A multi-pronged approach using a variety of control methods, including insecticide ear tags, can help control fly numbers in pasture settings. (Photo by Robert Waggener)

“Application matters,” begins Larry Hawkins.

On this beautiful spring day, Hawkins is in cow country to discuss flies, lice and cattle—and some of the common mistakes he sees when it comes to controlling the former two so they don’t chew up the last one.

As this old-school veterinarian begins his conversation, it becomes crystal clear that a deliberate, well-planned routine can help ensure that every product is working as hard as it possibly can.

When Hawkins tours cattle-working facilities in an effort to help producers get the upper-hand on economically damaging parasites, he often sees routines that aren’t helping cattle—or the bank accounts of cattle producers.

One of the most common mistakes involves the application of pour-ons to control lice and troublesome horn flies.

“As cattle are being treated, I often see someone simply squirt a little bit of product on the back of each animal,” says Hawkins, a technical services veterinarian for Bayer Animal Health.

“So when you only spray a spot 1′ or 2′ long on an animal’s back, you are asking an awful lot from an insecticide when it comes to controlling lice and other parasites that are out on the nose and down into the armpits, brisket and groin.”

Hawkins encourages producers who have followed this routine to instead ensure fairly complete coverage of the animal.

“So if the label says to use a 30 cc dose, put 4 or 5 cc on the poll, and then spread the rest of the dose from the withers to the tail head,” Hawkins says. “That way you are getting the insecticide to places where lice are far more likely to come into contact with it.”

Though just spraying the back of an animal can be effective in controlling horn flies in the short-term, Hawkins notes, “To get good residual control, it’s much better to spread the product out.”

Like pour-ons, sprays can be “very, very effective” in controlling external parasites, he says.

But a common spraying problem is using too fine of a spray mist, either to save money or simply because time wasn’t taken to adjust the nozzle.

“An animal might look wet when getting sprayed with a fine mist, but the mist stays on the end of the hair and doesn’t get to the skin,” Hawkins says. “Make sure you open up the nozzle enough that you’re getting a bigger droplet. That bigger droplet will get closer to the skin; it will get to the depth of the problem.”

Insecticide ear tags are also effective in controlling flies, but placement is important.

“It’s common for producers to put tags high on the front of an ear or on the back of the ear so they aren’t hooking on bale feeders and don’t obstruct the view of ID tags,” Hawkins says.

But such application is limiting the effectiveness of an ear tag.

“Ear tags dispense insecticides when they touch something, like when momma reaches down to nuzzle her calf or when she turns around to groom herself.”

Hawkins believes that the best placement is on the front, with at least half of the tag hanging beneath the perimeter of the ear.

“If half of the tag is hanging below the bottom of the ear, it will come in contact with another animal much better than if it’s hidden inside the cup of the ear or if it’s high on the ear.”

Hawkins concludes, with emphasis: “It’s always key to read and follow label instructions, and consider one’s own safety when applying products. It’s easy to put focus on your cattle and become nonchalant about personal safety.”