The diagnostic methods of diseases can be divided into general diagnostic methods and special diagnostic methods.
The general diagnostic methods are inspection, auscultation, and olfaction. The essence of visual diagnosis is to observe diseases with the naked eye. Therefore, the practice of visual diagnosis has proved that visual diagnosis is a simple and valuable method to examine diseases in the clinic.
When inspecting, the examiner in the cattle farm should observe the diseased dairy cattle from 2 to 3 meters away from the diseased cattle in an all-round way. The order is to turn from the front to the left, then walk to the back, stop at the front and rear, observe the state of the chest, abdomen, and buttocks on both sides, and then go through the right side to the front. If abnormalities are found, they can follow the opposite order. Get a little closer to the bovine body and return to the front left.
The visual examination includes an examination of the whole body condition of the diseased dairy cow and an examination of the related parts of the disease.
When inspecting, cattle farmers should pay attention to the mental state, nutrition facts status, changes in body posture, overall appearance, secretion and excretion, and respiratory status of the sick cattle. First, the overall impression should be obtained, and then the observation should be focused on all parts. The order is head, neck, chest, waist, abdomen, hind buttocks and limbs. When some diseases are serious, they can be diagnosed at a glance, such as a rumen swelling, paralysis of production, and placenta failure.
Auscultation is a diagnostic method to distinguish the nature of sound by hearing.
Cough is mostly caused by exogenous or internal injuries. Where the voice of sick cows is weak and short of breath, it is mostly fatigue injury; the loud voice is true and mostly exogenous; those who want to cough but dare not cough are mostly pulmonary diseases; those who cough loudly are mild for ventilation; and those who cough half-voice are severe for stagnation of lung.
Belching: the physiological function of cows and ruminants. If dairy farmers fail to hear the belching of cows, the rumen function will be impaired.
Moaning: Sound made by diseased cows when they feel pain in the course of the disease. Generally, the moaning of diseased cows is accompanied by other symptoms, such as moaning with rumen swelling, moaning with abdominal pain, and lying-up moaning of pregnant cows during the non-prenatal period.
It is common to identify cow diseases by olfaction, such as the odor of garlic in the exhaled gas or milk production of cows with ketosis.
The special diagnostic method refers to some special examinations used in general clinical diagnosis to finally confirm the clinic. The main methods are probe diagnosis, puncture examination, dissection diagnosis, and diagnostic fluid diagnosis.
Exploration includes two difficult methods: one is to diagnose esophageal obstruction or gastric emphysema by inserting a gastric duct or a special esophageal probe into the esophagus or rumen of dairy cows; the other is to open the abdominal wall and the rumen by surgical method, and extend the hand into the abdominal cavity or the rumen for examination, that is, exploratory laparotomy, in order to examine and treat gastric diseases.
Puncture examination is the use of thick needles or probes into a lesion site to examine pathological changes, such as the abdominal cavity and swollen parts of the puncture examination.
Anatomical diagnosis is to examine the characteristic pathological changes of the dead cattle or the typical cattle with serious diseases by on-site bovine anatomy. For example, an autopsy of dead cattle with intestinal tuberculosis showed intestinal mucosal ulcer and cheese of mesenteric lymph nodes. In clinical diagnosis, a bovine autopsy is usually performed by a veterinarian.
Some diseases can be diagnosed by field tests or laboratory diagnosis with special diagnostic fluid, and the diagnosis can be made on the spot according to the test results. If cow recessive mastitis on-site rapid diagnosis (CMT), only 10-25 seconds can be used to make the diagnosis.