Prevention and treatment of emphysema gangrene in farmed dairy cows

Emphysema gangrene, commonly known as "black leg disease", is an acute septic infectious disease of cattle, which is mainly characterized by black gas swelling in the plump part of the muscle (especially the thigh). It is also called black leg disease and gangrene. The pathogen is Rhizoctonia emphysematosus, which is exclusively anaerobic and can survive for as long as 5 years in vivo.

In recent years, the climate of Bayinbrook District in Hejing County is changeable, it is rainy all the year round, the temperature is humid and the temperature is on the low side. The low temperature climate and humid valley pasture environment provide excellent forage for livestock, but there are also cases of emphysema gangrene of dairy cows that have not been found for many years.

Cow emphysema gangrenous disease mainly harms yellow cattle, and yellow cattle are the most susceptible, and most of them occur in calves under 3 years old. the main source of infection is diseased cattle, followed by sheep and buffalo, but this case is rarely reported in dairy cows.

I. case investigation

In August 2003, 3 cows suddenly fell ill in a herd in Gongnai Township, Hejing County, and their body temperature rose to 41-42 ℃. Their appetite and ruminating stopped, and they were limping. Among them, 2 cows showed swelling in the thigh muscles and pain in finger pressure, and one cow died in the morning of the next day.

Second, clinical symptoms

The cow had a sudden attack, the body temperature increased to 41 ℃, the appetite and ruminating stopped, and the diseased cow developed claudication. Two of the cows had swelling of the thigh muscles and pain in the finger pressure. The seriously ill cow could not afford to lie on the ground, with swelling in the plump part of the muscle, severe edema in the muscle and subcutaneous, blackened skin, pressed and twisted pronunciation, cut open the swelling area, and a dark red foamy and sour-smelling liquid flowed from the incision. Local lymph nodes were enlarged, dyspnea, and died the next morning.

III. Changes in autopsy

The carcass of the dead cow decayed and expanded rapidly, the mouth, nose and anus flowed out of a dark red liquid with foam, the affected muscle was black, the cross section was spongy, and contained liquid with bubbles. The liver and kidney were slightly enlarged, the liver was slightly swollen, and there were brown-red necrotic lesions of different sizes on the section, and a large amount of blood and bubbles flowed out after incision.

IV. Laboratory inspection

Under the condition of strict disinfection, the smears of muscle and edema fluid at the swollen site of the lesion were stained with alkaline blue and examined under microscope.

Microscopic examination results: there are single or paired arrangement, do not form a long chain, blunt circles at both ends of the large bacilli connected together without capsule. Clostridium emphysematosum with spores is located at one end or center of the cell, making the cell dilated in a prismatic shape with peripheral flagella.

5. Diagnosis

According to the case investigation, clinical symptoms, autopsy changes and laboratory examination, emphysema gangrenous disease was determined.

VI. Clinical diagnosis and treatment

1. Prevention

The diseased cattle were examined head by head, the diseased cattle and suspected cattle were isolated and treated on the spot, and other cattle were vaccinated with emphysema gangrene vaccine immediately. It is strictly forbidden to eat sick and dead cattle, and their contaminated feces, urine, bedding grass, etc. are deeply buried together with corpses. The contaminated sites are thoroughly disinfected with 25% bleach solution and 3% formalin solution to prevent the formation of emphysema and anthrax foci.

two。 Treatment

The onset of ① is urgent and the course of disease is short. After discovering the diseased animals, systemic treatment with large doses of antibiotics should be used immediately in order to control the development of the disease. We used penicillin, clindamole intramuscular injection, while giving 5% glucose and sulfadiazine sodium intravenous injection, the purpose is to cooperate with the treatment, cardiotonic, fluid replacement, in order to improve the effect of treatment.

In the early stage, ② was injected intramuscularly with the oil Lupine penicillin at the swollen part of the cow. In the middle and later stage, the swollen part of the diseased cow was cut open, and the necrotic tissue was removed and fully rinsed with 2%PP solution or 3% hydrogen peroxide. The purpose was to embalm, produce carbon dioxide, and inject around the swelling (the swollen area should not be cut or punctured).

③ due to the severe poisoning symptoms of the disease, but also according to the systemic condition of cardiotonic and detoxification and other treatment.

VII. Preventive measures

1. In recent years, animal husbandry has brought considerable economic benefits to farmers and herdsmen. Many farmers only pay attention to raising livestock, while neglecting the epidemic prevention of livestock diseases, which has led to the rise of some epidemics that have not appeared for many years. The occurrence of this case fully shows that "veterinary prevention and treatment should give priority to prevention". The prevention of epidemic diseases is the most critical and effective measure to control or even eliminate livestock diseases.

two。 Diseased animals are the main source of the disease. therefore, when the disease occurs, the sick herds should be quarantined immediately and treated in isolation. Other herds should also be immediately vaccinated with emphysema gangrene vaccine to prevent the spread of germs.

3. Clostridium emphysematosum is exclusively anaerobic, which mainly exists in the tissue and edema fluid of dead cattle. It can form highly resistant spores in diseased bovine tissue. According to the pathological characteristics of the disease, spores can survive for 10 minutes in 0.2% mercury solution, 15 minutes in 3.0% formalin solution, and more than 5 years in soil. Especially after the tissue fester and edema fluid of dead cattle pollute the environment, healthy cattle are infected by eating soil, forage and drinking water containing a large number of emphysematous Clostridium gangrenum (spores). At the same time, the disease can also be spread through wounds, blood-sucking insects and mosquito bites. Therefore, if the disease is prevalent in one place, it should be transferred to the pasture immediately, it should be strictly disinfected and sterilized, and other cattle should also be forcibly vaccinated to prevent the epidemic.

4. It is not allowed to dissect the carcass of cattle that died of the disease at will, and it should be strictly forbidden to eat, so as not to cause more pollution. Sick and dead animals should be buried or incinerated in places outside the pasture where the groundwater level is low.

5. After the occurrence of this case, it is necessary to control and eliminate the source of the disease in a short time. Therefore, the animal husbandry and veterinary epidemic prevention department of our county took active measures to prevent and prevent the occurrence of emphysema gangrene in dairy cows, and vaccinated all cattle against emphysema gangrene. Specific practice is: every spring and autumn two seasons inoculate emphysema gangrene vaccine, large, calf individual hypodermic injection 5 ml, continuous injection vaccine for 3 years. Calves at the age of 6 months must be immunized once more. Cattle in the marginal areas of the epidemic must also be vaccinated continuously within three years and an immune zone must be established and must not be taken lightly.

6. The local swelling of emphysema is very similar to malignant edema. Veterinarians are easy to make mistakes in diagnosis and ignore the existence of emphysema, resulting in the sudden occurrence of the disease. Therefore, through effective capital investment, the ability of epidemic prevention at the grass-roots level should be strengthened to ensure that veterinary technicians can make a correct judgment through advanced laboratory testing.