Mycoplasma Gallisepticum Vaccine

Product Description

Mycovac-L is a live vaccine, prepared from the Merck Animal Health 6/85 strain of Mycoplasma gallisepticum in a freeze dried preparation sealed under vacuum. The 6/85 strain is unique in that it is highly immunogenic for chickens and non-pathogenic for turkeys, does not readily spread to adjacent houses of chickens and is biologically stable. This vaccine has been propagated under exacting standards. The immunizing capability of this vaccine has been proven by various procedures including the Master Seed Immunogenicity Test.


This product has been shown to be effective for the vaccination of healthy chickens 6 weeks of age or older against M. gallisepticum.


  • Highly immunogenic, with very mild reaction
  • Not pathogenic to turkeys
  • Does not spread to adjacent chicken houses
  • No ovarian transmission
  • Serum will not convert MG plate antigen: easy to distinguish vaccine response from field infection


  • Mycoplasma gallisepticum (MG)

Vaccination Programs

Many factors must be considered in determining the vaccination program for a particular farm or poultry operation. To be fully effective, the vaccine must be administered to healthy receptive birds held in proper environment under good management. In addition, the response may be modified by the age of the birds and their immune status. Seldom does 1 vaccination under field conditions produce complete protection for all individuals in a given flock. The amount of protection required will vary with the type of operation and the degree of exposure that a flock is likely to encounter.

Coarse Spray Administration

Calculate the water volume needed. For example, a machine which dispenses 21 ml to a box of 100 chickens – total volume for 2,000 doses is 420 ml of non-chlorinated water. For coarse spray in chicken houses, follow manufacturer’s direction for the particular spray machine. Add rehydrated vaccine and mix thoroughly.


2,000 dose sizes


2. All chickens should be vaccinated at the same time.
3. Do not medicate chickens with antibacterial drugs five days prior to or after vaccination.
4. The 6/85 strain of MG is not pathogenic for turkeys, but care should be taken in the application of the vaccine and handling of the chickens so as to maintain very tight disease security.
5. This vaccine should not be administered within two weeks of any live Newcastle, bronchitis or laryngotracheitis vaccination.
6. Do not administer this vaccine within four weeks of onset of egg production or after egg production has begun.
7. Use entire contents when first opened.
8. Do not vaccinate within 21 days before slaughter.
9. Store at 2° to 8°C (35° to 46°F). Do not freeze.
10. Inactivate unused contents before disposal.
11. Do not mix with other products, except as specified on this label.
12. This vaccine is to be used only in states where its usage is permitted and is to be used in compliance with applicable state and federal regulations.
13. In case of human exposure, contact a physician.


This vaccine has undergone rigid potency, safety and purity tests, and meets Merck Animal Health, U.S. and local regulatory requirements. It is designed to stimulate effective immunity when used as directed, but the user must be advised that the response to the product depends upon many factors, including, but not limited to, conditions of storage and handling by the user, administration of the vaccine, health and responsiveness of the individual chickens and the degree of field exposure. Therefore, directions should be followed carefully. A safety data sheet (SDS) is available upon request This and any other consumer information can be obtained by calling Merck Animal Health Customer Service at 1-800-211-3573.


Keep a record of vaccine, quantity, serial number, expiration date, and place of purchase; the date and time of vaccination; the number, age, breed, and locations of chickens; names of operators performing the vaccination and any observed reactions.

Contact our sales or technical services representatives to help design a custom vaccination program.


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For additional information, please see the product label.
For more information regarding efficacy and safety data, go to

*Data on file, Merck Animal Health

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