The disease mainly occurs in suckling pigs aged 1 ~ 3 days. Piglets that become ill about 24 hours after birth, if not treated in time, the mortality rate can reach 100%, and piglets that become ill over 7 days old are very rare. Sows with bacteria are the main source of infection of yellow dysentery. Pathogens pollute the environment with feces, and the skin and nipples of sows are infected by bacteria, which leads to the illness of piglets. Usually diarrhea starts at one end, and then the whole litter of piglets is diarrhea, often a litter. Not only do the piglets in the same litter get sick, but almost all the piglets that continue to give birth are infected, forming a vicious circle. Poor sanitation may often occur, and good sanitation also often occurs.
(1) The clinical symptoms are usually a few hours after birth, and a litter of piglets comes one after another. The earliest onset occurred at 8 ~ 12 hours after birth. It was found that one or two piglets were depressed, exhausted and died soon, and then other piglets had diarrhea and discharged watery feces. The feces are yellow paste or thin as water, containing small pieces of curd, with bubbles and stench, and flow down the anus. Sick pigs are depressed, do not eat milk, and soon lose weight and dehydrate. Due to dehydration, the eyes of the sick pig sank, and the skin below the abdomen was purple, and finally died of exhaustion. The course of disease is 1 ~ 5 days.
(2) Pathological changes The pig carcasses were severely dehydrated. The main change is acute catarrhal inflammation of intestinal mucosa, which is characterized by a large amount of yellow liquid content and gas in the intestine, intestinal cavity expansion, intestinal wall thinning and intestinal mucosa turning red. Duodenal lesions are the most serious, followed by jejunum and ileum, and colon is lighter. The stomach is full of yellow curd with sour taste, edema of gastric mucosa and dark red fundus. There are diffuse small bleeding spots in mesenteric lymph nodes. There are small necrotic foci in liver and kidney.
According to its epidemic situation and symptoms, a diagnosis can generally be made. You can also take the contents of the anterior segment of the small intestine and send them to the laboratory for bacterial isolation, culture and identification.
(3) Prevention and control experience
First of all, comprehensive health and epidemic prevention measures must be taken against this disease. Strengthen the management of sow feeding, do a good job in disinfection of delivery rooms and utensils, and control the temperature and humidity of pigsty environment. Before giving birth, the sow's breasts should be disinfected. First clean the nipple with clean warm water, and then clean the nipple, breast, lower abdomen and anus with 1% potassium permanganate in turn. At the same time, let piglets eat colostrum early to enhance immunity.
The second is to immunize sows in pig farms with frequent diseases, improve the level of maternal antibodies in their colostrum, and enable piglets to obtain passive immunity. Inject bivalent genetic engineering vaccines of Escherichia coli K88 and K99 before delivery/0/5 ~ 30 days, and let newborn piglets take preventive drugs, or inject antibacterial drugs into sows and feed them with milk for prevention. Sick piglets should be treated in time.
Third, oxytetracycline, sulfamethazine, gentamicin, streptomycin, norfloxacin, kanamycin and other drugs can be used for the treatment of this disease. Alternating treatment with more than a dozen drugs is effective. It is very effective to treat the disease with antiserum in the early stage. Oral or intramuscular injection of antiserum after birth has a good preventive effect.