Investigation Of Infective Diseases In Large-scale Broiler Farms

With the development of animal husbandry in China, broiler breeding industry has madeconsiderable progress and the breeding mode had a great transformation which changed fromfree-ranging to intensive and large-scale. This investigation cost6months and collected somestatistics which consist of breeding scale and slaughter situation of11breeding sheds of4breeding bases and species of infective diseases and their mortality of5breeding sheds of2breeding bases. Furthermore, diagnoses targeted to Newcastle disease, Salmonellosis,Coccidiosis were analyzed. The results are as follows:1. Breeding scale and slaughter situation: chickens were slaughtered almost every2months, and every breeding shed accommodated7500-10000chickens. With the temperaturedropping, breeding density was up-regulated and the slaughtering rate kept going up whichretained between94.0～99.6%.2. Species of infective diseases and their mortality: the mainly pathogens which causedchickens dead were Newcastle disease, Salmonellosis, Coccidiosis. The mortality of thesepathogens were participated60.34%,73.29%and74.47%respectively in total mortality.3. Diagnosis of Newcastle disease: preliminary diagnosis was made by the clinicalsymptoms and pathological changes. There were8positive epidemic materials byhemagglutination test in all the10tested materials, suspected of ND infection. There were121epidemic materials were tested by RT-PCR and electrophoresis. Result indicated38ofthem were positive and the positive incidence was31.4%.4. Diagnosis of salmonellosis: Make a preliminary judgment through clinical symptomsand pathological changes；The pathological material of disease was inoculated in MacConkeymedium, if colorless and transparent large colonies were appears, Salmonella infection wassuspected. After generating three times in LB medium, the bacteria were inoculated in Xyloselysine desoxycholate agar (XLD) plates for cultivation, the clonies would be pink with orwithout black center and few clonies would be yellow with or without black center,Salmonella infection was further determined.5. Diagnosis of coccidiosis: The tail feathers were contaminated with blood or bloodystools; Pathological autopsy revealed bilateral swelling of the cecum; Hemorrhagic spots andbleeding spots in Serosa; Hemorrhage, edema and necrosis in Cecal mucosa.Through the survey of broiler breeding company, we preliminary understand broilerbreeding conditions in China. We timely give feedback to the company, enables the companyto make timely adjustments to ensure the healthy development of broiler farms.