EFFECTING FACTORS ON THE VACCINATION AGAINST NEWCASTLE DISEASE FOR COMMERCIAL BREEDS OF CHICKS: INFLUENCE OF MATERNALLY DERIVED ANTIBODIES

Abstract

In order to evaluate the protection of passive antibodies of Newcastle disease, chicks of commercial line from three distinct incubators commercialized in the city of Goiânia were submitted to four types of treatment. The first group was vaccinated in the first day of life, the second on the seventh day of life, the third, in the fourteenth and the group not vaccinated (control). The chicks received ocular via 0.03 ml of Lasota against the Newcastle disease. The immunologic answer was evaluated through the Hemagglutination - Inhibition tests and total protection tests, challenging from the first through the forty-second day, with intermission of a week. The sorological results of maternal antibodies showed that the geometric mean HI titres (expressed in log2) decrease strongly from the first to the third week, the same happened with the challenge tests, with 98% of protection on the first days of life, with average percentage of 26% on the third week. It was verified, within the experiment conditions, when it's established a single vaccination, the ideal age is around fourteen days; though the average of mortality in this group during all phases of the experiment was 22.86% was not possible to obtain the percentage level of total protection.