By: Paul Kropp
Central Life Sciences
As cattle producers, our ultimate goal is to efficiently raise as many pounds of beef per acre as genetically possible. Without a fly control program in place, horn fly populations can swell up to 4,000 flies per animal. The impact of flies can be directly seen in cattle performance.
Using an insect growth regulator, like Altosid® IGR or Clarifly®, is one of the most powerful ways to limit the impact of flies. Working as a feed-through fly control product, the active ingredient is passed through to the manure, where horn flies lay their eggs—ultimately interrupting the fly life cycle.
An Oklahoma State University Study by Dr. Justin Talley showed that insect growth regulators (IGRs) leading to improved weight gain and feed efficiency. The cattle group fed the IGR gained 0.33 more lbs/day as compared to the control group.
Keep in mind, fly activity is influenced heavily by weather, and spring time means fly time. The warmer temps mark the start of fly season when overwintering horn flies start to emerge, ready to feed on cattle with painful bites and the ability to spread disease-causing bacteria within the herd.
To achieve the best results with insect growth regulators and limit flies on cattle, we recommend following the 30/30 approach with just 3 easy steps:
1. Ideally start feeding FortiGraze® or RangeMax® tubs with an IGR, approximately 30 days before the average daily daytime temperatures reach 65°F. This is when overwintering flies emerge. We want to ensure the manure is adequately treated before flies emerge.
2. Continue feeding the IGR through the fall and an additional 30 days after the first frost has been recorded. his step will reduce overwintering pupae, giving you a jump start on the next fly season.
3. It is important to monitor fly populations, mineral intake, and cattle size to ensure sufficient product is consumed to minimize fly populations. In cases of periodic spikes in populations you can supplement your efforts with a horn fly insecticide such as insecticidal spray to reduce the adult fly population and allow the herd to stay on track.
Figure 1. Last Frost Map (Start up to 30 days before this date)
Figure 2. First Frost Map (End 30 days after this date)