timing for pour-ons

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Jun 1, 2004
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Central, TX, 60 mi. E of Austin
About two months ago we treated our herd with Cydectin. Now at the beginning of June, heel flies (gad flies) are plaguing the cattle and causing them to run around with their tails in the air.
My question is if there is enough residual toxicity to kill the grub when it enters the body at this time or if another treatment is necessary the next time we pen (end of June or so)? I would like to know at what point killing the grubs in the cow's system will endanger the cow.
I would really like to interupt the life cycle of these heel flies and reduce the problem in the future. Any advice is appreciated.
Your questions regarding timing are all rather specific to your location, which nobody knows but you. To be on the safe side, ask a local vet. The only problems that I have had personally have occured in the dead of winter with sale barn cattle of unknown treatment status. That is in East Texas. I'm sure others have different experiences. Have never had a problem with Cydectin in October and November, so if you typically use it in the Fall, you should be alright to wait until then with respect to not
endangering the cow.

You didn't ask, but we used Cydectin on about 180 cows and Ivermectin pour-on on 130 last fall. Not sure that the Cydectin is worth the extra cost. In fact, I'm starting to lean toward NOT. The 5 liter AgriLabs Ivermectin from Valley Vet is too good to pass up at $205 delivered to your door.

As far as interrupting the life cycle and reduce the problems in the future, keep dreaming. I just don't see it happening, but good luck, anyway!

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