to the next chapters about project management and research.
J.M. VAN LEEUWEN(1, 2) AND G.J. VAN ESSEN(1)
1.Institute for Animal Science and
Health (ID-Lelystad), Department of Immunology, Pathobiology and Epidemiology, PO Box 65, 8200 AB Lelystad. 2.Address from 1 Feb.1998: Kempenaar
04-21, 8242 BE Lelystad.
ABSTRACT
The objective of developing in urbanised
countries, areas with natural ecological processes, in particular herbivory by large generalist ungulates, and high
biodiversity is constrained by human values. As a consequence management policy
and the strategy for health care of ungulates in these areas can be summarised
as 'doing nothing, unless..' The aim of this study is to discuss the issues of
managing the health and welfare of Heck cattle in the Oostvaardersplassen
during the winter of 1998-99 and to propose new approaches to project
management and research for the future. The project should aim to set up new
standards as basis for care. Possible management interventions and measures are
discussed. New National and European rules are needed to allow natural
processes involving disorders and infectious diseases, which may lead to either
recovery or death, without damaging the interests of urban people and livestock
producers.
INTRODUCTION
Wild and semi-wild ungulates play an important
role in the development of natural ecological processes. They contribute,
first, their presence in the ecosystems as living organisms with their
particular characteristics. The second contribution is their influence on the
structure and functioning of ecosystems. Ungulates are instrumental in
maintaining biodiversity by reducing colonisation by dominant trees and
maintaining open areas for pioneer herbaceous and woody plants. Oak, hazel,
cattle and horses are therefore symbols for wilderness (20).
The various ruminants have different
feeding strategies (18,20) :
*Grass and roughage feeders (cattle,
sheep) feed on grass and other fibre-rich material, like twigs and bark;
*Concentrate selectors (roe deer,
moose) prefer young, protein-rich leafs, buds, shrubs, herbs, and fruits;
*Intermediate feeders (
Non-ruminants such as horses and the omnivorous
wild boar are mainly grazers. The feeding strategies of ungulates in an
ecosystem have a strong influence on the vegetation, but the habitats (forest,
heath, mudflat, wet grassland) also influence the feeding behaviour of the
animals, both wild and domesticated ones.
Conservation management with the objective of
maximising biodiversity and natural processes can adopt an almost passive
management strategy, which has been called 'doing nothing, unless..' (11).
Several constraints (
|
*Isolation and fragmentation
of habitats by e.g. fencing may constrain mate choice, leading to
inbreeding, and limit movements between habitats. *The selection of species
such as the semi-wild Konik horses, Heck cattle or
wild *Agriculture and
Infrastructures (e.g. dykes, canals) influence hydrology, soils and the
availability of minerals. *Urbanized environments,
with high densities of people and traffic, industrial pollution and the
associated regulations and laws of society, such as for animal health and
welfare. *Subjective choices
of the objectives for biodiversity or the naturalness of the reserves. |
The aim of this paper is to discuss the issues
relating to the management of the health and welfare of Heck cattle in the Oostvaardersplassen during the winter of 1998-99, and to
propose methods of project management and research as a follow up for the
future. This study does not to deal with the disease hazards of
'keeping' (semi) wild animals in
ISSUES IN MANAGING THE HEALTH AND
WELFARE OF UNGULATES: THE CASE OF THE OOSTVAARDERSPLASSEN
The Oostvaardersplassen
ecosystem.
The ungulates in the Oostvaardersplassen
play a role in providing suitable habitat for large numbers of internationally
important bird species, e.g. greylag geese, waders, spoonbills, herons. This
area, consisting of about 3,600 ha of marshland and 2,000 ha of drier grassland
and scrub, is classified as category A, the highest value for natural habitats
(17) in the
Starvation and death in a Heck bull
group in winter (21).
In the autumn of 1998, waterlevels
in the Oostvaardersplassen marshes were high and thebody condition of the Heck cattle before the winter was lower
than normal. During the wet winter of 1998-99 there was a serious lack of food
in some areas, probably worsened by digging work by the managers in the
territory of a bull group. Some of the older somewhat solitary living bulls
suffered a shortage of food, but initially they did not move to better areas:
these had been occupied by a large herd of several hundred cows with their
calves, and stronger bulls. At the end of January the bull group moved to a
higher, drier place with more food, but of inferior quality. At the same time
snow covered the frozen pastures and several bulls began to suffer digestive
problems; when the first animals succumbed autopsies were done by the Animal
Health Service. Over a period of 3 months 71 animals died (mainly bulls, 14,4 %
of the total Heck population). During this same period a total of 91 ungulates
died, (7,4 % of the 1233 Heck cattle, Koniks and red
deer).
The following considerations led to the
decision 'to do nothing, unless..' for the suffering bulls:
*providing extra food for animals
has several disadvantages (see Supplementary feeding);
*animals can be caught for
slaughter, or shot. However artifical regulation has
disadvantages which are outlined in
Regulation of the number of animals;
*survival of the fittest is an
important goal for a self-maintaining and strong population.
Low ranking bulls were driven away
from the best areas through social competition. It
is possible that the animals need to
see others dying before learning to disperse towards
other feeding areas;
*monitoring of population size shows
that the carrying capacity of the area was not
reached until 1997 (3); the average
body condition of the population in 1998-99 was
adequate, in March 1999 it varied
between 5-7 on a scale of 10 (personal observation);
*the dying animals were quiet,
perhaps hypothermia and digestive problems caused the
animals to be lethargic and
disoriented (1). The hypothermic crisis may have speeded
death, but to prevent unnecessary
and helpless suffering 13 animals were shot. (N.B. of
JvL: According to the Ethical Guidelines of the
Nature Manager Staatsbosbeheer, made
later on in 1999, this number is too
low!);
*with the arrival of spring (April
1999) the availability of food increased rapidly and the
chances of survival improved daily.
It is clearly essential to document this and
future die-offs. These may appear exceptional incidents, but patterns may thus
be detected which allow more appropriate responses by management.
PROJECT MANAGEMENT AND RESEARCH FOR
THE FUTURE
The issues.
The issues involved in caring for ungulates in Oostvaardersplassen are similar to those involved in other
cases of management of wildlife. They are complex because they cover three
levels of organisation of biological systems, individuals, populations and
ecosystems (12).
*In the case of accidents and
incidents involving individuals the main issue is whether or not to provide
aid. As this inevitably involves anaesthetising and catching the animal this
aid may be more stressful than 'doing nothing'. Therefore, in near-natural
reserves 'giving first aid' often resolves to putting an end to serious,
unnecessarily long interventions and suffering by killing the victims when
there appears to be no hope of recovery. In a real wilderness this is done by
large predators.
*In cases where a population suffers
reproductive and social problems (these are common in horses) veterinary
interventions, other than shooting, may help individuals, but can reduce the
well being of the population (e.g. by saving mares with a genetically based
propensity to dystocia, this trait could spread in
the population).
*At the ecosystem level the
resulting high densities of ungulates can cause serious erosion and overgrazing
(e.g. by elk Cervus elaphus
in the the northern range of
Project management and research.
Dilemmas in management often resolve to choosing between two unsatisfactory alternatives (22). A method to deal with the issues mentioned above is to develop standards with respect to health and welfare of the ungulates. These standards should be based on an analysis of information on the state of the population in relation to its resources (body condition; reproductive and mortality rates). Professional project management (8) should be used, with a definition of the problem, formulation of explicit standards, and careful monitoring. The results of the project can then contribute to redefining certain objectives (adaptive management). See figure below.
Standards
for the management of ungulates.
Management of animals within nature reserves of
the size found in
|
* Body condition of the animals,
proper for several seasons. * Reproductive rates at
biologically 'normal' levels (fertility, pregnancy and birth rates). * Mortality rates at biologically
'normal' levels (for all seasons, and age and sex classes). * Demographic profiles of the
populations (age and sex ratios) biologically 'normal'. * Impact of the animals on the
ecosystem maintains its quality (biodi-versity,
carrying capacity etc.). |
PRACTICAL MANAGEMENT ISSUES
Supplementary feeding.
Feeding of ungulates in winter is supposed to
result in (21):
*artificially high densities of
animals;
*artificial reduction of the feeding
range of the population, since the animals
concentrate around the feeding
areas;
*the animals remain dependent on
man;
*an artificially high fecundity,
distorted timing of births with perhaps some even in
midwinter because animals in good
condition come into oestrus earlier (needs further
research);
Additional feeding may be beneficial
for individual animals, but not for the development of natural processes (3).
In exceptional circumstances the manager may be
forced to give extra nutrients or pasture. When the area has a structural
deficiency of essential nutrients (e.g. minerals) the manager is clearly
obliged to provide supplementary minerals permanently just to maintain the
population (e.g. in sandy areas deficient in phosphorus). In a year when
the body condition of the population is exceptionally poor, mortality is
exceptionally high (say, more than 10 % over a couple of months), in a period
when there is little prospect of plant growth, and when a 'crash' of the
population is undesirable, then animals which are obviously at risk should be
removed and cared-for outside the reserve (5). This policy will lead to
variable ungulate densities and therefore variable impact on the ecosystems.
Ecological theory leads to the prediction that this will be favourable for
plant and animal biodiversity (5).
Regulation of the number of animals.
General principles.
*Natural density-dependent processes
which reduce reproductive rates and increase mortality (disease, predation,
(9,23)) should have priority over artificial interventions to prevent
overpopulation. The situation becomes complicated when the diseases can infect
man and livestock e.g. brucellosis in
*If natural regulation is
insufficient, human intervention may be necessary. Contraception (13) is
excessively artificial. The alternatives are catching or shooting. Reduction
culls can be regular, about 10 % every year or periodic, about 50 % removed
every 5 years or so.
The exact procedure of the
interventions is important too: one can regulate by
*selecting individuals, looking through
the 'eyes of the wolf', 'the eyes of the butcher', or 'the eyes of the health
manager',
*removing subpopulations ('the eyes
of the nature manager') for legally permitted export of ungulates to other
natural areas with more room, such as in Eastern and
*random removal may be the least
controversial, though this, too, is 'unnatural'.
Perhaps the best method will prove
to be a combination of natural and artificial regulation.
Regulation in practice at Oostvaardersplassen.
*From 1984 until 1997 the population of Heck
cattle and Koniks in the Oostvaardersplassen
increased exponentially. Between 1987-96 the mortality of the ungulates varied
between 5-10 % (3). If mortality is to be taken as an indicator of
overpopulation, over 10% of the population therefore needs to die before
mortality is considered excessive. As far as body condition is concerned the
average yearly score for the Heck cattle in the period 1991-96 in October was 8
and in March 6 (on a scale of 0-10) and for the Koniks,
9 and 7 respectively. A provisional conclusion based on these two parameters is
that there was no evidence for overpopulation until 1997. (N.B. According to
GWTA Groot Bruinderink et
al. in Dynamic interactions between Ungulates and vegetation in the Oostvaardersplassen, 1999, there is for the next 5-10 years
no danger for overpopulation). All the animal welfare standards mentioned
in
*Apart from these animal welfare standards, the
standards related to the structure and functioning of the ecosystem may be
another reason to intervene. The current debate on natural regulation in
Recommendations.
The problem of regulating population sizes
needs further research on analogous situations which are appropriate references
for the system in question. Observational studies in the field and systems
modelling are important and complementary approaches. National and European
rules which allow more natural methods of regulation are needed.
Introduction of animals and the
connectivity of natural areas.
Introduction of (semi) wild animals needs a
feasibility study in advance and intensive support in the form of scientific
research for many years. A justification for the introduction of these animals
is that natural colonisation is not yet possible. Increased connectivity of
natural areas in
Semi-wild or domestic ungulates
'going wild'.
Pleistocene remains of Aurochs (Bos taurus) are
found in most European countries,
CONCLUSIONS
*In winter 1998-99 starvation and death of Heck
cattle in the Oostvaardersplassen brought the
hands-off management policy in nature reserves of limited size into public discussion. Project management developing
biological and socially acceptable standards is an appropriate way to handle
the different options on the care of the health and welfare of ungulates in
this area. That requires analysing analogous situations all over the world as
references, and for conducting population dynamics studies involving both field
observations of wild and free-ranging ungulates, and modelling ecological
processes at the population and ecosystem levels.
*National
and European rules are needed to allow natural processes in herds of free-ranging
ungulates involving disorders and infectious diseases, with consequences which
could be either recovery or death.
REFERENCES
1. Blood
DC, Radostits OM, Henderson JA. et al. Veterinary Medicine. 6e Ed., Bailliere Tindall,
2.Broekhuizen S. Diseases in wild animals in
relation to nature management. Vet.Quart. 1996, 18:
S143-145
3.Cornelissen P. and Vulink
J.Th. Large Herbivores in Wetlands. Evaluation of
grazing management in the nature reserve Oostvaardersplassen
in The Netherlands. (Dutch Report) Flevobericht 399.
1996;1-142
4.Dobson AP, Hudson PJ. Microparasites:
Observed Patterns. In: Grenfell BT. &Dobson AP. (Ed): Ecology of Infectious
Diseases in Natural Populations.
5.Duncan P. Horses and Grasses: The nutritional
ecology of Equids and their impact on the Camargue. Ecological Studies 87. Springer,
6.Essen G.J. and Leeuwen
J.M. van. Assessment of health risks of large semi wild herbivores in urbanized
areas. Vet. Quart. 2000; 22:112-6.
7.Fokkinga A. A country full of cattle.
Husbandry animals in the
8. Groote G.P., Sasse C.J. and P. Slikker.
Project management. Methods and techniques for working with projects. Marka-paperback; Het Spectrum.
1990;1-319.
9.Hofmann RR. Institute for Zoo Biology and
Wildlife research. Research group Wildlife Diseases.
10.Huff D.E., Varley
J.D., Soukup M., Foley M., Hiebert
R. Natural regulation in
11.Kampf H. Grazing in Nature Reserves.
Ministry of Agriculture, Nature and Fisheries. 1998; Report (English) and URL:
http://www.minlnv.nl/grazers/
12.Keulartz J., Belt H.van
der, Gremmen B., Klaver I., Korthals M. Good times
, bad times. Ethics on large grazers (Dutch). Wageningen
13.Kirkpatrick J.F., Liu I.M., Turner J.W. Jr, Naugle R., Keiper R. Long-term
effects of porcine zonae pellucidae
immunocontraception on ovarian function in feral
horses (Equus caballus) J.Reprod.Fertil. 1992; 94: 437-44
14.Kleiner K. Oh give me a home...New
Scientist, 1999; 162: 18-19
15.Leeuwen H.J.C.
van. Personal Communication. Synoptics Integrated
Remote Sensing & Geographical Information Systems Applications.
Wageningen.1999; http://www.synoptics.nl/index.html
16.LYNX-Nature conservation planning in
17.Ministry of Agriculture, Nature Management
and Fisheries. Ecosystems in the
18.Molenaar J.G. de. Domesticated large herbivores
in natural areas and woods: a desk study. I. The working of grazing. ISSN:
0928-6888. IBN-report 231.1996;1-228
19.Morrison P. Mammals, Reptiles and Amphibians
of
20.Vera F.W.M. Metaphors for the Wilderness.
Oak, hazel, cattle and horse. Wageningen. Thesis, 1997
21.Veterinary committee of the Oostvaardersplassen. Reports (Dutch) of the health status
of ungulates with data of the manager, the local veterinarian and the Animal
Health Service till 1999.
22.Webster's Third New International Dictionary
of the English Language Unabridged. Merriam-Websters
Inc.
23.Wieren S.E.van, Groot Bruinderink G.W.T.A., Jorritsma I.T.M. en Kuiters A.T. Ungulates in the forest landscape. Backhuys Publ., Leiden. 1997;1-224
=====
3. WAT BETEKENT NATUURLIJKE BEGRAZING VOOR HET DIER? Versie 29-nov-2001 De
literatuurstudie nav de beheersverantwoordelijkheid in de Oostvaardersplassen (OVP) is verricht door Jaap van Leeuwen.
Het commentaar van Ed van Klink, Sjeng Lumeij, Elsbeth
Noordhuizen en Joost Oosterbaan van de
‘Werkgroep beheer grote grazers OVP’ van de
VGWWF is in de tekst verwerkt en wordt
op diverse plekken (cursief) weergegeven
oVP
IN HET KORT.
Het oorspronkelijke vogelgebied van de OVP is zo'n 30 jaar geleden spontaan ontstaan uit een ongebruikt stuk moerasgebied na inpoldering van een deel van het IJsselmeer. Men heeft daarna enkele soorten grote grazers ingebracht, zoals Heckrund in 1983, Konikpaard in 1985 en Edelhert in 1992 om het ideaalbeeld van een open vogelgebied te ondersteunen. Vervolgens zijn deze grazers tot intrinsiek onderdeel van het ecosysteem verklaard. Het wetland, de vogels en de grazers doen het tot nu toe zonder noemenswaardige hulp prima (2), echter de nodige vragen zijn gerezen over gezondheid en welzijn van de ingebrachte dieren (17). Waar ligt het kritisch punt: wat doet de natuur bij het bereiken van de draagkracht van het gebied of is de draagkracht al bereikt? Wat betekent zelfregulatie in dit verband en wat zouden wij als mens moeten doen? (4,5). (Diverse onderzoekvragen dienen zich dus aan: ontstaat landschapserosie, massale sterfte van dieren, onderlinge verdringing van diersoorten, vertrek van vogels? Een onafhankelijk retrospectief onderzoek naar de beschikbare ziekte- en sterfteoorzaken van grote grazers in de OVP gekoppeld aan reeds verzamelde demografische data (13) wordt sterk door de Werkgroep bepleit).
BegripsOMSCHRIJVINGEN
Natuurlijke
begrazing
-Begrazing door grote herbivoren is onder natuurlijke omstandigheden een belangrijk proces. Een echt natuurlijk landschap is waarschijnlijk zowel in ruimte als tijd zeer afwisselend, bestaande uit alle denkbare sucessiestadia tussen bos en steppe. Omdat 6 van de 18 soorten grote herbivoren in West en Midden Europa volledig zijn uitgestorven zijn natuurlijke systemen op enkele punten niet volledig te herstellen. Evenwel, omdat met het paard en het rund nog alle voedselstrategieën beschikbaar zijn, worden er goede vooruitzichten verondersteld voor het herstel of de vorming van ecosystemen, ook die van open landschappen met daarin veel inheemse dieren en planten (3).
-Natuurlijkheid betekent dat ecologische processen zoveel mogelijk ongestoord hun gang kunnen gaan. Natuurlijke begrazing houdt voor het dier zowel de ontwikkeling van de populatie als van het soorteigen gedrag in (5). Gedrag is in het algemeen een belangrijke, vroegtijdige, reactie van mens en dier op gebeurtenissen of veranderingen in hun omgeving. Vanzelfsprekend treden er ook allerlei inwendige fysiologische veranderingen op, maar gedragsverandering is als eerste uiterlijk zichtbaar (12). In Nederland is geen onbeperkte migratie en er zijn geen predatoren. Er is naar gestreefd de kans op zelfredzaamheid van de grazers zo groot mogelijk te doen zijn door te kiezen voor ecologische vervangers van uitgestorven dieren, dat wil zeggen: het Heckrund en de Konik voor resp. de oeros en de tarpan. De interactie tussen soorten grote grazers kan leiden tot concurrentie en/of facilitatie (5). In feite vormen de OVP een zomerhabitat voor grote herbivoren en kunnen vraagtekens worden gezet bij de natuurlijkheid van jaarrondbegrazing (22).
-In nagenoeg-natuurlijke eenheden zoals de Veluwe, het Duinlandschap, de Westerschelde, de Dollard en de Boschplaat op Terschelling draagt natuurlijke begrazing slechts in beperkte mate bij aan de biodiversiteit. Deze bestaat vooral uit de aanwezigheid van de grazers op zich (1).
-Er is gedurende 10 jaar ervaring opgedaan met begrazingsprojecten in rivier- en beekdalen, zoals de Gelderse Poort, de Beuningse Uiterwaarden, de Grensmaas, de Zandmaas en het Beneden-Geuldal. De opgedane ervaringen zijn illustratief voor de verschillen tussen natuurlijke begrazing en seizoensbeweiding (7) en ook leerzaam voor andere gebieden:
--Natuurlijke begrazing gaat uit van jaarrondbegrazing en het gegeven dat er niet meer dieren kunnen lopen dan dat er in perioden van voedselschaarste (nawinter) aan voedsel beschikbaar is. In de praktijk betekent dit, dat er in de zomer een overvloed aan voedsel is, dat planten massaal tot bloei en zaadzetting komen, dat er 's zomers ruigtes ontstaan, waarin dieren dekking en voedsel vinden, dat bomen en struwelen de kans krijgen om op te groeien en dat uiteindelijk een gevarieerd landschap ontstaat, waarin duizenden planten- en diersoorten kunnen leven. (Deze situatie zou volgens verwachting ook in de OVP moeten bestaan). Bij seizoensbeweiding wordt het aantal dieren afgestemd op de hoeveelheid voedsel in de zomer. In de praktijk betekent dit dat de begrazingsdichtheid 's-zomers 10-30 keer hoger ligt dan bij natuurlijke begrazing. Planten komen niet of nauwelijks tot bloei. Voor insecten en zaadetende vogels is er weinig voedsel. Er ontstaan geen zomerruigtes. Jonge boompjes en struiken worden opgevreten. Kortom: de levensexplosie die bij natuurlijke begrazing optreedt blijft bij seizoensbe-weiding uit.
--Bij natuurlijke begrazing gaan de dieren 's-winters de ruigtes te lijf, ze eten twijgen en schillen bomen en struiken. Ze beďnvloeden de structuur van de vegetatie en er ontstaat een mozaiekpa-troon van grasland via struwelen naar bos. Bij seizoensbeweiding ontstaan veel scherpere overgangen tussen grasland en bos, het bos groeit dicht door het ontbreken van wintervraat.
--Natuurontwikkeling heeft baat bij meerdere soorten grazers. Ze hebben eigen voedselvoor-keuren en intensiteiten van grazen. Bij seizoensbeweiding is vaak sprake van 1 soort.
--Belangrijk is de sociale structuur en het gedrag, bijv. het bouwen van latrines, de zandbaden die hengsten en stieren graag nemen, de afsplitsing van groepen en de afzondering van moeders met hun jongen. Bij seizoensbeweiding is meestal sprake van 1 geslacht en 1 leeftijd, meestal jong, omdat oud een ongewenste vleeskwaliteit geeft. In de natuur hebben oudere dieren een sleutelrol bij kennisoverdracht en verplaatsingen.
--Dedomesticatie (dit begrip is wetenschappelijk slecht onderbouwd: eenmaal verloren geneti-sche variatie kan men niet terugfokken, maar welke restanten van de genetische aanleg kunnen alsnog tot expressie worden gebracht?) geeft dieren een natuurlijke rol in het ecosysteem. Bij seizoensbeweiding ontstaat geen goede terreinkennis, zoals ligging van water en voedselbronnen, vluchtroutes bij wateroverlast.
--In de winter kunnen grote grazers tot 25 % van hun lichaamsgewicht verliezen door vetver-branding (25 % is waarschijnlijk veel meer dan vet alleen). Zwakke dieren sterven het eerst. De rest eet bast en takken. Bij seizoensbeweiding kan dit niet.
--Bij natuurlijke begrazing ontstaan ruigtes als agrimonie, stekelnoot, nagelkruid en klissen, waarvan het zaad zich verspreidt via de vacht der dieren.
--Bij seizoensbeweiding treedt sterke bemesting op en vertrapping van de bodem, hetgeen een aanslag is op de basis van de voedselketen.
--Boerenvee is voor natuurlijke begrazing minder geschikt, vanwege de vroege vruchtbaarheid, de dikke uiers, de kwetsbaarheid bij slecht weer en de afhankelijkheid van de mens.
Biodiversiteit is niet zozeer 'behouden van wat je hebt', maar 'behouden van heterogeniteit en dynamiek in het landschap'. Belangrijk hierbij zijn de storingen, zoals bijv. een fluctuerende populatieomvang. Natuurlijke processen, die leiden tot heterogeniteit dienen zoveel mogelijk kansen te krijgen. Deze processen leiden tot ruimtelijke variatie, die in ecologisch opzicht optimaal kan worden genoemd. Chaos is hierbij de belangrijkste strategie. Het toelaten van omgevingsfluctuaties en het toestaan dat een ecosysteem zich blijft ontwikkelen in soortensamen-stelling en populatieverhoudingen past hierin. Er bestaat geen ideale situatie waarin een gebied moet verkeren. Er moet ruimte zijn dat de natuur zichzelf kan ontwikkelen(5).
Draagkracht
is geen statisch gegeven, maar het niveau
waarop zich zonder menselijk handelen een evenwicht instelt tussen
populatiegrootte en vegetatie/biomassa (22). (Dit geldt mogelijk alleen in een compleet ecosysteem.)
Probleemstelling
doelstelling en randvoorwaarde
Het doel van de OVP is 'de ontwikkeling van een zo compleet mogelijk zoetwatermoeras-ecosysteem op een zo natuurlijk mogelijke wijze. Randvoorwaarde is dat er onder de voor dit doel ingezette grote grazers geen sterfte van enige omvang cq. welzijnsprobleem mag optreden ten gevolge van een tekort aan voedsel' (5). Tussen doelstelling en randvoorwaarde bestaat een duidelijk spanningsveld, waaraan de Leidraad van de Staatssecretaris van LNV aandacht besteedt (16). Maar is dit voldoende?
Problemen met de Leidraad van lnv
-Ofschoon de Koninklijke Nederlandse Maatschappij voor Diergeneeskunde erkent dat de Leidraad aan een aantal bezwaren tegemoet komt, blijft ze ongerust. Dieren mogen niet ondergeschikt worden gemaakt aan de door de mens gewenste ontwikkeling van een ecosysteem. Herhaling van calamiteiten, zoals in de winter van 1998-99, moet zonder meer worden voorkomen. De uitwerking van de Leidraad is teveel afhankelijk van de interpretatie van de beheerder. Deskundigen worden onvoldoende structureel gehoord. Het als niet gehouden beschouwen van grazers kan in het algemeen tot misbruik leiden op zorggebied. De jaarlijkse monitoring kan strijdig zijn met bepaalde landelijke dierziektenbestrijdingsprogramma's (11).
-Het probleem dat de beheerder van de OVP met de Leidraad heeft is dat deze zowel natuurlijkheid als doel heeft maar tegelijk op grond van draagkrachtbeoordeling preventieve aantalsregulatie voorschrijft teneinde verhongering te voorkomen. De criteria voor deze beoordeling zijn echter niet operationeel (5). Bovendien, waar moet men jaarlijks met de honderden gezonde dieren naar toe (15): voor de destructor zal weinig maatschappelijk draagvlak zijn, getuige de recente verontwaardiging over het 'ringruimen' bij MKZ ; diverse andere bestemmingen zijn wettelijk of juridisch zo goed als afgesloten! (16).
Ethische kwesties
-Uit onderzoek blijkt dat natuurbeheerders, boeren, bezoekers en dierenbeschermers te verdelen zijn in natuurliefhebbers en dierenliefhebbers. Dierenliefhebbers hebben de neiging grote grazers als huisdier te zien, waarvoor de zorgplicht moet worden gehandhaafd. Natuurliefhebbers beschouwen ze meer als wilde dieren, die daarin niet verschillen van herten en vossen. Deze visies leveren in de discussie een patstelling op, die ook niet door juridische literatuur kan worden opgeheven (14). (Het gaat hier om een zwart-wit tegenstelling tussen dier- en ecoethiek. In beide gevallen geldt evenwel een morele én wettelijke zorgplicht, met name in de sfeer van populatiebeheer!). De tegenstelling natuur en dier ligt echter dieper.Het publieke debat over verhongering en verwaarlozing van in nood verkerende dieren leidt gemakkelijk tot polarisatie, waarbij de partijen de categorieën natuur en cultuur tegenover elkaar stellen. Er is geen ruimte voor een middengebied (9). Zolang men uitgaat van de instrumentele waarde lijkt de gedragscode tamelijk eenvoudig (behoud). Wanneer men echter een meer intrinsieke waarde als uitgangspunt kiest ligt de zaak moeilijker: welke ruimte mag de mens nemen en welke ruimte moet aan de natuur of het dier gegeven worden? Strekt de ethische norm zich uit naar elk organisme of naar de soort of misschien het ecosysteem of juist naar de variatie aan ecosystemen? (9).
-Wereldwijd is het met de biodiversiteit slecht gesteld, ook in het dichtbevolkte Nederland. Als medeondertekenaar van de Conventie inzake Biologische Diversiteit (1992) heeft Nederland de verplichting op zich genomen dit probleem serieus ter hand te nemen. Om het tij te keren heeft er in het natuurbeleid een omslag plaats gevonden van een defensieve naar een offensieve aanpak, waarin het accent is verlegd van natuurbescherming naar natuurontwikkeling. De gebeurtenissen in de OVP markeren hierin een belangrijk keerpunt(9). Maar welke normen en waarden als moreel kader voor de omgang met dieren dienen hierbij te gelden? Het gaat concreet om 4 breed geaccepteerde principes, zoals geen kwaad doen, weldoen, respect voor de eigen waarde van het dier en rechtvaardigheid. Wordt er geen willekeur betracht binnen diverse grote eenheden natuur, zijn de doelen redelijk en is het loslaten van beschikkingsmacht als argument voor niets-doen geen vooraf gemaakt keuze? (11).
Juridische problemen
-De Gezondheids- en welzijnswet voor Dieren (GWWD-artikelen 36 en 37) stelt regels aan het eigen belang van alle dieren, gehouden of niet. Dit stelt grenzen aan onbelemmerde verwilderingsprocessen (16).
-De EU-Regeling aanwijzing besmettelijke dierziekten is neergelegd in de GWWD. Bij Mond- en klauwzeer kunnen daardoor extra passende maatregelen worden genomen om de ziekte te bestrijden. Intensieve monitoring of enting van deze dieren in de natuur kan echter op praktische problemen stuiten. Bij de bedrijfsgebonden ziekten, zoals IBR, waarvan de bestrijding aan het bedrijfsleven is overgelaten kunnen eveneens uitvoeringsproblemen ontstaan (16).
-De
Destructiewet (artikel12) verplicht de houder om kadavers van runderen en
paarden te destrueren, althans indien de terreingesteldheid dit niet onmogelijk
maakt (16). Deze verplichting staat haaks op de doelstelling van de natuurlijke
diversiteit (8).
-Volgens de EU-Verordening Identificatie en Registratie van runderen (EG nr.820/97) moeten alle runderen worden geoormerkt. Transport van deze dieren naar andere natuurterreinen is niet zonder meer toegestaan op grond van de PVV-verordening-art.5 van 1998 (16) Bij het oormerken van bijv. pasgeboren kalveren kan, vanwege het onberekenbare gedrag van de koeien, voor de veiligheid van de beheerder niet altijd worden ingestaan. In die gevallen worden deze natuurgebieden niet beschouwd als veehouderijbedrijven. In het verleden is voor transport tweemaal ontheffing verleend door het PVV. (De I&R-verplichting voor runderen is vooral bij veewetziekten van belang: wat zijn de consequenties van het achterwege laten van I&R bij bijv. een MKZ-bestrijding en welke prijs voor uitvoering van de I&R is te hoog als alle evenhoevigen in noodgevallen moeten worden geruimd in plaats van gevaccineerd?).
-Met het oog op de Europese veterinaire regelgeving ter zake kan ook het in het consumptiekanaal brengen van niet-geidentificeerde/geregistreerde dieren uit grote eenheden natuurgebied niet worden nagestreefd (16). Dit beperkt de afzet van overtollige dieren.
-De a.s. nieuwe Flora- en Faunawet heeft tot doel de bescherming van in het wild levende soorten, terwijl de GWWD bescherming biedt aan de dieren zelf. In beide wetten is sprake van zorgplicht (16) Of dit tot onduidelijkheid leidt zal moeten blijken.
Oplossingsrichting
- Problemen met de Leidraad verdienen de aandacht. (De ongerustheid van de KNMvD over de Leidraad moet bij de overheid neergelegd worden. Hetzelfde geldt voor eventuele uitvoeringsproblemen die beheerders er mee ondervinden).
-Om
knelpunten in de aanpak op te heffen is behalve monitoring flankerend onderzoek
essentieel (4). (In bijlage dezes worden
door de Werkgroep beheer OVP naast het reeds genoemde retrospectieve onderzoek
de volgende onderzoeksvoorstellen gedaan:
*Kwantificering infectierisico's: Welke
risico's lopen veehouderij en natuur bij het uitbreken van infectieziekten,
zoals veewet-, handels- en zoönotische ziekten? Hoe worden
de risico's beheerst? Wat is het effect van barričres, ruimtelijke afstanden en
(inter-)nationale corridors op de verspreiding van
ziekten? Hoe kunnen eventuele risico's van kadaverafbraak te velde worden
ingedamd?
*Fysiologisch en ethologisch welzijnsonderzoek:
Waar ligt de grens tussen fysiologisch afslanken en pathologisch verhongeren?
Kan men op grond hiervan het moment van afschot vaststellen en het welzijn van de grazers waarborgen?
Parallel hieraan loopt het ethologisch onderzoek inzake zelfredzaamheid,
migratie-, foerageergedrag en de ontwikkeling van sociale structuren.
*Dier en maatschappij: Hoe breed of smal is het draagvlak voor dit
type natuurontwikkeling in Nederland, vergeleken met andere landen?
*Grote grazers in het consumptiekanaal: Kan
men door quarantainemaatregelen samen met identificatie en registratie de
dieren verantwoord afvoeren naar het slachthuis in plaats van naar de
destructor? Dit is een beleidsstudie.
Gezien de onderzoeksachterstand is een
verhoogde inspanning realistisch. De onderzoeksvragen naar de randvoorwaarden
van natuurlijke begrazing moeten bij de overheid neergelegd worden door de
Instituten, de Vereniging Gezondheid en Welzijn Wilde Fauna en de
Beheerder(s)!)
Wat
het beheer betreft is geconcludeerd, dat voortzetting van het 'experiment'
grote grazers binnen de huidige kaders voorlopig moet worden voortgezet (4). De
Leidraad biedt daar mogelijk ruimte voor, waar ze zegt (p.6) dat het model (6)
voor de OVP laat zien, dat pas over 10 jaar sprake zal zijn van tamelijk
constante aantallen runderen en paarden. (De Werkgroep OVP merkt op: Tot nu toe ziet het
er niet naar uit dat zich een verantwoord evenwicht zal vormen, waarbij crashes
kunnen worden uitgesloten. De afweging van doel en aanpak van het 'experiment'
dient vooraf te worden gemaakt en goedgekeurd).
-De tegenstelling tussen dier en natuur is betrekkelijk, ze bestaat slechts als onderdeel van die tussen cultuur en natuur. Hier ligt een interessant punt. Door de aanwezigheid van de mens zijn veel natuurlijke processen onderbroken, maar de mens komt zelf ook voort uit de natuur en is in staat de natuur te herstellen en te ontwikkelen via 'controlled decontrolling of ecological controls' (9). R.Gardiner stelt: 'Het mysterie is dat dezelfde natuur, die zich schijnbaar niet bekommert om het lijden van haar schepselen, in Homo Sapiens tegelijkertijd een schepsel voortbrengt dat zich daar wél om bekommert of tenminste om kán bekommeren' (18). De meeste milieufilosofen zijn het er over eens, dat de natuur deel zou moeten uitmaken van het ethisch domein. Ze vinden zelfs dat er een 'elfde gebod' nodig is, dat normen stelt voor de omgang van de mens met de aarde en de natuur. In de 20e eeuw worden allerlei ecosystemen naar believen hersteld, gereproduceerd of ontworpen en de gentechnologie stelt de mens in staat nieuwe soorten organismen te creëren. Nu de 'achtste dag van de schepping' is aangebroken, de dag waarop 'de mens het werk van God overneemt', zijn - zo betogen veel ethici - de verantwoordelijkheidsvragen dringender dan ooit. Tevens veranderen de opvattingen in het natuurbeheer. De systeemtheoretische zienswijzen verliezen aan het eind van de 20e eeuw aan betekenis, wanneer onderzoekers wijzen op de onvoorspelbaarheid waarmee allerlei systemen in de natuur zich ordenen. De aandacht gaat uit naar de spontane zelforganisatie die vanuit een schijnbare chaos blijkt te kunnen optreden, waarbij zich systemen vormen die bij een kleine verstoring weer instabiel kunnen worden. De wanorde en vormeloosheid die met chaos en wildernis verbonden worden staan in tegenstelling tot de ordening van het beschaafde en gecultiveerde milieu. Beschaving kan voor velen het gezicht aannemen van gekunsteldheid, benauwende regelgeving en conventies. De mens gaat als reactie daarop wildernis maken! Deze activiteit is nieuw! Het is opvallend dat hierbij nieuwe opvattingen over oorspronkelijke natuur naar voren komen. Waar men in het verleden de oerwildernis vooral beschouwd had als een dicht woud, zien sommige ecologen nu een open boslandschap met kudden grote grazers (18,20). Daarnaast krijgt het, vroeger afkeer opwekkende, moeras een extra waarde. In Nederland begint men in natuurontwikkelingsprojecten aan de reconstructie van het oerlandschap. De natuur wordt naar de mythe van wildernis geschapen (18).
BETEKENIS VAN NATUURLIJKE BEGRAZING VOOR HET DIER.
Wat is de intrinsieke of eigen waarde van natuurlijke begrazing voor het dier en met welke uitgangspunten cq. randvoorwaarden moet men rekening houden? (4,5)
Populatieontwikkeling:
1.Er wordt gestreefd naar een ongestoorde wisselwerking tussen grazer en ecosysteem ten gunste van de biodiversiteit; de grenzen van de draagkracht zijn daarbij dynamisch. Voor het beheer van het complete moerasecosysteem van de OVP ligt het streefbeeld niet vast: men stimuleert spontane ontwikkelingen, voortvloeiend uit ogenschijnlijke wanorde; er is monitoring van waterstand, voedselvoorziening, klimaatverandering, effecten op het landschap en op het dierenbestand (13); waar nodig worden natuurlijke processen ondersteund.
2.Kleine grazers zoals de ganzen, de ontelbare andere vogels en de vos hebben zich spontaan gevestigd in het reservaat van de OVP. Bij introductie is gekozen voor wild, zoals edelhert en voor ecologische vervangers van uitgestorven dieren, dwz. het Heckrund en de Konik voor resp. de oeros en de tarpan.
3.Er
treedt zowel facilitatie als concurrentie op binnen
en tussen diersoorten, te weten hoefdieren, vogels, vossen en insecten.
4.De kringloop van leven en dood is beperkt: natuurlijke sterfte is niet gedefinieerd, er is geen predatie, wél gerichte afschot door de parkwacht (maar niet ter regulering van de populatieom-vang als zodanig), kadavers gaan naar de destructor, kadaverafbraak is juridisch alleen bij wild toegestaan, mits geen risico voor besmetting.
5.Men
verwacht in 2002 een omvang van bijna 2000 hoefdieren in de OVP;
de dieren hebben een levensverwachting, die enkele malen hoger ligt dan bij
vee. (Toch sterven ook al veel jonge
dieren).
Ontplooiing van soorteigen gedrag:
6.Sociale structuren worden gevormd ivm (sub-)kuddes, voortplanting en nakomelingschap.
7.Men ziet foerageergedrag en er is migratiemogelijkheid op ca. 2000 ha vruchtbare, droge grond. In een gesloten gebied zoals de OVP zonder corridors naar elders hoeft de jaarrondbegrazing niet persé het toppunt van natuurlijkheid te zijn, vooral ook omdat het gebied kenmerken van een zomerhabitat heeft.
8.Autonomie of zelfredzaamheid wordt via natuurlijke selectie bevorderd. Ondersteuning van dit proces vindt plaats via protocollair voorgeschreven monitoring van gezondheid, gedrag (bepleit), conditie én gerichte afschot mede ter voorkoming van verhongering of uitzichtloos lijden van zieke of zwakke dieren. Preventieve aantalsregulatie in het najaar en structurele bijvoeding in de winter doorkruisen het onder 1, 3, 6, 7 en 8 genoemde streven.
SLOT
-De balans tussen diergezondheid-, welzijns- en natuurwaarden verdient meer aandacht. Ethiek is meer dan dieren geen pijn, leed of letsel berokkenen en/of hun gezondheid en welzijn niet schaden. Het voorkómen van uitzichtloos lijden bij individuen is slechts een ondergrens (19,21), de bevordering van gezondheid en welzijn van dieren gaat verder, zoals het respect hebben voor de intrinsieke waarde (eigen waarde) en de integriteit van het dier, evenals het zoeken naar evenwicht in de soortspecificiteit en het stimuleren van het vermogen zich zelfstandig te handhaven (9,11).
-De ontwikkeling van natuurwaarden binnen de gestelde randvoorwaarden betekent, dat structureel sprake is van co-evolutie van natuur en cultuur. Om knelpunten op te heffen is daarom gerichte ondersteuning, gebaseerd op monitoring en flankerend onderzoek nodig!
-Verantwoording van deze nota: het is de taak van de dierenarts te zoeken naar alternatieven, nieuwe perspectieven en ethisch verantwoorde oplossingen voor situaties waar de gezondheid en het welzijn van het dier in het geding zijn. (10). De Werkgroep beheer grote grazers in de Oostvaardersplassen van de Vereniging Gezondheid en Welzijn Wilde Fauna (VGWWF) poogt hier invulling aan te geven.
Referenties
1.Al, E.J., H.M. Beije. Begrazing en natuurdoeltypen.
Bosbouwvoorlichting (1996); 7:114-117
2.Bremer, P., L. van den Berg, G. Euverman
& V. Wigbels. Nieuwe natuur op oude zeebodem. De Oostvaardersplassen en de bosgebieden van Flevoland. SBB,
Zwolle (2000)
3.Bunzel-Drüke M., J. Drüke
& H. Vierhaus. 'Quarternary
Park': grote herbivoren en het natuurlijk landschap voor de laatste ijstijd.
Vakblad Natuurbeheer (2001), 4: 49-52
4.Expert meeting over Grote grazers in de Oostvaardersplassen. Verslag, 10 juli.(2001)
5.Gelder, A. de. Grote grazers in de Oostvaardersplassen. Een proeve van invulling van de beheersverantwoordelijk-heid op basis van natuurlijkheid,
draagkracht en biodiversiteit. Discussienota 3e concept, mei (2001)
6.Groot Bruinderink, G.W.T.A., J.M. Baveco, K. Kramer,
A.T. Kuiters, D.R. Lammertsma, S. Wijdeven.
Dynamische interacties tussen hoefdieren en vegetatie in de Oostvaardersplassen.IBN-Rapport
(1999); 436
7.Helmer, W. Natuurlijke begrazing versus
seizoensbeweiding. Vakblad Natuurbeheer (2001), 4: 67-69
8.Kampf, H.Grote grazers en
het beleid. Vakblad Natuurbeheer (2001), 4: 89-92
9.Keulartz J., H.v.d.Belt, B.Gremmen, I.Klaver & M.Korthals Goede tijden, slechte tijden; ethiek rondom
grote grazers (1998)
10.KNMvD. Dierenarts: spil in een gezonde samenleving.
Beleidsplan. Utrecht; (2000)
11.KNMvD-Rapport over: Gezondheid en welzijn van grote
grazers in natuurterreinen. (2001)
12.Koene, P. Ethologie en grote grazers: wat wil de
mens? Vakblad Natuurbeheer (2001), 4: 76-78.
13.Kolen, M., P. Cornelissen,
N. Beemster, W. Altenburg, Y. van der Heide & M. Platteeuw. Vegetatie, begrazing en vogels in een zoetwatermoeras. Monitoringsprogramma
Oostvaardersplassen 1999/2000. RIZA,
(2001)
14.Korthals, M., J. Keulartz,
H.van den Belt, I.Klaver en
B.Gremmen. Strijd in en om de natuur; ethiek rond
grote grazers. Vakblad Natuurbeheer (2001), 4: 79-82
15.Leeuwen, J.M.van.
Beslisboom aantalsregulatie. Discussienota voor de
Werkgroep beheer grote grazers van de Vereniging Gezondheid en Welzijn Wilde
Fauna. Juli, (2001)
16.LNV-Staatssecretaris G.H.
Faber. Leidraad Grote Grazers met Vervolgbrief aan 2e
Kamer, jan/apr. (2000)
17.Lumeij, J.T. en J. Oosterbaan. Grote grazers in het
Nederlandse wetland 'de Oostvaardersplassen'. Tijdschr. Diergeneeskd (2000); 125
(7): 230-34
18.Schouten, M.G.C. De
natuur als beeld in religie, filosofie en kunst. KNNV,
Utrecht, (2001)
19.Tramper, R. etal.
Ethische richtlijnen. Richtlijnen voor het omgaan met zelfstandig levende
dieren in de terreinen van
Staatsbosbeheer. Centrum Bio-ethiek en Gezondheidsrecht UU in opdracht
van SBB; (1999).
20.Vera, F.W.M. Metaforen
voor de wildernis. Eik, hazelaar, rund en paard. PhD.Thesis
WUR (1997)
21.Vereniging Natuurmonumenten. De omgang met dieren.
Richtlijnen voor verantwoord omgaan met dieren in natuurgebieden van
natuurmonumenten.. NM,; (1999/2000)
22.Vulink, J.Theo. Hungry Herds. Management of temperate lowland
wetlands by grazing. Min. V&W, DG-RijksWaterstaat, Dir. IJsselmeergebied,
Lelystad, (2001)
Bijlage: Onderzoekvoorstel RANDVOORWAARDEN NATUURLIJKE
BEGRAZING. (23-nov-01)
Prioriteitsvolgorde
is willekeurig.
1.Retrospectief onderzoek naar ziekte- en
sterfteoorzaken van grote grazers in de OVP.
Basis is de protocollair voorgeschreven monitoring van ziekte, sterfte, autopsie, conditie en gedrag tezamen met de gerichte afschot in het voorjaar. Deze studie betreft een onafhankelijke klinische en pathologische evaluatie van de beschikbare veterinaire data gekoppeld aan de gegevens van populatieontwikkeling. Als referentie worden relevante (inter-)nationale data gebruikt.
Omvang: 3 maanden (x 3: voor rund, paard en edelhert) onderzoekstage dierenartsopleiding.
Mogelijke trekkers: Hoofdafdelingen Landbouwhuisdieren en Pathologie UU.
2.Kwantificering infectierisico's.
Hoe groot zijn de wederzijdse risico's van veehouderij en natuurlijke begrazing voor het uitbreken en de verspreiding van infectieziekten. Hoe kunnen de risico's worden beperkt of vermeden? Dit onderzoek sluit aan bij rampen als MKZ, maar ook bij eventuele problemen ivm IBR, BVD (handelsziekten), (para-)tbc en brucella (zoonosen). Wat is het effect van barrieres, ruimtelijke afstanden en internationale corridors op de verspreiding van ziekten? Wat is het effect van vaccinatie in plaats van ruimen? Is voor MKZ de huidige monitoring voldoende? Hoe groot zijn de risico's voor de gezondheid van mens en dier van het laten liggen van dode dieren in het veld.?
Omvang: 2 AIO's
Mogelijke trekker: Consortium Kwantitatieve Veterinaire Epidemiologie van Wag.,Utrecht en Lelystad.
3.Fysiologisch en ethologisch
welzijnsonderzoek.
Hoe kan de overgang tussen fysiologisch afslanken en pathologisch honger lijden worden vastgesteld? Hierop kan men het moment van afschot afstemmen en het welzijn van dieren waarborgen. (Thans is conditiebeoordeling op afstand de operationele parameter. Deze zou kunnen worden ingezet als modelmatige controle voor het navolgende onderzoeks-alternatief: vanaf het begin van de winter worden periodiek de vetvoorraden onder de huid, in de vang en in de koekoeksgaten, evenals de huidturgor - als maat voor de uitdroging - gemeten en de pensactiviteit gekwantificeerd. Ook kan men 'on site' klinisch-chemisch onderzoek doen. Over de bemonstering is overleg nodig met de beheerder (onderzoek in combinatie met gerichte afschot of verdoving, aselecte of selecte steekproef).
Parallel hieraan loopt het ethologisch onderzoek ivm zelfredzaamheid, migratie-, foerageergedrag en de sociale structuren.
Omvang: 2 AIO's
Mogelijke trekkers: Hoofdafdeling Landbouwhuisdieren (UU) en Kennis Eenheid Dier (WUR).
4.Dier en Maatschappij.
Wat zijn de maatschappelijke aspecten van natuurlijke begrazing met betrekking tot het dier? Natuurlijke begrazing trekt veel maatschappelijke belangstelling, ook internationaal, maar het is tegelijkertijd een omstreden fenomeen. De probleemstelling moet worden uitgewerkt. de
Omvang: 1 AIO
Mogelijke trekker: Interfacultaire (WUR en UU) Hoofdafdeling Dier en Maatschappij.
5.Grote grazers in het consumptiekanaal.
Op dit moment worden - conform de Destructiewet en de Leidraad - alle hoefdieren van de 'grote eenheden natuur' vroeg of laat naar de destructor gebracht. Dit is een enorme vernietiging van waardevol bio-materiaal, hetgeen maatschappelijk-ethisch amper te verdedigen is. Hoe kan men bereiken dat het vlees van gezonde grote grazers veilig en (internationaal) geaccepteerd in het consumptiekanaal wordt gebracht? Ook de I&R-regeling en de EU-regelgeving moeten hierbij betrokken worden. Het resultaat heeft mogelijk spin-off voor het populatiebeheer.
Omvang: postdoc.(beleids-)studie van ca. 3 maanden
Mogelijke trekkers: Hoofdafdeling Voedingsmiddelen van dierlijke oorsprong (UU), KvW en LNV
NB. Overleg met de beheerder(s) moet nog
plaats vinden.
4. ANIMAL WELFARE AND ANIMAL
HEALTH CARE
(The next Figures with comments are
presented by me during Workshop presentations held on April and May 2000 in Lelystad and Wageningen as part of Excursions of Danish
Nepenthes and German Nature Managers and Policy makers to the
J.M. VAN
LEEUWEN, Veterinarian-Pathobiologist, Kempenaar 04-21, 8242 BE Lelystad.
We will focus our attention to the Oostvaardersplassen area as an example. After some years of
adaptation there is a steep development of the number of large herbivores till
now on. Only the roe deer population decreased from 111 in 1993 till 30 in
1998. The possible reason for that is a change in vegetation from wood/shrubs
to grasses. They can leave the area through the fences.
So there is no indication at all for flattening
of the curves and a study of several Institutes (e.g. Alterra,
1999) indicated that it may last 5-10 years before the maximum level is
reached.
This fact is important for the next case.
ANIMAL WELFARE
DEATH FIGURES LARGE HERBIVORES IN
OVP DURING THE WINTER 1998-9
|
|
Population on 1-1-1999 |
Died till week 13 |
Shot
(included in death numbers) |
Death % |
|
CATTLE OLDER BULLS YOUNG ANIMALS OLDER COWS |
493
170 |
71 50 14 7 |
(8) (6) (2) |
15
8 |
|
HORSES |
370 |
14 |
(3) |
4 |
|
RED DEER |
370 |
6 |
(2) |
1,5 |
|
TOTAL |
1233 |
91 |
(13) |
7,4 |
Ref.: www.minlnv.nl/infomart/parlemnt/1999/
Above Figure represents an important
welfare issue during the winter 1998-99. It was a very wet situation by
continuous rainfall in autumn and winter. Animals had a lowered condition in dec. already. Overall death % was not very high (7,4 %),
but death in the cattle population was 15 %. Within cattle the older bulls and
the younger animals were at risk. So the mortality profile was not
representative over the whole population. Animals at risk lived in the very wet
parts of the area with poor vegetation. They refused to migrate on an early
moment to drier places. They did it in fact in Feb., when it became very cold.
In combination with the sudden change in food composition (more crude fibre and
woody plants) the animals got a strong indigestion and some of them died in a
lethargic state. The stronger animals however survived and recovered in April
and may. Staatsbosbeheer did not give extra food, but
they shoot in total 13 animals to make an end of their starvation.
2
Then the discussion started in the country about the
'hands off policy': for several organizations this policy is unacceptable and
it looks not conform the current animal legislation of welfare. Staatsbosbeheer however says that giving extra food may be
very detrimental for the animals.
Adverse effects of supplemental feeding may be:
*It disturbs the order in the area between and
within the animal populations and produces stress, fighting, and competition;
*It suppresses the migration behaviour within
the area; some populations stay too long on the same location;
*It may be a precedent for next years and if
yes:
*It gives an artificial higher carrying
capacity of the area;
*It makes that female animals may come earlier in
oestrus and this may give repro-duction problems in
the beginning of the next winter.
But shooting animals too early (in
dec. e.g.) may also be detrimental for the population:
*It intervenes the natural selection to
self-sustainability of animals;
*It may give stress too.
2
At
this moment SBB has planned to shoot animals at risk later on in the winter
period to prevent death by serious starvation. They have formulated their
policy in Ethical Guidelines, made in 1999 with the help of internal and external
advisors (e.g.bioethics, ecologists, ethologists, and veterinarians). Also Natuurmonumenten
has made guidelines and the Ministry of Agriculture, Nature Management and
Fisheries has formulated directives in Jan. 2000. All these authorities are
agreed about the notion that you have to
Solve and prevent serious and hopeless suffering of the free ranging
animals in the near natural areas.
Solve may mean: shooting animals to stop
starvation before death.
Prevention means: regulation of the population
size; prevention of crashes and connection of the small, fragmented areas.
2
In
conclusion you may say that the discussion about the principle of solving
individual problems is passed. But it is still very important to work it out in
detail and to communicate this with the society and the public.
What
does this mean for our animal care discussion?
HOW CAN WE DESCRIBE THE RELATION BETWEEN LARGE HERBIVORES AND MEN AS FAR
AS ANIMAL WELFARE IS CONCERNED?
1.Our main ambition is to get maximal
independence, self-sustainability and autonomy of free living animals with
minimal human intervention.
2.The pitfall is neglection
and this may be unnoticed or unintended; in fact it is unwanted.
3.The only reply for that is to give some sort of
care, but not to much, because:
4.This may introduce a dependency of care and
that is the opposite of our main ambition.
So care is complementary with
maximal autonomy.
This care must be appropriate: not too less,
not too much and also of the just quality.
The main questions about appropriate care are:
how, what, when and why?
To bring us further first some words about
animal health.
2
HEALTH CARE.
Table 3 gives a survey of several
relevant infectious diseases to concern about.
The
relevance of the selected diseases may be influenced by the classification
(A,B,C) of the OIE and by the current situation (a,b,c)
in a specific country. When there is a control program to become free from a
certain disease, you have to discuss the necessity and conditions for
eradication of that disease in the category of Large Herbivores in near natural
areas. Examples are IBR, BVD, Paratbc, Tbc, and Brucellosis.
The
way to handle with the situation of infection risks is given in the next
scheme.
DISCUSSION.
Total hands-off policy in near-natural areas with respect to animal welfare and health is unacceptable in a civil society. Hands-off policy is only possible within certain limits related to the quality of nature and to relevant rules about animal welfare and health. The best option for Heckcattle and Koniks is to give them a special status within the Law of animal health and welfare of animals (GWWD). Arguments for this are:
- They are
de-domesticated, feral animals, neither wild nor domesticated.
- They have an
appropriate need for care, because they are very self-sustainable.
- They have under
certain conditions to be excluded from the (EU) obligation to submit the
animals to I&R, because this system is unnatural and very difficult to
realize in practice.
- They have under
certain conditions to be excluded from the obligation to participate in
national control and/or surveillance programs for e.g. IBR, BVD, Paratbc, Leptospirosis.
These category of diseases are important for national husbandry, not for
nature. It is necessary to exclude mutual risks by appropriate risk
management.
- They have under
certain conditions to be excluded from the ban to leave the carrions in
the field, the obligation to render the carcasses and to the prohibition
to bring the meat of healthy animals in human consumption
- They have under
certain conditions to be excluded from the ban to transport them to other
(natural) sites.
1.Appropriate
care has to be defined by protocols, ready for certification. This may be very
important for safeguarding the special status of the large herbivores.
2.Appropriate
care is an essential animal right, authorized by law. With respect to large
herbivores it is combined with the role of maximal autonomy in near-natural
areas.
3.Appropriate
care for all free ranging herbivores needs development of standards and methods
in relation to
- regulation of the
population size and estimation of the carrying capacity
- evaluation of behavior of feeding, breeding, reproduction
- evaluation of
mortality patterns and physical condition scores.
Lelystad, May 2000.
======
5. VETERINARY AND ANIMAL WELFARE
ASPECTS OF LARGE MAMMALS IN NEAR NATURAL AREAS.
Dr. Jaap M. van Leeuwen, Veterinarian~Pathobiologist
Nepenthes excursion Oostvaardersplassen (OVP) on 21-08-'02
SHEET 1
*This type of quadrants is used by management
consultants. It gives an idea of the contradictory relations between different
matters.
*Autonomy, freedom and self-reliance are
important features for free ranging animals. It stimulates these animals to
care for themselves in good and bad times. It is the core business of natural
grazing. 'Natural' is defined by these features.
*Doing nothing however may have a pitfall,
called neglect: "Let them die, let them suffer, let them being sick by
micro-organisms, because it is all nature!!" The decision however if an
area of some 1000 of ha. is nature or not is made by human beings. So wé are responsible for the type of nature and for the
conditions and the quality of that nature.
*That means that sometimes some form of care
has to be given. The discussion is about the type of care, how much, when and
why care, etc. "Care" has to be defined.
*Giving blind care may soon lead to an
overdose, such as extra feeding in winter time on a regular basis, too much
medical care, protection of weak animals against bad circumstances, etc. !!
This is the opposite of the mentioned core business of autonomy.
*Nature management has to cope with all these
contradictory elements. The aim of grazing management in near-natural areas is
neither to achieve a maximum of freedom alone, nor to give care for health and
welfare alone, but at least a combination of both. What are the characteristics
of that type of care?
SHEET 2
ANIMAL CARE IN THE CASE OF NATURAL GRAZING PAY
ATTENTION TO:
*INFECTIOUS PROBLEMS
*SERIOUS GENETIC LOSSES
*SUFFERING AND EXHAUSTION TILL DEATH
*BARRIERS IN FREE MIGRATION AND TRANSPORT
*DESTRUCTION AND DEGRADATION OF BIOMASS
*MANAGEMENT OF POPULATION SIZE
*CONSUMPTION OF MEAT
*Real threats in the EU are: massive culling and
destruction of animals in cases of FMD, CSF, ASF, BSE, TBC, Brucellosis. What
can we do about it? In the EU. Comment : real threat is not necessarily for the
wild animals themselves, but also for man and livestock. (discussion-sheet 3)
*Genetic losses may occur by crashes (may be
good for the ecosystem, but how natural are some crashes?), by stamping out and
by domestication of wild animals (sheet 4)
*Suffering and exhaustion till death are quite
normal in pure nature, though suffering may be shortened by animals of prey.
But in our society all animals have got rights. We will discuss this point in
(sheet 5)
*Physical barriers in nature or legislative
ones in traffic prevent the spread of infections, but may be also harmful in
natural perspective. (sheet 6)
*Destruction of biomass in closed rendering
factories serves the hygiene in our densily populated
country. But are the reasons for doing that in nature correct or is this an
example of overdose of care and security? (sheet 7)
*Structural management of population size needs
knowledge about carrier capacity of the area, population development and
natural behaviour of animals. The methods of regulation have to be developed
too. Rejection however of this type of management ŕ
priori may be contradictory with the official Guidelines and the Welfare Act
(Sheet 8).
*Meat of wild is normally accepted food in our
society, just as meat of kept animals from the husbandry. Why is meat of
semi-wild animals not accepted till now? (sheet 9)
*The above mentioned questions and
contradictions play a role in the concept of natural grazing in our small part
of the western world. So, in other parts as in
SHEET 3
INFECTIOUS THREATS : SUGGESTIONS FOR CONTROL
*CLINICAL OBSERVATIONS Taking into account
livestock industry and human health risks
*PATHOLOGICAL AND MICROBIOLOGICAL
INVESTIGATIONS
*CONTROL MEASURES FOR INFECTED AND SUSPECTED
free-ranging ANIMALS
*QUANTIFICATION OF RISKS OF AGENT TRANSMISSION
IN RELATION TO INTERVENTIONS
* Endemic infections may be useful to build up
a good immunity; and may be no threat for the wild population, and its direct
environment
However, livestock industry may want a disease-free
situation. Also, new diseases may be introduced which can create threatful situations for wild animals, domestic animals and
men. In such cases, early warning is essential.. How? Monitoring wildlife
health.
*You have to start with clinical observations
by park rangers and veterinarians looking for abnormal morbidity or mortality.
Particular attention should be given to symptoms indicative of notifiable diseases, though one should remember such
symptoms can vary in different species; this must take place by protocol, on a
regular basis and have to be reported.
*Laboratories are necessary to make or to
confirm the diagnosis. No further laboratory investigation of suspected
clinical cases may be very dangerous in cases of FMD or CSF. Sampling a too
small group of animals minimize the chance to make a diagnose in an early
stage. Also in cases of TBC, Paratbc, Brucellosis,
etc. the damage afterwards will be much greater.
*Eradication in cases of FMD concerns in
principle the whole herd. This virus is very contagious. In cases of CSF
however, eradication of boars may be partial by hunting. When the transmission
rate (R0) of that virus is lowered between 1 (one), the spread of the infection
will be stopped and the infection disappears. At the moment, when there is an
infection of swine fever in boars in
*Risk assessment has to be supported by
analysis and quantification. A better understanding of the epidemiology of notifiable diseases in wildlife is required. Though
absolute risk free is impossible, security measures or interventions to
minimize risks can then be developed (which are not necessarily those which
apply in the livestock industry) Important interventions are isolation and
vaccination.
To
save precious genetic material (Schoonebeker sheeps) it may be possible in the future to use markervaccines. The use of these vaccines in combination
with specific diagnostic tests has still to be accepted within the EU. The
current scenario of nonvaccination is that both
infected ánd suspected, but healthy animals have to
be destructed.
SHEET 4
SERIOUS GENETIC LOSSES
*CRASH : PHOCINE DISTEMPER VIRUS INFECTION IN
SEALS
*STAMPING OUT: HERDS WITH FMD
*DOMESTICATION
*Some think a crash of harbour seals by massive
infection with Phocine distemper virus may be very
natural , but questions arise about the cause of the crash. A century ago there
were around 3 times as much seals in the Dutch Waddensea
than now (14000 versus 5000). So, overpopulation seems not to be a real cause.
(comment : it's not shown to be a cause in the case of the seals but population
numbers are of course also linked to available resources (e.g. habitat), so
that if these diminish you may end up with fewer total numbers but a relative
overpopulation). In 1988 the death % was about 64. Till now 20-25 % . A
polluted environment was shown to have impaired the seals' immune defence. And
how natural is the death of apparently healthy animals in good condition?
New in this case is the Trilateral Seal Expert
Group with representatives of
*Stamping out of complete herds of large
herbivores to control FMD is a real threat today. In the Dutch outbreak of 2001
a herd of Schoonebeker sheep was eradicated. This
herd of 140 animals were vaccinated such as a lot of cattle herds because the
rendering capacity was restricted and fast rendering of all the target animals
needed too much time. To make the country official free afterwards all the vacinated animals had to be destructed. People are afraid
that the virus is still alive in vaccinated animals and this may be true, but
it is never proven that vaccinated animals excrete or transmit the virus.
Vaccination gives a well proven transmission block. Denying this is a
misunderstanding, playing a role in international trade. A solution for the
future may be the use of markervaccines. The EU is
financing experiments of the
An extra argument in the case of the Schoonebeker sheep was that on a total Dutch population of
1400 Schoonebeker sheep the eradication of this small
herd was not a real threat for the population. But what should be the policy
with a Heckcattle herd and a
*Domesticated cattle has been selected for
centuries on traits serving humans, and consequently "wildness genes"
may have been lost. The importance of this genetic loss is unknown, as the extent
to which it may cause the free-living animal to be in-adapted to react
appropriately to circumstances when is set out in dutch
nature areas, and to which it therefore causes suffering. This is determinative
for the dependency of care, and requires further research
SHEET 5
ANIMAL WELFARE
*PREVENTION OF UNNECESSARY AND HOPELESS
SUFFERING
*FREE DEVELOPMENT OF THE POPULATION AND OF
SPECIES-SPECIFIC BEHAVIOUR
*As we said, suffering and exhaustion till death
are quite normal in pure nature. In our society however animals have got
rights. Can we solve this dilemma?
*In other words: suffering and death may give
natural contributions to the free development of the population and of
species-specific behaviour of the animals. In any case they must have played an
essential role in the biological evolution in the past. But do we still live
with this kind of nature and what is the sense or role of wild nature in our
culture today? That is a difficult one.
*In 2000 the Dutch Government introduced for
the first time in history Management Guidelines for natural grazing to protect
health and welfare of the animals. The formal guidelines were in accordance
with several Acts, such as for Health and Welfare of Animals, Flora&Fauna, Rendering, Meatinspection
a.s.o. and with rules about Transport or I&R.
Both of the above mentioned points are very important. Just before 2000 some
Nature Management Organizations in the NL, such as SBB and NM, had built these
criteria in their own Ethical Guidelines. They are practising these principles
with success already over several years. SBB do it as follows (when I am wrong,
Adri will correct me): in periods of food shortage in early spring starvation
till death of animals is prevented by shooting these animals before endless
suffering. The criteria for serious starvation are based on clinical scores of
the physical condition and judgement of the behaviour of individual animals.
In the view of an independent viewer like me
there are some suggestions to make:
1.You can bring the condition scores and other
data (age, autopsy) in a predicting model, also important in the communication
with the public. This model has to be worked out by model builders.
2.It should be informative to complete the
clinical scores of physical condition with additional measurements like the turgor of the skin, the movements of the rumen, etc.
3.Clinical chemistry (ketone
bodies, fatty acids, a.so.) may be helpful to
standardize the model.
4.Ethological observations of individuals give
important information on processes affecting population health and viability.
It ought to be carried out more frequently for understanding welfare in the dedomestication process. Fortunately, there is now a person
(Machteld van Dierendonck)
starting ethological work on the Konikponies in the Oost Vaarder Plassen.
These
suggestions are done for future investigations. They may contribute to
differentiate between physiological losing of weight and pathological
starvation. It may also bridging the gap between ecological and animal
disciplines.
SHEET 6
BARRIERS IN FREE MIGRATION AND TRANSPORT
*POSITIVE ASPECTS OF BARRIERS
*NEGATIVE ASPECTS OF BARRIERS
*Physical barriers in nature and legislative
ones in traffic prevent the spread of infections, but may also be harmful in
natural perspective.(sheet 2)
*Transport of animals over the current roads
needs permission of the authorities.What is positive
on that? Le me explain it to the critics: to prevent spread of dangerous and
contagious micro-organisms like FMD, CSF, BSE etc. the OIE, the EU and every
country use a strict system of restriction rules. One of them is the obligation
to use I&R. All animals must be identified and registrated
to trace the source of infection afterwards. Besides, before transport, the
animals have to be examined for absence of certain infections. If not you may
transport your problems to others. Also important is that health monitoring
take place on a regular basis by using the examination protocols. The use of quarantines
is also important for transport.
Even barriers may be important in nature to
stop unwanted spread of infections over the whole area. You can use the
barriers to close international connecting zones, national corridors and local
passages over or under the roads, for example.
*The negative aspects of barriers are well
known by you. Also in our small country natural areas are fragmented and
isolated from each other, just like islands. Free migration by herbivores
between these islands is nearly impossible (though
SHEET 7
DESTRUCTION AND BIODEGRADATION OF BIOMASS
*DESTRUCTION IS A BONUS FOR HYGIENE
*BIODEGRADATION IS A BONUS FOR BIODIVERSITY
*In animal husbandry destruction of biomass concerns
carcasses unsuitable for consumption or contaminated with agents or substances
dangerous to other animals and men. In our country it is also forbidden to burn
carcasses in the open field or to bury them in the ground. On European level
you have to face the fact that in some countries ASF, rabies and tbc are still present. There is also free trade of food
products in the EU and consumerorganizations or the
public-in-general are very concerned about the safety margins of our food.
Destruction as alternative for biodegradation and consumption means: prevention
of spread of infection, especially in the absence of scavengers.
*Biodegradation however is aloud for red and
roe deer or boars and why not for semi-wild and feral animals? This question
needs more attention.
How real are the risks of transmission of
agents in the larger unities of nature? Are these risks quantifiable, is it
possible to confine the risk of transmission, can you formulate prerequisites
and conditions for safe biodegradation, such as monitoring of animal health of
herbivores, absence of priority agents, minimal distance of dead carcasses to
agriculture and public, role of scavengers, a.s.o.
At least a documented risk analysis is
necessary to support nature policy in this field.
Biodegradation of carcasses in the area is the
last essential step in the process of natural grazing. Besides it supports the
idea of biodiversity, but I am sure you know all about this.
SHEET 8
MANAGEMENT OF POPULATION SIZE: PROS AND CONS
*MASSIVE DEATH CAUSED BY OVERCROWDING OPPOSES
THE WELFARE LAW
*AUTONOMY MEANS SELF REGULATION
*Structural management of population size needs
knowledge about the carrier capacity of the area, population development and
natural behaviour of animals. The method of regulation has to be developed too.
In the absence of large predators an ecosystem is fundamental incomplete, the
top of the food pyramid is lacking. Men should play a replacement role. How?
Nature managers should know very well how to handle with this. They can develope a decision model and make the best of it. Besides,
rejection ŕ priori of this type of management may be
contradictory with the official Guidelines and the Act of Welfare.
*Till now however SBB follows an other way.
Neither massive death nor overcrowding are clearly proven, so she supports the
idea of self regulation of the population size to serve the autonomy of nature.
She realizes very well, that application of preventive and artificial
regulation by men may easily lead to structural repeated interventions and she
is anxious to do that in this type of nature. Besides, practical objections are
that it is still difficult to determine the optimal size of the population or
the carrying capacity of the area. The arguments for doing nothing are only valuable
when they are not offending the Law. 'Management by walking around' preventing
hopeless suffering support the concept of autonomy.
At the moment a question arose about possible
problems in
SHEET 9
CONSUMPTION OF MEAT: YES OR NO?
*CONSUMPTION OF MEAT OF SEMI WILD HERBIVORES
SHOULD BE VERY
*CONSUMPTION OF MEAT OF HERBIVORES IS AGAINST
THE CONCEPT OF NATURAL GRAZING
*Meat of wild is normally accepted food in our
society, just as meat of kept animals from the husbandry. If consumers eat
products from biologic-dynamic origin or from kept wild boars in Nature Parks,
why not from semi wild herbivores? Why is meat of semi-wild animals living in
the same area as other wild animals, not accepted for consumption till now?
There is undoubtedly an international I&R problem to differentiate this
product from uncontrolled or husbandry meat. When the semi wild herbivores are
monitored properly on health status there are no substantial objections for
consumption, they are even better controlled than the other wild. The health
control conducted by protocol need perhaps a certification step to identify
this meat from uncontrolled and husbandry meat. If doing so what is than the
problem?
*It is obvious that the concept of natural
grazing means that dead animals belong first to nature itself. This concept
serves the biodiversity. However consumption of meat means that healthy living
animals have to be caught and killed, because weak and sick animals are not
ideal for consumption. Only as part of population management, nature managers
can be forced to catch and kill a lot of animals, say 20 - 50 % of the
population, to prevent overcrowding by simulating a natural crash. And then the
discussion about consumption starts again.
*The problem of the above contradiction may be
the absolute character of the 2 statements. Perhaps the best solution is that
both consumption and biodegradation are aloud under certain conditions. This
point need the attention of decision makers and political parties.
SHEET 10
NATURE AND CULTURE
*PRIMITIVE NATURE MAY BE ASSOCIATED WITH CHAOS
*CULTURE MAY BE ASSOCIATED WITH ORDER
*ORDER IS ORIGINALLY PRODUCED OUT OF CHAOS (Prigogine)
*NATURE AND CULTURE DOES NOT NECESSARILY MEAN A
(General Reference: M.G.C. Schouten.
Nature as image in religion, philosophy and art (in Dutch); KNNV,
In the very interesting book of Matthijs Schouten you can read,
*that the Chaos theory in terms of nature means
that spontaneous self organization may occur from a situation of apparently
chaos;
*that after little disturbations
new eco systems may become instable;
*that the system-theoretical-approach of the
last century is succeeded by the chaos-theoretical-one.
*that unpredictable, dynamic wild nature
confront the overorganized western culture today,
where civilization often means oppressive regulations and conventions.
*that new concepts of nature can develope as swamps or open landscapes with large herbivores
in stead of high density woods.
*that nature is our responsibility and part of
the ethical domain. Gardiner says: The mystery is that the same nature that
doesn't care about the suffering of her creatures have produced in Homo Sapiens
a creature, that concern or may concern this matter.
*the instrumental value of nature means a clear
code of conservation; the integral value of nature however is more complex, it
means at least more respect for the autonomy. In near natural areas both values
are important.
*Our conclusion today is: care for nature and
for animals in nature is appropriate when it is directed to serve the highest
quality of nature and of animal life; that means maximal freedom in combination
with essential care. It is also important to study the cultural aspects of
nature. The awareness of nature and the images of nature in several cultures
are important both for nature as for the cultural development of mankind.
Visit
also the sites of the Dutch Society for Wildlife Health, Dutch
Ministry of Nature
(search: ‘grazers’), Hans Kampf, Veterinary discussions (Dutch)
First: Aug 2002
Update: Jan 2005
