First, characteristics of broilers and broilers
1, broiler has a high production performance, performance is rapid growth, high feed rewards, fast turnover broilers in just 56 days, the average weight can be from 40 grams to 3000 grams or more, eight weeks increased by more than 70 times At this time, the feed ratio is only about 2:1.
2. Broilers are sensitive to changes in the environment and have weaker adaptability to the environment. They require relatively stable and suitable environments. The suitable temperature for broiler chickens is 1-2°C higher than that for laying chicks, and the time for broiler chickens to reach normal body temperature is about one week later than that for laying chicks. Broilers are also not heat-resistant after they are slightly older, and they are prone to heat-stroke deaths during the high temperatures in summer. The rapid growth of broilers requires a higher oxygen demand. If the ventilation is insufficient in early breeding, the incidence of ascites may be increased.
3. Poor disease resistance Regardless of the large-scale chicken breeding, disease is still the biggest hidden danger of chicken breeding. From the chicken's anatomy and physiology, it is not difficult to see the reasons for the poor disease resistance of chickens: (1) The chicken's lungs are small and connect with the air, which fills all parts of the body and even enters the bone cavity. In this way, airborne pathogens can enter the lungs and airways along the respiratory tract, and thus also into body cavities, muscles, and bones; (2) The chicken's geminal and vasculature holes open in the cloaca, and the eggs are vulnerable during production. Contamination, so some chicken disease spread vertically through the egg? Chicks; (3) chicken does not? M diaphragm, abdominal infection is easy to spread to the various organs of the chest, chest infection is also easy to spread to the abdominal cavity; (4) chicken has no lymph nodes, equal There are no checkpoints to stop pathogens from passing through the body. Therefore, under the same conditions, the disease resistance of chickens is worse than that of geese and ducks, and the intensive breeding of the plants has the problems of rapid spread, severe disease, and high mortality. Even if they die, they will severely affect the production of eggs, which could easily cause production problems. direct economic loss.
Air passes through the nose and throat to the lungs and air bags. The lungs are spongy, bright red, and cling to the side of the chest. The lungs are covered with blood vessels under the mucous membranes of the tertiary bronchioles, so the lungs are the main place for gas exchange. The airbag is a unique organ of the bird. Its main function is like a bellows, which sucks air in and pushes it out for exchange in the lungs. The airbags communicate with bones and other organs to reduce their weight. This anatomy is the result of the evolution of the birds' ancestors to adapt to flight. It is precisely this feature that causes poultry to rapidly develop systemic infections after external pathogens enter the body through the respiratory tract.
Second, the importance of ventilation
While maintaining the proper temperature of the house, good ventilation is extremely important. The life activities of broilers are inseparable from oxygen. Adequate oxygen can promote the metabolism of chickens, maintain the health of chickens, and increase feed conversion.
Good ventilation can vent moisture, ammonia, dust and excess heat to provide sufficient fresh air for the flock. Poor ventilation and high ammonia concentrations can cause serious losses in production. In production, many breeders often only pay attention to temperature and neglect ventilation in the early stage of brooding. In severe cases, they cause increased perihemogenic ascites in broilers. Poor ventilation during the second, third and fourth weeks may increase the incidence of chronic respiratory diseases and E. coli in chickens. In the mid and late broilers, the demand for oxygen is increasing and the amount of excrement is increasing. The amount of ventilation and ventilation must be increased on the basis of maintaining the proper temperature. At this time, ventilation and ventilation are the main means to maintain the normal environment.
Late management of broiler production should focus on ventilation. As broilers are large in size, have large feed intake, and excrete a large amount, they exhale carbon dioxide, shed body heat, excreted water, ammonia gas accumulated in chicken manure, and floating in the air Dust, etc., if it cannot be discharged in a timely manner, the living environment in the house will become more and more severe, which will not only seriously affect the growth rate of broilers, but also increase the mortality rate of broilers. In the later period of broiler rearing, the body weight can almost increase by about 1.4 per day, and the death of one will cost about 20 yuan. The importance of late-stage management to improving economic efficiency is self-evident.
Farmers' misunderstandings raise households under the premise of heat preservation. There are such misunderstandings that they do not dare to ventilate, especially at the age of three weeks, they fear that chickens catch cold and catch cold and neglect the ventilation and ventilation, resulting in a serious over-standard harmful gas in the chicken house. Ammonia, hydrogen sulfide and other harmful gases stimulate chicken respiratory epithelial cells. Cause mucosal cells damage, respiratory epithelial cells have the first gateway to prevent viruses and bacteria from invading the body, or mucosal immune host, played a crucial role in the entire disease prevention system. If it is damaged due to insufficient ventilation, that is, the door of the body's respiratory defense system is opened, the bacteria and viruses will be reproduced in large numbers by reproduction, and transmitted to various organs through the circulation of blood, causing infectious diseases in the flock. . In addition, because the epithelial cells of the respiratory tract have been damaged, our vaccines will encounter immunosuppression when producing antibody titers. Without good antibody titers, the body will also be protected against viral diseases.
In order to master the method of ventilation, to form a gas flow, harmful gases are generally lighter than air, are concentrated above the chicken house, so we have to take this method according to the characteristics of the convection method for ventilation. That is to open the two sides of the window into the fresh air harmful gases discharged from the ventilation outlet at the top, and to avoid the thief wind, when the thief wind directly blows the chicken's abdomen, to increase the temperature while ventilation, do not take advantage of that point of coal money, only Only by improving the environment of the sheds can we make the chicken population less susceptible to disease, and it can be cured after the onset of disease.