国产女人18毛片水,成人免费淫片免费观看,日韩精品久久不卡中文字幕,美女一级毛片直播,欧美综合色区,国产精品久久久久aaaa,亚洲日韩精品欧美一区二区

In the past, the traditional family pig breeding equipment used to raise whatever kind of pig it had, but it didn't pay much attention to the breeding of excellent breeding pigs. However, in order to develop modern large-scale pig breeding, we must consider the selection of good strains of breeding pigs, which is one of the lifelines of breeding pigs.
In order to adhere to the sanitation, improve the environmental conditions, cut down on the manual cleaning, the modern pig equipment factory has used the leaky floor laid on the dung and urine ditch. At present, a common idea in the scientific community is that the variety of influenza A H1N1 virus is closely related to the ecological environment of industrial scale pig farms in North America. Some scientists say the virus contains the genetic elements of the virus found in 1987 pig farms in Indiana.
In order to adhere to the sanitation of the fence, improve the environmental conditions and cut down on the manual cleaning, the modern pig farm is widely used to lay the leaky floor on the dung and urine ditch. There is also some scientific support for the possibility that this dense industrial scale breeding method will produce new viruses. Recently, a study conducted by the Pew Charitable Trust Fund and Johns Hopkins Bloomberg School of public health found that this kind of factory feeding may add the risk of new virus transmission, including swine flu and bird flu
However, with the development of pig breeding equipment, the system of solid-liquid separation, anaerobic treatment and biogas treatment has been carried out in the pig farm. The sewage has almost reached zero discharge, and mosquitoes and flies have lost the breeding conditions. The pig house is not as smelly as the usual pig farm and there are no swarms of flies. In the pig farm, there are a lot of advanced pig raising equipment, such as overhead bed, positioning fence, leaky floor, active food trough, active water dispenser, online conservation equipment and advanced thermal insulation and ventilation equipment. Scientific and reasonable pig house structure ensures the safety and health of the pig population