dc.description.abstract | Mycoplasma gallisepticum (MG) may cause chronic respiratory disease (CRD) in chickens, an endemic disease in poultry flock and economically significant disease of poultry industry not only in Indonesia but also in many countries around the world. CRD are included in the category of notifiable disease, which means in CRD case occur in the field should be immediately reported to government to be handled. Only few farmers are aware that CRD caused economic losses from upstream to downstream. Economic losses is not caused by high mortality, but is caused by reduced egg production, reduced fertility and hatchability in the range of 8% to 30%, increased embrio mortality up to 20%, increased chicks mortality up to 10%, inhibited weight gain, and increased feed convertion. This study aims to (1) determine a seroprevalence of MG in commercial layer farm in Blitar Regency; (2) create an overview map of the distribution of CRD cases in commercial layer farm; (3) identify any risk factors involved in the CRD infection in some commercial layer farms in Blitar Regency. The study was using cross-sectional field study design, in which data was only taken at one time. The data of blood serum sample of commercial layer and the data of questionnaire from farmers and poultry experts was collected. Blood serum sample from commercial layer chickens tested in laboratory using rapid serum agglutination (RSA) test. Data of laboratory results was processed to determine the crude seroprevalence rate and standardized risk ratio value. Data from the questionnaires distributed to farmers were processed using Cramer’s V correlation test and logistic regression in SPSS version 17, while the data from poultry expert questionnaires were processed using Analytical Hierarchy Process (AHP) in Expert Choice computer program. The results showed that 26 samples of 264 samples tested were found positive for MG, while 238 were found negative, indicating a share of 9.85% among of respiratory disease. Positive sample for MG was found in 10 sub-districts and negative sample was found in 12 sub-districts. Bakung sub-district has the highest risk of MG infection (SRR = 5.0), followed by Udan Awu sub-district (SRR = 4.0). Gandusari and Sutojayan sub-districts have the same SRR value (SRR = 3.0), the other five sub-districts (Srengat, Wlingi, Selopuro, Wonotirto, and Wates sub-districts) only has SRR value 2,0. Binangun sub-district has SSR value 1,0 while the other sub-district has the lowest risk of MG infection (SRR = 0.0) Based on Cramer’s V correlation test showed that the very significant variables (p < 0.01) of laboratory test results were the feed storage procedure (r = 0.252; p = 0.000), flocking density (r = 0.232; p = 0.001), vitamin intake (r = 0.194; p = 0.007), feeding techniques (r = 0.197; p = 0.001) and intensity of house disinfection (r = 0.198; p = 0.006). The logistic regression analysis results showed that the very significant risk factors of MG infection in commercial layer farm were the flocking density of 1501 to 3000 birds (p = 0.004; OR = 3.4) and higher vii (p = 0.001; OR = 6.1), bird feeding once a day (p = 0.002; OR = 0.3), house disinfection once every two weeks (p = 0.009; OR = 1.2) and once a month or only in case (p = 0.006; OR = 3.9). Based on AHP analysis for risk factors of MG infection in commercial layer farm showed that risk factor for flocking density higher than 3000 birds has the highest value (0,203) compare with the other factors, followed by vitamin intake of twice a month (0.127) and vitamin intake only in case of a disease (0.119). | id |