Does your cow worry about flies? Yes

If your cattle are stomping, grouping, twisting their tails, or licking their backs trying to get rid of flies, that’s a sign of anxiety. The behavior is actually a syndrome that vets consider to be a “fly problem”.

“This is the activity that cows and calves will do in an attempt to attack the fly population on their own if there is no insecticide used in the system,” says Craig Payne, veterinarian at the University of Missouri.

The condition, left unchecked, can cause cattle to reduce feed intake and lose weight. Payne says studies of feeder cattle show calves with fly control gain 15 to 30 pounds during the grazing season compared to those without control measures. Thus, the fact that a farmer treats against flies has an effect on the profitability of the cattle operation.

Types of flies in cattle

Beef producers should be on the lookout for horn flies and flies that deal with flies that make livestock uncomfortable this time of year. But Payne says the horn fly is causing the most economic damage.

Adult horn flies have a brownish-gray or black body and are shiny. “With horn flies, you can identify them simply by where they are on the animal,” Payne told a MU Forage and Livestock town hall. “So they’re going to be found in the shoulders, the neck area, maybe on the stomach.” Horn flies tend to spend the majority of their life on the animal.

By far, horn flies will be the biggest economic impact on the beef herd, Payne says, and that’s because of aggressive feeding behavior. Horn flies need a blood meal for egg production, which means they feed on livestock more than 40 times a day. This excessive feeding of animals creates stress.

Craig Sheppard, University of Georgia,

SHINY PEST: Adult horn flies have a brownish-gray or black body and are shiny, which almost makes them glow on a cow’s belly. The body is 3.5 to 5 millimeters long, about half the size of a house fly.

Unlike horn flies, face flies are non-biting flies that cluster around an animal’s eyes and mouth. They also congregate around open wounds. “Where we’re concerned about face flies is their potential to contribute to pink eye problems,” Payne says.

However, these flies despite their name do not stay on the face for long. Instead, they spend most of their time on other objects or along waterways, making it more difficult to control. The fly face reaches its peak in July and August.

Farmers who see either of these, along with symptoms of concern about flies, should treat their livestock.

Label beef cattle

Fly tags are the most common control method among cattle producers.

Payne says the labels are incorporated either with an organophosphorus compound or with a pyrethroid. The insecticide is released from the label, but it doesn’t just stay in the head and neck area, says Payne. It actually disperses over the animal’s coat.

The companies advertise that the fly tags are effective for up to five months. However, Payne realistically says it takes around 12 to 15 weeks. So farmers need to plan when to place tags on cattle.

“If they are applied too early, at the end of the summer, when the fly control populations start to reappear, the enclosure will be out and you will not get the control time you expect”, Payne warns. He recommends that farmers apply fly tags when they see around 200 flies per animal – but since it is difficult to count flies, he adds: “That would roughly represent the number of flies that fit in the palm. of your hand. “

Whitney Cranshaw, Colorado State University, Bugwood.orgfly face

NOT THE FACE: Face flies are about 6-8 millimeters long and have four dark bands on the top of their thorax that are gray in color. They are very similar to house flies. Control is important because face flies overwinter as adults in barns and become active again in the spring.

The number of tags depends on the size of the body. Typically, for a mature cow, fly control can be accomplished with two tags. For younger calves, it would be a tag.

“If the calves are paired with the cows, while the cows are grooming these calves, some of this cow’s ear tag insecticide will end up on the calf and help provide some control as well,” Payne adds. He recommends using only one class of insecticide and not mixing and matching on an individual animal.

Speaking to companies that sell fly tags, Payne finds that they receive a lot of complaints after rain events. What happens is that the rain washes away the insecticide and at the same time there is an increase in the fly population due to the humidity.

“What will ultimately happen is that the insecticide will redisperse within five days to a week, and you will be back to a level of control as long as your label is still effective,” he adds. “So if you experience this and have placed any flight tags, don’t run over to the phone and call your animal health rep, just give them a little and these will come back.” at the level of fly control you expect. “

Additional fly control options

Fly tags are not the only way to control populations. Payne offers a few other fly control methods for cattle producers.

Sprays or pourers. These products will kill the flies immediately, but this is a one-time treatment as sprays do not offer much residual control. Payne is warning cattle producers that they will need to use them more frequently, from seven to 21 days depending on fly activity and weather conditions. This adds work for the farmer and sometimes stress for the animal.

Farmers should also avoid generic dewormers as a fly control method. It cautions that frequent use of these products may result in resistance to pest control.

Feed through control. This method of prevention includes insect growth regulators, or IGRs, which can be fed by minerals or trays. It is designed to break the life cycle of the fly. Start feeding IGR at least two weeks before fly season. Although the method involves little labor for the farmer and low stress for the animals, it is expensive.

Dust bags. Rubber dust bags on the back can be used, but cattle should be forced to use it frequently, Payne says. These should be used in areas where livestock are forced to pass under them in a walkway, around a mineral feeder, or any other high-use area. This method also requires farmers to refill the bag every two to three weeks for optimal fly control.

Regardless of the fly control method, Payne says using more than one method together is a good idea. “Using feed-through and beacons will give you the best control,” he says.

Fly resistance is real

Beef producers should alternate active ingredients or types of insecticide to counteract resistance. Payne recommends using two years of organophosphates, then one year of pyrethroids.

“One thing you’ll notice with organophosphates is that they don’t necessarily do a good job of controlling face flies,” he adds. “As far as I know, they’re going to be a bit higher when you switch to this organophosphate rotation. So, you might just have to smile and put up with it during this time.

Payne says farmers should remember that the main focus during fly season is horn fly control because of their economic impact on the farm.

Another reminder: don’t let fly tags after drop. Resistance comes after continued exposure to a drug, even at low levels, says Payne. “If we applied these labels, we have to cut them in the fall to avoid exposure to low doses,” he says.

About Jermaine Chase

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