How are pullorum disease in newly hatched partridges diagnosed and treated in partridge farming?
Diagnosis and prevention and treatment
Based on the characteristics of mass onset and death among young partridges and grayish-white foul-smelling diarrhea, a preliminary diagnosis can be made. After laboratory bacterial isolation and identification, it was confirmed as partridge pullorum disease. The partridge farm was immediately locked down, and 63 severely affected partridges were isolated separately from 584 mildly affected and asymptomatic partridges; the partridge house was cleaned, ventilation was strengthened, and stocking density was adjusted. The partridge house was sprayed and disinfected with 1:300 Baidusha while the partridges were present, once per day, for 3 consecutive days; the whole flock was immediately given norfloxacin at 0.05% mixed into feed and ciprofloxacin at 0.02% in drinking water for 5 consecutive days. The 63 severely affected partridges were injected intramuscularly with 2 ml:0.5 g (500,000 units) kanamycin sulfate at 0.1 ml per bird, twice per day, for 3 consecutive days; contaminated feathers and feces were promptly cleaned up daily and disinfected with 2% NaOH; dead partridge carcasses were soaked in 2% NaOH for half an hour and then deeply buried. On the morning of the next day after these measures were taken, 5 mildly affected partridges died, and the remaining partridges showed improved spirits and increased feed intake; 22 severely affected partridges died, and the remaining partridges gradually improved in spirit, with some already seen foraging. On the third day, 4 severely affected partridges died, and the spirits and appetite of the remaining partridges gradually returned to normal. A follow-up visit half a month later showed that the partridge flock had fully recovered and was growing and developing normally.
Summary and discussion
1. Partridge pullorum disease mainly affects young partridges. Its transmission routes can be either through eggs or horizontal infection through the digestive tract and respiratory tract, with transmission through contaminated eggs being the most common. In general, with infection inside the egg, dead embryos or weak embryos unable to hatch occur during incubation, and some also die rapidly from septicemia shortly after hatching without symptoms before death. In this case, disease and death began at 2 days of age, and the peak deaths occurred on the 4th day of infection (598 deaths) and the 5th day (605 deaths), with typical symptoms and lesions such as grayish-white foul-smelling diarrhea, caseous material in the ceca, and dilated ureters filled with urates, indicating that this case was infected during incubation or after hatching. In addition, field observation showed that the farm had poor sanitary conditions, a damp partridge house, poor ventilation, and excessive stocking density, among other predisposing factors. Therefore, this led to the outbreak of partridge pullorum disease.
2. After the partridges became ill, the farm took active treatment measures, namely oral administration of oxytetracycline at 0.02% mixed into feed. However, because the oxytetracycline dosage was relatively low, the drug could not reach an effective concentration after entering the partridge body, and thus failed to inhibit the growth and reproduction of Salmonella pullorum, making the treatment ineffective. To treat partridge pullorum disease, the oxytetracycline dosage should be: 0.04%-0.08% in feed and 0.02%-0.04% in drinking water. If the dosage is insufficient, the treatment goal cannot be achieved. Partridge farms (households) should pay sufficient attention to this.
3. The principle of preventing and controlling partridge pullorum disease is to eliminate the introduction of pathogens, eliminate carriers and chronically affected birds within the partridge flock, and strictly implement hygiene, disinfection, and isolation systems. The measures are to purify the partridge farm, establish a Salmonella-free partridge flock, regularly conduct plate agglutination tests in healthy partridge flocks, and promptly cull positive and suspicious partridges; strengthen feeding management and environmental hygiene, and strengthen the cleaning and disinfection of breeding eggs, hatcheries, cages and houses, and equipment; purchased partridges should be isolated and quarantined, and only after being confirmed healthy may they be mixed into the flock.