I know this is an old thread but I too had some curiosity about vaccine experiences. To date, of the birds I have sent to the state vet, none have had any of the major diseases. Yet.
But, I have a neighbor who has Mareks per lab finding. So now I vaccinate.
Has anyone come across any recent data or had any personal experience with a 2nd administration of Marek's vaccine being more effective? I have read material that indicates there are benefits to a booster shot done 1-3 weeks past the first vaccination. There are no lab studies that support it officially but data from field challenges in the real world do support boosting, at least in countries other than USA.
It is my understanding that when there are breaks in MDV vaccine effectiveness, its likely because there has been exposure to a second and more virulent strain of Marek's; if thats the case the multiple strain vaccines could be of higher value in the real world where backyard keepers are more likely to be exposed than all-in, all-out commercial producers (where broilers usually are slaughtered before onset of tumor growth anyways).
Has anyone located a source for the polyvalent vaccine? I know the big boys have access to it through their field guys but has anyone here been able to get anything other than Serotype 3 through a vet or online source?
@ ashlieneevel, I don't think any of the reconstituted live virus vaccines can be successfully saved for later use. And while they say "don't do it" I imagine if a bacterin based vaccine was kept sterile, they could be used later. Example is the MG vaccine because its not a live virus, its a killed bacteria (also known as bacterin) placed in a stable substrate. Problem is, how long could it be kept for, who knows? At least to expiration date on the vial, I would assume.
@ ashlieneevel RE: Are there any dangers in introducing a vaccinated chicken into a flock that hasn't been vaccinated? i.e. selling one of your vaccinated chickens to another backyard hobbyist who hasn't vaccinated any of their chickens? I imagine the answer to this might be dependent upon which vaccines were given so any clarification on that part would be appreciated also.
The Serotype 3 vaccine (the type available from Jeffers, First State etc) can not cause Mareks infection in chickens. This vaccine is live but it is not the type of virus that gives tumorous growths to chickens. Its a turkey herpesvirus. Similar family so the chicken's immune system recognizes the virus and makes antibodies to it, but it is not at all the same as the actual virus that causes MDV in chickens.
The reason people think its dangerous to put a vaccinated chicken with an unvaccinated chicken is they fear the vaccinated could give it to the unvaccinated. This is true. But not because the vaccine caused the disease; rather its because in a vaccinated chicken you can not tell if the chicken is infected because the vaccine "hides" the effects of the virus that we normally see. However, that chicken would still have to be infected in the first place to pass it to another chicken.
If you gave a vaccinated chicken who is MDV positive to a person with a MDV negative flock, yes their existing flock, particularly their younger birds will likely begin to fall sick. So if someone has a MDV positive flock they should not give vaccinated or unvaccinated chicks to anyone else without making them aware (my neighbor keeps selling chicks to people because he thinks its ok since he vaccinates).
. I was curious if you have added or removed any vaccinations to your schedule since? I also have a few other questions:
