Animal welfare refers to the adaptability of the environment in which animals live to meet their basic natural needs. It has been proved that if animals are healthy, comfortable, well-nourished, safe, free to express their nature and not threatened by pain, fear and pressure, they can meet the requirements of animal welfare. As early as the beginning of the18th century, some scholars in Europe suggested that animals have feelings and pains just like people, but they can't be expressed in words. This paper expounds the main factors affecting animal welfare, such as feeding management, transportation, slaughtering and processing.
1 feeding
1. 1 microorganism
At present, aquaculture is gradually tending to intensive farming, and large-scale farming makes the breeding density too high, and microorganisms in livestock houses become the main pollution sources, mainly including pathogenic and non-pathogenic microorganisms. This has shortened the route of transmission, and the artificial environment has made the epidemic of diseases appear certain laws. Knowing the content and different types of microorganisms will increase the monitoring of environmental quality (table 1, table 2). Studying microorganisms in large-scale farms will help to prevent diseases and guide environmental sanitation management, which is of great significance to protect animal health and improve animal production. At present, many livestock diseases are caused by air, such as tuberculosis, asthma and reproductive syndrome. The occurrence of diseases promotes the use of antibiotics and veterinary drugs, which in turn leads to the decline of the quality of livestock products, endangering food safety and consumers.
Non-pathogenic microorganisms will also increase the burden of animal immune organs, and may also inhibit immune function, so that animals are often in sub-health state, such as poor spirit, reduced exercise, loss of appetite, increased secretion and so on. However, the production performance will decline, and the incidence and elimination rate will increase. The current culture mode makes the culture density too high and the air quality poor, which facilitates the spread of microorganisms. There are too many pathogenic bacteria and non-pathogenic bacteria in the barn, which pose a threat to animals and humans, thus reducing the quality of livestock products. At the distance of 5 meters from the barn, the content of aerobic bacteria is 23.6%, and the content of anaerobic bacteria is 53. 1%. Microorganisms in the house spread out of the house, polluting the surrounding environment and causing harm to livestock and human body. The economic losses caused by diseases caused by microorganisms are much higher than those caused by traditional diseases [1].