Vaccination is an important barrier to ensuring the health of a flock and one of the most important aspects of production management. The following principles must be observed: “Focus on effectiveness, not results; focus on quality, not process; be scientific and reasonable, and do not follow blindly.”
I. Before Immunization
1, personnel responsible for immunization must complete pre-job training and meet the technical requirements before they are allowed to perform the work. Large-scale farms generally combine a master-apprentice training approach with guidance from professional instructors.
2, before immunization, conduct a comprehensive and detailed assessment of the health status of the flock to be immunized. Pay attention to balancing the animals’ immune function (大芪芍（Astragalus Polysaccharide Oral Solution）), reducing immunization stress (益肽灵), and understanding the different vaccines. For example, flocks showing any abnormal conditions must not be immunized, or immunization must be postponed. This is especially important for live attenuated vaccines that can irritate the respiratory tract, such as freeze-dried infectious bronchitis vaccines, freeze-dried Newcastle disease vaccines with strong respiratory tropism, and infectious laryngotracheitis embryo vaccines.
3, Cleaning and disinfection of equipment required for immunization
(1) Continuous syringes for immunization (disassembled), needles, lancets, tweezers, etc. must be cleaned beforehand and sterilized in boiling water in a sterilizer for 15–20 minutes before use.
(2) Plastic items that cannot be boiled for a long time to disinfect them, such as droppers, connectors, and dropper bottles, must be cleaned beforehand and soaked in boiling water for 10 minutes before use.
(3) Immunization equipment and supplies that have been cleaned and disinfected must be rinsed with distilled water before use. During use, the principles of aseptic technique must be followed to prevent Pseudomonas aeruginosa disease (with particular attention to breeding chickens).
4, Before immunization, inspect the vaccine quality; vaccines with problems should be discarded and not used.
5, Before immunization, calibrate the dose of all immunization equipment before use according to the dose required by the prevention and control plan.
二、During immunization
1, Strictly follow the prevention and control schedule, vaccine types, dosages, and methods of use specified in the immunization plan.
2, handle chickens gently during vaccination to reduce stress.
3, vaccination procedures
（1）Vaccination quality: correct site, standardized procedure, accurate dosage, and zero missed vaccinations.
（2）Vaccination speed: for injection vaccination, no more than 600 chickens per person per hour is recommended; for intranasal drops and eye drops, no more than 500 chickens per person per hour is recommended.
（3）Immunization process: No deaths, bleeding, missed vaccinations, missed immunizations, or escaped chickens. At the same time, divide the flock into cages, set the number of chickens per cage, and classify them. Cull sick, weak, injured, large, and small chickens, and manage them in separate groups.
（4）Immunization needles: Use No. 7 needles before week 10, and No. 9 needles after week 10. The needle tips must be sharp and free of burrs.
（5）Immunization during the laying period: To prevent stress and feather pecking, A. Handle the chickens gently during vaccination; B. In H-type houses, be sure to transfer all chickens in each cage by inverting the cage; C. Inject at the base of the left wing; D. Prewarm the oil-based vaccine to approximately 40°C (the bacterial vaccine to approximately 32°C); take measures to keep it warm during use; E. Add Vc to the drinking water at 200 ppm; F. Reduce the light intensity to a level that does not interfere with the immunization personnel’s work.
（6）Immunization accountability: Clearly defined duties and individual responsibility; immunization records must be traceable.
4, Precautions for Immunization with Freeze-Dried Vaccines
(1) Prepare immediately before use. Keep the freeze-dried vaccine and diluent refrigerated before immunization.
(2) Check the vacuum level of the freeze-dried vaccine. Discard and do not use any vaccine that has lost its vacuum.
(3) Administer the reconstituted freeze-dried vaccine within 2 hours; discard and do not use any remainder after that time.
（4）During vaccination, the vaccination dose should be checked and adjusted as needed.
（5）For wing-web vaccination, use 6–8 milliliters of diluent per 1000 chickens. Ensure the needle groove is filled with vaccine and is not pointing downward. Be sure to pierce the featherless triangular area.
（6）For eye-drop vaccination, typically use 30 milliliters of diluent for 1000 doses of vaccine. Hold the chicken’s head level and administer the drops vertically into its eye from a vertical height of 1–2 centimeters. Release the chicken after it closes its eye and absorbs the drops.
（7）After eye-drop vaccination, track the proportion of chickens with blue tongues to make a preliminary assessment of vaccination quality.
( 8 ) Effect of diluent temperature on vaccine potency
A. After preparing the vaccine with diluent at 4℃, the potency of the infectious bronchitis vaccine can be maintained for 4 hours in an environment at 2–8℃.
B. After preparing the vaccine with diluent at 4℃, the vaccine potency decreases by 1 titers after 2 hours at room temperature.
C. After preparing the vaccine with room-temperature diluent, the vaccine potency immediately decreases by 1 titers at room temperature, and after 2 hours, the vaccine potency drops to 0.
5, precautions for inactivated vaccine immunization
(1) Remove the vaccine from the pre-warming pot and place it in an insulated container containing warm water at 35℃－40℃ (30－32℃ for bacterial inactivated vaccines), and take measures to keep the vaccine warm during use.
(2) During vaccination, shake the vaccine regularly before and during administration.
(3) During immunization, check the immunization dose at all times and adjust the syringe dose as needed.
(4) For inactivated vaccine administration, use a No. 7 or No. 9 short needle. For neck administration, inject the oil-based vaccine subcutaneously at the rear of the neck, at 1/3. For breast administration, point the needle toward the tail and hold it at an angle of 15-30 degrees to the injection site. Insert it into the subcutaneous tissue or superficial muscle of the breast. Do not insert the needle vertically, to avoid puncturing the thoracic cavity and injuring the internal organs. For administration at the wing root, fully expose the muscles at the base of the wing and insert the needle directly into the muscle. Take care not to insert it too deeply, and avoid hitting the bone.
(5) During vaccination, change needles promptly to prevent cross-infection; do not use “one needle all the way through.” As a guideline, use a new needle at least once every 200 birds.
(6) Pre-warming process for inactivated vaccines ( 500 mL/bottle): refrigerator at 2-8 degrees → leave uncovered at room temperature of about 25 degrees for at least 12 hours → pre-warm, covered, in a pre-warming pot at 35-40 degrees (bacterial vaccines: 30-32 degrees) for at least 3 hours → keep covered in hot water in an insulated box at 35-40 degrees (bacterial vaccines: 30-32 degrees) → put on the insulation sleeve and use for injection.
6, Key points for drinking-water vaccination
（1）Before administering a drinking water vaccine, pre-clean the drinking water equipment, including the medication tank, pressure-reducing water tank, and water lines.
（2）For drinking water vaccination, the volume of water should be 50–60% of the total daily feed consumption, and must be consumed within 2 hours; it must not take longer than 3 hours.
（3）When administering a drinking water vaccine using a medicator, be sure to calculate the water volume for diluting the vaccine based on the setting on the medicator.
（4）To reduce the adverse effects of water temperature on the vaccine, add a suitable number of ice packs to the water used to dilute the vaccine beforehand to lower its temperature.
（5）For drinking-water vaccination, the drinking water must not contain any disinfectant ingredients. At the same time, add a vaccine stabilizer according to the volume of drinking water to chelate and purify the water, reducing the damage water quality may cause to the vaccine and also serving as an indicator of the water’s color.
（6）Determine how long to withhold water from the flock according to seasonal temperature changes, especially the ambient temperature on the day of drinking-water vaccination. Adjust the water-withholding period as appropriate. As a general guideline: 2 hours in summer, 3 hours in spring and autumn, and 4 hours in winter.
（7）When vaccinating the flock via drinking water, be sure to flush water through every water line at the end of each line until colored vaccine water flows out. Check the nipple drinkers at the end of each line to ensure that the water dripping from them is colored vaccine water. This step is especially important, as it directly determines whether drinking-water vaccination in the flock succeeds or fails.
（8）After drinking-water vaccination is complete, in poultry houses with a pressure-reducing water tank, wait until the tank is completely empty. Tap the nipple drinker on the line from which colored vaccine water last flowed during flushing at the end of the line. Provide clean water only once no vaccine water drips from the nipple. In poultry houses with a pressure-reducing valve, wait until the float in the pressure observation tube of the pressure-reducing valve has dropped all the way to the bottom. Then tap the nipple drinkers on the lowest water line, and provide clean water only after no vaccine water drips from them.
III. After immunization
1, cleaning and disinfection of equipment used after immunization
(1) After immunization is completed, the equipment used, such as continuous syringes, tweezers, reusable needles and lancets, should first be soaked in disinfectant, then thoroughly and repeatedly washed with warm clean water, and then disinfected with boiling water in a sterilizer for 15－30 minutes. Remove the equipment and place it in a drying cabinet to dry for later use.
(2) Cleaning and disinfection process for continuous syringes: disassemble → use food-grade cleaning agent to remove grease → repeatedly rinse with warm clean water → disinfect with boiling water → reassemble loosely → dry in a drying cabinet.
(3) Plastic products that cannot be sterilized by prolonged boiling, such as droppers, connectors, and dropper bottles, should first be soaked in disinfectant, then thoroughly rinsed repeatedly with warm clean water, and then soaked in boiling water for 20 minutes. Remove them and place them in a drying cabinet to dry for later use.
(4) After immunization is complete, promptly soak the instruments and supplies used in disinfectant to avoid contaminating the environment.
2, Post-immunization cleanup
After immunization is complete, classify and collectively disinfect all utensils used. Items that will not be reused should be rendered harmless after disinfection, for example, by deep burial or incineration. After immunization is complete, inspect, organize, and clean the vaccine preparation area and immunization area, and disinfect the vaccine preparation area.
3, fill in the vaccination card
Record the vaccine name, immunization date, immunization house number, immunization method, quantity of vaccine used, vaccine production batch number, vaccine expiration period, vaccine manufacturer, etc. The person responsible for immunization should complete the form in detail and submit it to the production department for filing and future reference.
4, observation of the flock after immunization
（1）After immunization with inactivated vaccines, observe the flock’s mental state and changes in feed and water intake. Conduct clinical necropsies on dead chickens and analyze the cause of death so that the vaccine type, immunization site, or method can be changed as needed.
(2) After immunization with live attenuated Newcastle disease, infectious bronchitis, and Mycoplasma lyophilized vaccines, observe for changes in the respiratory tract. Note, however, that respiratory reactions caused by these vaccines should last no more than 2 weeks; otherwise, supportive medication should be administered to the flock.
(3) After immunization with a live attenuated infectious laryngotracheitis (ILT) chicken embryo lyophilized vaccine, observe for changes in the eyes and respiratory tract.
A. Before immunization with a live attenuated ILT chicken embryo lyophilized vaccine, reduce dust in the poultry house. The more dust there is, the more severe the vaccine reaction; take particular care during seasons when ventilation is limited.
B. Before immunization with a live attenuated ILT chicken embryo lyophilized vaccine, it is best to first immunize once with a live attenuated ILT vaccine, such as a genetic engineering vaccine or a tissue cell vaccine. This can greatly reduce the immune reaction to the chicken embryo vaccine.
C. The reaction process for the laryngotracheal chicken embryo vaccine is generally as follows: Around 3 days after vaccination, occasional chickens develop tearing and redness in the eye; around 5 days, the vaccine reaction reaches its peak, with more chickens showing eye symptoms, and a very small number of individual chickens also developing coughing and wheezing; around 6 days, the reaction begins to subside, and the number of chickens with symptoms decreases significantly; around 7 days, the symptoms of the immune reaction have basically disappeared.
(4) Around 7 days after immunization with the fowlpox freeze-dried vaccine, observe whether scabs have formed at the fowlpox wing-web inoculation site.
This article was compiled by the Technical Committee of Zhengyuan Dadi based on content shared by Teacher Zhang Jingyong and the course materials.