Episode 302 - Fly Frenzy: Understanding and Controlling Flies on Your Farm - UMN Extension's The Moos Room

00;00;12;01 - 00;00;34;16
Brad
Welcome to The Moos Room, Brad again by himself. I know Emily was off this week at an extension conference presenting, some of her work at a national extension conference. So I guess you get to listen to me again, rant about something. One thing that I wanted to talk about, it's been kind of driving me, I guess, crazy and probably everybody crazy.

00;00;34;22 - 00;01;01;08
Brad
And that's flies right around the 4th of July. Here it is just gone mad with flies, especially up here in the upper Midwest. We've had a lot of rain inches, lots of rain. I've talked to a lot of different farmers and there's so much rain everywhere. And of course that breeds flies, mosquitoes and all kinds of things. But I wanted to talk about flies because it's pretty important on my mind.

00;01;01;14 - 00;01;20;07
Brad
We're also doing a research study on flies this summer, so I wanted to talk a little bit about flies and why it's important to manage them on your farm. And then maybe a little bit of the research that we've been working on and what's going to happen into the future. So why is it important to manage flies on your farm?

00;01;20;08 - 00;01;48;06
Brad
Well, there are many behaviors of cattle that are caused by flies, and that leads to decrease production. And in dairy cattle, it's reduced milk production in beef cattle reduce growth rate. Sheep, goats, you name it, reduce growth rates and obviously flies on farm. They have the potential to increase disease transmission, whether that's pinkeye or some of the other diseases.

00;01;48;06 - 00;02;15;14
Brad
Mastitis, anaplasmosis. We're trying to figure out if this Lucas's thing that's happening on our farm is from flies. We're not sure yet, but we have an idea that maybe Lucas's maybe spreading by fly bites on our farm. We're not sure yet. Don't quote me on that, but we're exploring that idea. Obviously, lots of flies cause problems to humans.

00;02;15;14 - 00;02;46;21
Brad
I know the milkers at our dairy are always talking about flies and flies in the milking parlor, and flies bothering the cows. Cows are kicking milkers off, you name it. It's a big problem, but there's different kinds of flies that affect different areas of farms and cause different behaviors. So I want to talk about those. Most people say all the flies are out, but there's many different flies that are causing issues on farms.

00;02;46;23 - 00;03;10;23
Brad
And the typical ones, at least here in the upper Midwest, they're stable flies, house flies, face flies and horn flies. And really, we have to figure out what flies are bothering our animal before we can try and figure out how to manage them. So we need to be able to identify the types of flies that are we're dealing with, maybe understand a little bit of their lifecycle so we can effectively manage them.

00;03;10;26 - 00;03;36;25
Brad
So let's first talk about flies that are found in confinement. So there's this difference you know confinement versus pasture. So let's talk about confinement. These are in barns. They reproduce in organic debris that's usually found in bedding or manure. Probably the biggest one is the stable fly. And do they bite cattle. Yes they do because they are blood feeders.

00;03;36;25 - 00;04;06;27
Brad
So they're sucking the blood of the cow or whatever livestock that is. So they have this sharp piercing mouth part that penetrates the hide and they feed on the blood of the cows, and usually they feed about 1 to 2 times a day. So they lay their eggs in decaying organic material. Like I said, spilled feed, manure, bedding, you name it.

00;04;06;29 - 00;04;33;11
Brad
The eggs that are laid are a lot. We'll just say over 500 to 1000 eggs per fly, and it takes about 30 days or so to develop into an adult from an egg. And they usually live 2 to 4 weeks. So a lot of these flies that we see their lifespan is very short. Just a few weeks, I think most people think, oh, the flies are around.

00;04;33;11 - 00;04;56;27
Brad
They live a long time. No flies are. They turn over really fast. They breed a lot, lay lots of eggs, and they only last a few weeks. So the flies that you see early on here early July, these are not the flies you're going to see in August or September. Those ones are being laid right now. So where do we usually find the stable fly.

00;04;56;29 - 00;05;17;22
Brad
We find it on the legs of an animal, always on the legs. So those are the ones that are biting the legs. They're causing cows to bunch stomp their feet. Lots of tail switching. Probably the biggest one is foot stomping, especially in the milking parlor. Kicking the milkers off because that's where they're biting. They're biting the legs of the animals.

00;05;17;25 - 00;05;47;29
Brad
And one key factor and trying to identify some of these flies is that they feed facing up. So the fly is always up on the legs. So the head is north. And so they're never really pointed downwards. So they're always facing upward. And these animals really and these flies don't really stay on the cows. So they rest and overnight in vegetation or structural surfaces they go hide somewhere and then they come back to the flies.

00;05;47;29 - 00;06;14;11
Brad
So the stable flies might not be on the cows the whole time. Obviously, like I said, they can cause bunching, heat stress, decreased feeding, decrease, average daily gain. Milk loss is somewhere in the 1 to 4 pounds. And across the US about a $2 billion annual economic loss from stable flies. So stable flies probably the biggest culprit in in confinement settings.

00;06;14;13 - 00;06;41;08
Brad
Well let's talk about houseflies. So these are the ones obviously in your house. Everybody thinks oh we'll get flies there. House flies know most of them tend to be more stable flies. But so what is a housefly. So do they bite cows. No, they don't bite cattle. They're not blood feeders. They have spongy mouthparts and they feed on secretions from the eyes or the nose or the mouth, things like that.

00;06;41;08 - 00;07;12;12
Brad
They also feed on plant sugars and manure. But the key there is they don't bite cattle. So if you have cattle that are stomping, kicking from fly bites, they're not house flies, stable flies. So house flies are really found in decaying organic matter. They probably don't lay as many eggs, 500 eggs per fly. They usually are 2 to 4 weeks for development from an egg into a fly.

00;07;12;14 - 00;07;38;16
Brad
And they live about 2 to 4 weeks just like everybody else, except if they're hibernating. So where are they found? On the animal. They're found on the head, the face, the tail, head and the vulva. Teats around wounds, and they rest overnight in vegetation. They can cause irritation of cow decrease feeding things like that. But their true economic loss is not great.

00;07;38;18 - 00;08;04;20
Brad
Houseflies tend to be more of nuisance flies than anything, and they're not often found on the cows. Really, just around the face. Maybe. But house flies are not found on cows. So let's talk a little bit about pasture flies. So if you have animals that are outside, not necessarily even on pasture could be outside in a lot.

00;08;04;22 - 00;08;35;04
Brad
You might see horn flies and horn flies are considered a pasture fly. And they because they reproduce in cow dung pads. So and manure on pasture so do horn flies bite cattle. Yes they do just like to stable fly. They have a sharp, piercing mouth that penetrates the hide and feeds on blood. Now these animals feed a lot more than a stable fly.

00;08;35;04 - 00;08;58;09
Brad
So like I said, stable flies feed about 1 to 2 times per day. Horn flies 20 to 40 times a day. So they're biting cattle 20 to 40 times a day. That's a lot. That's a lot. So very similar to the stable fly about maybe a little bit less actually 10 to 14 days from eggs to development. So their turnaround time is much, much faster.

00;08;58;12 - 00;09;23;11
Brad
They live about 2 to 4 weeks. Where do you find horn flies? More than likely you'll find them on the back, on the sides and on their belly. They're really in the shaded areas during the heat of the day, so they maybe are more on the belly during the hot parts of the day. But if you see these small little flies about half the size of a housefly on their back and their wings are flat, those are horn horn flies.

00;09;23;17 - 00;09;48;04
Brad
They feed facing downward. Remember the stable fly or feed facing up. Horn flies feed facing down. So that's a true tail way of trying to figure out what horn fly you have. So they also cause cattle bunching, heat stress, decreased feeding, decreased milk production, decreased growth all the same like a stable fly. So what's the other pasture fly face flies.

00;09;48;06 - 00;10;09;28
Brad
That's the other one that causes some issues on cattle. Now are these blood feeders. No they are not. They are. They feed on secretions from the nose, the eyes or wounds. So kind of like a housefly, but you find them on the face. Typically you find them only on the face or the head. They're not on the legs, they're not on the back.

00;10;09;28 - 00;10;36;23
Brad
There nowhere else to be found. They're only on the face of the animal. A number of face flies. If you get ten face flies per animal, it really decreases their feeding time. So that's probably one of the biggest things that cause animal irritation decreased eating behavior. They also can cause disease spread. So the biggest issue with face flies is spreading pinkeye.

00;10;36;25 - 00;10;57;21
Brad
That is probably the major economic impact of face flies to cattle trying to help control the face flies may help control the spread of pinkeye. So that's where it's spreading. You're flying from one cow to the next, just spreading pinkeye. An interesting fact of all of these flies that I talked about. The question is, how far can they fly?

00;10;57;21 - 00;11;25;00
Brad
Well, the horn fly can fly 1 to 2 miles and maybe up to ten miles. Stable flies can fly 12 miles. Face flies 2 to 4 miles. House flies 1 to 2 miles. So what does that mean? Well, they can fly a long distance. So if the neighbor has spilled manure, spilled feed that's breeding flies, they can certainly fly over to your operation.

00;11;25;06 - 00;11;50;17
Brad
No problem. If they're close. So that's one of the things that's always tough to find is it's like, well, everything's clean around here. How do we why do we keep getting these flies? Because they can fly long distances. And that's probably one thing that people really don't think about is these flies are very versatile and can go just about anywhere.

00;11;50;19 - 00;12;17;02
Brad
Okay. Let's talk about prevention of these flies and then talk a little bit about some of the research that we've done. So here is probably the general fly control strategies for all of the species. Probably the biggest one manure management. So cleanliness and sanitation. So remove or compost manure frequently to eliminate the breeding sites. So if there's feed spilled in feed bunks but clean it up bedding.

00;12;17;02 - 00;12;38;27
Brad
Be sure to clean that up. Clean up all of the rotting hay or grain manure piles. Anything that has decaying matter is in effective way to control stable flies and house flies. Dry bedding is probably one. Keep bedding areas dry to prevent fly egg laying, so if you have dry bedding, they're not going to lay their eggs there.

00;12;39;00 - 00;13;06;17
Brad
They're going to lay their eggs in moist bedding drainage. So eliminating standing water is probably one of the good things. Obviously your ideal for some fly larvae not all of them, but it would help some people use fly predators so they release parasitic wasps that target fly pupae, some farms like them, and some farms. It hasn't worked. I think they've tried it on our research farm and it didn't really work.

00;13;06;17 - 00;13;28;00
Brad
The problem is we're so spread out. We have a lot of animals and you just we would need a lot of flies to help control all of the breeding sites for flies on our farm, you know, and we're not going to be able to clean up all the feed, all of this, build manure, everything all the time to help prevent those problems.

00;13;28;00 - 00;13;52;29
Brad
So for our farm, maybe the fly predators didn't do so well. Some places it did. Some places it has obviously fans so high speed fans in barns disrupt fly flight and screens keep the flies out. So the more air movement in a barn, the probably less flies you're going to have. It's not going to be zero, but it's going to reduce them.

00;13;52;29 - 00;14;24;13
Brad
If you're on pasture or pasture rotation, obviously it helps reduce, buildup of flies in one area, spreads out the manure a little bit, but maybe not quite as effective because the flies can fly 1 to 2 miles and then fly traps. Obviously fly traps fly baits. People use a lot of those sticky traps. Ultraviolet light traps. Yes, they do help control some of the flies, but probably in the end they're not controlling them fast enough.

00;14;24;16 - 00;14;50;10
Brad
They, like I said, sticky traps. They can help monitor fly populations and help you determine what maybe other management practices you need fly baits. They're really effective at controlling house flies, but none of the other flies in. We've used a fly vacuum here before and it's really helped. Maybe some of the horn flies, but there's still other methods to help control those.

00;14;50;13 - 00;15;17;18
Brad
So you really have to know what flies you have on your farm to help control some of these obviously sprays, biological controls. Obviously some people use ear tags with insecticides on face flies to help control. They probably don't work as good as what they should. Sometimes we use sprays or insecticides. Yes, they work, but you have to keep using those in animals so that can be an issue.

00;15;17;23 - 00;15;37;10
Brad
I think the big thing is that there's not one silver bullet. It's like, oh, well, we're going to put an insecticide on and it's going to solve our fly problems. It is not. You'll probably need to if you use, insecticide to help control the slides. You also need to have good sanitation on farms. And that will help control them as well.

00;15;37;13 - 00;15;58;20
Brad
Some farmers also ask, what about what about chickens? What about chickens? On farm chickens should help control fly larvae. And if they're out there, you should have less flies. Some people swear by that. Some people use ducks. Other things like that. Well, I'm not sure that I actually believe all of that. We did a study here one time where I.

00;15;58;23 - 00;16;29;29
Brad
I had 500 chickens on pasture trying to control flies. Did it control flies? Absolutely not. It didn't control any of the flies. And why was that? Because we have too many cows and there was only 500 chickens. Actually, I did some calculation. If I was to control the flies on pasture, I would probably need somewhere in the 3 to 4000 chickens following my 100 cows on pasture to be able to control the flies.

00;16;30;02 - 00;16;57;04
Brad
So in the end, though, I would become more of a poultry farmer than I would a dairy farmer trying to control the flies. So it just it's not feasible. Especially to have 3 to 4000 chickens on pasture. I can't even imagine what that might look like, but I just don't think that most people don't have enough poultry, chickens, ducks, you name it to help control the the populations of flies on their farm.

00;16;57;04 - 00;17;21;14
Brad
So that's probably one of the things that, I'm not sure that it actually works. Not sure that it actually works. So one of the new things that I've just started with a research study this summer is working with a company called mad Gene that has developed a horned fly vaccine. If you want to learn more about the magazine we had them on, maybe episode 255, way back in September of 2024.

00;17;21;14 - 00;17;51;00
Brad
So way last fall. I've decided to try that out, working with them on seeing if I can help control horned flies, see if it's working in our our farm. So it's basically a vaccine that was developed for specifically for horn flies, obviously in our pasture based herd, that's one of the biggest thing. So this vaccine could be a long term sustainable solution that will help reduce fly populations and probably an important tool to fight them.

00;17;51;02 - 00;18;22;04
Brad
Now, is it going to create zero flies on our farm? Absolutely not. But I think it'll be a good tool. So how does this med Gene Horton fly vaccine work? Well, it's designed to target and use the host immune system to produce antibodies that impact the ability of the horn fly to take a blood meal. So basically, horn flies, they use a protein called thrombus, stassen as an anticoagulant.

00;18;22;04 - 00;18;47;21
Brad
So when they feed, they bite the animal. They take blood from their animal. So basically that means that the host animal's blood does not coagulate during feeding. So when they're biting the cow, they produce this protein so it doesn't coagulate the blood. So this horn fly vaccine, basically it produces antibodies that would interfere with that thrombus and protein.

00;18;47;21 - 00;19;15;26
Brad
So thus when the horn fly feeds, it ingests the antibodies which block thrombus stays in activity. So that means the blood meal that that fly just took from that cow or whatever it might be, coagulate. So it coagulates inside the fly. The fly takes a smaller blood meal, and this negatively affects their reproductive cycle, causing fewer eggs to be laid.

00;19;15;29 - 00;19;45;28
Brad
The result would be smaller future horn fly populations by basically your decreasing the volume of future generations. So we've been studying that in almost 200 animals at our dairy. We've vaccinated them in May at two dose vaccine two mils, and then three weeks later we give it again. And we've been monitoring fly populations in our cows since then.

00;19;46;01 - 00;20;08;14
Brad
So we have some students out counting flies twice a week looking at all of these, animals. They have no clue which animals got the vaccine or not. Only really, Brad knows how to, knows which ones got the vaccine. So they're out counting flies and trying to figure out to see how well this vaccine does in reducing corn fly populations into the future.

00;20;08;17 - 00;20;33;21
Brad
Although it is crazy, the horn flies are out. We know that it is the 4th of July horn fly by the 4th of July, and there's a lot of them. But I'm hoping that this will help decrease those populations in the future. So just the last little bit here, another interesting topic that we talk about, flies and some of the research that we've done in the past and just recently at our dairy is talking about coat color in fly in cattle.

00;20;33;21 - 00;20;59;03
Brad
So basically we wanted to look at horn fly resistance and to see if coat color had any association with reduction in fly loads. So basically we found so we did this in Holstein cattle in pasture based cattle on a bunch of farms a couple of years ago. And basically we found that black coated Holsteins attracted more horned flies than white coated Holsteins.

00;20;59;03 - 00;21;29;25
Brad
So animals that had more white on them had less horn flies. And basically we found a gene. Basically it's the gene. So it's known for influencing coat color. And this was associated with fly load and coloration. So basically it's interesting that coat color has an influence on flies and whether the fly loads are high or not. So that was in Holsteins well last year.

00;21;29;25 - 00;21;51;11
Brad
And we still have done it for a couple of years here. Had a student pulled together the data looking at coat color in our research herd here in Morris. And we have Holsteins. And like I said we have crossbred you name it. So we basically collected coat colors from, well over 500 animals and looked at the predominant color that they had.

00;21;51;13 - 00;22;24;09
Brad
So we had black and white. So it's kind of a combination of both black and white. We had black cell animals that were pure black animals that were brown. We had red and white solid red and then white. So more than 50% white. And we counted flies to look at fly load on these animals. Well, interesting fact is we probably numerically we found more flies in our organic herd than we did our conventional herd, but nothing statistically significant.

00;22;24;12 - 00;22;53;24
Brad
Why is that? Well, our conventional animals tend to be outside as well, not necessarily always on pasture, but they're on dry lot, so they can have a lot of flies as well as stable flies, horn flies when they're outdoors. So what about coat color? Well, which animals had the most fly load? Animals that were 100% black. So the total black ones had more flies, black and white and brown animals tended to have way more flies.

00;22;53;24 - 00;23;19;03
Brad
So those really darker colors then red and white, red and white animals. So black coated animals had the highest average fly scores compared to red and white coated animals had lower ones. So it's kind of interesting even. Who would have thought that coat color would have an impact on fly prevalence in dairy herds? How does that work? What do you do with that information?

00;23;19;03 - 00;23;46;00
Brad
Well, it's tough because you can't determine if you start breeding animals. What sort of white percentage or black percentage or even in a crossbred rotation, how much white to red or brown that you're going to get. But it might be helpful in knowing what breeds to select in the future, how to manage flies on your herd, and something to be cognizant of as you think about fly loads in the future.

00;23;46;00 - 00;24;14;15
Brad
Well, I think we'll end it there. Hopefully you learned a little bit about flies and that flies are not always flies. You have to determine what kind of flies you have to help determine what best way to control them is, because whether you have flies in confinement, flies on pasture, house, flies below, flies, you name it. Probably one of the things is best is trying to determine what flies you see on your farm.

00;24;14;15 - 00;24;34;11
Brad
So you can determine how to treat them. And with that, if you have any comments or questions or want to know more about flies, I've been doing Flies research here for well over ten years. Probably let me know. And we can talk about flies. So with that, I thank you for listening.

Episode 302 - Fly Frenzy: Understanding and Controlling Flies on Your Farm - UMN Extension's The Moos Room
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