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Show Pathologist Tells Of Vaccine Use In Poultry Flocks If chicken pox has occurred on the premises cf a poultryman, or on closely adjacent premises during dur-ing the past year, it is' wise to vaccinate all new additions to the flock, whether young or mature stock, advises Dr. D. E. Madsen, animal pathologist of the Utah State Agricultural college. Experiments show that there is little, if any, retardation of growth when birds are vaccinated befor. entering production, says Dr. Madsen. Mad-sen. Vaccination while birds are in production, however, may cause a definite decrease in production and sometimes loss of a considerable consider-able number of birds. The best age to vaccinate is when the birds are between 50 and 90 days eld. The chicken-p r o d u c e d vaccine should be used when non-producing birds are immunized while the pigeon-produced vaccine is probably prob-ably the safest product to use on birds which are laying. Care should be taken to us; only a reliable product, such as that dispensed by licensed eterin-arians, eterin-arians, who, according to thj state la'", are the enly persons authorized author-ized to administer live-virus vaccines, vac-cines, Dr. Madsen warns. In deciding to use the vaccine, however, it should be rememberea savs Carl Frischknecht, assistan-extension assistan-extension poultryman, that chickens chick-ens cannot be immunized against a disease without actually giving them a mild case of the disease. A live virus is needed to produce immunity and some of the bird? may become earners. Once the live virus has been brought onlo the premises it may be necessary to vaccinate annually thereafter. |