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| dc.contributor.author | Belayneh Lulie | |
| dc.date.accessioned | 2025-07-29T08:09:05Z | |
| dc.date.available | 2025-07-29T08:09:05Z | |
| dc.date.issued | 2025-07 | |
| dc.identifier.uri | http://ir.bdu.edu.et/handle/123456789/16804 | |
| dc.description.abstract | on their comparative efficacy across different vaccine types and chicken breeds. Therefore, this experimental study was conducted from October 2024 to January 2025 at the Andassa Livestock Research Center poultry farm to evaluate the humoral antibody response of NCD vaccines in Tillili and Koekoek chicken breeds.The study comapared three vaccines (I2 thermostable, LaSota, and HB1) along with a positive control. The specific objectives of the study were to evaluate the antibody responses to the three vaccines and the positive control in both breeds, to identify risk factors associated with variations in antibody responses,to determine the magnitude of mortality and survival of chickens and to assess differences in maternally-derived antibody levels between the Tillili and Koekoek breeds. A Completely Randomized Design with a 2x4 factorial arrangement was employed. A total of 480 day-old chicks (DOCs), comprising 240 indigenous Tillili and 240 exotic Koekoek, were randomly assigned to 24 pens (20 birds/pen). A total of 1,092 blood samples were collected one day before and 14 days after each vaccination, with 964 samples successfully processed. Antibody titers against NCD were quantified using an indirect ELISA. Independent and paired t-tests were used to compare mean antibody titers between the treatment and control groups before and after vaccination, respectively. Additionally, multiple linear regression, and Cox regression were used to evaluate and quantify the effect of covariates on mean antibody titer and chicken mortality rates, respectively. The overall chick mortality percentage across all treatment groups was 4.6%. During the study period, 76% of chickens developed protective antibody levels against NCD across the four treatments. Koekoek chickens exhibited significantly higher maternal antibody levels (mean titer 4,460.3) compared to Tillili chickens (mean titer 202.3) during the first week of life. A relatively higher antibody response (5475.4 ± 2821.1) was also detected in Koekoek compared to Tillili (4200.9 ± 2092.8. Overall, antibody responses were higher at 42days postvaccination with thermosatble vaccines (6031.2±420.2), Comparison of vaccine types revealed significant differences in antibody levels before and after vaccination among bleeding dates (P = 0.0274) and between treatment groups (P = 0.0002). However, an independent t-test comparing the positive control and treatment groups revealed no significant difference (P=0.1954) in antibody responses. The Multiple linear regression revealed that sex (P = 0.0172), bleeding time (P = 0.001), and age (P = 0.000) were statistically significant with mean antibody titer. In conclusion, all three vaccines elicited protective immunity, with the positive control achieving relatively the highest efficacy, followed by the thermostable vaccine. This suggests that the thermostable vaccine demonstrates comparable practical advantages for field use, especially in areas where cold chains are limited. | en_US |
| dc.language.iso | en | en_US |
| dc.subject | Veterinary Epidemiology and Economics | en_US |
| dc.title | Comparative Evaluation of Humoral antibody Responses to various Newcastle disease Vaccines in Chickens at Andassa Livestock Research Center, Northwest Ethiopia | en_US |
| dc.type | Thesis | en_US |
