AGRICULTURAL EXTENSION SERVICE
NEWCASTLE, INFECTIOUS BRONCHITIS AND
POX VACCINATION FOR POULTRY
Prepared by Veterinarians in the Department of Veterinary
Science of the University of Florida Agricultural Experiment Station
and the Florida Livestock Board
Vaccination, a technique by which poultry are rendered re-
sistant-to disease, is of practical value in the prevention of cer-
tain diseases of poultry. Vaccines which are commonly employed
in Florida include those used against Newcastle, infectious bron-
chitis, and fowl pox. It has been demonstrated that the immun-
ity resulting from vaccination is primarily dependent upon three
factors: (1) age at which applied, (2) physical condition of the
bird, and (3) the number of times the bird is vaccinated for a
Obviously a fixed vaccination program adaptable to every
poultry operation cannot be formulated, as management prac-
tices vary from farm to farm. Nevertheless, a vaccination sched-
ule applicable to most poultry operations can be stated in gen-
Only healthy flocks should be vaccinated because vaccination
in most instances constitutes a temporary stress. Any condi-
tion which lowers the physical resistance of birds, such as chill-
ing, overheating, coccidiosis, etc., constitutes a stress. If birds
are vaccinated when their physical resistance is low, a severe
vaccination reaction may follow as a result of additional stress.
Many broiler producers prefer not to vaccinate against any
of the three above-mentioned diseases, even though satisfactory
treatments for these diseases are not available.
Newcastle Disease.-Intraocular, intranasal, water, spray or
dust vaccines may be administered at 3 to 7 days of age, and may
be repeated as recommended by the manufacturer.
Infectious Bronchitis.-Intraocular, intranasal, water, spray,
or dust vaccines may be given at 3 to 7 days of age.
Vaccines combining the viruses of Newcastle and bronchitis
are available for simultaneous protection against both diseases.
They do not confer as solid immunity as in instances in which
these vaccines are applied separately.
Vaccination Reactions.-A reaction in 7 to 10 days generally
follows vaccination for Newcastle and bronchitis. It is gener-
ally manifested in the form of mild respiratory symptoms char-
acterized by sneezing. Feeding of an antibiotic at a therapeutic
level (100 to 150 grams per ton of feed) for a period of 2 weeks
following vaccination frequently results in less severe reactions
and minimizes the possibility of "triggering off" chronic respira-
tory disease in the flock. Recent evidence indicates that there
is little correlation between the severity of the reaction and the
degree of immunity produced by the vaccine.
Fowl Pox.-In some areas broiler producers find it necessary
to vaccinate against fowl pox at an early age. In case 'day-old
chicks are vaccinated against this disease it is important to
wait at least 14 to 21 days before any other vaccination to allow
birds to recover from any reaction which may have followed pox
Newcastle Disease.-Vaccination methods are the same as
listed for broilers and should be repeated as recommended by the
manufacturer. In addition, wing-web vaccine may be admin-
istered at 5 weeks of age, or 10 to 12 weeks of age if the birds
had been vaccinated as baby chicks.
Infectious Bronchitis.-Vaccination for this disease is gen-
erally performed at 3 to 7 days and 14 to 16 weeks by any of
the methods mentioned under broilers.
Combined vaccines containing both Newcastle and infectious
bronchitis viruses are generally used and provide some protec-
tion against both diseases by a one-step procedure. However,
the combined vaccines do not confer as solid immunity as in
instances in which these vaccines are applied separately.
Outbreaks of Newcastle and infectious bronchitis -have a
devastating and often permanent effect on non-vaccinated lay-
ing birds. Both diseases cause respiratory symptoms, a rapid
decline in egg production, and a marked alteration in the interior
and exterior quality of eggs. For these reasons, it is recom-
mended that replacement birds always be routinely vaccinated
against Newcastle and infectious bronchitis.
Fowl Pox.-Unless a heavy mosquito population makes it
mandatory to vaccinate at 1 day of age, the stick method of
vaccination with fowl pox vaccine is recommended before 10
weeks of age. In any event, vaccination for Newcastle disease
and/or infectious bronchitis should come either before or after
pox vaccination at a sufficient interval (21 to 28 days) to allow
the birds to recover completely from any previous vaccination.
FACTORS AFFECTING DEVELOPMENT OF IMMUNITY
1. Physical condition of the birds affects development of im-
2. There is wide variation in the virulence of viruses used
by the manufacturer in the production of vaccines. There is
more standardization in the case of Newcastle vaccine than in-
fectious bronchitis vaccine.
3. Immunity varies widely with the method of application
and the virus used. The finer the particle size of the virus in
the vaccine the more severe the reaction when sprays or dusts
4. A 6-week-old bird has more ability to develop immunity
than a day-old chick. This ability is maximum in a young adult.
5. Amount of immunity already possessed may affect the
development of additional immunity.
6. Immunity varies widely with the degree of exposure to
7. In some instances one vaccine may interfere with another.
8. Nutrition plays an important part in the development of
COOPERATIVE EXTENSION WORK IN AGRICULTURE AND HOME ECONOMICS
(Acts of May 8 and June 30, 1914)
Agricultural Extension Service, University of Florida,
Florida State University and United States Department of Agriculture, Cooperating
M. O. Watkins, Director