Delivery of thermostable Newcastle disease (ND) vaccine to chickens with broken millet grains as the vehicle

Abstract

The efficacy of treated broken millet grains as a carrier for delivery of thermostable Newcastle disease (ND) vaccine HRV4 to free-range chickens in three locations was assessed by haemagglutination
inhibition (HI) test and challenge experiment. Out of 256 birds fed with first dose of the vaccine, 130 (50.8%) produced detectable HI antibody but only 16 (6.3%) attained serum antibody level of log2 3.0
adjudged protective. From the locations, Igumale (74 birds), Kuru (88 birds) Riyom (94 birds), only 1 (1.4%), 8 (9.1%) and 7 (7.4%) attained log2 titre 3.0, respectively. A booster vaccine dose 2 weeks later
on 236 of the birds led to 126 (53.4%) attaining HI (log2) titre 3.0 [Igumale (63 birds), Kuru (86 birds) Riyom (87 birds) had 33 (53.5%), 46 (53.5%) and 42 (48.3%) respectively attaining log2 titres of 3.0]. Out of a total of 70 buy-back chickens challenged, 49 (70.0%) survived. The break down showed that from Igumale (20 birds), Kuru (25 birds) Riyom (25 birds), the survivors were 13 (65.0%), 19 (76.0%) and 17 (68.0%), respectively. Out of 28 unvaccinated control birds challenged, only 4 survived. The overall results showed that millet, if properly treated, could be a good vaccine carrier and that the method of vaccination was relatively efficacious.