Pig barn ventilation management tips: pig farmers need to master these key points

Summers are hot, and pig barn ventilation is very important. On July 18, 2016, agricultural technology extension workers in Manzhouli visited pig farmers in their jurisdiction to explain the points to note about pig barn ventilation. At present, the ventilation methods used in most small and medium-sized pig farms can be divided into three types: roof ventilation, transverse ventilation and longitudinal ventilation.

Roof ventilation. Roof ventilation refers to using the density differences between different gases, without mechanical equipment, to make the air inside the pig barn flow up and down, so that waste gases in the barn can be discharged outside through the top of the roof in a timely manner. Roof ventilation can greatly reduce the concentration of waste gases in the barn, ensure fresh air inside the pig barn, and reduce the incidence of respiratory diseases and other problems. For pig barns equipped with low-level ventilation windows and slatted floors, roof ventilation lets fresh, cool outside air enter through the low-level ventilation windows and blow directly onto the pigs, carrying away the heat they give off and the waste gases they expel, which can produce an obvious cooling effect, especially after washing the pig pens in summer. Roof ventilation can be achieved by opening windows in the roof, installing roof-powered fans or roof fans, and other methods.

Transverse ventilation. Transverse ventilation is generally natural ventilation or fans installed on the walls, and is mainly used for ventilation in open and semi-open pig barns. To ensure smooth ventilation in the pig barn, full consideration must be given to site selection, barn layout and orientation, and barn design. It is best to make the barn orientation perpendicular to the local prevailing wind direction, so that transverse ventilation can be used to the greatest extent. The air inlets for transverse ventilation generally consist of glass windows and rolling curtains. When installing the rolling curtains, the curtains should overlap the side walls by about 8 cm, which can prevent drafts from entering. At the same time, fly screens should be installed on the inner side of the rolling curtains to prevent flies, mice and other pests from entering and ensure biosecurity. It is best if the rolling curtains can be opened from top to bottom, allowing waste gases to be discharged from the top of the curtain and balancing air exchange and heat retention.

Longitudinal ventilation. Longitudinal ventilation usually uses mechanical ventilation and is divided into two types: positive-pressure longitudinal ventilation and negative-pressure longitudinal ventilation. Generally speaking, positive-pressure longitudinal ventilation is mainly used for pig barns with poor airtightness; negative-pressure longitudinal ventilation is used for pig barns with good airtightness, forcibly extracting air from inside the barn through fans to form negative pressure, so that outside air enters the barn through the air inlets under atmospheric pressure.

The main harmful components in pig barn air are ammonia, hydrogen sulfide, carbon dioxide and dust; among them, ammonia and hydrogen sulfide have the greatest impact on pig production performance and health. To ensure normal animal growth performance, these harmful gases must be controlled through reasonable ventilation so that the air hygiene quality of the pig barn meets the requirements.