Disease prevention and control strategies of chickens aged 4 to 6 weeks

(1) blockade and isolation of the brooding area to prevent the spread of diseases by personnel, goods, vehicles, other chickens and so on. Keep the environment inside and outside the chicken house hygienic; persist in disinfecting chickens and outside the house, and when there is no live vaccine, be sure to disinfect twice a day to reduce the content of pathogens in the environment.

(2) the chickens at this stage have the ability to regulate body temperature from initially to completely, so in the relationship between temperature and ventilation, the relationship between temperature and ventilation should gradually transition from heat preservation to equal emphasis on temperature and ventilation, and finally to ventilation. In the later stage, when there is a contradiction between ventilation and heat preservation, we should first ensure the ventilation of the chicken coop, and then consider the temperature. In the control of light, it is necessary to reduce the light intensity to less than 10 lux.

(3) continue to provide chickens with high nutrition, full price and balanced feed.

(4) the immune organs of chicks are basically mature and can produce immune response well, so it is necessary to strengthen the immunity to avian influenza, throat transmission and fowlpox.

(5) the mental state, food intake, drinking water, feces and respiratory symptoms of the flock should be carefully observed at least once a day. When there are signs of disease, it is necessary to determine the type of disease in time and take measures to control the further development of the disease.

At this stage, we should focus on the prevention and control of Newcastle disease and fowlpox, and do a good job of throat transmission immunity at the same time.

1 Newcastle disease

Because the immune system of chicks is not perfect, no matter what kind of immune procedure is adopted, it is difficult to produce good humoral antibodies, so in the chicken stage, the local mucosal antibodies produced by live vaccine mainly provide good protection to chickens. In the current domestic environment, chicks are faced with the threat of Newcastle disease virus at any time after coming out of their shell. considering that the production of local mucosal antibodies is little affected by maternal antibodies, it is necessary to vaccinate live Newcastle disease vaccine in time to produce local mucosal resistance against disease infection as soon as possible. Preferably at the age of 1 day, and no later than 3 days at the latest.

The combination of live vaccine and inactivated vaccine can complement each other's advantages and produce strong protection against diseases. The immunogenicity of oil emulsion inactivated vaccine was significantly enhanced after the addition of oil adjuvant, and it was less interfered by maternal antibody, which could induce strong and lasting immunity. The immunity of chicks in the stage of immunization should protect the whole breeding area, and the antibodies produced by immunization before laying need to protect the whole laying cycle, so the immunity of these two stages should be combined with live vaccine and inactivated vaccine.

The occurrence of Newcastle disease is mainly atypical, because the antibody of the flock is uneven, so it is very important to monitor the antibody level of the flock. It is necessary to ensure that the level of HI antibody is not less than 6 during the breeding period and not less than 9 during the laying period, and that the attenuated vaccine should be vaccinated once every 2 or 3 months during the laying period.

After the occurrence of Newcastle disease, a large dose of attenuated vaccine can be used for emergency immunization, supplemented with antibiotics to prevent secondary bacterial infection.

2Infectious laryngitis

2.1 strict isolation and thorough disinfection of diseased chicken sheds and non-diseased chicken sheds, strengthening feeding management and preventing spread.

2.2 immunity: the first immunization at the age of 5 to 6 weeks, and the second immunity at the age of 13 to 14 weeks, which can protect the whole laying period; during immunization, the vaccine manufacturer should be carefully selected, the vaccine dosage should be strictly controlled, and the vaccine with good immune effect and little side effect should be selected, and the immune dose should not exceed 1 dose; in order to prevent immune reaction, conjunctivitis can be controlled by administration of drugs sensitive to respiratory tract during immunization. The use of eye immunization, it is best to avoid one side, to prevent conjunctivitis on both eyes at the same time; interference with the immunity of live Newcastle disease vaccine, the two kinds of immunity should be more than 10 days apart.

2.3 urgent vaccination. The epidemic speed of the disease is slow, and good results can be obtained by emergency vaccination for chickens with early diagnosis.

3 Fowlpox

The disease can be well controlled by inoculating the vaccine twice. Generally, the disease is first vaccinated at the age of 2-3 weeks, and the second inoculation is carried out at the age of 4-5 months. Use a special seed stabbing device in line with the standard, and at the same time check whether the needle slot is full of liquid medicine; it is strictly forbidden to pierce the muscle or bone; check the immune effect 7-10 days after the inoculation; because the local immunity at the vaccination site can be maintained for a long time, the immune effect is not good when the second vaccination is carried out in the same site, so the second vaccination should be on the opposite side of the first vaccination site. Because of the biological characteristics of this virus (pro-epithelial virus), thorn seed is the most effective immune method.