Source: Michael Fielding, MEATINGPLACE, 1/4/16

Researchers at Aarhus University in Denmark have developed a method that uses an infrared camera to remotely measure the temperature of the sow.

"It’s very important to know the heat radiation of the skin, the so-called emissivity, if the infrared measurements are to be converted to a body temperature," researcher Dennis Dam Sørensen said in a news release. If the emissivity reading has a margin of error of just 0.05°C, this produces an error in the body temperature estimate of around 0.5°C.

Sørensen took both infrared pictures of sows and measured their body temperature in a conventional way with a thermometer. By relating the infrared pictures to knowledge of the actual body temperature at the time they were taken, he worked out a set of references.

But researchers noted that remote measurement of body temperature must take into consideration air particles that can disturb the measurements. So Sørensen was analyzed whether ammonia and dust affected the measurements. He found that there was an inverse relationship between the amount of ammonia and dust in the air and the temperature measured.

"This indicates that the infrared radiation from the sow was absorbed by the particles in the air," explained Sørensen, who also examined the influence of the sow’s hair and the dampness of the skin on measurements. The presence of hair had no effect, but wet skin provided lower temperature readings.

"This shows that it is important to measure the temperature on dry skin if you want an accurate figure," he said. It is also important to measure the temperature in the right place on the sow. His study showed that the best place to measure was at the root of the ear rather than the shoulder or the udder.

Timely measurements
A cost-benefit analysis showed that the use of infrared heat measurements for measuring fevers in sows may lead to considerable savings for the producer, particularly if the technique is used in automatic monitoring systems.

The study focused on sows around the time of farrowing and on the clinical health complex PPDS (postpartum dysgalactia syndrome in sows) that encompasses a variety of problems , such as mastitis, metritis and agalactia or lack of milk production (MMA). Early detection of the problem using temperature measurements may save the lives of piglets and reduce the use of antibiotics.

"A systematic or automatic monitoring of all sows with an infrared camera would be very useful for detecting the sows that may have problems," Sørensen said.

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