Beat the buzz this fly season

Mar 30, 2022

Regardless of when fly season begins, it’s helpful to have a fly control program in mind before the fly population gets out of hand. It’s advised to start a fly control feed-through program at least 30 days before fly season to really allow that active ingredient to get passed through the animal system and stay on it until the first frost. And, doing so can really improve the productivity of your herd and, ultimately, your bottom line.


Apple Podcast Subscribe Instructions >

Stitcher Subscribe Instructions >



Announcer: I’m Tom Martin here with Jill Peine, nutritionist with Crystalyx® Brand Supplements, to talk about fly control. Welcome back, Jill.

Jill:  Thank you, Tom.

Tom: So, it’s that time of the year again for cattle producers to start thinking about ways to help mitigate flies this upcoming season. What should cattlemen be considering as we approach fly season?

Jill: Yeah. You know, here we are approaching mid-March, as we record this podcast, and fly season has started in the southern parts of the U.S. and will be working its way here, north, as temperatures begin to warm up. Here in Minnesota, where I’m at, you know, I may have a little bit of spring fever, but we still have snow on the ground, so it’s hard to think about fly control. But, you know, I know for many of my southern friends in the southern states, it’s closer on their radar as far as fly control measures happen.

A diagram that comes to mind that often circulates at this time of year is a map that really lays out when to expect flies, depending on where you live. So, in the far southern U.S., like South Texas, Louisiana, Florida, we’re looking at March 1 as a typical fly emergence. Mid-March, being the next tier up, into California, West Texas and over into the Carolinas.  April 1, we’re looking at Kansas, Missouri, much of Kentucky and the Virginias. And then, going on through mid-April, parts of Oregon, Colorado, Iowa, Ohio. And then, into mid-May, we see the states further north like Wyoming, the Dakotas, Minnesota, New York and so on, when these folks can start expecting flies to emerge.

But really, regardless of when fly season begins, you know, it’s helpful to have a fly control program in mind before the fly population gets out of hand. So, it’s advised to start a fly control feed-through program at least 30 days before fly season to really allow that active ingredient to get passed through the animal system and stay on it until the first frost. And, doing so can really improve the productivity of your herd and, ultimately, your bottom line.

Related article: Beat the buzz this fly season


Tom: Well, let’s expand on this a little bit. Can you talk to us about the economic impact of the horn fly?

Jill: Sure. Yeah. Not only are flies a nuisance, but they’re also economically devastating. Flies can spread disease, they often cause stress on the animals, and that results in a loss in production.

The face fly is known for its unwanted contribution to pink eye. Pink eye is bacteria that tend to develop resistance to antibiotics, which can further frustrate the treatment. Plus, if you add in the cost of time and labor for treatment, that can really add up. So, one of the keys to pink eye prevention is fly control.

The horn fly, specifically, is one of the most economically damaging pests to pasture cattle, and it costs the cattle industry anywhere around $1 billion or more each year. And just to put that number, $1 billion, into perspective, I looked up some of the other numbers to compare it to, and the annual estimated loss for BRD, bovine respiratory disease, is $600 million, and pink eye is estimated at $100 million each year. So, a pretty substantial loss coming from the horn flies at $1 billion.

And additionally, an adult horn fly really only lives anywhere from two to four weeks, but during that time, they can lay up to 500 eggs during their lifetime. And they’ll take about 20–40 blood meals per day, which results in a number of gallons of blood lost per animal each season, and that loss of blood is a loss in nutrients that, you know, the cow may have otherwise been able to utilize, resulting in poor production, and literally drains the profits from the herd.

In addition to this, flies can cause stress, and this will disrupt the grazing pattern of cattle, as they may bunch up and find shade or do whatever they can to try to mitigate the flies that are attacking them.

For the spring calving herds especially, fly season overlaps with breeding season, and if we are artificially inseminating cows based on heat detection, animals may not display their heats as strongly as they may otherwise. Or when we turn out the bulls, we want to make sure that they have access to fly control as well, to help control the population of the flies so they can go out and do their job on the cows and not be overstressed or try to find ways to hide from those flies instead.

We also need to keep in mind the importance of fly control for our developing heifers. We know that replacement heifers are critical to the, you know, future profitability of a beef operation. And, typically, we don’t see a return on investment until maturity and when they wean a series of calves. But while developing, these heifers are often faced with horn fly populations similar to the cowherd. And as heifers develop, there are hormonal changes that occur, including estrogen and progesterone levels. And it’s been shown that as those estrogen levels rise, then fly irritation also increases, making these heifers in standing heat especially vulnerable to an increase in fly numbers. You know, my last point here when thinking about the economic impact I’d like to bring up is that horn flies may lead to mastitis and blind quarters beginning in heifers. And this may be caused by the flies feeding on the blood vessels of the teat, causing irritation and eventually scabs to develop, leading to staph aureus bacteria, which is the primary cause of mastitis, to really incubate in that teat structure. And it’s the bacteria that can damage those milk-producing tissues leading to blind quarters within the udder. And I’ve read that there’s some university research that predicts 75% of heifers have some kind of teat or udder infection even before they calve, with an estimated 50% of those being linked back to the bacteria spread by the horn flies. And as heifers calve and begin to lactate, this blind quarter can cause a drop in milk production, which may be unfavorable to our calf weaning weight.

So, long story short, thinking about the economics, the benefits of an effective fly control program include measures like cattle spending time grazing and not congregating, cows producing more milk, which then allows for calves to grow faster, cows have better breed back, zero health problems, you know, all the things that impact the bottom line. And we can help achieve those by delivering fly control in a feed-through supplement.

Tom: A small creature with a big impact. How does feed-through fly control work?

Jill: Yeah, good question. For Altosid® IGR pesticide, the way it works is cattle consume it through a supplement, and then it is carried through and passes through the digestive system. It’s not absorbed by the animal, but it is excreted through their manure. The flies then lay their eggs in that fresh manure patty, which eventually turn into larvae. Once those larvae start consuming what is surrounding them, which has been treated with that Altosid IGR, the IGR is what mimics the hormone that is responsible for the growth and maturity of that larva into an adult fly and basically reverses it and prevents the fly from actually maturing, and that’s why it is considered an insect growth regulator, or IGR. ClariFly® fly control’s method prevents that larva from creating an exoskeleton. So, again, it is a feed-through, goes through the digestive tract and into the manure just the same, but the mode of action and the active ingredient of ClariFly prevents the house, stable, face and horn flies all from developing into adults, which, again, interrupts their life cycle. Rabon Oral Larvicide is also passed through the digestive system, remains in the manure and actually kills the developing larva from the physical contact. So, with Altosid IGR, it mimics the hormone, ClariFly prevents them from creating an exoskeleton, both interrupting the fly’s life cycle. And the Rabon actually kills the larva through attacking the nervous system, and that’s how it prevents flies from maturing and, ultimately, controls the fly population.

Tom: Jill, we’ve heard about using garlic to repel flies. Does that work and if it does, are there supplement options available with garlic?

Jill:  Yes, garlic has been used in supplements now for a number of years and has been used successfully to help repel flies. There’s an active ingredient in garlic called allicin. And when garlic is broken down, it breaks down into disulfide compounds, which are excreted by the animal through their skin or lungs, which help repel the flies and potentially other insects.  So, the mechanism with garlic is different than those other feed-through larvicides, but it’s the odor that helps repel the flies. And there are a number of anecdotal accounts that have found that garlic is effective as a means to repel flies.

And then, there’s also research out of Canada that has compared fly numbers on cows that were fed garlic and a mineral compared to some without garlic, and they saw a 50% reduction in the fly counts on those animals that were offered garlic. We hear a lot of interest in the garlic compounds currently, and also, we feel, moving forward, there will be continued interest. And while it’s effective, you know, we need to remember the mechanism is a little different than our traditional fly control methods in that the garlic repels the flies and doesn’t disrupt their life cycle, you know, to help control the population like ClariFly or IGR do.

We do have a handful of Crystalyx formulas out there with added garlic as an option, and those are the Mineral-lyx with a garlic option, Hi-Mag Fescue-lyx, and then, in the Blueprint® line, we have the Crystalyx Blueprint 20% All Natural and the Blueprint 6% Phos, both with garlic options. And then, for our friends in Canada, we have the Mineral-lyx GFC available with garlic.

TOM: Well, just as a means of kind calibrating expectations. If producers use feed-through fly control, can they expect to completely eliminate the fly population?

JILL: Yeah. The short answer to that is no. I think if producers are looking to completely eradicate the fly population by feeding the fly control, they will be disappointed. Now, the economics threshold for horn fly population in a given environment is around 200 flies per animal. So, you know, 200 flies per animal is an acceptable level. By using a fly control, we can help keep the fly population under the threshold level. So, with a feed-through product, you know, we’re looking at working to control the number of flies, and at the same time, with a supplement like Crystalyx, we are also delivering those essential minerals and vitamins and, in some formulas, supplemental protein all at the same time.

TOM: Is feed-through fly control safe for horses if they are grazed together with cattle?

JILL: Now, that’s a good question and one we get quite often. Rabon and ClariFly are both approved for use in horses, such as the Mineral-lyx with ClariFly or Rolyx-Max containing Rabon.  While there are a number of fly control formulas out there that are labeled for both use in horses and cattle, we typically recommend supplementing horses with Stable-lyx with ClariFly, which we have received a lot of good reviews on from customers in regards to controlling the fly population. And it is specifically formulated for horses.

TOM: So, where can listeners go to find out more about Crystalyx fly control options?

JILL: You know, the Crystalyx website is a good resource. More information about fly control can be found there, and product listings and options are outlined there in great detail.  Also, Crystalyx Brand Supplements has an app, and within that app, you can go in and sort out fly control options that best fit the needs of your cattle.

And, as always, you can always reach out to us or your local Crystalyx dealer for more information on fly control and products to use this spring and summer.

TOM: All right. That’s Jill Peine, nutritionist with Crystalyx Brand Supplements. I’m Tom Martin. Thank you for joining us, Jill.

JILL: Thank you.

TOM: And, thanks for listening.