Prevent heat stress in pigs

Prevent heat stress in pigs
May 31, 2021

Proper ventilation and cooling tools are essential to keep pigs healthy and feeding through the summer

By Jackie Clark
Staff Writer

Air quality in pig barns is key to the health and growth of pigs. As the weather gets warmer, farmers must strategically use ventilation and cooling tools to prevent heat stress in their animals. 

“We change our strategy in the summer,” Nat Stas tells He’s a Pennsylvania-based technical services manager for PIC, a swine genetics company. “In the winter we’re worried about minimum ventilation and keeping the air quality good but also keeping pigs warm and growing. But in the summer, it kind of switches.”

Pork producers “want to keep the pigs cool and comfortable because we know heat stress can impact feed intake and average daily gain,” he explained. 

The desired room temperature in the barn remains similar, but settings may change to achieve that temperature. 

“In the summer months we want to set our temperatures a little bit cooler than our desired room temperatures,” Stas said. 

Ventilation equipment may also require maintenance after the winter months, he added. “Belts can be dry rotted on fans, fans may not be working properly.” 

Producers should remove dust and apply grease where needed. In places that experience very cold winters, be sure to open snow doors “so we’re not restricting those fans and the fresh air that they’re getting as well,” he said. 

“When you look at any type of fan, you should essentially be able to look directly out of it. The louvers should pretty much be horizontal or perpendicular to the fan,” he explained. “If they’re starting to flap or hanging low that’s a good indicator that we’re either not getting the fan power that we’d expect to get, so oftentimes it’s a motor and a belt issue. Or if they’re flapping oftentimes those fans are starved for fresh air meaning that we’re not feeding them with enough fresh air and so the pressure on that fan is really high. That’s a good indicator that we need to open up our curtain or our inlets more and make sure our snow doors on our sockets are opened up as well.”

Meanwhile, farmers should keep an eye out for pigs showing signs of heat stress. Pigs may drink and waste more water in an attempt to stay cool, Stas explained. Farmers may also see changes in feeding times. 

“Lots of parts of the northern U.S. and Canada still have some cooler morning or cooler nights throughout the summer. Pigs will change their feeding pattern to eat during the coolest parts of the day,” Stas said. This behaviour is “a good indicator that it’s getting warm, and they’re going to start to eat less.” 

One way to try to prevent consequences of heat stress is feeding “higher energy diets in the summer to try to maintain that growth with lower feed intake,” he added. 

Farmers may also use a wetting system to keep animals cool. 

“We want to steer clear from fogging systems and make sure that we’re using a sprinkler-style system that is producing a relatively large droplet or sprinkle of water because we want that water to penetrate the hair of the pig,” Stas explained. Contact with the skin allows for evaporative cooling.

The system should cover 50 to 60 per cent of the pen so pigs don’t compete for space, he added. 

“Run it for maybe a minute or two on, and then we want to shut it off for enough time for that entire pen to get dry. Not only the pigs, but the floor,” he said. “If we kick it back on too early while it’s still damp in there, we’re simply adding humidity to the environment.” 

Depending on the ambient temperature and cooling protocol, you should be able to cool pigs by about 6-8oC, Stas said. 

However, “if it’s already really warm out, that differential between that air temperature and the pigs skin temperature is less, so we kind of run out of cooling effect in some cases,” he explained. 

Keep in mind that a humid environment can be a breeding ground for certain bacteria or other pathogens. 

“We have peaks and valleys of when certain viruses and bacteria hit, but we can’t ever slack off on focusing on biosecurity,” Stas said. 

“It’s kind of a balance where we accept the fact that we may produce a slightly more humid environment but hopefully we cool those animals, reduce the heat stress and keep them feeding and healthy (to support) their immune system to be able to balance those challenges,” he explained. 

artbyPixel\iStock\Getty Images Plus photo

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