The Fundamentals of Killing Spring Time Horn Flies on Cattle

by Caitlyn Andrews April 15, 2016

Fundamentals of Killing Springtime Horn Flies in Cattle

They're back. Those nasty horn flies that make an appearance every year and bite away at your cows' hides. Horn flies show up in the spring, but they remain a problem well into the fall. Now is the time to start fighting back.

Horn flies in cattle are not just a nuisance, but they can affect productivity. Here's a quote from a Farm & Ranch Guide article discussing the impact of horn flies on profit:

“High horn fly populations can cause blood loss and increased cattle stress or annoyance,” says Ted Perry, cattle nutritionist with Purina Animal Nutrition. “Annoyance can cause cattle to use their energy to combat flies, change their grazing patterns and cause cattle grouping. Ultimately, it can lead to decreases in milk production, causing a reduction in calf weaning weights.”

Horn Flies on Cow

Image By Scott Bauer - Public Domain

About Horn Flies

First off, let's talk about horn flies. What are they and what makes them different from every other fly that finds its way on your cows?

  1. Horn flies are small biting flies about the half the size of house or stable flies.
  2. Horn flies can be identified as gray with two stripes on their thorax. They have piercing mouthparts like stable flies.
  3. Typically, you'll find horn flies flocking on the backs of cattle and laying eggs in cow dung.
  4. Horn fly eggs hatch in manure pats and require 6 to 8 days to pupate.
  5. Horn flies take up to 40 blood meals per day. If you have a horn fly problem then a single one of your cows could be losing up to one pint of blood per day! Ouch!
  6. According to research, horn flies cost the cattle industry anywhere from $700 million to $1 billion in losses annually!

Ok, now we know a little bit more about horn flies. Let's talk about how we can get rid of them.

Horn Fly Control on Cattle

So, what can you do to control horn flies on your cattle? There are plenty of effective products on the market to help you keep your horn fly population under control.

Fundamentals of Horn Fly Control

1. Sanitation

The most effective horn fly control starts with good sanitation. Keep up with pasture maintenance and rotation as well as keeping stables clean and disinfected to reduce fly populations.

2. Fly Control Products

Now it's time to look at the variety of fly control options available to you: Pour-on insecticides, Fly sprays, Dust bags, Ear tags, Injections, Feed additives, Fly baits, and traps.

3. Integrated Pest Management (IPM)

IPM is a program based on prevention, monitoring and control of pests through biological, cultural, physical and chemical management tools. IPM programs vary and it helps to have someone experienced with integrated pest management help you come up with the right solution for your farm.

Here are just a few products that make excellent additions to an IPM program: 

A feed supplement that prevents flies from developing into adults, such as Clarifly Larvicide.

VetGun delivery system, an innovative insecticide delivery system that allows you to apply insecticide from a distance to reduce stress.

The bottom line is that horn fly season is here. Without implementing a fly control plan now, you risk losing herd productivity. Prevention pays off when it comes to fly control.

You can learn more about horn with this Horn Fly101 fact sheet from AgriLabs.

Caitlyn Andrews
Caitlyn Andrews


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