In recent years, although the vaccine immune density of broilers and laying hens has been increasing, the protection rate and clinical cure rate of the disease are getting lower and lower, the production performance is declining year by year, the stress response is getting bigger and bigger, and the death rate is increasing year by year. , Respiratory diseases, intestinal diseases can not be cured for a long time. Everyone is constantly thinking, what is the problem?
Practice has proved that immunosuppression and mycotoxin contamination are two important factors that lead to the above phenomenon of poultry.
What are the hazards of immunosuppression?
① Stress reaction occurs. When the chickens are given normal epidemic prevention, the body cannot produce the proper immune response, and the antibody uniformity is poor; when the respiratory vaccine is vaccinated, the reaction is strong, and there is no respiratory symptoms when not vaccinated. Respiratory symptoms such as snoring, nasal throwing, and coughing occur one or two days after vaccination; Laying hens are inoculated with oil seedlings, and egg production drops.
②The production performance is reduced. Such as poor growth and development of broilers, uneven body weight, poor feather development, and some "stiff chickens", especially young chicks; poor production performance, such as high feed-to-meat ratio of broilers, low egg production rate of laying hens, peak egg production The period remains short.
③Reduced resistance. Diseases are frequent, and infection with diseases can cause more serious symptoms, such as mycoplasma, Escherichia coli, coccidiosis, etc.
2. The reason
is to take the bird flu epidemic prevention of laying hens as an example. Originally, epidemic prevention was not required. Now, general chicken farms need to be immunized twice for H9 and 4 times for H5. Coupled with the prevention of other normal diseases and the prevention of new diseases, the immune response system of chickens has changed from the original normal working state to a long-term overload state, and the body appears "immunosuppression".
At present, the main clinical immunosuppressive diseases of chickens are: reovirus, reticuloendothelial hyperplasia, bursalitis, Marek's disease, J-subgroup leukemia, infectious anemia, fungal infection, etc.
3. Prevention measures
At present, the problem of poultry immunosuppression disease faced by the poultry industry actually occurs all over the country. Only due to the development of vaccine technology and frequent immunization, as well as the large and frequent use of various health care products, the virulence of viruses such as pharyngeal infection, schizophrenia, influenza, bursa and other viruses has been greatly reduced. Typical clinical symptoms and lethality began to develop into low virulence, low pathogenicity and latent asymptomatic infection.
At the time of clinical diagnosis, sometimes chickens do not die, so it is normal for breeders and veterinarians to ignore them. However, the fact that there are no clinical symptoms, does not cause mass death of chickens, and does not affect drinking water and food too much, does not mean that they are not harmful to chickens. Especially when other diseases occur in chickens, the harm is actually very large. For example, the refractory respiratory diseases that occurred frequently in the Central Plains last month were caused by the existence of recessive or subclinical transmission of the larynx, resulting in "incomplete treatment."
These immunosuppressive diseases are mainly manifested in the clinical occurrence of respiratory diseases, colibacillosis, salpingitis and peritonitis and other chicken diseases. Various drugs and prescriptions are used to treat them, but the effect is not good or easy to repeat. This is mainly due to the existence of immunosuppression, which causes the body to be unable to "establish an effective defense barrier" under antigenic stimulation. Careful diagnosis will reveal that the thymus is smaller than normal, or there is mucus in the bursa, or the spleen is fragile and easy to rupture, etc., which are worthy of vigilance and attention during diagnosis and treatment.
Treatment methods: Enhance immunity and anti-virus
1. Strengthening immunity is not a drug, but a feeding management that strengthens biological safety as the core, such as necessary disinfection to remove the source of infection. With fewer viruses entering the body through the respiratory tract and digestive tract, the body will have less immunity against foreign invaders, and its immunosuppression will be greatly improved.
2. Strengthen the purification of various pathogens of breeders and cut off vertically transmitted diseases; optimize the feed nutrition according to the analysis of the influencing factors of the feed formula, so as to increase the immunity of animals from the perspective of balanced diet nutrition. Use some "anti-virus" or "immune-enhancing" Chinese veterinary medicines with astragalus, ginseng, Codonopsis, etc. as the main ingredients, to expel evil outside the country by increasing the power of righteousness in the body, so as to keep the virus away from us .
① Broiler. In recent years, the growth of broiler chickens has been slow, and clinical cases of muscular gastritis and glandular gastritis have occurred frequently and cannot be cured for a long time; diarrhea has been severe, coccidial enteritis has recurred, and the susceptibility of Escherichia coli has increased; Seriously affect feed remuneration and normal growth; severe immunosuppression occurs. After vaccine immunization, the antibody in the chicken cannot reach the due titer, and the susceptibility to viral diseases such as atypical Newcastle disease and avian influenza in the later period of rearing is greatly enhanced. Farming risks are increasing.
② breeders. Egg production, fertilization rate, dead embryo rate, hatching rate decreased, eggshell quality decreased, and immunosuppressive disease was high.
③ laying hens. The decline in egg production and eggshell quality seriously affects the production performance of laying hens.
① The impact of rising prices of feed raw materials on mycotoxin poisoning. Among the protein feed ingredients, rapeseed meal, cottonseed meal, peanut cake, sunflower kernel cake, coconut flour and palm kernel meal are more likely to be contaminated with mycotoxins than traditional protein feed ingredients such as soybean meal. When the price of traditional feed ingredients rises, feed manufacturers choose to use alternatives to soybean meal, which increases the chance of mycotoxicosis. Similarly, rising corn prices will force feed processors to look for alternatives to energy feed ingredients, including rice bran and wheat bran by-products, etc. The increased use of by-products and feed ingredient substitutes can reduce feed costs, but also lead to the introduction of pollution The odds of a raw material for mycotoxins are greatly increased.
②The feed material is moldy and deteriorated. The moldy deterioration of corn, soybean meal, fish meal, etc. in feed raw materials is the direct cause of mycotoxin contamination and even poisoning of chickens. Changes in the global climate provide good conditions for the growth and reproduction of molds. There is too much rain in the harvest season of corn, which may have been moldy in the ground before harvesting. The toxins produced by moldy corn mainly include Aspergillus flavus, gibberellin, and vomitomycin. Soybean meal and fish meal can also contaminate mold and produce mycotoxins during storage.
③ Litter pollution. The litter of ground chickens mainly includes peanut husks, rice husks, wheat straw, sawdust, etc. These litters are prone to mold under high temperature and high humidity environment. Feeding of litter or feed dropped on litter during aquaculture can lead to mould infection or ingestion of mycotoxins.
3. Prevention measures
① Do a good job in feeding management, try to eliminate mildew factors, avoid the use of moldy feed or feed materials, and do a good job in the storage of feed and feed materials. Strengthen the disinfection of the chicken house, prevent the litter from becoming moldy, and replace the moldy litter.
②Traditional Chinese medicine mixes that absorb mycotoxins and regulate the intestines are often used; copper sulfate, iodine, and gentian violet can be tried to drink water, and drugs such as nystatin can be tried; mildew inhibitors or mycotoxins adsorbents are appropriately added to the feed. Broilers are treated with a course of antifungal and mycotoxin-clearing drugs every 15 days for therapeutic prevention; layers or breeders are used for 5 days a month; layers or breeders are used a course of treatment every 30-45 days, even at 3- Prevention of vertically transmitted mold and its toxins begins at 5 days of age.
③The resistance of young chicks is low, so the quality of No. 1 feed must be guaranteed. Adequate nutrient supply in early growth is the biggest key to raising chickens well. The 15-day-old to the peak egg laying period is a sensitive period, and must not use mold-contaminated feed.