FLY CONTROL FOR CATTLE

Cattle pests, such as flies, cost cattlemen both in treatment costs and in lost production, due to irritation of the pests and the diseases they cause or transmit.  In a survey of California cattlemen, face flies were rated as the worst pest, followed by horn flies and stable flies.

Face flies, in addition to producing eye irritation due to their feeding, serve as mechanical carriers of the causative agent of pinkeye in cattle (infectious bovine keratoconjunctivitis [IBK] caused by the bacterium Moraxella bovis). This condition consistently ranks as one of the top five most costly diseases in California beef cattle.  Feeding by horn flies, stable flies, horse flies, and other bloodsucking flies mechanically transmits several disease organisms as well as causing irritation and physiological changes that decrease weight gains. 

Both face flies and horn flies develop resistance to insecticides over time.  For maximum prevention, it is advisable to switch the class of drug you use each year or two.  If you used an organophosphate ear tag last year, use a pyrethroid ear tag this year.  Additionally, if you plan to use a pyrethroid ear tag this year, use an organophosphate spray this year.  Alternating the classes of drugs in this manner will increase the success of your preventive program.  It will zap those flies harder, remember this is war!  It is also recommended that application of ear tags be delayed until the fly population is relatively high so that the possibility of them developing resistance is lowered.  Sprays, back rubbers, face rubbers, and dust bags can be helpful in reducing the fly populations early in the season, before ear tag application.  Then, as the fly populations increase, apply the fresh ear tags to achieve maximum benefit.  Always follow the manufacturer’s label directions for ear tag application.  If they call for two—use two ear tags!  If they recommend ear tags for calves or if ear tags for calves are needed to prevent Pinkeye in the calves—use the tags in the calves.  Remember, in the fall, always remove the ear tags.  If the ear tags are left in the cattle the flies that over winter—particularly the face flies that over winter will develop resistance to the drug you used and it will no longer be effective.

Face flies and horn flies lay their eggs in cow manure and the larvae only develop in cow manure.  Therefore, some of the compounds that are fed or given in bolus form that kill the larvae in the manure pat can be very effective.  Examples of this include the slow release bolus with diflubenzuron (Vilgilanteâ). This compound is an insect growth regulator (IGR), which is safe, and cross-resistance does not develop.  Another IGR that is used in “feed through” products is methoprene.  Other products are available that can kill the fly larvae when used as a “feed through”.

SOME IMPORTANT ITEMS TO KEEP IN MIND FOR FLY CONTROL AND PESTICIDE USE ARE:

1. Plan ahead for insecticide and ear tag purchases; fly season always comes, even if delayed by cool weather or rain.

2. Consult with your veterinarian regarding active ingredient(s) in these products and their record of effectiveness in your area.

3. Always follow instructions, warnings, and precautions: these products can be toxic to you, your children, pets, and others working with them around the chute.

4. Follow label withdrawal times and keep records of treatment dates, products and lot numbers.

REGISTERED PESTICIDES FOR CATTLE: 2002

EAR TAGS
Product Name	Active Ingredient	Chemical Class	Manufacturer
Atroban Extra	Permethrin	Pyrethroid	Schering-Plough
BovaGard	Diazinon	Organophosphate	Y-Tex
Cutter Blue	Fenthion	Organophosphate	Bayer
Cutter Gold	Cyfluthrin	Pyrethroid	Bayer
Diaphos Rx	Diazinon + Chlorpyrifos	Organophosphate	Y-Tex
GardStar Plus	Permethrin	Pyrethroid	Y-Tex
New Z Diazinon	Diazinon	Organophosphate	Farnam
OPtimizer	Diazinon	Organophosphate	Y-Tex
Patriot	Diazinon	Organophosphate	Fermenta
PYthon	Zeta-cypermethrin	Pyrethroid	Y-Tex
Warrior	Diazinon + Chlorpyrifos	Organophosphate	Y-Tex
X-Terminator	Diazinon	Organophosphate	Destron-Fearing
ZetaGard	Zeta-cypermethrin	Pyrethroid	Y-Tex

SPRAYS
Product Name	Brand Names
Dichlorvos	Vapona
Permethrin	Ectiban, Permectrin, Atroban, Permethrin, Insectrin
Tetrachlorvinphos	Rabon
Tetrachlorvinphos-Dichlorvos	Ravap

POUR-ON APPLICATIONS
Product Name	Brand Names
Permethrin	DeLice, Expar, Hard Hitter

BACK RUBBERS AND FACE RUBBERS
Product Name	Brand Names
Permethrin	Ectiban, Insectrin
Tetrachlorvinphos-Dichlorvos	Ravap

DUST BAGS
Product Name	Brand Names
Tetrachlorvinphos	Rabon dust

FEED-THROUGH INSECTICIDES
Product Name	Brand Names
Tetrachlorvinphos	Rabon oral larvicide
Methoprene	IGR Mineral, Starbar

SLOW RELEASE BOLUS WITH IGR (Insect Growth Regulator)
Product Name	Brand Names
Diflubenzuron	Vigilante

(Note: Active ingredients are available under a number of brand names and those listed are examples only and not specific endorsements or recommendations. ALWAYS READ AND FOLLOW LABEL INSTRUCTIONS.)

John Maas, DVM, MS
Diplomate, ACVN & ACVIM
Extension Veterinarian
School of Veterinary Medicine
University of California, Davis