Managing External Parasites of Beef and Dairy Cattle

A l a b a m a
ANR-482
A & M
a n d
A u b u r n
U n i v e r s i t i e s
Managing External
Parasites of Beef and
Dairy Cattle
E
xternal parasites cost Alabama cattle producers
millions of dollars each year. They cause losses,
such as decreased weight gains, decreased milk
production, and damaged carcasses and hides. Several of
these pests also damage cattle by transmitting diseases
from animal to animal.
The most important pests of cattle are horn flies, stable
flies, face flies, lice, ticks, mosquitoes, and several species
of horse flies. Horn flies, stable flies, face flies, horse and
deer flies (tabanids), and lice are the most damaging pests,
and they all usually require control measures each year.
Pests of Cattle
Figure 1. Horn fly: (a) adult (b) eggs (c) maggot (d) puparium
Horn flies. Horn flies are somewhat smaller than house flies
and are some of the most damaging pests of cattle. They
are blood suckers and feed on the shoulders, backs, necks,
bellies, and around the horns of cattle (Figure 1). Horn flies
stay on the animal day and night and leave only to lay eggs
in fresh cow manure. They fly from animal to animal only
when the animals are close together. They are resistant to
most insecticides used for their control. Horn flies develop
economically damaging populations from May through
September in Alabama. Untreated populations range from
500 to 1,000 flies per cow. Horn flies significantly reduce milk
production in both dairy and beef cattle. Weaning weights in
beef cattle are reduced by 20 to 40 pounds per calf weaned.
Horn fly resistance to insecticides has become a
serious problem; however, insecticide resistance can be
effectively managed with an annual rotation of classes of
insecticides. For example, a rotation involving the exclusive
use of pyrethroids for one year with the exclusive use of
organophosphates the following year.
Stable flies. Stable flies are about the same size as house
flies (Figure 2). Their mouthparts are adapted for piercing
the skin of animals and sucking blood. They typically feed
with their heads directed upward. Feeding usually occurs
on the legs, shoulders, and lower portions of the sides of
beef cattle. They develop in moist, decaying vegetation
such as hay feeding areas, piles of silage, and manure
mixed with straw. Removal of these breeding areas will
help control stable flies. After feeding, stable flies rest on
barn walls, posts, and fencing. They may be controlled by
spraying these surfaces with a residual spray. Pyrethroids
such as permethrin are most effective.
Figure 2. Stable fly: (a) adult (b) larva (c) puparium (d) side view of
head detailing the mouthparts
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Face flies. The face fly is well-established in the northern
third of Alabama. It closely resembles the house fly,
although it is slightly larger (Figure 3).
Face flies have mouthparts adapted for irritating
the eyes and nostrils of cattle, which causes a mucous
discharge that the flies feed on. They are found on and
around the animal only when feeding or depositing eggs
in fresh manure. Once face flies have fed on mucus and
other secretions, they fly away to resting sites such as
vegetation and the sides of barns and houses. Face flies
are strong fliers and readily fly 5 to 10 miles to infest
other herds of cattle. They are capable of transmitting the
organism that causes pink eye.
Figure 5. Mosquito life cycle
Ticks. Several species of ticks are found in Alabama. A
common life cycle is shown in Figure 6. Ticks require
brush or wooded areas for development and are most
abundant in wooded areas and along cattle paths in
wooded pastures. Heavy infestations are common in some
areas of Alabama.
Figure 3. Face fly
Cattle lice. Several species of lice are found on cattle in
Alabama. Some suck blood, while others have chewing
mouthparts that produce scab-like injuries (Figure 4).
Cattle lice complete their development on the infested
animal. They are more abundant during the cooler months,
especially in late winter. They cause skin irritation that
results in cattle scratching and rubbing to the point of hair
loss and bare patches of skin.
Figure 4. Cattle lice: (a) cattle biting louse (b) long-nosed cattle
louse
Mosquitoes. Mosquitoes suck blood from cattle. They
breed in water and are usually more abundant in shaded
areas. They do most of their feeding in late afternoon and
at night (Figure 5).
Alabama Cooperative Extension System
Figure 6. Common life cycle
Horse flies and deer flies. Horse flies and deer flies are
known as tabanids. They are vicious, persistent, external
parasites of cattle (Figure 7) and are able to inflict severe
bites that cause blood loss. Breeding and development of
tabanids occurs in damp soil or water in low, swampy areas.
These pests are extremely difficult to control, partly
because of their ability to fly long distances (up to 20
miles) for a blood meal. Severe infestations occasionally
occur, requiring unusual and extreme control measure. A
few insecticides are repellant to horse flies and give cattle
temporary relief from attacks. The synthetic pyrethroid
permethrin (Ectiban, Atroban, Permectrin) used as a spray
is effective as a repellant for 7 to 10 days.
Figure 7. Black horse fly: (a) larvae (b) pupa (c) adult.
Deer flies: (d) and (e)
Cattle grubs (heel flies). Adult heel flies resemble bees
(Figure 8). In the early spring, they lay eggs on the hair
of the legs and bellies of cattle. Because adult heel flies
resemble bees, they frighten cattle during the egg laying
process, causing the cattle to run in an attempt to get
away from the flies. Tiny grubs hatch from these eggs and
bore through the skin and into muscle tissue. They begin
migrating upward toward the back of the animal in the
fall. From November to March, the grubs are found on the
backs of cattle as cysts or warbles. As the grubs mature,
they leave the cysts, drop to the ground, and complete
their development, emerging as adults in March and April.
The heel fly has only one generation per year and
is very susceptible to insecticides. The common use of
systemic parasiticides and other insecticides that are
effective at very low concentrations has reduced heel fly
populations to very low levels.
Figure 8. Adult cattle grub flies
Insecticide Applications, Formulations,
and Equipment
Insecticide formulations commonly used on livestock are
prepared as dusts, wettable powders, emulsifiable concentrates,
liquid suspensions, aerosols, systemic pour-on insecticides, ear
tags, stomach bolus larvicides, and oral feed-through larvicides.
Each type fits particular application techniques.
Power sprayers, knapsack sprayers, compressed-air
sprayers, automatic mineral box spray devices, rubbing
devices, dust bags, aerosol sprays, pour-ons, stomach
boluses, and insecticide salt blocks or premixed feed or
mineral mixtures are all used satisfactorily under different
circumstances to control external parasites of cattle.
Exercise caution when using pour-ons or any of the
other systemic insecticides. It is important that amounts
be applied according to age and body weight. Caution
and consideration should be used when applying pourons along with oral drenches or other organic phosphate
insecticides. Do not treat animals that are sick or under
great stress. Treatments for grub control should be applied
before the end of October in Alabama. If grubs are
found on the backs of cattle during the winter months,
formulations of insecticides other than systemics should be
used to control them.
The effectiveness of boluses or feed-through larvicides
may be limited if treated cattle join pastures with large
herds of untreated cattle.
Tables 1 and 2 list the pests of beef and dairy cattle
and the insecticides that are labeled and recommended for
their control. Table 3 lists each insecticide recommended
in this publication, showing the class along with labeling
on beef or lactating dairy cattle or both. Table 4 lists
insecticide ear tags labeled for cattle, which shows the
insecticide name, class, and labeling on beef or dairy cattle
or both.
Insecticide Safety Precautions
Use extreme caution when treating livestock. Read
and follow all label precautions and recommendations and
observe the following safety precautions:
1. Do not treat sick animals.
2. Do not use more insecticide than is recommended
and do not use more than one insecticide at a time.
3.Because some insecticides are secreted in milk or
stored in body fat, it is important to observe all precautions
and conform to the regulations regarding the minimum
time allowed from last treatment to sale or slaughter.
4. Do not use insecticide formulations for livestock
treatment unless this use is listed on the container label.
5. Do not use any insecticide in a dip unless it is
recommended.
6. When using an emulsifiable concentrate, be sure
it mixes uniformly with the water; if an oil layer forms, do
not use it.
7. When applying insecticides to livestock or around
barns, do not contaminate feed, food, or water troughs,
and do not allow run-off into streams.
Managing External Parasites of Beef and Dairy Cattle
Table 1. Beef Cattle and Nonlactating Dairy Cattle External Parasite Control
Pest
When to Treat
Insecticide
Application
Formulation
Cattle grubs
May 15 to
October 1
Coumaphos 11.6 EC
(CoRal)
Avermectrins
Ivomec 0.5%
Ivomec 1.0%
Eprinex 0.5%
Dectomax 0.5%
Dectomax 1.0%
Mitbemycin Cydectin 0.5%
Minimum
Days to
Slaughter
Comments
Spray
0
Pour-on
Injectable
Pour-on
Pour-on
Injectable
Pour-on
48
48
0
35
45
0
Follow label
directions
"
"
"
"
"
"
"
Note: The cattle grub has only one generation per year and is very susceptible to most insecticides. The widespread use of Avermectin and
related treatments for internal parasites (i.e., Ivomec, Dectomax, and Cydectin) and insecticides that are effective at very low dosages (i.e., the
pyrethroids) has reduced the cattle grub populations to very low levels. However, in herds where deworming treatments or other insecticide
treatments are not regularly used, cattle grubs may still cause damage.
Horn flies
May to
September when
flies average 200
flies/cow
Coumaphos 11.6 EC
Spray (CoRal)
Spray
0
Follow label
directions
Cyfluthrin 1.0%
(Cylence)
Dimilin (Vigilante)
Pour-on
0
Bolus
0
Avermectin (Ivomec)
Pour-on
48
Methoprene (Inhibitor)
Bolus
Mineral Mix
Spray
Pour-on
Back rubber
0
Control for 1
to 4 weeks
Control for 2½ to
3½ months
Control: spring, 6
weeks; summer, 4
weeks
Control for 2 to 3
months
Phosmet (Prolate)
Back rubber
0
Spinosad (Elector)
Pour-on
Spray
Spray
Back Rubber
2
Ear tags 1/cow
0
Diazinon + Chalorpyrifos
(Warrior)
Ear tags 1/cow
0
Endosulfan (Avenger)
Ear tags 1/cow
0
Zeta-cypermethrin
(Python)
Ear tags 1/cow
0
Permethrin
(Permectin, Delice, etc.)
Stirofos + Dichlorvos
(RaVap) 28.3% EC
Recommended insecticides applied as cattle ear tags
Diazinon (Patriot)
Horn flies
Back rubber
0
0
Control for 3 to 4
months
Control for 2½
to 3½ months
Control for 4 to 5
months
Control for 3 to
3½ months
Note: Large horn fly populations reduce milk production in cows. This results in reduced weaning weights of 20 to 40 pounds in calves
if horn flies are not controlled, so it is very important that horn flies be controlled during spring and summer when calves are nursing.
Ear tags are the most effective treatment available for horn fly control and are usually effective for a period of 3 to 4 months if a good
rotation program of different insecticide classes is followed. Avenger is an organochlorine and in a different class of insecticide than either
pyrethroids or organophosphates. Table 4 shows a listing of most of the insecticidal cattle ear tags formulated for use on cattle. Most are
effective for only 1 to 2 months because of insecticide resistance. They are not in the recommended section for one of the following three
reasons: established ineffectiveness, insufficient data, or the active ingredient of the pyrethroid involved builds unusually high levels of
insecticide resistance. Insecticides that cause high levels of resistance do not fit well into an annual rotation program. However, these tags
may be effective on other pests of cattle. Alabama Cooperative Extension System
Stable flies
Early spring,
March – May, when
high populations are
present
Permethrin 10 EC
Spray animals
and resting
areas
0
Stirofos +
Dichlorvos (RaVap) 28.3%
EC
Spray animals
and resting
areas
0
Note: Stable flies are controlled best by eliminating breeding sites (moving hay bale feeding sites often) and spraying stable fly resting areas
(barn walls, fences, and posts) with a long residual insecticide.
Horse flies
Early to mid-summer
Permethrin 10 EC
Face flies
Spring to early
summer
Coumaphos 11.6 EC (CoRal)
Cyfluthrin 1% (Cylence)
Permethrin 10%
Stirofos + Dichloros 28.3%
EC (Ra-Vap)
Spray animals
at 7- to 10-day
intervals
Spray or forced
use of back
rubbers with
face flaps
Pour-on
Spray or forced
use of back
rubbers with
face flaps
Spray or forced
use of back
rubbers with
face flaps
0
Active as a
repellant;
follow label
0
0
0
0
Note: Cattle insecticidal ear tags used for horn fly control also aid in face fly control.
Lice
Ticks
Mosquitoes
Cooler months
Late Winter
Early Summer
Warmer months
Amitraz 12.5 EC (Taktic)
Spray
0
Coumaphos 11.6 EC (Coral)
Spray
0
Avermectrin (Ivomec)
0.5%
1.0%
Dectomax 1.0%
Spinosad (Elector)
Milbemycin (Cydectrin) 0.5%
Permethrin 10% EC
(De-lice)
1%
Cyfluthrin (Cylence) 1%
Phosmet 11% EC
(Delphos, Prolate)
Stirofos + Dichlorvos
(RaVap) 28.3% EC
Coumaphos 11.6% (CoRal)
Permethrin 10% EC
1%
Stirofos + Dichlorvos (RaVap)
28.3% EC
Permethrin 10% EC
0
Pour-on
Injectable
Injectable
Pour-on
Pour-on
Spray
Pour-on
Pour-on
Spray
0
2
0
0
0
21
Spray
0
Spray
0
Spray
Pour-on
Spray
0
Spray
0
0
Managing External Parasites of Beef and Dairy Cattle
Table 2. Lactating Dairy Cattle External Parasite Control
Pest
When to Treat
Insecticide
Formulation
Cattle grub
Horn flies
May 15 –
October 1
April – October
when fly
populations
reach 100/cow
Eprinomedrin (Eprinex)
Pour-on
Minimum
Days to
Slaughter
0
Coumaphos 11.6% EC
(CoRal)
Pour-on
0
Cyfluthion 1% (Cylence)
Pour-on
0
Endosulfan (Avenger)
Ear tag 1/cow
0
Dimilin (Vigilante)
Bolus
0
Methoprene (Inhibitor)
Bolus
0
Methoprene
Mineral fed
Free choice
Spray
Pour-on
Spray
0
Ear tag 1/cow
0
Spray animals and
resting areas
Spray resting areas
Spray
0
Spray or back
rubber – forced use
with face flaps
Spray or back
rubber – forced use
with face flaps
Spray or back
rubber – forced use
with face flaps
Pour-on
Spray
0
Spray
0
Pour-on
Spray
Pour-on
Pour-on
Pour-on
0
0
Permethrin 10% EC
Stable flies
March – May
Horse flies
Early to midsummer
Face flies
Spring to early
summer (North
Alabama)
Stirofos + Dichlorvos
(RaVap) 28.3% EC
Zeta-cypermethrin
(Python)
Permethrin 10% EC
Spinosad (Elector)
Permectrin 10% EC
Coumaphos 11.6% EC
(CoRal)
Permethrin
Stirofos + Dichlorvos
(RaVap) 28.3% EC
Lice
Cooler months
Cyfluthion 1% (Cylence)
Amitraz 12.5 % EC
(Taktic)
Coumaphos 11.6% EC
(CoRal)
Spinosad (Elector)
Permethrin 10% EC
(DeLice)
1%
Cyfluthrin 1% (Cylence)
Eprinomectin (Eprinex)
Alabama Cooperative Extension System
Application
Comments
Control for 1 to 4
weeks
Control for 4 to 5
months
Control for 2½ to
3½ months
Control for 2 to 3
months
0
0
0
0
0
0
0
0
0
0
Control for 3 to
3½ months
Repellant action
effective 7 to 10
days
Ticks
Mosquitoes
Premises
(house flies,
other filth
flies, stable
flies)
Late winter
– early summer
Spring – fall
Spring – fall
(when high
populations are
present)
Amitraz 12.5% EC
(Taktic)
Coumaphos 11.6% EC
(CoRal)
Spinosad (Elector)
Permethrin 10% EC
(DeLice)
1%
Stirofos + Dichlovos
(RaVap) 28.3% EC
Permethrin 10% EC
Spinosad
Spray
0
Spray
0
Pour-on
Spray
Pour-on
Spray
0
0
Spray
Spray
0
0
Table 3. Insecticide Treatments Recommended in This Publication
Insecticide
Class or Type of Treatment
Amitraz (Taktic)
Avermectrin
(Ivomec)
(Dectomax)
Coumaphos (CoRal)
Chlorpyrifos
Cyfluthion (Cylence)
Diazinon
Dichlorvos (Vapona)
Dimilin (Vigilante)
Endosulfan (Avenger)
Eprinomectin (Eprinex)
Methoprene (Inhibitor)
Milbenycin (Cydectrin)
Permethrin
Phosmet (Prolate)
Spinosad (Elector)
Stirophos (Rabon)
Zeta-cypermethrin
(Python)
Organophosphate
Macrocyclic Lactones
Lactating Dairy
Yes
No
Organophosphate
Organophosphate
Pyrethroid
Organophosphate
Organophosphate
Insect Growth Regulator
Organochlorine
Macrocyclic Lactones
Insect Growth Regulator
Macrocyclic Lactones
Pyrethroid
Organophosphate
Spinosyn
Organophosphate
Pyrethroid
Yes
Yes
Yes
No
Yes
Yes
Yes
Yes
Yes
No
Yes
No
Yes
Yes
Yes
Labeling
Beef
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
yes
Note: Horn fly resistance to insecticides can be managed more effectively by an annual rotation program of insecticide classes.
Managing External Parasites of Beef and Dairy Cattle
Table 4. Insecticide Cattle Ear Tags
Tag
Insecticide
Class
Atroban Extra
Avenger
Commando
Co-Ral Plus
Permethrin
Endosulfan
Ethion
Diazinon +
Coumanphos
Beta-cyfluthrin
Diazinon +
Chlopynifos
Pirimiphos methyl
Lambdacyhalothrin +
Pirimiphos methyl
Fenvalerate
Permethrin
Cypermethrin +
Chloropyrifos
Diazinon
Diazinon
Zeta-cypermethrin
Lambdacyhalothrin
Fenvalerate
Diazinon +
Chlorpyrifos
Diazinon
Zeta-cypermethrin
Diazinon
Permethrin
Pyrethroid
Organochlorine
Organophosphate
Organophosphate
Labeling
Lactating Dairy Beef
Yes
Yes
Yes
Yes
Yes
Yes
No
Yes
Pyrethroid
Organophosphate
Yes
No
Yes
Yes
Organophosphate
Pyrethroid +
Organophosphate
Pyrethroid
Pyrethroid
Pyrethroid +
Organophosphate
Organophosphate
Organophosphate
Pyrethroid
Pyrethroid
Pyrethroid
Organophosphate
No
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
No
Yes
No
Yes
No
Yes
Yes
Yes
Yes
Yes
Yes
Organophosphate
Pyrethroid
Organophosphate
Pyrethroid
No
Yes
No
Yes
Yes
Yes
Yes
Yes
Cylence Ultra
Diaphos L
Dominator
Double Barrel
Ectrin
GardStar Plus
Max-Con
Optimizer
Patriot
Python
Saber Extra
Super Deckem
Warrior
X-Terminator
ZetaGard
Z-Diazinon
Z-Permethrin
Note: For all insecticides listed in this publication, read and follow all label directions for proper missing instructions, application
rates, and precautions. It is illegal to use any pesticide in any manner inconsistent with the label. Any trade names listed are for
convenience only. No endorsement of products is intended, nor is criticism of unnamed products implied.
Gene Strother, Extension Entomologist, Professor Emeritus, Entomology and Plant
Pathology, Auburn University
Use pesticides only according to the directions on the label. Follow all directions, precautions, and restrictions
ANR-482
that are listed. Do not use pesticides on plants that are not listed on the label.
The pesticide rates in this publication are recommended only if they are registered with the Environmental
Protection Agency and the Alabama Department of Agriculture and Industries. If a registration is changed
or cancelled, the rate listed here is no longer recommended. Before you apply any pesticide, fungicide or
herbicide, check with your county Extension agent for the latest information.
Trade names are used only to give specific information. The Alabama Cooperative Extension System does
not endorse or guarantee any product and does not recommend one product instead of another that might
be similar.
For more information, call your county Extension office. Look in your telephone directory under your
county’s name to find the number.
Issued in furtherance of Cooperative Extension work in agriculture and home economics, Acts of May 8 and
June 30, 1914, and other related acts, in cooperation with the U.S. Department of Agriculture. The Alabama
Cooperative Extension System (Alabama A&M University and Auburn University) offers educational programs,
materials, and equal opportunity employment to all people without regard to race, color, national origin,
religion, sex, age, veteran status, or disability.
4M, Revised April 2007, ANR-482
© 2007 by the Alabama Cooperative Extension System. All rights reserved.