[Live vaccine for oral immunization against avian encephalomyelitis of fowl].
Strain C 2653 have proved to be applicable with good success as a live vaccine to treat avian encephalomyelitis. The virus is excreted by immunised animals up to roughly three weeks from immunisation and absorbed by non-immunised animals. Propagation and excretion of the immunisation virus will bring about sufficient immunity of the entire herd, within something between four and eight weeks from immunisation. Something between two and four per cent of the individuals in one herd are treated by crop instillation, which works well in cases of floor keeping. Yet, contact of all animals with the immunisation virus cannot be ensured, if the same technique is applied to animals kept in cages. Administration of the vaccine in pressure compensating vessels of the cage nipple lines or valve-operated drinking grooves in floor-keeping fowl houses will increase the amount by vaccine needed by the factor of 2.5, as compared to crop instillation, but the entire stock will be immunised in a shorter period of time, with 80 per cent of man-hours being saved. Application to floor-kept animals can be further simplified, which was demonstrated by the experimental prototype of a new drug proportioning device. Five times more vaccine will be needed, as compared to crop instillation, but that higher quantity is offset by more savings in man-hours.