Flies thrive in humid weather and we have had plenty of that this summer! The real issue with flies-other than being annoying-is that they spread bacteria cow to cow. Flies have been linked to spreading several types of “summer mastitis” and have even been known to spread Staph aureus. If your SCC has been creeping up, it may be due to fly infestation.

But flies are hard to kill off and control. Let’s talk a bit about a few things that may help. 




Flies are difficult to control, but worth the effort.  Controlling the flies means better SCC, less mastitis and prevention of pink eye and other bacterial diseases in most herds. Here are some things that help get the flies under control:

1. Try a pour on, spray or oiler
Most fly sprays contain permethrin, an active fly killer that doesn’t knock flies out of the air-but will kill them within a few minutes. Use a concentrate of 10% permethrin or greater to mix for a pour-on, spray or oiler.

2. Switch active ingredients.
Most fly sprays use pemethrin, but others use organophosphates. Try switching active ingredients if the permethrin products don’t seem to be effective any longer.

3. Try a fly larvicide
Larvicides are put are fed to cattle and kill fly eggs in the manure. The most common fly larvicides are Clarifly and Rabon. Clarifly takes 30 days to be fully active-so putting it in later can still help in the fall. Rabon, a organophophate and a bit harsher, works in a shorter amount of time. However, fed continuously, fly eggs become more easily resistant to Rabon

4. Try tape.
Sticky tape is available in all forms: wide for parlors, narrow for calf pens-you name it. Sticky tape is very effective when used with other methods of control.

 5. Reduce standing water
Standing water in old tires, plastic and puddles are breeding grounds for flies that sprays or larvicides won’t work as effective control. Empty out and dry those spots out if you can.

6. Clip weeds and grass around buildings.
Weeds and grass are breeding areas for flies-especially in humid weather. Clip for extra control.

7. Try baits, traps or wasp control
Some folks swear by one of these as an addition to their fly control plan. 

8. Keep fans clean and working to full capacity.
Fans, air movement, not only keep animals cool, but reduce the “hang” time of flies. Towards the end of summer, when the flies become even more intense, fans that have operated over most of the summer get clogged with dust and are operating at a lower capacity. 

Do you have a fly control method that works? If you do, let me know! I’m always learning and can use a good tip.

Great talking to you again.