Vaccination is an integral part of a good poultry management programme, as it is key in the success of a farm.
However, it should not be a substitute for bio-security and sanitation because vaccination may not totally protect birds that are under stress or in unhygienic conditions.
The primary objective of vaccinating a flock is to reduce the level of clinical disease and to promote optimal performance.
Poultry vaccines are biological products that induce an immune response to the specific disease-causing agents.
The bird’s immune system will react, creating a “memory” response of antibodies and immune cells, according to the type of antigen in the vaccine.
The more a bird is exposed to the same antigen, the greater the antibody response and resulting protection.
This is the reason many flocks are vaccinated multiple times for the same disease – to maximise the immune system’s response.
Poultry vaccines come in three general forms: modified or attenuated (live), inactivated (killed) and recombinants.
Live vaccines are milder forms of field strains that are naturally or genetically modified.
Inactivated vaccines are whole viruses or bacteria that have been inactivated during production and formulated into an injectable form. Recombinant vaccines are made by using live virus or bacteria as a vector to transport the gene coding for the protective antigen of a second infectious agent for which immunity is desired.
When handling poultry vaccines, observe the following: transport in well-insulated cool boxes containing ice packs to keep the temperature constant, store in temperatures of between 2oC to 8oC, avoid exposing them to freezing, extreme heat and intense light and only mix live vaccines with diluents (reconstitute) just before application.
VACCINATE WHEN IT IS COLD
Further, inactivated vaccines should be removed 24 hours prior to vaccinating so that the product can warm to room temperature or alternatively, use warm water (not exceeding 100oF) for not more than five hours, never expose vaccines to direct sunlight and lastly, gently agitate bottles containing inactivated vaccines thoroughly prior to use.
Vaccinations should always be done during the cooler part of the day, either early morning or late evening.
Before vaccination, ensure that there are sufficient doses to cover the flock and that the birds are healthy. Also ensure that the vaccines have not expired.
In East Africa, broilers are vaccinated against Infectious Bronchitis (IB), Newcastle Disease (ND) and Infectious Bursal Disease (IBD/Gumboro) while layers should be vaccinated against mareks, infectious bronchitis, NCD, Gumboro, fowl pox, fowl typhoid and fowl cholera.
REQUIRE MORE VACCINES
Layers require more vaccines since they remain in production for longer (usually about 18 months) compared to broilers that are slaughtered at two months old.
This means that layers are exposed to diseases for longer and need re-dosing with vaccines.
It is not recommended, neither is it necessary to vaccinate broilers beyond day 24, since the vaccine cover is sufficient until slaughter (if slaughter is done at the conventional time of 60 days).
Furthermore, vaccination is stressful to the birds and doing so beyond this period (day 24) slows down their growth at a time when fast growth rate is of paramount importance
Commercial layers can be dewormed at 18-19 week, while fowl pox susceptibility increases with elevated temperatures.
It is also worth noting the following when administering vaccines:
- Administer vitamins a day to vaccination and three days after to minimise stress.
- Never mix vaccine and vitamins.
- Do not vaccinate sick birds. In case of any ongoing antibiotic flock treatment, withdraw the treatment three days prior to vaccination.
- Minimise vaccine reactions by reducing exposure time after preparation.
- For vaccines administered through drinking water, the drinking time should be at most three hours. Discard the remaining water, wash the drinkers and provide fresh water mixed with vitamins.
Kimetei is based at the Animal Sciences Department,