What are the prevention and treatment methods for bovine necrobacillosis?

Necrobacillosis is a chronic infectious disease caused by Fusobacterium necrophorum. Clinically, necrosis of tissues such as the skin, subcutaneous tissue and digestive tract mucosa is commonly seen, and metastatic necrotic foci may also form in the internal organs.

1. Symptoms.

The incubation period is 1 to 3 days. The common disease types in cattle are foot rot and diphtheria. The former is more common in adult cattle. At the beginning of the disease, the animal is lame, and small holes and wound cavities can be seen at the sole of the hoof, containing necrotic and putrid inflammatory products. It appears as foul blackish odorous watery fluid. In addition, abscesses form between the toes, at the coronary band and at the heel, with pus leakage and necrosis of the surrounding skin. The inflammation can spread to the synovial bursa, tendons, ligaments and joints, and in severe cases the hoof capsule falls off. Severely affected animals lie down and are unable to rise, showing systemic symptoms, with elevated body temperature, poor appetite, increased pulse and respiration, and may even develop pyaemic septicaemia and die. Liver abscess foci and necrotic metritis may also occur.

In calf diphtheria, the body temperature rises above 41 degrees C at the beginning of the disease, and yellow purulent discharge flows from the nostrils. Fibrinous necrotic inflammation occurs throughout the oral mucosa and in the pharynx, and the mucosa is rough with greyish-white pseudomembranes, which form ulcers after detachment. In calves with pharyngitis, there is mandibular oedema causing inability to swallow and severe difficulty in breathing. When the lesions spread to the lungs or metastasise to the internal organs, they can lead to death of the affected cattle.

2. Prevention and treatment.

1. Treatment.

(1) For foot rot, clean away the mud and dirt from the hoof, then thoroughly wash with 1% potassium permanganate, apply a mixture of formalin and pine tar in a 1:4 ratio, and bandage. Keep the affected cattle on a dry floor or cement ground. Abscesses should first be incised to drain the pus, then the necrotic tissue should be removed, washed with hydrogen peroxide, and then bandaged with iodoform-sulfonamide mixture.

(2) For diphtheria, first remove the pseudomembranes, rinse with 1% potassium permanganate and then apply iodine glycerin, several times a day. When there are systemic symptoms, use antibacterial drugs such as tetracyclines, quinolones and sulfonamides, while also supplementing vitamins.

2. Prevention.

Disinfect cattle sheds regularly, keep them clean and dry, remove faeces and urine promptly, ensure good drainage in exercise yards, and detect and treat hoof injuries early.