ABSTRACT


Sergio Rosende O.1, Héctor Hidalgo O.1 y Enrique Bergqvist A.2
 
The lentogenic strains of the Newcastle disease virus: B1 (Hitcher), La Sota and Palo Alto were used to inmunize 25 day-old broiler chickens as la single clase. After 20 days they were challenged with a velogenic isolate intramuscularly.The chick protective clase 50 per cent (CPD50) value of each vaccine strain was shown to be 320 per intraocular dose. The heamagglutinating inhibiting (HI) antibody titer were not directly related to protection.
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1Méds. Vets., Departamento de Patología Veterinaria, Facultad de Medicina Veterinaria, Universidad de Chile. Casilla 13, Correo 15, Santiago, Chile.
2Méd. Vet., M. S., Programa Producción Avícola, Estación Experimental La Platina, Instituto de Investigaciones Agropecuarias, Casilla 10, La Granja, Santiago, Chile.