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Planning Ahead: Fly Control for Beef Cattle

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May 2, 2019


Announcer: Farm and Family is a production of the Mississippi State University Extension Service.

Amy Myers: Today we're talking about planning ahead for fly control for beef cattle. Hello. I'm Amy Taylor Myers, and welcome to Farm and Family. Today we're speaking with Dr. Brandi Karisch, Mississippi State University Extension beef cattle specialist.

So Brandi, why is fly control in beef cattle so important?

Brandi Karisch: Amy, horn flies in particular are little bugs that can cause big trouble for beef producers. This spring, we've had wet and mild conditions that really make ideal breeding conditions for these horn flies. As we see temperatures start to rise, they quickly start to show up in full force. It's been estimated that production losses for the entire beef industry attributed to this little horn fly are estimated at over $730 million.

Amy Myers: Wow. That is a lot. It must be really important to control these flies. What do these production losses result from?

Brandi Karisch: Amy, these production losses come from a variety of factors, things such as blood loss, toxicity, and disease, and growing cattle and lactating cows are often hit the hardest. For example, if we're talking about average daily gains for stocker cattle, they've been estimated to be reduced by over 13% of high infestations of horn flies.

Amy Myers: Describe the lifecycle of these flies.

Brandi Karisch:  The horn fly is a blood-feeder that lives on the back, belly, and legs of its host. The lifecycle starts when that female fly leaves the host animal to lay eggs in fresh manure. Those eggs will then hatch in one to two days, and they'll turn into larvae. The larvae will feed and grow in the manure for three to five days, then change into pupae in the manure for six to eight days, and then the adult fly then emerges and starts the cycle all over again.

The adult fly lifecycle is actually only two to four weeks long, and she spends most of her time feeding. They'll feed for 10 to 25 minutes at a time and may feed up to 40 times a day.

Amy Myers: Yes. This is extremely annoying for us and for the cattle, of course. What are some options for producers to control these little pests?

Brandi Karisch: Amy, there's a variety of options that are available for producers for horn fly control. The newest of these options is actually a feed through product. With this method, that feed through insecticide actually doesn't kill the adult, but it stops that lifecycle that we were talking about and prevents those larvae in the manure from reaching maturity. We don't actually see any adult flies come out. With this method, it's important to remember that you have to feed it before the adult flies start to emerge in full force.

Another popular method or self-application device is back rubs or dust bags that are treated with an insecticide that's diluted in oil and then placed in a high traffic area of the pasture that the cattle then walk under and treat themselves.

Fly tags are another popular option. Those are simply ear tags that are impregnated with an insecticide. They're typically placed at two tags in the ear of the animal. It's recommended to re-tag when those fly counts start to get high.

The last option is a pour-on or spray-on insecticide. That requires a direct application.

Amy Myers:  What factors should producers consider when selecting the option that best fits them?

Brandi Karisch: Often, the first factor that most producers consider is price, but it's also important to consider how effective that product is that you choose to use to control those horn flies, how easy it is to use, and then how much labor is required to apply that product. It's important for producers to remember to rotate those different products and the active insecticide ingredients in them to prevent those flies from developing an immunity to those insecticides.

Amy Myers: Now for more information, where do we go?

Brandi Karisch: Amy, as always, you can visit our beef cattle extension website, which is now located at You can search for the beef cattle page. We've got lots of information about beef cattle related questions.

Amy Myers: Thank you so much. Today we've been speaking with Dr. Brandi Karisch, Mississippi State University Extension beef cattle specialist. I'm Amy Taylor Myers, and this has been Farm and Family. Have a great day.

Announcer: Farm and Family is a production of the Mississippi State University Extension Service.

Department: Animal & Dairy Science

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