A comparative study on the efficacy of local and imported live new castle disease vaccines in commercial broilers

Three hundred and fifty, day-old commercial broiler chickens were divided into seven groups, A, B, C, D, E, F and G. The chickens of group A were vaccinated by SPVC, while B, C, D and E, groups were vaccinated with IZO, TAD, Forte Dodge and Intervet by using live attenuated La Sota strain of NDV vaccine at day 7 and 22 of their age through drinking water. The chickens of group F were vaccinated with locally prepared SPVC live attenuated La Sota NDV vaccine at day 7 of their age through drinking water (D/W) and live attenuated Mukteswar ND virus vaccine at day 22 of their age as a booster dose through Intramuscular (1/M) route. The chickens of group G were treated as a control. The serum samples were collected at a week interval up to five weeks post- vaccination from all vaccinated groups and up to six week of their age from group G (control). The antibody titre was determined by haemagglutination inhibition (HI) test. The results revealed tha t the chickens administered with local NDV vaccine at day 7 and subsequent a booster dose at day 22 of their age produced same antibody titre as to imported vaccines. The antibody titres determined by HI were very low during 1-3 weeks post-vaccination in all vaccinated groups. Two weeks after booster dose, the antibody titre was higher and remained constant up to 6 weeks in the sera of chickens. However, the chickens with 14 days of their age showed very least maternal antibodies in their sera but after that period no maternal antibodies were determined in control group (G) throughout the experiment. The vaccinated chickens were challenged with a locally isolated Velogenic viscerotropic Newcastle disease virus at the dose rate of 100,000 ELD50 K/D/97 did show 40-80% protection against the challenge a week post- initial-vaccination. However, when the chickens were invited 2nd and 3rd challenge dose of NDV, a 100% protection was recorded at 1 and 2 weeks post-booster vaccinati o n. Whereas the chickens that were not provided vaccines and considered as a control group showed 100% susceptibility to the challenge virus. The Hl antibody titres were recorded at a week interval from the survivors of all vaccinated chickens after 1st, 2nd and 3rd challenge. No gross pathological lesions were recorded in all vaccinated groups, but lesions were recorded in feacal tonsils and proventriculus of control group G. A good level of maternal antibodies were recorded in the sera of chickens at 5 days of their age through HI test method. It is concluded that chickens administered with local La Sota and Mukteswar strains of NDV vaccines at day 7 and subsequent booster dose at day 22 of their age produced almost same antibody titres as imported vaccines i. e., TAD, IZO, Forte Dodge and Intervet. The haemagglutination inhibition antibody titres in the sera of chickens were recorded low up to 3 weeks post-vaccination in all groups irrespective of the type of vaccines and d ose of vaccines inoculated. However, 100% protection was recorded after booster dose of vaccine administered to the chickens. It is observed that vaccination through drinking water provided better immunity, less stress and economical in utilizing minimum labour. Furthermore, it is also recorded that local vaccines are good as compared to imported vaccines in the sense of more economical and less chances to introduce new field strains of NDV in the area.