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Digital infrared thermography: An early warning system?

Dave Wilkins Published on 19 September 2012

Imagine taking a cow’s temperature simply by snapping a picture of her head.

Want an early warning system to detect hoof disease or mastitis? Just snap a picture of the cow’s foot or udder.

These and other scenarios may be possible someday with digital infrared thermography.

Thermography measures the heat radiating from an object and records an image (still and/or video).

Technological advances have expanded usage and reduced the cost of portable thermography units in recent years.

Practical applications can be found in medicine, civil engineering and public safety. Firefighters, for instance, use thermal imaging to locate hot spots, see through smoke and find people.

Several recent studies have looked at the potential within the livestock industry. It’s possible the devices could be used for early detection of laminitis, mastitis and to measure body temperature.

But dairy producers will have to be patient.

It will likely be years before infrared thermography becomes an everyday diagnostic tool for herd health, researchers say.

In April 2011, researchers from the University of Wisconsin – Madison conducted a study on a commercial dairy to determine whether infrared thermography might be a possible new method for evaluating body temperature in fresh cows.

Using a hand-held thermal camera unit, researchers captured close-up images of each cow’s eyes. At the same time, they recorded the cow’s body temperature using a rectal thermometer and then compared the two measurements.

“What we found was that the camera is influenced quite a bit by the ambient temperature because of the reflection of heat from the eye,” says Arturo Gomez, a researcher on the study.

In cold weather, it’s tricky to get an accurate measurement with thermography, he says.

“In practice – mostly in areas like Wisconsin where the winter is very cold and the summer is very warm – we will need to make a little adjustment,” Gomez says.

Thermography will likely work better in milder climates such as California or Texas, he said.

The new technology will not replace rectal thermometers for measuring bovine body temperature anytime soon – “not without deeper study of the method,” he says.

Cows are most at risk of developing health problems in the two months immediately following calving – thus the focus on fresh cows in the study.

Elevated body temperatures can be an indication of infectious diseases such as metritis or mastitis.

Thermography would be a faster and less invasive method of measuring body temperature compared to the standard practice of using a rectal probe thermometer, Gomez says.

“The advantage is going in the front and measuring the temperature in the eye,” he says.

“At the same time, you can see whether the cow is eating or not. It’s a very nice practice and quite quick. It takes less than 10 seconds per cow,” he says.

The new technology could aid producers in their postpartum monitoring program and give them a head start in treating disease.

“Farms that look for a drop in appetite are better at preventing problems because they can act very soon and not wait (to see) a drop in milk production,” he says.

It could turn out that thermography is a useful tool even if it doesn’t compare well with rectal temperatures, Gomez says.

“Maybe rectal temperature is not as good alone as a detection method as thermal temperature combined with the appetite (monitoring),” he says. “We have not looked at that yet.”

Thermography could also be used to measure body temperature in dairy calves without getting inside pens and in beef feedlot situations, he says.

“With the camera, you can be one or two meters away. It’s not a big deal,” he says.

Because thermography is non-invasive, it could reduce stress on the animals and lessen the risk of spreading infectious diseases from cow to cow.

In recent studies looking at early detection of foot diseases in dairy cows, researchers have focused their thermal lenses on the coronary band region.

Danish researchers took measurements before and after hoof trimming and found a significant difference in temperature of the coronary band between cows with lesions and those without lesions.

Researchers in another study in Manitoba, Canada, concluded that infrared thermography may have potential as a detection tool for laminitis, but they said more data was needed before they could recommend the technology for commercial dairy use.

Rob Berry, a dairy specialist with Manitoba Agriculture, Food and Rural Initiatives, has participated in separate studies looking at infrared thermography’s potential for early detection of laminitis and mastitis.

His conclusion: Infrared thermography works but it’s not yet ready for prime time on the farm.

“If you want a cheap, non-invasive way of determining whether an animal has mastitis, thermography is a possibility,” Berry acknowledges.

“But right now the technology is not very applied,” he says. “It would be too difficult to use in on-farm situations without commercial development.”

With mastitis, inflammation of the udder typically results in an increase in temperature of the affected area within 24 hours of infection. The rise in temperature could be used in an early detection system.

But getting a good thermal image in a milking parlor is easier said than done, Berry says.

“One of the issues we had was getting the camera right behind the animal and being able to take clear images before she was milked,” he says. “We were kind of delaying things in the parlor.”

Berry finds the thermography units and imaging software to be fairly “clunky.”

To be practical, it would probably take a company integrating the technology into a currently available milking system, he says.

“I can see it working maybe with a robotic milker,” Berry says. “I think robotics is one area where it could really come into its own.”

Thermography systems are getting better and more practical all the time, he notes.

But the units still lack a speedy data interface that would allow users to quickly and easily determine if a cow has a mastitis problem or not, Berry says.

“I don’t think [mastitis detection] is there yet,” he says.

Dairy producers will just have to continue waiting. PD

Wilkins is a freelance writer based in Twin Falls, Idaho.

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