Alternative / Disease
Control
Biosecurity and
EradicationObviously the best way to deal with a disease is to avoid it.
Care should always be exercised to prevent introducing new diseases onto a
pullet or layer farm. Common disease carriers include people, vehicles,
equipment, wild birds, animals, and chickens themselves. New flocks should
be tested before being brought onto a farm and should have a known
vaccination programme.
SanitationCleanliness, sanitation and
strict traffic control are the most effective and least expensive tools in
a disease prevention programme. Physical removal of all litter, manure,
dust feathers and other poultry house debris to a spot remote from the
poultry house is the first step in an efficient clean-cut programme.
An
effective sanitation programme must include removal, dismantling and
disinfecting all equipment in the house, before the house itself is
cleaned and disinfected. High pressure sprayers and an effective
disinfectant are necessities for eliminating disease carryover. This must
be supplemented by a rodent and insect control programme. These efforts
must be continued for maximum effect.
After housing the flock, dead
birds must be removed and incinerated daily. Rubbish and debris should be
moved out on a regular basis and not allowed to
accumulate.
Traffic
ControlFoot and vehicular traffic threaten constant import of disease
organisms. Locked doors and a policy of no visitors is advisable. When it
becomes necessary to permit entrance of visitors, clean disinfected
footwear and outer garments should be provided. Feed and egg trucks and
their drivers, must be isolated from the bird area.
Portable equipment
should be confined to as few houses as possible and should be cleaned and
disinfected when transported between houses.
Vertically Transmitted DiseasesSome diseases are known to be
transmitted from infected breeders to their progeny. This requires the
production and maintenance of disease-free breeders as a first step in the
control of thesediseases at the commercial level. All breeders directly
under Hy-Line’s control are free of mycoplasma gallisepticum, Mycoplasma
synoviae, S. pullorum, S. gallinarum (typhoid), S. enteritidis, and
lymphoid leukosis. Due to the possibility of horizontal transmission of
any of these diseases. later generations may not remain free.
It is the
responsibility of the breeding stock and commercial flock owner to prevent
horizontal transmission of these diseases and continue testing to be
assured of a negative status.
Vaccination Programmes
Vaccination programmes need to be individually designed with
consideration for maternal immunities of the chicks, disease exposures
expected, vaccines available, routes of administration preferred and
planned use of inactivated injectable products.
Because of the
extreme variability of these factors among producers worldwide, we cannot
recommend one programme which would be satisfactory for all. We therefore
recommend that you consult your Veterinary Adviser on a programme suitable
for your particular circumstances.
Regardless of the exact programme, care always needs to be
exercised to ensure each bird is given an adequate dose of viable vaccine.
In our experience, most vaccination failures relate to improper
administration techniques.
Infectious Bursal Diseases
Special attention should be paid to IBD control. This disease
can have many subtle effects which are detrimental to pullet health. The
primary feature of IBD is immuno-suppression caused by damage to the bursa
of Fabricius which leaves the bird unable to fend off other disease
challenges. Secondary diseases such as gangrenous dermatitis, bacterial
arthritis and even Marek’s often result. Virtually all flocks are exposed
to IBD and therefore, should be protected by vaccination. Most breeding
stock receives a killed
IBD vaccine to boost maternal titers in the
chicks. Research at Hy-Line international has shown the optimum time to
vaccinate such chicks with intermediate strain live vaccines is at 18 - 20
days and again at 28 - 30 days of age. An extremely severe IBD challenge
may require an additional vaccination during this period.
Bursas can be
examined later to determine the extent of
protection.
Disease Control
A flock of pullets or layers can only perform up to its genetic
potential when disease influence is minimized.
The appearance of
various diseases can vary from a subclinical effect on performance to
outright severe mortality. The diseases of economic importance vary widely
between locations, but in every case the challenge is to identify and
control those diseases.