The twitch of an ear may be enough to show that an animal is getting sick.

A research project through the University of Calgary’s faculty of veterinary medicine is testing a special sensor attached to an animal’s electronic ear tag.

The sensor reads how much and how often the steer eats whenever it goes to the trough, as well as how much time is spent ruminating.

Cattle’s ears are constantly twitching while they eat, and the sensor also marks changes in ear motion. Ear flicks are different when cattle ruminate.

“We know feeding behaviour changes before we can see clinical signs of respiratory disease,” said Barbara Wolfger of the faculty at a veterinary conference held in Calgary June 19-20.

“The earlier we detect those animals the better our treatment is going to be and the lower the death losses and the lower the performance losses,” she said.

The system was developed and validated for dairy cattle, so the goal of the new study was to measure it for feedlot cattle.

Information from the sensors is sent to a computer, where cattle activity is calculated in one hour increments. These observations can show changes in behaviour and ear flicking.

Animals were put on test at Agriculture Canada’s research centres in Lacombe, Alta., and Lethbridge, where it was observed that sick animals eat less for a shorter period of time well before they are pulled for treatment.

They also ruminate less in the hours before being removed for treatment. Previous studies on feed intake found animals might go off feed up to seven days before they show clinical signs of respiratory disease.

The accuracy is not perfect, but it will be adjusted and improved for beef cattle, she said.