November 09, 2011

To increase feed efficiency, check the thermostat

By Madeline McCurry-Schmidt

At the International Conference on Feed Efficiency in Swine, held earlier this week in Omaha, Dr. David Renaudeau explained how stress from hot or cold temperatures can affect feed intake and reduce weight gain in pigs.

Pigs in colder environments have to use more of their energy to keep warm, which cuts back on the amount of energy going into growth. This is a big problem for growing piglets, which have lower energy reserves and body insulation.

“We can solve this problem through provision of additional feed,” Renaudeau explained.

It can also help to keep facilities warmer. Renaudeau cited a study that showed that pigs weighing 20 kg increase feed efficiency when ambient temperature reaches around 33°C.

Renaudeau, a researcher with the French National Institute for Agricultural Research (INRA), said that highly productive pigs are also highly susceptible to stress in hot temperatures. He said producers have selected for larger pigs over time, which is good for boosting production but has a big drawback: larger pigs have a harder time keeping cool.

“Thermal stress problems are generally accentuated when we use modern pigs,” Renaudeau said.

When temperatures increase, pigs will eat less in an effort to avoid additional heat generated during digestion. This isn’t just true in pigs—in the cattle industry, feed intake was a problem this summer as temperatures in the Midwest spiked and cattle stopped gaining weight.

Renaudeau said heat-stressed sows can also have delayed estrus and greater embryonic mortality when they do become pregnant.

“All of this has an big impact on economic losses,” said Renaudeau.

To reduce heat stress and increase feed intake, Renaudeau suggested providing animals with cooled water, fans and sprayed or dripped cool water. It could also help to increase energy intake by providing high-fat diets.


Piglets under a heat lamp. Producers face a "thermal dilemma" when trying to warm piglets while keeping sows cool. Image from NAL.

Many producers have trouble controlling heat stress and cold stress in farrowing peners. Piglets cannot control body temperature very well, so they need heat sources. But lactating sows need to stay cooler and be comfortable enough to feed and produce milk. Renaudeau called this a “thermal dilemma” for producers who want to cool the sow while protecting piglets from hypothermia.

In his talk, Renaudeau said he was curious about the development of farrowing pens that run pipes with cool water underneath the sow without cooling piglets.

“It could be interesting to test this floor-cooling system,” he said.