Buzz off! Challenge of keeping pest flies off cattle moo-tivates Vet Med researcher

When there’s a fly hovering around your head, buzzing incessantly in your ear, deftly avoiding your aggravated swatting, that pesky little insect is all you can think about until it’s over.

Dr. Rachael Coon, PhD, is thinking about flies a lot, too, but in a far more productive way. Coon, recipient of a Killam Postdoctoral Fellowship and postdoc in the Faculty of Veterinary Medicine, is researching how to combat pest flies that target cattle herds.

Controlling pest fly populations is important to keep cows happy and healthy. Flies cause cattle to exhibit physical avoidance behaviours like stomping, throwing their heads, flicking their tails and twitching. Flies also cause health problems by transmitting toxins and disease, reducing production, and can cause behaviours that lead to death. For example, pinkeye, which is transmitted among cows via flies, has been estimated to be responsible for $150 million in annual economic loss for American cattle industries.

For people, dealing with a fly just takes one good swat or a well-timed shoo out a window. For cattle, it’s not that simple. Coon is targeting the flies in two ways: on the cattle and in the fields where they breed. 

Getting flies off the cows — and on camera instead

When Coon describes the apparatus that will help keep flies off cattle, it sounds a bit like a car wash for cows. At W.A. Ranches, she is studying the usefulness of oilers — large devices that cattle walk through and rub up against — to help cows self-apply insecticides to keep pest flies from landing on them.

“The oiler is a big drum that has fabric tassels that the cattle walk underneath and rub their bodies on,” Coon says. “The fabric tassels have been saturated with a mineral oil that contains an insecticide. It’s almost like a beaded curtain that they walk underneath and it saturates their coat with the insecticide.” In addition to the fabric tassels, the oilers are outfitted with brushes and scratchers that cattle like to rub up against, so they’re already highly motivated to walk through them.

The insecticides are a treatment strategy, but Coon is seeking preventative measures, as well. The second part of the project is to monitor the pest fly populations to better understand what species of flies are most dominant and when.

Coon has modified a device originally created for tracking fruit flies in horticulture settings and adapted it for use with beef cattle. It has a 3D-printed surface with a sticky piece of paper attached to it, and, on the other, a small camera housed in a protective tube, pointing at the paper. The device is secured to an oiler, so that, when the flies take off from the cow, some of them land on the sticky paper. The camera takes a photo of the sheet every 20 seconds. The device is a called a “Sticky Pi” — named for the sticky piece of paper that flies land on, and the camera that operates on a Raspberry Pi computer.

“We can use machine-learning algorithms to record and identify the number of flies that are caught and the species,” says Coon. “What's neat about it is that it works on a phone. You could go out onto pasture and download this information directly from the devices.” Coon is hoping to achieve a better understanding of when populations of each type of pest fly are surging, and to what degree.

The integrated pest management (IPM) approach Coon is using, combining preventative and treatment strategies, is supported by the Beef Cattle Research Council of Canada. IPM recommends that producers first assess and identify what pests are present, and then monitor pest populations once measures to address the issue are in place.

“I think that my monitoring system could be one of the components in the future that's an opportunity for integration of technology into the integrated pest management system,” says Coon. “My hope is that, in the future, researchers can use this tool, as well as producers.”

Coon hopes that by developing tools to empower producers to manage pests in a targeted, strategic way, she can help promote sustainable long-term practices. “Monitoring fly populations would give researchers and producers a better understanding of when to apply pesticides,” she says. “We know that pesticides lead to pesticide resistance amongst flies, and they also can lead to a loss of biodiversity in the environment if they're overused.”

Opportunity at W.A. Ranches draws researcher back to Canada

Coon is happy to be home in Canada, and for the opportunity that the Killam Postdoctoral Fellowship is offering her. She completed her PhD at University of California Davis, but it was the draw of W. A. Ranches and the chance to study with its director, Dr. Ed Pajor, PhD, that brought her back to Canada.

“It's a very large ranch for a university and it has many animals. From a research point of view, having a sample size (like) that is almost unheard of, especially in cow-calf operation," says Coon. "Having the ranch staff who are so knowledgeable and can give me insights into the practicalities of running a ranch that I as a researcher am not going to have is invaluable. Calgary is very special in that regard. I’m very grateful for the opportunity."