鸡马立克氏病免疫失败原因与对策

Disease prevention is the top priority in poultry farming. Common diseases fall into four categories: viral, bacterial, parasitic, and nutritional-metabolic. Viral diseases include avian influenza, Newcastle disease, infectious bursal disease, and Marek disease, most characterized by rapid transmission and high mortality. Bacterial diseases include pullorum, colibacillosis, infectious coryza, and chronic respiratory disease.

Vaccination is the core measure for preventing infectious diseases. Standard layer immunization: Marek vaccine at day 1, ND-IB bivalent at day 7, IBD at day 14, ND booster at day 21, AI vaccine at day 35, and EDS vaccine before laying. All vaccinations must follow proper procedures, and vaccines must be used within 2 hours of dilution.

Major duck diseases include duck plague, duck viral hepatitis, infectious serositis, and Tembusu virus disease. Duck plague mortality can exceed 90%. Duck viral hepatitis primarily affects ducklings under 3 weeks. Major goose diseases include gosling plague, paramyxovirus disease, and fowl cholera. Gosling plague caused by parvovirus has 70%-100% mortality.

Medication plays a supporting role in disease control. Antibiotics for bacterial diseases should be selected based on sensitivity testing to avoid resistance. Coccidiosis control uses rotation or shuttle programs. Chinese herbs like Coptis, Scutellaria, Isatis, and Astragalus polysaccharides effectively boost immunity as antibiotic alternatives.

Biosecurity system construction is fundamental for disease prevention. Farms should implement closed management with strict control of external personnel and vehicles. Production, living, and isolation zones should be separated with disinfection channels between them. Workers must change clothing and footwear before entering production areas. Dead birds must be properly disposed of through harmless treatment.

Candling inspections during incubation include first candling (days 5-7), second candling (days 11-14), and third candling before transfer. First candling checks fertilization and early development, second checks development progress, and third removes dead embryos. After transfer, turning stops and quiet conditions are maintained. Chicks remain in the hatcher until feathers dry, followed by sexing, vaccination, and beak trimming.

Geese are classified as large, medium, and small types. Large breeds like Shitou goose reach 10-12 kg for adult males. Medium breeds like Wanxi White, Zhedong White, and Sichuan White weigh 5-7 kg and produce 30-50 eggs annually. Small breeds like Taihu, Huoyan, and Wulong geese have superior reproductive performance at 60-100 eggs per year, serving as important genetic resources.

Farm site selection is fundamental to successful poultry farming. The site should be elevated, dry, and well-drained with groundwater level below 2 meters. It must be at least 500m from residential areas, 1000m from major roads, and 3000m from other farms and slaughterhouses. Water sources must be abundant and meet national drinking water standards, with reliable electricity supply.

Ducks have higher crude fiber utilization than chickens. Meat ducks in finishing phase require 16%-18% crude protein with 2900-3000 kcal/kg ME. Beijing ducks reach 3.2-3.5 kg at 42 days with FCR of 1.9-2.2:1. Geese primarily consume green roughage, with adults consuming 1.5-2.5 kg of grass daily and achieving 45%-50% crude fiber digestibility.

Goose farming profitability varies by model and breed. Commercial geese take 70-90 days reaching 4-6 kg, with 3-4 batches possible annually in southern regions. Production cost is 45-55 yuan per bird including 10-15 yuan for goslings and 25-30 yuan for feed. Common white geese sell at 16-20 yuan/kg while premium breeds like Shitou reach 25-30 yuan/kg.

Modern farms should apply reduction, resource recovery, and harmless treatment principles. Common treatment processes include aerobic composting, anaerobic biogas fermentation, and biological conversion using fly larvae or earthworms. Wastewater undergoes sedimentation-anaerobic-aerobic combined treatment with reclaimed water reused for greening. Dead birds must undergo harmless treatment through high-temperature rendering or biodegradation.