Tetanus is an acute and poisonous human and animal infectious disease, which is caused by Clostridium tetanus infection through trauma. It is also called umbilical cord wind, lockout, ankylosis, etc. The main characteristic of diseased cattle is that the body's skeletal muscle or some muscle groups continue to appear tonic spasm, and will show obvious excitement by external stimulation, which seriously damages the economic benefits of cattle production. Next, let's get to know more about it: Cause analysis of tetanus in dairy cows, clinical symptoms of tetanus in dairy cows and prevention and treatment measures.
Clostridium tetanus is the pathogen that causes the disease. Clostridium tetanus causes infection through wounds and produces toxins, which damage the motor central nervous system of the body, thus causing the onset of the disease. Clostridium tetanus is a Gram-positive bacterium, which has no capsule, flagellum, can move by itself and can grow well under anaerobic conditions. It is widely found in nature, such as soil, feces, and dust. It is very easy to cause the disease in susceptible cattle through wound infection.
Dairy cattle tetanus is usually sporadic in all parts of the country. Any livestock can be infected, among which dairy cows are more susceptible. The disease is mainly caused by wound infection, especially deep and narrow wounds (such as stabs, nails, etc.), and is closed by necrotic tissue, feces or soil to form an anaerobic environment, which is very prone to the disease. Also, surgical operations and preventive injections are not strictly disinfected, improper service, cow delivery process can only damage the birth canal, postpartum infection, calf castration, umbilical cord broke too short, will form trauma, if not timely and effective treatment will often lead to disease. Some diseased cattle are usually unable to determine the route of infection. This is because the wound has healed before the symptoms appear after the invasion of spores. It takes a certain time for the invaded spores to grow and reproduce in large quantities under anaerobic conditions and produce a large number of toxins, thus causing the disease.
The disease has a latency of about 1-2 weeks. In the early stage of onset, the head muscles of diseased cattle showed ankylosis spasm, abnormal feeding, chewing and swallowing movements, and the speed was slow. With the progress of the disease, the whole body appeared obvious ankylosis, showing mouth atresia, a large number of salivation, showing a linear shape. The back of the neck is rigid and straight, showing vein grooves, prominent instantaneous membranes, erect ears, abdominal contraction, straight tail, slightly tilted to one side. The spine tends to be straight and sometimes angular arch deflection occurs. The limbs are rigid, the joints are difficult to flex, the hoofs can not be raised, refuse to walk, it is difficult to turn or retreat, as long as the foundations are inverted, it is impossible to stand on its own. Also, the reflex of diseased cattle increased significantly in the early stage, and all light, sound, touch or other actions could promote the symptoms to aggravate. Short breathing and superficial, can reach several times the normal frequency.
Generally, the disease can be diagnosed according to the history of trauma and clinical symptoms of diseased cattle. However, cattle often do not show typical clinical symptoms, the main feature is tail root tremor, and not all diseased cattle will have such typical symptoms, so it is necessary to use smear microscopy and animal test to diagnose the disease, and can also be used for differential diagnosis.
Smear microscopy. Under sterile conditions, the exudates or necrotic tissue smears of wounded parts of diseased cattle were stained for microscopic examination and Gram-positive Bacillus spp. could be seen in the microenvironment like drumstick or badminton racket.
Animal experiments. Emulsions were prepared from the obtained materials and injected into the tail roots of healthy mice. Symptoms usually occur after 2-3 days. Also, the blood of diseased cattle can also be taken, and 0.5 mL can be injected into the muscles of mice buttocks. Symptoms will appear after 18 hours.
Immunoprophylaxis. Tetanus toxoid is commonly used to prevent the disease, and cattle can be immunized regularly every year in areas where the disease is more prone to occur. Generally speaking, a subcutaneous injection of 1 mL is suitable for adult cattle, the dosage of calves is reduced by half, and then injected once after 6 months. The immunity of cattle can be formed after one month of vaccination, and the immunization period is one year. The second year of vaccination, once again, can be effectively protected for four years.
Western medicine treatment. First, the toxin should be neutralized. According to the age of the diseased cattle, a proper amount of anti-tetanus serum was injected intravenously. The dosage of adult cattle was 500,000-900,000 IU each time, and that of calves was 20-400,000 IU each time, three times a day for three consecutive days. At the same time, with the injection of 40% urotropine, the dosage of 50 mL for adult cattle and 20-30 mL for calves was used once a day for 5 consecutive days. Then sedation should be carried out. The diseased cattle can choose to inject the appropriate amount of chlorpromazine. The dosage of adult cattle is 250-500 mg each time, and the dosage of calves is 150-200 mg each time, twice a day. Then spasmolysis was carried out. The diseased cattle could choose to inject the proper amount of magnesium sulfate solution intramuscularly or intravenously. The dosage of magnesium sulfate solution was 100 mL for adult cattle and 25 mL for calves, twice a day for one week. Finally, the pathogen should be thoroughly cleared, i.e. the pus, necrotic tissue and foreign body in the wound should be thoroughly cleared, and then rinsed several times with 3% hydrogen peroxide or 2% potassium permanganate until the wound is completely washed, and smeared with 5% iodine tincture or sprayed with appropriate amount of iodoform sulfonamide powder, once a day, until the wound is completely recovered.