Part Seven
Disease patterns
Ducks, we are told, suffer fewer of the 'standard' diseases
than either chickens or turkeys - Marek's disease, infectious
bursal disease (Gumboro), infectious bronchitis, fatty liver
and kidney syndrome and rhino-tracheitis. Between them, these
and other conditions account for a mortality of six per cent
in intensive chicken and turkey houses, even under optimum
conditions.
The duck industry portrays ducks as being tough and healthy.
Cherry Valley boasts a 'livability of 95 per cent at 47 days
of age' (1). This, however, indicates an expected five per
cent mortality - not far short of the average figure for other
types of poultry.
Five per cent mortality equates to 500 duck deaths in a flock
of 10,000 birds before the age of 47 days. If this figure is
rolled out to the 18 million ducks slaughtered in the UK in
2004, this would indicate that, annually, just under one million
birds die before reaching 47 days. Undoubtedly, Cherry Valley's
figure assumes 'best practice'. Companies worldwide will fall
far short of this. A spokesman for Cherry Valley recently claimed
below three per cent mortality based on the company's own flocks
where husbandry may be better than the norm.
Five per cent? Three per cent? Sometimes a lot higher? The
question remains - if ducks are relatively disease-resistant,
why are they dying in such numbers? The very term 'infectious
disease' points to the vulnerability of birds forced to live
together in their thousands, without the benefit of fresh air
and space around them.
UK diseases
The following are the most common causes of death amongst
UK ducks from infectious diseases.
Duck virus enteritis (duck plague). A highly
infectious disease caused by the herpes virus, it can cause
mortality of up to 90 per cent. Ducks of all ages can be affected
and vaccination is often used to control existing outbreaks
rather than as a preventative measure.
Duck virus hepatitis (DVH). An acute and
highly infectious disease with death following within hours
of its onset. A live vaccine is available but vaccines are
not magic bullets. Antec International admits that although
vaccination plays an important role in the control of some
of these conditions, disease frequently still occurs (2).
E. coli septicaemia. Potentially fatal, treatment
involves dosing with a broad-spectrum antibiotic. It commonly
attacks young animals, especially those kept under intensive
and therefore stressful conditions.
Streptococcal septicaemia. Infection of the
blood caused by the streptococcus bacteria.
Pasteurellosis. A common secondary invader
following respiratory viral infections in poultry, including
ducks. It can also cause fowl cholera and septicaemia in ducks.
Salmonellosis. Disease caused by infection
with bacteria of the Salmonella type. Often attributable to
stress. Can be spread via feed and water contaminated by faeces.
Aspergillosis. Invasion or colonisation of
body tissues by a fungus, especially affecting the respiratory
tract. It is often caused by mouldy litter - a constant potential
problem because of damp litter in duck units.
Egg peritonitis. The main cause of death
in laying birds - female breeders. It is probably linked to
the unnaturally high output of eggs, achieved through decades
of genetic selection. Post-mortem examination may reveal yolk
debris, yolk caseous material or milky fluid in the abdominal
cavity, together with inflammation and distortion of the ovaries
as well as an offensive smelling mass of caseous material.
Alternatively the oviduct may be obstructed by a core of inflammatory
debris which may sometimes result in rupture of the oviduct
wall. A whole or partly formed egg may be impacted in the oviduct
and almost invariably, E. coli can be isolated from it (3).
Plantar pododermatitis. An ulceration of
dead skin tissue under the foot caused by contact with damp
litter and resulting in pain and lameness.
Starvation and injury
If the above diseases are not rampant and account for only
a small part of the three or five per cent mortality, as producers
claim, death must be from starvation or injury, possibly as
a result of aggression. Also, breeding heavy birds causes suffering
and sometimes starvation through difficulty in walking. The
Council of Europe, in its Recommendations Concerning Domestic
Ducks, states that 'Mallards fly, swim and walk efficiently
but the heavier domestic birds, in particular those selected
for meat production, may be unable to fly, have difficulty
in walking and be subject to leg disorders' (4). Incredibly,
in a letter to Viva!, Ben Bradshaw put forward Defra's official
position that there were "... no problems observed with leg
weakness in ducks." (8) This shows an alarming ignorance on
Defra's part - be it willful or otherwise.
Also, in crowded conditions, ducks get knocked over by other
birds and are often unable to right themselves. Even when put
back on their feet it takes some time for them to reorientate
themselves and they need to be watched for a while to make
sure the same thing doesn't happen again. In the packed conditions
of a shed containing up to 10,000 birds, it is likely that
stranded ducks go unnoticed. They may be trodden underfoot
by other ducks and die from injury or starvation. Cannibalism
may follow, either before or after death. Cannibalism is caused
by stress.
Antibiotics
There are currently four antibiotics currently authorised
for use in ducks in the UK. These are Amoxinsol 100, Amoxinsol
50, Amoxinsol Proportioner and Aurofac 100 Granular (7).
Amoxinsol (containing amoxicillin) for the treatment of Streptococcus
bovis, Pasteurella anatipestifer and E. coli.
Aurofac100 (containing Aureomycin chlortetracycline hydrochloride)
for the treatment of respiratory and systemic infections.
A spokesperson for a leading drug company gave his opinion
that ducks suffer from respiratory and other diseases but knew
of no precise data on the percentage of antibiotics given to
the duck sector of the poultry industry. Such figures are unlikely
to be collated anywhere. In light of two major reports on antibiotic
resistance in farm animals (Soil Association's The Use and
Misuse of Antibiotics in UK Agriculture and the House of Lords
Science and Technology reports), this is an unacceptable situation.
The Veterinary Medicines Directorate, an Executive Agency
of Defra, holds no information separating ducks from other
species in its figures for annual total usage of antibiotics
(7).
Global diseases
Large numbers of intensively-reared ducks have
been exported worldwide from the UK. World Poultry Misset (No.
7 Vol 13, 1997) provides a list of poultry diseases which can
occur anywhere in the world. Those affecting ducks are in addition
to those described above and include the following.
Adenovirus - associated with many
diseases including respiratory disease and viral arthritis.
Amyloidosis - associated with
infected lesions on the feet and amongst adults in heavier
strains of commercial ducks.
Ascites - More often associated
with chickens, it made its first appearance in birds kept at
a high altitude. It is mostly caused by increased oxygen demand
resulting from too-rapid growth in combination with restricted
blood flow through the small capillaries in lungs of birds
selected for 'meatiness' (5). Avian influenza -
Believed to be spread by close contact. Results in respiratory
distress and depression. The
recent outbreak of the deadly H5N1 strain in Asia has been
linked to ducks, which often do not show outwardsymptoms of
infection. A notifiable disease. Avian malaria -
Similar to the human form of the disease.Avian salmonellosisAvian
staphylococcus - Associated with a wide variety of
diseases including arthritis and tenosynovitis.Bacterial
synovitis - An infection of the joints, tendons and
surrounding tissues resulting in lameness. Fowl Pest
(Newcastle disease) - Ducks show few signs of infection
even with virulent strains of fowl cholera but
the disease can spread via ventilation apertures into the
environment. Vaccines have little effect in overcrowded
conditions where management is poor and may even produce the
disease. It is a notifiable disease. Keratoconjunctivitis
(Ammonia blindness) - It is caused by ammonia in concentrations
of 170ppm or more (6). Poorly managed, damp litter in badly
ventilated housing can be instrumental in triggering this extremely
painful disease, which can result in haemorrhages of the conjunctiva
and corneal ulcers. Damp litter is a major problem in duck
units and some countries tackle it by allowing only nipple
drinkers or by keeping ducks on wire flooring.
Yolk sac infection (Omphalitis) - Often the
result of poor conditions in hatcheries, it can cause 100 per
centmortality in the worst outbreaks by infecting most organs.Perosis -
Slipped tendon - a leg deformity in ducklings, causing lameness.
Tibial dyschondroplasia - A skeletal deformity
associated with rapid growth and mineral imbalances.Cloacitis
(Vent gleet) - An infection of the cloaca in breeding
ducks and drakes - occurs particularly 'under dirtyconditions
of husbandry' (6). Scarring can damage the vent, making egg
laying and even defecating impossible.
Visceral gout - Caused by renal failure,
it results in swelling and ulceration of the joints.Starve
out - This results when young or injured birds fail
to recognise or reach food and water points.Rickets -
A nutritional disorder caused by lack of certain minerals,
vitamins and trace elements.
Diseases of intensification
Birds have always suffered from a range of diseases and wild
birds are implicated in the spread of some of the most serious
threats such as Newcastle disease. However, many of the conditions
listed above are the result of intensive farming methods.
The increasing popularity of duck meat both here and abroad
will inevitably cause an escalation in the incidence of these
diseases, guaranteeing large-scale suffering amongst the duck
population. Recent, disastrous outbreaks of Avian Flu - both
in Asia and Europe - have prompted fears of an inevitable pandemic.
The World Health Organisation insists that free-range poultry
are being infected by wild birds, who carry the virus but are
not affected by it. The United Nations Food and Agriculture
Organisation has placed the blame for the impending outbreak
on livestock markets, poor biosecurity and the trade in live
poultry and dismisses the charge that wild birds are responsible
for its spread. The World Health Organisation, however, insists
the answer is to put all poultry into factory farms - ignoring
their past advice to end to all intensive farming. Which, if
done, will also further accelerate the reckless over-use of
antibiotics which is already a major human health problem.
Though killed while still, in effect, baby birds, modern ducklings
will still have had time to endure much pain and discomfort
before reaching the slaughterhouse. It is likely that their
entire life, no matter how short, will be one of acute stress
and perhaps disease and severe pain.
References (part seven)
- Cherry Valley, Super M2 information booklet
- Antec International,
Poultry Disease Control
Programme
- Poultry Diseases, Ed. F.T.W. Jordan, Bailliere Tindall,
1990, p39
- Council of Europe, Recommendation Concerning
Domestic Ducks, 1999, Article 3(d)
- As 3
- Cook, JKA et al., Diseases of Ducks, Poultry
Diseases, 1996
- Email to Viva! from Dr Kay Goodyear, Defra’s
Veterinary Medicines Directorate, 2005
- Letter to Viva! from Ben Bradshaw MP, Minister forNature
Conservation and Fisheries, 26 July 2004
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