New Poultry Health Series

Each month we will be added a new article dealing with poultry health and disease prevention. Please send along your suggestions.

The following articles are from the Fourth Edition 
"Poultry Health Handbook"--PennState College of Agricultural Sciences
written by L. Dwight Schwartz, DVM.

 Why we Vaccinate Poultry

Preventive medicine includes any procedure that will prevent a disease or decrease its severity. Vaccination is one of the more effective ways to prevent specific diseases. This is why we vaccinate poultry-so the birds are protected from explosive disease outbreaks. Viruses stimulate the development of immunity better than do other types of microorganisms, so most poultry vaccinations are against viral disease's. Marek's Disease, Newcastle Disease, Infectious Bronchitis, Laryngotracheitis, Fowl Pox, Avian Encephalomyelitis, Infectious Bursal, and Hemorrhagic enteritis account for a majority of all poultry vaccinations.

Vaccination is inoculation with a specific biological substance (an antigen) to stimulate resistance or immunity to a particular disease. Usually the biological substance is a small dose of an attenuated (ie, weakened) live virus to give protection against a specific disease. The presence of this small amount of virus triggers the defense mechanism of the body to product either antibodies or certain cell types to attack the virus. The immune system has the capacity to remember that specific virus so at subsequent exposure, if the time is not too great between exposures, more antibodies or cells will be produced to attack the virus. Scientists have developed attenuated forms of most viruses that stimulate antibody production with little danger of causing the disease. Even some killed viruses stimulate the production of antibodies. With these diseases, the 100-percent safe killed virus is used to avoid possible losses in the flock.

Short term protection against a particular disease can be given by vaccination with an antiserum. An antiserum contains antibodies taken from blood serum of animals already exposed to and with some immunity to the disease. Further discussion on ways that immunity develops follows.

Immunity will be reliable if vaccination is given under optimal conditions: that is, when the vaccine is handled, stored and administered properly; the birds are susceptible, healthy, and vigorous; the nutrition is adequate; the host is parasite-free; and the environment is good.

Occasionally, so -called vaccination outbreaks do occur. The factors that influence vaccine-response in poultry are many, mainly depending on the host and environment. Seldom are all factors considered when vaccination programs are undertaken. Ordinarily some protective immunity is conferred when poultry are vaccinated, although the vaccine in itself cannot guarantee it. When vaccination failures occur, all aspects of the vaccination program should be reviewed.

Facts:

1. A general vaccination schedule--such as those supplied by vaccine manufacturers, poultry books and other sources is only a guide. As a rule, such a guide must be modified to meet your specific needs.

2. Strict sanitation and isolation are essential for a vaccination program.

3. Vaccination of chicks younger than 10 days cannot be expected to produce uniform or lasting immunity, even in the absence of parental immunity.

4. Use fresh vaccines.

5. Each vaccine is designed for a specific method of application . Use only the recommended method

6. Immunity from ND-IB combination vaccines will give dependable protection for only 3 months.

7. Do not vaccinate in advance for laryngotracheitis unless there is a history of the disease on your farm. It is one vaccine that can used after onset of an outbreak. It will halt the spread of infection.

8. Flock immunity against AE should be checked by tests on fertile eggs soon after the flock is in production.

9. In problem areas requiring fowl-pox vaccination of baby chicks, the flock should be revaccinated after reaching 8 weeks of age or older to assure lasting immunity. Like LT vaccination, FP can be administered as treatment during outbreaks.

Tips:

l. Know the disease history of your farm

2. Do not vaccinate sick birds (except for LT or FP)

3. Record all vaccination dates, manufacture's lot numbers, and other information on history chart

4. Do not vaccinate for LT, FP, or FC unless you have a problem on your farm or area.

5. If there is a history of Fowl cholera on your farm, consult a poultry pathologist .

6. Learn the advantages and limitations of each vaccine.

7. Protect vaccines from heat and direct sunlight

8. Follow manufacturers directions

9. Be sure each birds gets it proper dose

10. Use a full 500 doses for 500 birds. Do not stretch the vaccine

11. Do a careful job, don't rush.

12. When using the drinking water  method, be sure the water is free of sanitizers and chlorine. Live virus vaccines are destroyed by these chemicals.

13. Most vaccines are living, disease-producing  agents, Handle with care.

14. After vaccinating, burn or disinfect all opened containers to prevent accidental spread to other poultry.

15. If possible, vaccinate when temperature in the poultry house is mild (50-80F). Temperature extremes are stressful and reactions to stress may interfere with an optimum immune response.