Pig breeding and building environment

Pig production, pig producers, genetics, nutrition, building environment, pig housing, heat stress, mechanical ventilation, natural ventilation, gravity ventilationOne of the most important factors in pig production is the environment of the buildings that house pigs through their process of breeding, growth and maturityPig production is big business. Worldwide, more pork is consumed than any other meat, well ahead of poultry and beef. As a result, successful pig producers are always looking for better ways to do what they do.


There are several factors that impact whether a producer is successful, i.e. genetics, nutrition, management and building environment. One of the most important is the environment of the buildings that house pigs through their process of breeding, growth and maturity. To fully understand how building environment impacts the fate of market pigs is to understand the very nature of pigs.
Most varieties of pigs are susceptible to stress, heat stress in particular. Why? Because pigs lack sweat glands and cannot cool themselves, and so the proper building temperature allows pigs to spend less energy on keeping their own body heat at the desired level. This allows them to gain weight faster, which makes the process more efficient. This is why conventional wisdom tells pig producers that if they control the interior environment of the buildings, they will maximise growth and growth-to-feed ratios. After all, a producer’s primary goal is to maximise his operation at every level and remain profitable.

Mechanical vs natural ventilation
Because the atmosphere around us is a mixture of dry air and invisible water vapour, it is subject to change, depending on weather conditions. As a consequence, ventilation is one of the key elements in pig production and there are two types to choose from: Mechanical ventilation and “natural” or “gravity” ventilation.
There is no perfect system, so producers must select the system that is most acceptable to them and best suits their management goals. In many cases, it comes down to cost, with some exceptions. Utilising mechanical ventilation, proper air movement can be generated through tunnel ventilation. This is a type of exhaust system, whereby fans are mounted at one end of a building and act as pumps to move air through the interior of the building.
The primary result is the removal of heat and moisture from the building’s interior. In addition, it limits the build-up of harmful gases, such as ammonia and carbon dioxide. 
Another part of the mechanical ventilation system is called evaporative cooling, which refers to the cooling effect produced when water evaporates. Evaporative cooling pads are mounted on the side or end of a building and are designed to cool the outside air as it is pulled through pads and through the interior. Evaporative cooling is the most inexpensive way to cool the air – much cheaper than using refrigerants and compressors.
Natural or gravity ventilation relies on doors or panels to allow the wind to blow against and through the building. With smaller pigs and in milder climates, natural ventilation is often a sufficient method of keeping the building at a desired temperature.
Mechanical ventilation also occasionally uses natural ventilation by utilising curtained side walls, particularly in gestation and finishing houses and in locations with more moderate temperatures. Then too, curtained side walls are a logical fall-back method of ventilation if there is a power failure with the mechanical process.

The role of proper insulation
Originally, those who developed modern ventilation systems, conducted their research by testing houses that were not sufficiently insulated, which meant there were probably leaks that compromised the accuracy of the tests.
Fans pulled air through seemingly obscure interior areas, such as sidewalls, endwalls, and ceilings. As a result, some of their findings may be questionable. The better type of building is the sealed building, one devoid of leaks. With a tight building, insulation can be much more effective and ensure that the building interior can be controlled as needed. Once again, as with ventilation, the goal is to adjust the interior of the building to the desired effect, regardless of the outside climate.
With a drop ceiling, insulation can be installed that reduces heat transfer from the sun in warmer climates and prevents loss of heat in the colder climates. In these instances, the attic becomes a buffer zone that results in lower energy costs and the ability to maintain consistent interior temperatures. Then too, insulation is the least expensive component of a pig house, so it follows that it will generate the highest return on investment.

Making the right decision
Meeting pre-determined production goals measures the success and profitability of farms, and those goals depend, in large part, on the efficiency and productivity of the houses. When reviewing building proposals, and the producer senses the building doesn’t quite fit the asking price, don’t be afraid to ask the following questions:
• Is the building designed and engineered to meet local requirements, such as wind seismic factors, etc.?
• To what code is the building designed?
• Are all components coming from a single source, or are some items, such as insulation, curtains, PVC coated wire or doors outsourced?
• Does the manufacturer provide an on-site, certified supervisor to ensure the construction process moves along on schedule?
• Can the components be easily shipped to the site and easily erected?

These are questions every producer should ask before signing a building contract. After all, selecting an experienced and dependable manufacturer, with a history of producing quality houses, coupled with offering dependable customer service, will go a long way toward helping pig producers meet their goals and maintain a good return on their investment. While the building environment is just one piece of the puzzle, its importance is critical.

By Kris Molander (Project Manager for the Agri-housing Division of BETCO).

Alain Charles Publishing, University House, 11-13 Lower Grosvenor Place, London, SW1W 0EX, UK
T: +44 20 7834 7676, F: +44 20 7973 0076, W: www.alaincharles.com

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