Optimizing pig sheds is vital for maintaining herd health, but in the winter months, getting the environment right is especially important in warding off illness.
Poor air quality can increase the risk of respiratory diseases, while failure to maintain environments correctly can cause pigs stress, resulting in outbreaks of tail biting.
Key to getting things right is looking at pig sheds to make sure ventilation and overall design are as good as they can be, according to UK farm advisory service AHDB Pork.
Even at low temperatures, air exchange has to take place to provide pigs fresh air to breath, and to remove stale air containing microbes, dust, harmful gases, odors and water vapor.
Circulating fresh air in cold temperatures can, however, cause pig temperatures to drop below their normal range of 38.7-39.8℃ (101.7-103.6°F).
This drop, known as a pig’s lower critical temperature, will cause the animal to use food energy to keep warm, affecting growth rates and leading to a reduction in production efficiency.
Similarly, cold areas in a shed can force animals to change their dunging behavior, leading to issues with cleanliness and pig health.
Balancing insulation with ventilation
The answer, says AHDB Pork, is a careful balance of insulation and ventilation during the winter.
“The benefits of good insulation are largely lost unless the ventilation rate is accurately controlled. Similarly, good ventilation control is only fully exploited with good insulation,” a spokesman says.
“It is important, particularly during periods of cold weather, to retain the heat produced by the pigs within the building in order to warm the cooler air coming in from outside.
“If a lot of heat is lost through the walls of the building, additional supplementary heat will be required, which will increase costs.”
By modern standards, older buildings where poorly insulated when they were built, often with no insulation in the walls or rood, or with little control of the air passing through the building.
To deal with the problem, AHDB Pork recommends taking steps to ensure the worst of the winter weather is kept outside of the main building.
As well as checking the sheds for anything that needs to be repaired such as guttering or missing roof tiles, closing up summer ventilation panels and closing gaps in the space boarding can help by keeping out the wind.
“This is particularly important in the space boarding above where the pigs usually lie if there are no kennels for them to get under, as cold air may drop straight onto the pigs’ backs,” the spokesman says.
The best solution is to create a kennel over the lying area, he adds.
“The kennel should be big enough for all the pigs to lie under when they are fully grown. Many kennels are made with a straw layer or straw bales as insulation to keep the pigs warm, but straw is a definite fire hazard and using it also means it is not possible to adjust the kennel lid height easily.
“If the lids are made of lightweight framing and cladding with a sandwich of insulation material such as polystyrene or polyurethane in between, it’s possible to raise and lower the lids, meaning you can control ventilation and get in to inspect the animals when you need to.”
In addition to looking at ventilation and insulation, carrying out a biosecurity audit will help fend off outbreaks of winter-loving viruses such as porcine reproductive and respiratory syndrome, says National Pig Association senior policy adviser Georgina Crayford.
“[Winter is] the season when disease associated with the virus that causes PRRS increases,” she says.
“The virus survives better in cooler, damper and darker conditions. It can also be more difficult to properly clean and disinfect pig buildings, vehicles and equipment during the winter.
With diseases able to spread quickly in housed systems, keeping an eye out for any symptoms of illness and putting a control plan in place quickly is key, she says.
“Farmers are strongly advised to carry out a biosecurity audit with their vet to identify and tackle any weak points which might allow the virus to enter their farm.
“Successful management of PRRS virus can also ultimately lead to a reduction in the need for treatment with antibiotics.”