Bronchopneumonia, also known as lobular pneumonia, can cause inflammation of the bronchi or bronchioles along with the pulmonary lobules. Many pathogenic factors can cause the disease. The main pneumonia symptoms are that the alveoli of bronchioles and a few pulmonary lobules are filled with inflammatory exudates such as white blood cells and epithelial cells, showing cough persistent, relaxation fever, rapid respiratory rate, and abnormal respiratory sounds on lung auscultation. The author summarized the pathogenesis and treatment of the disease.
The main cause of cow disease is cold, coupled with poor feeding management, which makes weak cows very susceptible to infection. The disease is usually susceptible to virus infection in calves and old and weak dairy cows and is more susceptible to disease in winter and spring cold season. When dairy cows inhale spores, dust, smoke, ammonia, and other irritating gases, they can induce the occurrence of the disease. Lack of nutrition, weakness, and senility of dairy cows, and inadequate intake of minerals and vitamin A can also cause the disease.
Besides, when dairy cows suffer from endometritis, tuberculosis, malignant catarrhal fever, mastitis, and foot-and-mouth disease, pathogens can invade the lungs through blood or lymphatic circulation, thus secondary to the disease. Besides, the disease can be secondary to bronchitis and some parasitic and infectious diseases, such as ascariasis, pneumonia, foot-and-mouth disease, tuberculosis, influenza and so on. If the cow is overtired, leading to physical weakness, it will also cause the disease.
Dairy cows undergoing cold stimulation can accelerate the decomposition of tissue proteins in vivo, resulting in a large amount of macromolecule colloidal proteins in the blood, and macromolecule colloidal proteins can stagnate in the pulmonary capillaries through blood circulation, further lead to pulmonary capillary congestion, macromolecule colloidal proteins, and cold stimulation can make monocytes. The function of the macrophage system is reduced, which results in the weakening of its activity and the obvious decrease of the body's resistance, then influence the milk nutrients.
Besides, the proliferation and invasion of pathogenic microorganisms cause lung inflammation. Initially, inflammation is often confined to the bronchus. Then, the bronchial mucosa begins to spread gradually to the alveoli, and bronchoalveolar congestion and swelling are caused by the proliferation of bacteria. Then mucous and serous exudates are produced and secreted, causing epithelial cell exfoliation. The disease is characterized by lobular inflammation, and inflammation caused by individual lung lobes does not occur at the same time, so in clinical cattle, there is relaxation fever, and there is a focal scattered voiced in the lungs. The cattle rancher should pay more attention to this kind of disease.
3. Clinical symptoms and pathological changes
In the early stage, the diseased cattle will show symptoms of acute bronchitis, such as the runny nose, cough and so on. The diseased cattle began with a painful short cough, then gradually changed to grow cough and wet cough, but the pain was alleviated due to the increase and thinning of the exudate lungs. The diseased cattle first had serous nasal fluid flowing out of both nostrils and then turned into mucous or mucopurulent.
As the course of disease progresses, when the lungs are damaged, the diseased cattle show appetite abandonment, slow rumen peristalsis, stop rumination, feces excreted are less and less than those excreted, and diarrhea occurs in some cases, resulting in a significant reduction of lactation performance; cyanosis of visible mucosa; body temperature reaches 40-41 C, showing intermittent fever (relaxation fever) and shallow breathing.
And fast, 40 to 90 breaths per minute and standing will straighten the head and neck, nose wing flapping, serious even mouth breathing phenomenon, frequent coughing even cough blood up, wet and weak; pulse weak and thin, heart rate accelerated, up to 90 to 100 beats per minute.
The disease mainly occurs in the lobules of the lung, especially in the anterior and inferior parts of the lung. There are many scattered pneumonia lesions of different sizes, and each lesion is composed of one or a group of lobules, and the lobules of the lung are mainly located in the branches of the bronchi where the lesions occur. The lesion's lung tissue is dark red, solid and does not contain air. The lesion small pieces cut by the human in water is found to sink immediately.
Because of the different degrees of the lesion, the sections of the lesion lung tissue show different colors, and there will be plasma fluid or blood outflow when pressed. The pulmonary interstitium is dilated and infiltrated with plasma exudates. It is peptone-like. In inflammatory lesions, the bronchial cavity can be dilated and filled with exudates, and compensatory emphysema often occurs around inflammatory lesions.
When Dexter cattle are auscultated in the lungs, the alveolar sounds in the affected areas will weaken or completely disappear. On the contrary, the alveolar sounds around the lesions are more severe and produce bronchial twisting or breathing sounds. For percussion, semi-voiced or voiced sounds, i.e. solid sounds, can be produced in the affected areas, while drumming sounds around the lesions can be detected by X-ray examination. The boundary is blurred, and scattered lesions exist in the anterior and lower parts of the lung, and the number is uncertain.
Blood samples were collected for laboratory tests. It was found that the total number of neutrophils and leukocytes in the blood increased significantly, about 2 *104 per cubic millimeter. In the case of viral pneumonia, the total number of lymphocytes and white blood cells in the blood decreases. The urine of dairy cows was detected to be acidic, that is, the pH value was less than 7, and the qualitative results of urinary protein were positive.
Oral treatment. 1 mg bent mine hydrochloride tablets per kilogram of body weight can promote the rapid recovery of the disease; 0.17-0.2 g trichlorfon tablets (synergistic sulfadiazine tablets) can also be taken per kilogram of body weight. At the same time, the same amount of sodium bicarbonate can be taken twice a day; tetracycline antibiotics and bromobenzyl-cyclohexyl ammonium can also be taken together for 4-6 days.
Feed administration. Antibiotics such as florfenicol can be added to the diet of diseased cattle. The dosage should be 1.5 times of the instructions. At the same time, an appropriate amount of vitamin B13 or cobalt preparation can be added to improve the curative effect. If the phlegm of diseased cattle is more, sodium bicarbonate and ammonium chloride can be mixed in the diet 1-2 g each, twice a day. When the diseased cattle were treated with sodium sulfamethoxazole, 250g was added to each ton of feed, and vitamin B6 was used together for 4 days.
Drugs for drinking water. Xielxing (ofloxacin is the main ingredient) was added to the drinking water of diseased cattle, and it was prepared according to the proportion of 4 kg water per 10 g powder. It was used continuously for 5 days so that it should drink more water.
Direct spray. 10%-20% acetylcysteine solution was sprayed directly on the throat and upper respiratory tract of diseased cows, or 3-5 ml 5% acetylcysteine solution was dripped directly or from tracheal intubation into trachea twice a day.