Piglet colibacillosis is a type of piglet intestinal infection caused by pathogenic E. coli. According to the age of the piglets, the clinical symptoms and the serotypes of the pathogenic bacteria, the piglet Escherichia coli can be divided into three types: piglet jaundice, piglet ferrets and piglet edema disease. At present, this type of disease has a wide range of epidemics, high morbidity and mortality, which seriously affects the development of the pig industry. In-depth discussion of the cause of the disease, and put forward practical and preventive measures, is of great significance to improve the economic benefits of pig production.
1 characteristics of the disease
1.1 Piglet jaundice
Piglets can occur from a few hours after birth to one week old, and are more common in 1-3 days of age. The disease duration is short, the incidence rate in litters is 90%, and the mortality rate is almost 100%. It is characterized by severe diarrhea, yellow or yellow-white serous feces, and rapid dehydration. Most cases have no vomiting. The epidemic is not seasonal, and it occurs mostly during the littering period, and it usually lasts after a pig farm.
1.2 piglet white pheasant
It mainly occurs in piglets within one month of age, and is more common in 10 to 20 days of age. The incidence rate is high, about 50%, and the mortality rate is low, but it can seriously affect the growth and development of piglets after tolerance. It is characterized by a white porridge-like stool with a foul smell, and the body temperature does not change much. The disease can occur all year round, but it occurs frequently when the climate is abrupt, such as severe cold, early spring and hot season.
1.3 piglet edema disease
It mainly occurs in piglets after weaning, and sometimes piglets of several days or four months old occur, especially in pigs that grow fast and have good health. The incidence rate is not high, generally 10% to 30%, but the mortality rate is very high, above 90%. It is characterized by sudden onset, head edema and neurological symptoms. The occurrence of piglet jaundice usually no longer occurs.
2 Causes of the disease
2.1 pathogen serotype
The pathogens causing piglet jaundice, piglet white pupa and piglet edema disease are pathogenic E. coli, but the serotypes are different. The serotypes of enterotoxin-producing Escherichia coli (ETEC), which are common in piglet jaundice, are O8, O60, O149, O147, etc. The Escherichia coli serotypes that cause white piglets in piglets are mainly O8:K88, O5:K88, etc., edema disease is E. coli caused by an adhesion factor and capable of producing exotoxin, the serotypes are mainly O139 (most common), O138, O141, O45 and O8. From the serotypes reported in various regions, the difference is large, and the dominant serotypes of different pig farms or groups in the same region are not completely consistent. Specific to a pig farm, the pathogen serotype is relatively stable, and in the same epidemic at the same place, it is often limited to 1 to 2 types. The serotypes that cause disease in pigs often carry K88, K99, 987P, F41, F42, F7, and the like.
2.2 Environmental factors
E. coli is widely found in the environment and can enter the pig through the digestive tract. Because the development of the digestive system and immune system of piglets is not perfect, it can not inhibit the growth and reproduction of pathogenic Escherichia coli in the intestine. Therefore, poor sanitation and climate change, such as wet and cold sheds in the pig house, fouling in the house, sudden climate change, and damp rain, it is particularly easy to induce the disease. If there are a large number of pathogenic E. coli in the environment or in the sow, the piglets can be infected with the bacteria.
2.3 Management factors
Improper feeding and management is also an important factor in inducing this disease. In the case of sows, poor feeding management, poor feed quality, and sudden replacement of feed can cause sows to lose weight and digestive dysfunction, excessive or too much lactation, too little or too little, and poor milk, resulting in piglets The disease is caused by digestive disorders. Inadequate management of piglets can reduce the resistance of piglets to various stress factors, thereby inducing yellow and white piglets.
2.4 Nutritional factors
The piglet's digestive system is not well developed, the digestive juice is insufficiently secreted, and the lack of pepsin leads to a very low ability to digest protein. Therefore, if the piglet is fed with high-protein feed after weaning, or if the feed is not restricted, the piglet should be fed or not pay attention. Feed transition, sudden refueling, easily lead to gastrointestinal dysfunction, the normal micro-ecological balance in the intestine is destroyed, causing a large number of pathogenic E. coli to proliferate, producing enterotoxin, causing edema disease in piglets. Secondly, in selenium-deficient areas or feeding selenium-deficient feed, it can cause edema disease in piglets; iron deficiency in piglets leads to anemia, which can also cause white blood or edema in piglets.
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3 control measures
3.1 Immunization
The most effective measure to prevent yellow and white piglets is to use a vaccine to immunize pregnant sows and to obtain protective antibodies from newborn piglets through colostrum. The choice of vaccine should be based on the actual situation of the farm. If the serotype of the vaccine is consistent with the serotype of the farm, the best results can be achieved. If the conditions permit, you can prepare your own vaccine. The vaccines currently being promoted and used include two types: whole-bacteria inactivated vaccines and genetically engineered vaccines. The whole-bacteria inactivated vaccine mainly uses strains with K88, K99, 987P or F41 cilia antigens. The usage is one injection at 6 weeks and 2 weeks before delivery, and the effect is excellent. The genetically engineered vaccine has a domestically produced K88-LTB bivalent genetic engineering seedling, and a K88-K99 bivalent genetic engineering seedling. According to the instructions, both vaccines are injected once every 20 to 30 days before delivery. Practice has proved that the effect of using secondary immunization is better than one-time immunization. The method is to immunize once every 30 to 40 days before birth, and to re-immunize once every 15 to 25 days. ST, LT and cilia antigens can also be used to construct antigens for genetically engineered vaccines. If the protection rate is low after vaccination, it may be that the bacterial serotype of this field is inconsistent with the vaccine serotype, and other serotype vaccines should be replaced in time.
3.2 Drug prevention
Antibiotics are added to the sows 1 week before and 1 week after delivery to remove pathogenic E. coli from the sows. 1 to 2 days before the birth or on the same day, the sows are given or injected with antibacterial drugs, preferably long-acting antibacterial drugs, such as long-acting antibacterial agents - special effects of rice first, demi first. It can also be used for intramuscular injection of ofloxacin 0.3-0.4mg/kg, 2 times/d, continuous administration for 2 days for prevention, preferably with mother and child. After the piglet is born, a few drops of gentamicin are dripped from the mouth, and an antibiotic such as oxytetracycline is added to the feed, which can prevent disease and promote growth.
3.3 Microecological preparation prevention
Microecological preparations have the unique function of maintaining micro-ecological balance, biological oxygen scavenging, biological antagonism, enhancing immunity, synthesizing various enzymes and nutrients, and the abuse of antibiotics makes the problem of E. coli resistance increasingly intensified, thus microecological preparations It is widely used in the prevention and control of piglets. Probiotics can be fed before the colostrum is eaten by piglets, such as non-pathogenic E. coli NY-10, probiotics, sputum, and yampang, etc. The effect of preventing edema by promoting bacteria (DM423 strain) is also good. Note that you should not take antibiotics while taking a microecological preparation.
3.4 Implementing “self-supporting self-supportâ€
For pig farms without piglet E. coli, we should try our best to “self-support and self-supportâ€. If it is necessary to purchase, we must transfer from the non-epidemic areas and do a good job in quarantine. For purchased pigs, they should be moved into the isolation ring and kept alone for 3 to 4 weeks. When it is confirmed that there is no disease, it can be rearranged with the pigs after thorough disinfection. The herd should be regularly quarantined and found to have timely isolation treatment and comprehensive measures.
3.5 Strengthening the management of delivery rooms
The right temperature is the key to raising piglets, and low temperature is one of the important factors leading to yellowing and death of piglets. Generally, the house temperature should be controlled at about 20 °C, and a local high temperature environment should be provided for the piglets. At the same time, the cold and heatstroke prevention work of sows and piglets should be done according to seasonal changes.
Prevent the enclosure from being too humid, especially in closed pig houses. Because the pig's excrement, drinking water, washing, disinfection, etc. will make the pig house too high humidity, the impact on piglets is more prominent. The relative humidity in the house can not exceed 70%, and it is ideal for "suitable temperature and low humidity".
After each batch of sows in the delivery room is transferred out, the housing must be thoroughly disinfected, and the surrounding environment of the farm should be disinfected regularly. The combination of washing, drying and disinfection can effectively kill the bacteria repeatedly. The sows need to be covered with clean grass before the birth. In the first 3 days after delivery, the delivery room is cleaned daily, kept clean and dry, and disinfected once every other week thereafter.
3.6 Strengthening the management of sows
The sow compound feed is supplied strictly according to the standard to provide adequate nutrition for fetal development, increase the birth weight of the piglets, the postpartum lactation of the sows and the disease resistance of the piglets. Keep the relative stability of the feed, do not feed the moldy, bad residue feed, add green feed to ensure sufficient milk. Do not feed high fat feeds during the week of the sow's prenatal and postpartum period.
The sows must be cleaned and disinfected one week before delivery to enter the delivery room. At the time of labor, the sows should be disinfected again, especially the sows and the breasts. Wipe the nipple and breast with 0.1% potassium permanganate at the time of delivery, and squeeze a small amount of milk from each nipple to clear and rinse the nipple.
3.7 Strengthen the management of piglets
Newborn piglets should strengthen their care, dry their back hair, fix their nipples, and eat colostrum as soon as possible. Timely iron, cobalt, selenium. Because of the high incidence of iron deficiency ferrets in clinical practice, the piglets were supplemented with 1 mL of blood (25 mg of iron, 1 mg of cobalt, 1 mg of selenium) on the 3rd day after birth, and 2 mL of heparin on the 10th day. Feeding early, the piglet feed is fed from the piglet until the weight reaches 15kg after weaning, and then gradually changed into weaned piglet material, that is, weaning does not refuel, which can effectively avoid the white piglet caused by weaning and refueling discomfort. Or the occurrence of edema disease.
4 treatment
4.1 piglet yellow and white
Early diagnosis, timely treatment, and whole litter administration can receive better results. Antibacterial, astringent, antidiarrheal, and digestive drugs are the main drugs. Principles of drug treatment: Do a variety of sensitive drugs in a drug susceptibility test to avoid long-term use of a single drug to prevent drug resistance; drug treatment must be combined with improved feeding management and elimination of pathogenic factors to achieve better results.
4.2 Piglet edema disease
The disease lacks specific treatment methods. At the beginning of the disease, sodium selenite and VE are treated in a timely manner, which has a certain effect on the disease. Since the piglets have absorbed most of the toxins when they have symptoms of edema, the treatment effect is not obvious. This disease is more comprehensive symptomatic therapy. Oral antibacterial drugs, salt laxatives, to inhibit or exclude bacteria and their products in the gut. Intravenous injection of glucose, sodium chloride, mannitol, etc., subcutaneous injection of sodium alcohol, oral diuretic, has a certain effect on chronic cases.
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