We have reached another fall season according to the calendar, although I’m not sure Mother Nature is paying attention. After living here for almost a decade, the crazy OK weather still surprises me!
One issue with the proliferation of warm temperatures in the fall is the continued population growth of horn flies on cattle. At this point in the year, much of our fly control options have run out, especially if producers have already used a combination of fly controls such as sprays or tags. Even though there is little we can do for flies this time of year, there are a few action items producers can achieve this fall to help with better fly control next summer.
Remove spent fly tags!
In Oklahoma, producers should expect to achieve about 90 days of control with a fly tag. That is, if proper chemical rotation has been practiced in the past. Producer applying tags with no heed to rotation may get less effective fly control. Also, most fly tags are applied in the early summer. When fall rolls around, those same tags have reduced efficacy and should be removed.
You may be wondering, “Why remove the tags, it’s just as easy to do it in the spring? Prompt removal is important because there is still a small amount of chemical on the tag — not enough to control the flies but just enough to allow living flies to build resistance to that chemical. In Oklahoma, mild temperatures allow some fly growth to continue through the winter. If fly tags are left in till next spring, there is the potential for several generations of horn flies to develop resistance to the chemical in that tag.
Dispose of spent fly tags properly.
Removal of spent fly tags is very important but so is their disposal. Instead of leaving the old tags littered around the chute, bag them up and put them in trash. Old tags on the ground still are a reservoir for flies to create resistance over the winter.
Record what fly control was used.
Fall is the perfect time to make record of what fly tags, pour-ons and sprays were used for both flies and other internal parasites (worms). Take a picture of the boxes with your phone or file a label to reference when you purchase products next season. Rotation of both internal and external parasite control is essential for the effectiveness of future products. By ignoring rotation, livestock producers are losing control options. Internal and external parasites are animal welfare issues and producers should heed label directions so that the products are still effective in the future.
OSU Extension has several useful references for fly control including chemical rotation guidance. County extension educators also have the resources to help you make the right fly control choice. Take advantage of the slower pace this fall and winter and make fly and internal parasite control decisions now.
Zook is Oklahoma Cooperative Extension Service northwest area livestock specialist.