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How to prevent the trypanosomiasis evansi in dairy cows?

Posted on: July 26, 2019, by Eleanor

Trypanosomiasis evansi in dairy cows is caused by the parasite of trypanosomiasis in the blood and hematopoietic organs of the body. The main clinical characteristics of diseased cattle are intermittent fever, body thinning, edema of lower limbs, anemia, dry tail tip, ear tip, necrosis and even shedding. The old epidemic area usually undergoes a recessive or chronic course, while the new epidemic area usually undergoes an acute course and spreads rapidly, resulting in the death of cows. The following specific to understand: the characteristics of Trypanosomiasis evansi in dairy cows clinical symptoms and prevention of Trypanosomiasis evansi.

Do you know how to prevent the trypanosomiasis evansi in dairy cows?
Do you know how to prevent the trypanosomiasis evansi in dairy cows?
  • Pathogenic characteristics

Generally speaking, the susceptibility of dairy cows to Trypanosoma evansi is relatively weak. Although some of them will die from the acute attack in the early stage of the epidemic, most of them will be in the state of carrying worms and will not occur. In the dry season when the temperature drops sharply when the body's resistance weakens, the disease will begin to occur, often with a chronic process, and eventually, lead to death due to cachexia. All kinds of Zoobenthos can be used as the source of infection of the disease. The onset season is closely related to the growth time of blood-sucking insects. For example, when the blood-sucking insects are active for a long time in summer, the epidemic time will be relatively prolonged. The disease is mainly transmitted mechanically by bloodsucking flies and tadpoles when they suck blood on the surface of dairy cows.

Trypanosoma evansi parasites in dairy cows can produce numerous toxic metabolites, which can cause the body to produce antibodies that can promote the dissolution of trypanosomes, cause trypanosomes to dissolve and die, and release numerous toxins, which can affect the central nervous system of the body, resulting in functional disorders, body temperature gradually increased, and motor ability decreased. Weak or uncontrollable, and so on, will then infringe on the body's hematopoietic system, prompting numerous red blood cells to dissolve, and eventually anemia due to a significant reduction in red blood cells. At the same time, toxins can enhance the permeability of the blood vessel wall, damage the blood vessel wall and cause subcutaneous edema. Later in the course of the disease, because the body accumulated for a long time without the product of complete oxidation, it would inhibit the central nervous system, thus showing mental depression, or even into a coma.

  • Clinical symptoms

Diseased cattle can be divided into acute and chronic types, most of which are chronic. Acute diseased cattle will have regular intermittent fever, the highest body temperature can reach 40-41.8 C, lasting 1-2 days to return to normal, 2-10 days later again, while chronically diseased cattle have no rules, sometimes in 1-2 months after a sudden rise, and then quickly reduce to normal body temperature, easy to be ignored, after several fevers will surface. It shows mental malaise, emaciation and weakness, lack of nutrition, dry and dull hair, exposed bones, skin cracking, layer by layer falling off or festering, limbs inflexibility, paralysis of hind limbs, unable to stand, the most obvious is swelling of lower limbs, often one limb or two limbs have pathological changes. Usually, the tubal bone, spherical joint and hoofs under the bowl joint or flying joint swell and become very thick. The skin is tense, and there is a slight sense of heat and pain. Over a long period, the epidermis will be broken and a small amount of yellowish viscous liquid will flow out or form a black scab. As the course progresses, the degree of swelling will gradually disappear or aggravate. Ring-like dry necrosis occurs at the tip of the tail, which falls off one by one. At last, only the tail root remains. At the same time, the tip of the ear also cracks and necrosis. The conjunctiva of diseased cattle was markedly congested and flushed at the initial stage, with continuous tears and viscous grey-white secretions. Later, the conjunctiva became pale as the congestion gradually subsided. Sometimes hemorrhagic spots were ranging from needle tips to rice grains on the conjunctiva, and the lymph nodes on the surface of the body became swollen.

  • Laboratory examination

Drop specimen examination. Fresh blood droplets were collected from the ear veins of diseased cattle when the body temperature rose. The slides were covered and pressed. Curved active worms could be observed by microscopy.

Blood smear examination. When the temperature of diseased cattle rises, blood is collected at a jugular vein. 3.8% sodium citrate solution is added according to the 4:1 ratio. The mixture is evenly mixed and put into a centrifuge. The centrifuge is carried out at the speed of 1500-2000r/min for 15 minutes. The supernatant is discarded and the precipitate of white blood cell layer is taken for the smear. After drying and fixing, Giemsa staining is carried out and the microscope is used. The curving willow-leaf trypanosome can be observed.

  • Prevention

Medication. The diseased cattle can be treated with 4-5 mg/kg methylthiouracil according to their body weight, and 10% water suspension can be prepared before use for subcutaneous or intramuscular injection, once every day, 2-3 times continuously. It can also be injected intramuscularly or subcutaneously with 1 mg/kg acridine hydrochloride injection according to body weight. If necessary, it can be used continuously for 2-3 days, and then at least 28 days off, pay attention to lactation can not be used. It is also possible to use 4-5 mg/kg Benel according to body weight, add the appropriate amount of sterilized distilled water to make 5% solution, and inject deep muscle into buttocks once a day for 1-2 days. If the symptoms are serious, it can be stopped for 2 days and treated for another course of treatment. Ivermectin injection of 0.2 mg/kg can also be injected subcutaneously according to body weight, and after that, there should be a 35-day off period, pay attention to lactation can not be used. It can also take 15 mg JKG albendazole orally according to body weight.

Strengthen feeding management. Keep the cowshed clean and disinfect regularly. To clean up the excrement in time, harmless treatment must be adopted. The bovine body is often brushed to keep its surface clean and avoid harmful diseases and insects. Cattle should be checked regularly so that suspected diseased cattle can be detected as early as possible. If diseased cattle are found, they should be isolated immediately to prevent further spread and spread of the disease. In areas prone to the epidemic, cattle can be prevented with drugs in time. Quinouramide preventive salts are often chosen to protect cattle for 3-5 months. Nagano can also be used to prevent the disease, and amoxicillin can be used to prevent the disease for 1.5-2 months. Amoxicillin can also be used to protect cattle for 4 months.

Do you know how to prevent the trypanosomiasis evansi in dairy cows?
Do you know how to prevent the trypanosomiasis evansi in dairy cows?

Diagnosis and treatment of trypanosomiasis evansi in dairy cows

  • Incidence

In mid-August 2001, an individual household introduced 13 dairy cows. By early September, some dairy cows had symptoms of anorexia, depression and elevated body temperature. The head of the household suspected of having a cold but did not improve after treatment with penicillin, streptomycin, and sulfonamides. By mid-September, a high-yielding cow had severe symptoms, weak hind legs, no ability to fall to the ground, paroxysmal cough, and finally died of exhaustion!

  • Clinical symptoms

During the disease period, the cow was depressed and its body temperature rose to 40.5 degrees, which continued to decrease for several days. Later, the body temperature rose again to intermittent fever, conjunctiva flushed red, pale yellow and bleeding spots. Diseased cattle fed, ruminated less and thinner, rough and dull fur, mental retardation, body droop, and limb skin edema or mass, late limb paralysis, lying on the ground, exhaustion and death. The diseased cattle died about 15 days after the disease.

  • Diagnosis

Pathogenic examination: fresh blood droplets were collected from the ear vein when the body temperature of the diseased cattle increased, dripped on the slide, covered with glass sheets and made into pressed sheets. Microscopic examination showed the active and curving spindle trypanosome. When the temperature of diseased cattle increased, blood was collected in the jugular vein, mixed with 3.8% sodium citrate solution at 4:1, centrifuged 15 MIN at 1500-2000 R/MIN speed in a centrifuge, and then the superficial fluid was removed to absorb the precipitate smear of the white blood cell layer. Dry, fixed and stained with Giemsa for examination. Microscopic examination showed curved Trypanosoma willow.

According to clinical, epidemiological and pathogenic examination, the diagnosis of Trypanosomiasis evansi in dairy cows was made.

  • Prevention and control
    • Symptomatic treatment

  Five cows were treated with 10% sodium acetate 20ML, 5% vitamin C 40ML and 5% glucose 500ML, and intravenously dripped slowly to enhance their resistance.

  • Killing Pathogens: After one day of symptomatic treatment, Bayer 205 was injected intravenously with a 10% solution of normal saline at the dosage of 3 g per head, and then subcutaneously with 3 mg/kg of Kangcongling and sterilized distilled water at a time.
    • Enhance immunity and promote rehabilitation of diseased cattle. After the first course of treatment with antigens and insecticides, Chinese herbal prescriptions were added: Codonopsis pilosula 60g, Atractylodes macrocephala 60g, Poria Cocos 60g, roasted licorice 30g, cooked Yellow River 45g, Paeonia lactiflora 45g, Angelica Sinensis 45g, Chuangong 30g, boiled and dregs removed, and irrigated at waiting temperature.
    • Strengthening Feeding Management and Preventive Insecticidal Treatment

To strengthen sanitary control of huts and sports areas, weeds around huts were eradicated and 2% trichlorfon solution sprayed to reduce the invasion of the media, tick, and timely cleaning and treatment of feces. Seven cattle were injected with anticonvulsant salt. The formula of ampere preventive salt: 1.5 parts of methyl Sulfurate pyrimidine and 2 parts of Naimidine chloride. The method is to take 35 grams of ampere preventive salt and put it into a 150 L volumetric bottle, add sterile distilled water to 120 L, and then add sterile distilled water to 150 ML after full oscillation. After mixing, inject subcutaneously. The dosage is 0.05ML/KG, 150-200KG, 10ML for each animal, 15ML for 200-350KG and 20ML for 350KG. After taking the above measures, the diseased cattle recovered completely, and the appetite, spirit and milk production of the cattle returned to normal.

  • Conclusion
    • Trypanosomiasis evansi is a hematological protozoonosis caused by Trypanosoma evansi parasitizing in the plasma of dairy cows and spreading by bloodsucking insect flies, characterized by high fever, anemia, and emaciation. On the one hand, due to the long-distance transportation of cattle and the hot weather, the sudden change of living environment leads to a decrease of resistance and induces the disease, on the other hand, because the area is an epidemic area of Trypanosomiasis evansi in dairy cows. It is understood that the disease has occurred many times in farmed cattle near the dairy farm.
    • When importing dairy cows from abroad, quarantine of origin should be done well, epidemiological history of epidemic diseases in the region should be paid attention to, and corresponding preventive measures should be taken in time. It is suggested that all newly imported dairy cows in the field should be subcutaneously injected with ampere to prevent salt. And strengthen the feeding management and disinfection of the surrounding environment of the pen to avoid insect-borne diseases.
    • Trypanosoma evansi proliferates in the plasma of diseased cattle, destroying the function of hematopoietic organs, weakening the ability of red blood cells to carry oxygen, leading to loss of weight, anemia, and death of cows with heart failure. In addition to symptomatic treatment, the combination of Chinese herbal medicine adjuvant treatment will achieve better results in promoting the rehabilitation of diseased cattle and improving the immunity of the body.
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