\m    18    5   79    2  1 'Introduction'
\m    33   10   61    2  1 'Lice'
\m    34   10   74    2  2 'General Information'
\m    47   14  114    2  2 'Cattle Lice'
\m   141   55  108    4  2 'Hog Lice'
\m   149   57  114    4  2 'Horse and Mule Lice'
\m   156   59   72    4  2 'Sheep and Goat Lice'
\m   163   60  120    4  1 'Ticks'
\m   173   63   87    4  1 'Cattle Grubs'
\m   184   66  105    5  1 'Flies'
\m   261   92   73    6  1 'Mites'
\t'November 1987'                                                  'II A-'
\a                    Dr. Phil Koehler, Extension Entomologist
\a
\a                                LIVESTOCK PESTS

                    Dr. Phil Koehler, Extension Entomologist
\h 1 'Introduction'


                                LIVESTOCK PESTS

                                  Introduction

External parasites, including lice, ticks, horn flies, house flies, stable
flies, cattle grubs, horse flies, deer flies and mosquitoes present a serious
problem to the beef and dairy industries of Florida.  These pests are most
prevalent during spring and summer months.  In Florida's warm climate,
however, many are a problem the year round.

Insecticides are available that will control most of the major external
parasites of livestock when applied thoroughly and at the proper times.
\h 1 'Lice'
\h 2 'General Information'


                                      Lice

General Information:

Several kinds of lice attack livestock in Florida.  Infested animals have a
hair coat, with a rough, coarse appearance and do not reach maximum production
or gain weight properly.  They rub against posts, fences and trees, lick
themselves and chew their tails (a sign of tail lice).  Lice spend the entire
life cycle on the host animals and are more prevalent during winter and
spring.  The best time to control lice is in the fall and winter.
\h 2 'Cattle Lice'


Cattle Lice:

Sucking lice, which feed on blood include (a) the long-nosed cattle louse (on
head, neck and brisket), (b) the short-nosed cattle louse (on head, neck and
brisket), (c) the blue louse (in rings on face, muzzle and around the eyes),
and (d) the cattle tail louse (discussed in a subsequent section).

One kind of biting louse, known as the cattle biting louse feeds on skin and
hair, causing itching, irritation, and hair loss.

The cattle tail louse is the most important damaging louse in Florida.  In
other parts of the United States the short-nosed cattle louse is the major
pest.  While much information is available for the control of the short-nosed
cattle louse, only limited information is available specifically on control of
the tail louse.  Important differences in the biology of these two species
require differing control strategies.

The cattle tail louse is a tropical louse species found in Florida as well as
other Gulf Coast states.  In 1945 the tail louse was introduced into Florida
and has since spread to be a serious cattle pest in the subtropical regions of
the United States.

The cattle tail louse is the largest louse species found on cattle.  Adult
tail lice are normally found on the last 18 inches of tail and deposit eggs on
the hairs of the brush.  Occasionally when heavy infestations occur adults and
eggs may also be found in the ears.
\v
\bAdult tail lice are normally found on the last 18 inches of tail and deposit
eggs on the hairs of the brush.  Occaisionally when heavy infestations occur
adults and eggs may also be found in the ears.

The eggs which are laid on the tail hairs may hatch in 9 days when temperature
conditions are optimal.  In winter when temperatures are low the eggs may not
hatch for 40 or more days.  Thus, during January and February egg densities
may build up on the tail brush.  These eggs will remain on the hairs through
the winter season to hatch when the temperatures begin to warm in the spring.

When the eggs hatch, the young nymphs migrate to the area of the eye, muzzle
and vulva surface.  They remain there to suck blood and grow through the
second instar.  The second instar nymphs may also be found around the neck
region and mid-region.  As the nymphs molt to the 3rd instar they migrate to
the anal region of the animal to suck blood.  Under optimal  conditions the
cattle tail lice will go through the entire life cycle (egg to egg) in as
few as 25 days.  Since the species has not been reared under laboratory
conditions the number of eggs laid per female is not known.

Cattle tail lice may be carried into a herd by introduction of infested
animals.  Once an infestation is in a herd, it may be spread by the direct
contact of animals or by contact of areas where animals have scratched or
rubbed.

The cattle tail louse may also be spread from animal to animal or herd to herd
by flies.  The third instar nymphs of the tail louse frequently migrate to the
backs and shoulders of animals.  There they can climb onto horn flies or other
flies frequenting the animal to be carried to new hosts.  One sample of 5000
flies taken from cattle were carrying 100 tail louse nymphs.  Flies which
frequent animals in a herd may play a significant role in the transmission of
tail lice.

The tail louse is a blood sucking louse, and extensive infestations may cause
anemia in cattle.  Infested cattle show poor condition, slower weight gain,
low vitality, and reduced milk production.  Heavy infestations of sucking lice
can cause abortion and anemia in animals.

Adult populations of more than 5 lice will cause economic damage to cattle.

Tail louse control can be readily achieved by timed treatments or
self-treatment with proper insecticides.  The first application should kill
almost all the nymphs and adults present on the animal at the time of
treatments.  Retreatment is then required to kill all nymphs and adults which
develop from eggs present during the first treatment.  Since none of the
labeled insecticides has good ovicidal properties, retreatment is essential.

Since cattle tail louse eggs can hatch up to 40 days after oviposition,
treatments must be reapplied at 3 week intervals to attain good control.
Continuous dust bag or backrubber treatment is the most successful control
method.

\bAlthough tail lice may be present year-round, certain times of the year are
preferable for treatment.  From early spring to fall are good treatment times.
Proper control procedures in the fall will prevent the winter build-up of eggs
and subsequent damage when the nymphs emerge.  Early spring application will
control the damaging emergence of nymphs from the over-winter buildup of eggs
as well as aiding in horn fly control.  Mid-winter treatments are not
economically feasible since the population is generally in the egg stage and
will not be killed by an insecticide application.

Late spring and summer applications for tail lice should be timed to obtain
control of both flies and lice.  Thus, optimum timing of proper pesticides can
result in the control of more than one pest for the cost of controlling one
species.
\h 2 'Hog Lice'


Hog Lice:

Only one kind, known as the hog louse, is found on hogs.  It does not attack
other animals.  Hog lice are found primarily on the inside of the upper part
of the legs, in the folds of skin about the neck, and around the ears.
\h 2 'Horse and Mule Lice'


Horse and Mule Lice:

The horse biting louse and the horse sucking louse attack these animals.  Both
kinds are most prevalent about the head, neck, withers and base of the tail.
\h 2 'Sheep and Goat Lice'


Sheep and Goat Lice:

Biting and sucking lice attack sheep and goats.  The sheep "ked", a sucking,
wingless fly may also be found on sheep.
\h 1 'Ticks'



                                     Ticks

In Florida, ticks are principally pests of horses and cattle, especially range
cattle.  The most common are the Gulf Coast tick, lone star tick, blacklegged
tick, spinose ear tick and cattle tick.  Damage to cattle includes loss of
blood, disease transmission, and tick paralysis.
\h 1 'Cattle Grubs'


                                  Cattle Grubs

Two species of cattle grubs are present in the United States.  One, the common
cattle grub, is found in Florida.  The other, the northern cattle grub may be
in cattle shipped to Florida from other states.  Damage occurs from excessive
running during heel fly season and direct penetration of the hides by the
grubs.
\b\v
\h 1 'Flies'
\v
\v
                                     Flies


Horn Flies:

These pests are blood suckers that remain on animals except when laying eggs.
They breed in fresh manure.  Horn flies, which congregate primarily on the
withers and backs, are more numerous on sick animals and on dark-colored
animals.  They may transmit animal diseases such as anaplasmosis.


Stable Flies:

These insects are blood suckers with a severe bite.  They breed in decaying
organic matter, such as green chip, refuse, piles of fermenting straw, weeds,
grass, peanut litter, refuse from packing sheds, citrus refuse and celery
strippings or wastes.  In West Florida stable flies breed in large numbers in
piles of vegetation washed up along the shores of bays and lakes.  Stable
flies have the habit of congregating on the sides of buildings and on fences
where residual sprays can be effectively applied.


House Flies:

House flies do not bite but annoy animals and may spread diseases.  They breed
in animal excrement and decaying vegetable matter.  Sanitation, screens and
insecticides are of major importance in house fly control.  Since house flies
have been able to develop resistance to most of the newer insecticides, there
has been a renewed interest in sanitation for fly control programs.  This
means getting rid of the breeding places.


Horse Flies:

About 188 species and subspecies of these flies are found in Florida.
Thirty-five species occur in numbers high enough to be of direct economic
importance to livestock.  These blood-sucking insects are vicious biters that
breed in wet areas.  There is no practical control for these pests on beef or
dairy animals.  Both blood loss and disease transmission make these important
livestock pests.


Screwworm Flies:

Several kinds of maggots infest wounds of warm-blooded animals in Florida, but
the one that feeds only on live flesh is the primary screwworm.  The State of
Florida and the United States Department of Agriculture, in cooperation with
other southeastern states, have eradicated the screwworm from the southeast
through mass releases of sterile male flies.

\bOf equal importance to the eradication of screwworm is the prevention of
reinfestation.  Since this pest will not normally migrate from the infested
southwestern states into the southeast, inspection stations have been
established along the Mississippi River to provide for thorough inspections
and proper treatment of all animals moving from infested states into the
southeast.

In Florida, the County Extension Director or Department of Agriculture
Inspector should be notified promptly of any suspected screwworm case in
livestock, pets, or wildlife.  Make a record of the infestation and save
samples of the eggs and maggots from the wounds.  Place the specimens in a
bottle or other small container filled with alcohol and send them to:

                          Division of Animal Industry
                               323 Fairview Road
                               Sebring, FL 33870

Treat wound with 1% Co-Ral, spray or dust.


Mosquitoes:

Several kinds of mosquitoes attack livestock.  They must have water in which
to breed.  Mosquitoes have piercing mouthparts and suck blood.
\h 1 'Mites'


                                     Mites

Different species of mange and scab mites attack horses, swine, cattle, and
sheep.  Included are Psoroptes, Sarcoptes, Chorioptes and Demodex mites.
These pests are too small to be seen with the naked eye.

They are both burrowing and surface feeders causing mange lesions through
severe skin irritations.
