Avishield IBD INT, lyophilisate for oculonasal suspension/use in drinking water, for chickens

One dose of vaccine should be administered to each chicken in drinking water, or by the oculonasal
route from 8 days of age depending on the level of maternally derived antibodies (MDA) in the flock.
Lyophilisate reconstituted in 100 mL of water appears as non-transparent suspension with low
precipitation.

The optimal vaccination date is influenced by a number of factors, such as status of MDA, type of
bird, infection pressure, housing and management conditions.
MDA can interfere with the immunity induced by live infectious bursal disease (IBD) vaccines, so the
optimum age for vaccination depends on both the level of residual MDA against IBD virus in the flock

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and the ability of the vaccine strain to induce the required level of immunity in the presence of MDA.
To predict the age when the MDA titre has sufficiently decreased to allow effective vaccination
(“break-through titre”), testing of serum samples of at least 18 chicks by serology and application of
the “Deventer formula” is advised. A break-through titre of 125 should be used.

The Deventer formula is as follows:

Vaccination age = { (log2 titre bird% - log2 breakthrough) x t _ } + age at sampling + correction 0-4

In which:
    bird% = ELISA titre of the bird representing a certain percentage of the flock
    breakthrough = breakthrough (ELISA) titre of the vaccine to be used
    t _ = half-life time (ELISA) of the antibodies in the type of chickens being sampled
    age at sampling = age of the birds at sampling
    correction 0-4 = extra days when the sampling was done at 0 to 4 days of age.

A high homogeneity of MDA levels in the flock is important to define the correct timing of
vaccination and guarantees a better active immune response to the vaccine. In case of a non-
homogenous flock where antibody levels vary widely between birds (i.e. CV greater than 30%), or the
stock originates from different sources, it is recommended to repeat the vaccination.
In such cases, timing of the first and second vaccination should be determined simultaneously, with
two different percentages (corresponding to the percentages of the flock that can be efficaciously
vaccinated) of all serum samples collected on the sampling day, using the Deventer formula.

1. In drinking water use
• Reconstitute the vaccine in a small amount of cool and clean water without traces of chlorine, other
  disinfectants or impurities, in a number of doses corresponding to the number of birds to be
  vaccinated. Where the number of birds is between the standard dosages, the next higher dosage
  should be used.
• The vaccine should be reconstituted immediately before use.
• Measure the correct volume of water for the number of birds to be vaccinated. The volume of water
  for dilution depends on the age of the birds, breed, housing conditions and weather conditions.
• The reconstituted vaccine should be diluted in the amount of water which will be consumed within
  1.5 to 2.0 hours (taking into account the different types of drinking systems for poultry).
• In order to determine the quantity of water in which the vaccine will be diluted, measure the volume
  of water consumed within a two hours period one day before vaccination.
• As a guideline for younger chickens (until 3rd week of life), apply the reconstituted vaccine to cold
  and fresh water at the rate of 1 000 doses of vaccine to 1 litre of water per day of age for 1 000
  chickens, e.g. 8 litres would be needed for 1 000, 8 day old chickens.
• In order to make the birds thirsty, withdraw the supply of drinking water up to 2 hours prior to
  immunisation (birds drinking behaviour varies, depending on the air temperature, type of birds,
  breed, management, weather conditions).
• The drinking system should be clean, without traces of chlorine, other disinfectants or impurities.
• If needed, turn the lights down low when the water is turned off. After the vaccine is in the drinking
  system, increase light intensity again. Increased light intensity will stimulate the birds to look for
  food and water.
• Always make sure that there is food available when vaccinating. Birds will not drink if they have no
  food to eat.

2. Oculonasal use
• Reconstitute 1 000 doses of the vaccine in 100 ml distilled water.
• A dose of reconstituted vaccine is 0.1 ml, i.e. two drops, irrespective of poultry age, weight and type.
  Instill one drop into an eye and one drop into a nostril.