Abstract:
A cross-sectional and longitudinal study were conducted between November 2019 to April 2020
on exotic chicken in Bahir Dar city, Northwest Ethiopia aimed to determine the incidence rate
and epidemiological determinants of exotic chicken morbidity and mortality. Cluster sampling
was used to select small scale chicken farms and chickens. Accordingly, a flock level
questionnaire was administered to 25 small scale poultry farms. A total of 10006 exotic
chickens from five small scale farms were regularly monitored for clinical health problems up
to 45 days old age. Data on different potential risk factors were collected using a recording
sheet and personal observations, whereas the causes of morbidity and mortality were recorded
using clinical and/postmortem examination and laboratory analysis. Survival analysis using
STATA 14 was employed to model the presumed explanatory variables with chicken morbidity
and mortality. Accordingly, the overall incidence rate of crude exotic chicken morbidity and
crude mortality risk rates were 6.58% and 6.4%, respectively. The incidence and risk rate of
major chicken diseases observed were spraddle leg (15.08%, 0.99%), cannibalism (7.54%,
0.51%), ascites (6.77%, 0.46%), omphalitis (4.77%, 0.32%), avian salmonellosis (2.46%,
0.19%), avian mycoplasmas (1.08%, 0.10%), respectively. Moreover, Newcastle disease,
mycoplasmas, infectious bursal disease, salmonellosis, and coccidiosis were the major
economically important chicken diseases ranked by chicken farm owners. Among the risk
factors investigated, the experience of the chicken caretaker (HR = 2.45, P = 0.000), source of
chicken (HR = 2.64, P = 0.000), ownership of chicken caretaker (HR = 0.41, P = 0.000) and
breed (HR = 2.35, P = 0.000) were found significantly associated with the incidence of crude
morbidity and mortality. Serological test using SAT and ELISA was employed to confirm the
suspected cases of Avian salmonellosis and Avian mycoplasmas, respectively. Among 99 sera
collected from clinically diseased exotic chicken, 30.7% and 14.8% were positive for Avian
salmonella and Mycoplasma galisepeticum respectively. In conclusion, the present study
revealed that the incidence rate of chicken morbidity and mortality found to be higher than the
economically tolerable level, which could significantly affect the productivity of small-scale
chicken farms. Therefore, subsequent application interventions towards the identified
determinant factors and pathogens of chicken morbidity and mortality are recommended.
Keywords: Bahir Dar City, Exotic chicken, Incidence, Morbidity, Mortality, Survival analysis