1) nutritional metabolic diseases caused by intensive feeding conditions, especially feeding errors, often occur in groups, and the same or different animals have the same or similar clinical symptoms at the same time or one after another.
2) Endemic Due to geochemical factors, the distribution of some mineral elements in soil is very uneven, such as the iodine content in soil, feed and drinking water in inland and plateau areas far from the ocean is insufficient, and endemic goiter is prevalent in people and animals.
3) The occurrence of slow-onset nutritional metabolic diseases must go through at least three stages: chemical disorder, pathological change and clinical abnormality, and it often takes weeks, months or even longer from the etiological action to the presentation of clinical symptoms.
4) A variety of nutrients are lacking at the same time. In nutritional failure such as chronic consumptive diseases and chronic digestive system diseases, not only protein is deficient, but also other nutrients such as iron and vitamins are obviously insufficient.
5) Nutritional metabolic diseases, characterized by malnutrition and low productivity, often affect the growth, development, maturity and other processes of animals, which are characterized by growth stagnation, dysplasia, emaciation, anemia, abnormal skin, heterophilia, hypothermia, milk production, egg production, wool production, meat production and litter size reduction, and even malnutrition syndromes such as infertility, oligopregnancy, abortion and stillbirth.
6) lack of characteristic symptoms. The main difficulties in early diagnosis are depression, loss of appetite, digestive disorders, growth and development stagnation, anemia, heterophilia, and decreased production performance. Early diagnosis is very difficult.
7) Low body temperature and non-infectivity, which is a significant difference between early group nutritional metabolic diseases and infectious diseases.
Prevention and control principle
1) scientific feeding: according to the species, varieties, uses and physiological stages of livestock and poultry, and according to the required nutritional standards and diets, ensure full-price feeding.
2) Regular monitoring: conduct regular sampling surveys on the herds, analyze the nutrition in the feed, and find and treat them early.
3) Comprehensive prevention and control: For regional mineral deficiency, we can improve the content of related elements in feed and pasture by improving vegetation, soil fertilization, foliar spraying of plants, feed exchange and other methods.