P Veterinary Science Mimeograph August, 1954
Series No. 55-4
UNIVERSITY OF FLORIDA HUME LIBRARY
AGRICULTURAL EXPERIMENT STATIONS
WILLIARD M. FIFIELD, Director G 4
GAINESVILLE, FLORIDA AUG 4 1972
EXTERNAL AND INTERNAL PARASITES AFFECTING CATTLE
I.F.A.S. Univ. of Florida
Leonard E. Swanson
Florida, with an abundance of moisture, sunshine, vegetation, and
sandy or mucky lands, presents a paradise for parasites. Improved
pasture and increased numbers of cattle per acre of lands increase
II. EXTERNAL PARASITES
A. External parasites must be controlled for profitable animal pro-
duction, as many of these pests are blood suckers, few are irri-
tants or nuisances, and many others are transmitters of disease
such as anthrax, anaplasmosis, Texas fever, filariasis (skin or
body cavity parasites), encephalitis (brain fever), etc.
1. Horn flies-are blood suckers; live on animal all the time
except to deposit ova on fresh manure.
2. House flies are surface feeders, breeding in filth.
3. Stable flies are blood suckers, breeding in citrus and forage
4. Ticks are blood suckers; breed in woods.
5. Mosquitoes are blood suckers; breed in stagnant water.
6. Lice: five species spend entire life on animal blood
7. Horse and deer flies are severe biters; suck large amounts of
blood; breed in water.
8. Ox warbles (grubs) or heel flies are seasonal; damage the
hide; pester animals.
2. Spraying, dip or hand treatments.
a. Beef cattle.
(1) DDT wettable powder 8 pounds, and BHC 6 percent Gamma
isomer, 4 pounds to 100 gallons of water.
(2) Toxaphene wettable 40%, 10 pounds to 100 gallons
(3) Toxaphene 42.8% and lindane 1.7% emulsion, one gallon
to 100 gallons of water.
b. Dairy Cattle
(1) Methoxychlor (Marlate) 50% wettable, 8-3/4 pounds
to 100 gallons of water.
(2) As above 25 pounds if lice are also a problem,
(1) As for beef cattle.
(1) As for beef cattle except sponge animals.
e. If Ox warbles are a problem, add 8 pounds Derris or Cube powder
to any of above mixtures.
III. INTERNAL PARASITES
A. Internal parasites injure the host:
1. Through mechanical injury such as biting and migration.
2. Through obstruction as in the case of a mass infection
of lungworms blocking the respiratory tract.
3. By injection of toxins such as occur in extreme hookworm
4. By tissue feeding such as maggots.
5. Anaphylactic reaction extreme sensitivity to touch
B. Skins and Body Cavities.
1. Filaria usually causing summer sores. May be seen in or
on any part of the body; however, cattle navel region is
C. Life Cycles.
1. All parasites of the Nematoda class are what is termed as
direct infectors. No intermediate host is required, with
the exception of filariae, which require an intermediate
host such as biting flies and mosquitoes.
a. Direct infectors depend on optimum moisture, temperature
and vegetative conditions to complete their life cycle.
The eggs are passed out of the host animal in the
feces and hatch, liberating a minute larva. This
larva, after three molts, is known as the infective
stage, at which time it crawls upon blades of grass
and is eaten by the grazing animal. Upon reaching
the digestive tract the larva finds its suitable lo-
cation in the host and reaches sexual maturity,
mates and begins laying eggs.
b. Filariae depend upon mosquitoes or biting insects to
complete their life cycle. The female worms lay
their larvae in the host tissue. These larvae are
picked up and circulated in the blood stream and
transferred to a new host by insect vectors. The
vector, feeding on the infected animal and taking
its blood meal, sucks up the microscopic larvae,
which further develop in the insect and at a sub-
sequent blood meal are re-injected into another
D. All parasites belonging to the class Trematoda (flukes) and class
Cestoda (tapes) require an intermediate host.
1. Liver flukes, rumen flukes and others of the Trematoda class
require a fresh water snail to complete their life cycle.
The young flukes that hatch from the eggs burrow into the
soft tissue of snails, develop, and are liberated into water
as tadpole flukes. These young flukes swim around in water
and attach themselves to blades of grass and are subsequently
eaten by cattle. This stage in the life cycle is known as
the infective or encysted cercariae stage.
2. Tapeworms, of the class Cestoda, in cattle require as an
intermediate host a microscopic grass mite. The tapeworm
segments are passed in the fecal material to the ground.
The grass mites feeding in this material ingest the tape-
worm eggs. These eggs develop into the infective stage within
the body of the mites. The mites crawl on grass and are
eaten with the vegetation by animals normally grazing. Upon
reaching the digestive tract of the host, the infective stage
of the tapeworm is liberated and subsequently selects its
normal location in the small intestine where it reaches sexual
maturity and begins its life cycle over again.
E. Protozoa, commonly known as coccidia, are direct infectors. The
animal becomes infected by eating food or drinking water which has
become contaminated with the coccidia oocysts. Houseflies, birds,
rats and man, etc., may serve as mechanical means of transporting
F. Damage done to the host.
1. In general parasites must live congenially with their host
in order to produce their kind; however, if by accident,
overcrowding, improper feeding, overgrazing or unsanitary
farm management practices, the animal becomes excessively
parasitized, they succumb to the ravages of the parasites.
The above statement, however, is not true for the human
tapeworm, as man (the host for the adult tapeworm) must
eat the uncooked meat containing the infective cyst, which
is found in beef muscle tissue.
2. Parasites, depending upon their location in the host and
type of food required for their existence, injure the
animal by feeding on blood, bacteria, tissue, bile,
epithelium, lymph, or by mechanical blocking of the
essential physiological functions of the respective
organs or tissues of the body.
G. Parasites are protected.
1. Internal parasite infection, whether it be in cattle or
other animals, cannot be seen in its protected home,
wherever the location in the body may be. They may be
likened to a closed book; you do not know of their
presence or absence unless accurate methods of diagnosis
1. It is very difficult to describe the symptoms of parasite
infections in cattle. Furthermore, in heavily infected
herds there is usually a mixed infection of the various
parasites. Again, it is difficult to differentiate between
the symptoms of parasitism, malnutrition and mineral
2. In general a parasitized animal is weak, emaciated, has a
rough haLr coat and is anemic, as shown by paleness of the
mucous membranes of the eyes and mouth. Occasionally
there is an edematous swelling (bottle jaw) observed in
liver fluke, hookworm and stomach worm infection. It has
been further observed that these parasitized cattle may
have a profuse diarrhea which alternates with constipa-
tion. If hookworm infection is heavy, the fecal material
will be black or blood tinged. In strongyloides infection
there is a profuse, foul smelling diarrhea intermixed with
diphtheritic membranes. In lungwrm infection the symptoms
are very pronounced in that the animals cough when excited
or driven. The mouth is held open, the tongue protrudes,
the head hangs low, and a creamy-like nasal discharge
exudes from the nostrils. The calf continually licks its
nose, and in later stages approaching death there is a
definite abdominal breathing and jugular pulse.
1. The most accurate method of determining parasitism is to
sacrifice the suspected animal either by slaughter or field
autopsy. Open each and every organ of the respiratory and
digestive tract, making careful inspection for the presence
or absence of any parasites.
2. Whenever animals are slaughtered from your ranch it is
advisable to follow them to the packing house and to have
the veterinary inspector pay close attention to the organs
to determine the presence or absence of parasites. The
inspectors and packers are very cooperative and will gladly
render a report on the parasite findings in your animals.
3. To diagnose parasitism in the living animal, take directly
from the animal approximately 1/2 pint of fecal material
and place in a pint jar or similar waterproof, clean con-
tainer, and leave in the icebox overnight to chill. Mail
this specimen to your local veterinarian or to the Experi-
ment Station for diagnosis and recommendations. Portions
of these samples are examined microscopically for the presence
or absence of parasite eggs. Each parasite egg has a dis-
tinct shape and color and can be readily identified. In
taking samples it is advisable not to pick individual animals
but to take a cross-section of your herd. A negative speci-
men does not necessarily mean the animal is free of parasites,
but that the sample was free of parasitic infection. It is
advisable to make several periodic parasite checks to
determine the true picture in your herd. Observe your
animals closely for symptoms of parasitism.
i. Plant improved pastures, preferably of the taller growing
grasses such as pangola, torpedo, bahia, para, clover, etc.
Low growing vegetation such as carpet grass forces animals
to graze too closely to the earth. Divide pastures into
small acreage and rotate cattle frequently, giving the
grasses an opportunity to develop, and, in turn, better
grazing for the cattle. Provide clean drinking water from
concrete or iron troughs, controlling the flow by automatic
floats. It is entirely impractical to rotate pastures
sufficiently long to eliminate parasites from cattle, as it
takes from 10 to 12 months of nongrazing to eliminate para-
sites from a given area. However, rotation of short duration
is very beneficial. Provide feeds such as hay and protein
supplements for the winter when the grasses are low. Keep
before your animals at all times a balanced mineral ration
which is well protected from the weather. Avoid deep shade,
low wet areas; provide adequate drainage of muck pastures,
and cap or otherwise control artesian well flow. Do not
allow standing water in your pastures for a period of over
21 days, and, if necessary, drain with a V-type ditch.
1. Administer, either by bolus or drench, phenothiazine accord-
ing to the dose schedule which is found on the label of each
and every package. In general the dose of phenothiazine for
cattle is 10 grams per 100 pounds live weight. Do not treat
just visibly sick animals, but treat all animals in that
particular herd and repeat treatment in 21 days. Furthermore,
it is advisable to continue this treatment in the fall and
spring each year, especially those animals under 18 months
2. Administer hexachlorethane, as a fluke drench, in doses of
10 grams per 100 pounds live weight, to all animals in
herds where liver fluke infection is found. Repeat in
21 days as the drug does not destroy the immature flukes.
Repeat periodically, as "A" above. In conjunction with
hexachlorethane treatment of cattle, drain your pastures,
control water, and treat all snail-infested areas with
copper sulfate to destroy the intermediate host snails.
3. There are a number of parasites of cattle which are not
removed by the two drugs mentioned above; however, the
most pathogenic ones are removed, allowing the animals
to overcome the other infections. Research is in progress
to find drugs and methods to remove all parasites from the
animal without injury to the host. Parasites in this
group include lungworms, cooperia, hookworms, tapeworms,