Fly control for livestock on pasture


Recent weeks have brought high temperatures and little rain depending upon the area you live in. Scattered showers or the lack there of for many of us has left many pastures in stressed conditions.

But what about your livestock and fly control?

Flies costs

I have seen estimates that flies cost U.S. livestock producers $700,000 to $1,000,000 dollars annually.

With lower livestock prices it is more important than ever to keep animal performance at an optimum. Flies can impact livestock performance by reducing weight gains, milk production and poor feed utilization.

The major flies of concern are horn flies, face flies and stable flies. Other annoying pests would include horse flies, deer flies, ticks and mosquitoes.

Horn flies

Horn flies are blood sucking and can be found on the backs of livestock feeding 30-40 times per day.

Recommended economic levels are reached when populations exceed 200 flies per animal and often peak this time of year.

The female adults only leave the hosts to lay eggs in fresh manure and the eggs normally hatch within 18 hours.

Stable flies

Stable flies are also serious insects affecting livestock since they too are blood sucking.

They are normally found feeding on the legs and belly regions of livestock and can also cause significant reductions in performance.

When these flies bite, which are often painful, livestock react to them by stomping there feet, gathering in groups or standing in streams and ponds. Because of the location of feeding areas on the animal, these flies can be the most challenging to control.

The adult female prefers to lay eggs in wet moist hay or straw mixed with manure found in feedlots or winter hay feeding areas.

Face flies

Face flies do not bite but rather feed upon livestock secretions from the eye, mouth and nose. This feeding can cause damage to eye tissue which increases the potential for infection and diseases such as pink eye.

The females do lay their eggs in fresh manure piles found in pastures.

Fly control

Several strategies can be used to help control fly populations.

  • Sanitation is one of the most important management strategies especially in and around feedlots and buildings. As long as breeding locations are available, other efforts will be minimized.
  • Larvicides are an option for pasture and feedlot situations either by applying directly to the fly breeding locations or used as a feed additive or incorporate into a mineral mixture.
  • For grazing livestock, the first step is to correctly identify which type of fly you have.
  • After correct identification, an application of insecticides directly to livestock can be accomplished using several application methods and products.

What to use

Options include fly tags, direct spray, misters, pour-on, self-application devices (dust bags or oilers), walk through traps and the newer gun devices that shoot an insecticide capsule and explodes upon contact.

One key factor when using the self-applied applicators is getting your livestock to use them consistently. Often times, producers will place the devices in locations that force the livestock to move through them, like at a waterer or mineral feeder.

Regardless of the method you use, always read the insecticide labels for limitations and withdraw times.

Finally, be sure to utilize an integrated fly control program to reduce resistance issues.
Insecticide resistance can develop if less than recommended levels of an insecticide is used, or by using the same insecticide or family of insecticides every year.

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