Know Your Opponent When Battling Fly Control

Barrett Simon, Livestock Production Agent

     Fighting back against flies is a battle that many producers have fought for a lifetime and that young producers, like myself, are only beginning.  However, one thing is certain, we will never be completely rid of them. Increased awareness and technology of insecticides have allowed us to make great strides, but these advancements are only truly effective when used correctly.  Even still, horn flies alone can cost our beef industry nearly $1 billion annually due to the negative impact they have one measurable traits such as weaning weight or ADG.  It is important to recognize what type of flies are prevalent in your program and what method(s) of defense might have the greatest impact on your herd health and pocket book.

     Horn flies are what most people think of when fly trouble is brought up.  These are the biting flies that are seen on the shoulder, rib, and lower portion of the belly.  Horn flies are expected to take anywhere from 20-30 blood meals per day. In addition to inhibiting gains and weaning weights, altering cattle behavior, and causing blood loss they also pose the threat of spreading diseases such as Anaplasmosis or Bovine Leukosis.  It is typically best to fight horn flies with more than one level of defense.  While fly tags and pour-ons may have been applied earlier in the year, it is important to keep an eye on the livestock and realize when further action may be needed.  The use of feed additives (Altosid or Rabon to name a few) and dust bags can be a great asset this time of year.  Even though it raises the labor requirement and can be a challenge to apply, spraying for flies in the heat of summer can prove to be a very effective means of control.

     Face flies, as you might guess, are the flies we see hovering around the eyes, nose, and mouth of cattle. Alternative to the horn fly, face flies do not bite but still irritate the host animal.  They will also crowd around cuts or open wounds. However, the biggest issue that face flies pose is the transfer of Moraxella Bovis, the carrier agent for bovine pinkeye. Though preventative vaccines should be administered prior to when the threat of pinkeye emerges, insecticide ear tags have proven to also be very impactful in reducing the amount of face flies around livestock, largely due to their proximity to the affected area. Keep in mind, alternating pyrethroid tags (CyGaurd) and organophosphates (Corathon) every couple of years will reduce the ability of the flies to build up immunity over time.

     Stable flies are another well-known pest to cattle.  These are the biting flies that typically land on the legs of the livestock and are the reason cattle can be seen stamping the ground and switching their tail. Standing partially in water and bunching together are common signs of the animals being bothered by stable flies.  Organic matter with moisture, dirt, or manure serves as a prime hatch ground for stable flies. Thus, cleaning bunk lines and pens frequently along with avoiding spills or wastes of commodities are good preventative measures for dealing with stable flies.  Once they have established themselves, spraying is the only method that is proven to reduce the amount of stable flies on cattle.

     Don’t get caught in the routine of fighting flies with the same tactics year after year. Some summer’s will be worse than others; so feel comfortable taking additional steps in fighting flies when they are more prominent. Explore new practices for fly control and remember - it is a long-term game.  Finally, it is imperative to realize fly control methods, both good and bad, not only play a role in our own operations, but are equally as impactful to our neighbors.