Intensive / Disease
Control
Biosecurity and
Eradication
Obviously 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
Control
Foot 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 DiseasesSpecial 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.