Mimeo Series No. 59-4
UNIVERSITY OF FLORIDA
AGRICULTURAL EXPERIMENT STATIONS
JOSEPH R. BECKENBACH, Director
INTERNAL PARASITES OF CATTLE, SHEEP AND GOATS
Leonard E. Swanson, Veterinary Parasitologis
Department of Veterinary Science
I. General Introduction
A. Parasitology is the science that deals with parasitism.
1. A parasite is an animal that lives upon or within another living
organism at whose expense it obtains nourishment and protection without
giving anything in return for this relationship.
2. Parasitism is the relationship between the host and parasite.
3. Helmii-'.h is a defined term for worms.
4. Helmi~chology is the study of worms.
5. Chemotherapy is the treatment of disease by administering chemicals
which effect the causative organism unfavorably but do not injure the
B. All animals are parasitized with one form or another of these helminths.
C. Wild animals are especially heavily parasitized and quite often serve as
reservoirs of infection for domestic animals.
II. Relationship of Parasites
A. Symbiosis The living together of two dissimilar organisms to the advantage
1. Mutualism is a form of symbiosis in which both symbionts are, in more
or less measure, benefited by the association.
2. Commensalism is a form of symbiosis in which one symbiont is benefited,
but its co-symbiont is neither benefited nor harmed.
3. Helotism is a form of symbiosis in which one organism enslaves the
B. In summary, a symbiont receiving the benefit is the parasite and the one
receiving the damage is the host.
III. Zooparasites are parasites which belong to the animal kingdom.
IV. Ectoparasites are those that are parasitic to the surface of the body.
V. Endoparasites are parasites which enter the body of the host, inhabiting the
alimentary canal, liver, lungs, blood and other tissue.
VI. The influence of parasites upon the host depends upon the number of parasites
present, location, the nature of their food, environmental conditions, and
age of the host. The effects of parasites on the host also depend on the
balance of minerals, vitamins and proper food intake.
VII. Parasites Injure the Host
A. Through mechanical injury such as biting and migration.
B. Through obstruction as in the case of a mass infection of lungworms
blocking the respiratory tract.
C. By injection of toxins such as occur in extreme hookworm infections.
D. Tissue feeding such as maggots.
E. Anaphylactic reaction extreme sensitivity to touch of ascarids.
VIII. Internal parasites of cattle fall into the following phylum and class
A. Phylum Platyhelminthes
1. Class Trematoda
a. Liver fluke (Fasciola hepatica)
2. Class Cestoda
a. Tapeworms (Moniezia expansa)
B. Phylum Nemathelminthes
1. Class Nematoda
a. Roundworms (Ascaris vitulorum)
IX. Internal parasites listed according to their location in the body
A. Bronchial tubes and lungs
a. Dictyocaulus viviparus (Cattle)
b. D. filaria (Sheep and goats)
c. Muellerius capillaris (Sheep and goats)
1. Liver flukes
a. Fasciola hepatica (Cattle, sheep and goats)
b. F. aegytlaca (Cattle, sheep and goats)
c. Fascioloides mgna (Cattle, sheep and goats)
C. Runen (Paunch)
1. Rumen flukes (Cattle only)
a. Paramphistomum cervi
b. Cotylophoron cotylophorum
D. Abomasum (True Stomach)
a. Haemonchus contortus (Cattle, sheep and goats)
2. Lesser stomach worm
a. Ostertagia ostertagi (Cattle and sheep)
b. 0. circumcincta (Sheep and goats)
3. Bankrupt worm
a. Trichostrongylus axei (Cattle, sheep and goats)
b. T. colubriformis (Cattle, sheep and goats)
E. Small Intestine
1. Threadworms (microscopic in size)
a. Cooperia spp. and Strongyloides spp. (Cattle, sheep and goats)
a. Bunostomum phlebotoman (Cattle)
b. B. trigonocephalum (Sheep and goats)
3. Threadworms macroscopicc in size)
a. Capillaria bovis (Cattle and sheep)
4. Threadnecked worm
a. Nematodirus spathiger (Cattle and sheep)
b. N. filicollis (Sheep)
c. N. helvetianus (Cattle)
a. Ascaris vitulorum (Cattle)
a. Monezia expansa (Cattle, sheep and goats)
b. M. benedeni (Cattle, sheep and goats)
F. Large Intestine
1. Nodular worm
a. Oesophagostomum radiatum (Cattle)
b. 0. columbianum (Sheep and goats)
a. Trichuris discolor (Cattle)
b. T. ovis (Sheep and goats)
3. Species of Coccidia (Protozoan)
b. Sheep and goats
E. auburnensis E. arloingi
E. alabamensis E. ah-sa-ta
E. subspherica E. crandallis
G. Skin and Body Cavities
1. Filaria usually causing summer sores. May be seen in or on any
part of the body, however, cattle navel is the common site.
I. Life Cycles
A. All parasites of the Nematoda class are what is termed as direct in-
fectors. No intermediate host is required, with the exception of
filariae, which require an intermediate host such as biting flies and
mosquitoes. The lungworm, Muellerius capillaris, life cycle is indirect
requiring snails and slugs as intermediate hosts.
1. Direct infectors depend on optimum moisture, temperature and vege-
tative 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 location in the host and reaches sexual maturity,
mates and begins laying eggs.
2. Filariae depend upon mosquitoes or biting insects to complete their
life cycle. The female wonns 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 micro-
scopic larvae, which further develop in the insect and at a subse-
quent blood meal are re-injected into another host animal.
B. All parasites belonging to the class Trematoda and class Cestoda 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 aoPi als. This stage in the
life cycle is known as the infective or encysted cercariae stage.
2. Tapeworms, of the class Cestoda, in cattle, sheep and goats 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 tapeworm 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.
C. Phylum Protozoa, class Sporozoa, 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. House-
flies, birds, rats and man, etc., may serve as mechanical means of trans-
porting this infection.
XI. Damage done to the host.
A. In general parasites must live congenially with their host in order to
produce their kind; however, if by accident, overcrowding, improper feed-
ing, overgrazing or unsanitary farm management practices, the animals
become excessively parasitized, they succumb to the ravages of the para-
sites. The above statement, however, is not true for the human tapeworm
as man (the host for the adult tapeworm) must eat the uncooked meat con-
taining the infective cyst, which is found in beef or pork muscle tissue.
B. Parasites, depending upon their location in the host and type of food re-
quired 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.
i. Internal parasite infection, whether it be in cattle or other
animals, cannot be seen in its protected home, wherever the loca-
tion 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 are utilized.
A. It is very difficult to describe the symptoms of parasite infections in
ruminant animals. Furthermore, in heavily infected herds there is
usually a mixed infection of the various parasites. Again, it is diffi-
cult to differentiate between the symptoms of parasitism, malnutrition
and mineral deficiency.
B. In general a parasitized animal is weak, emaciated, has a rough hair
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 animals may have a
profuse diarrhea which alternates with constipation. If hookworm in-
fection is heavy the fecal material will be black or blood tinged. In
strongyloides infection there is a profuse, foul smelling diarrhea inter-
mixed with diphtheritic membranes. In lungworm 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 continu-
ally licks its nose, and in later stages approaching death there is a
definite abdominal breathing and jugular pulse.
A. 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 in-
spection for the presence or absence of any parasites.
B. Whenever animals are slaughtered from the 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.
C. To diagnose parasitism in the living animal, take directly from the
animal approximately one-half pint of fecal material and place in a pint
jar or similar waterproof, clean container, and leave in the icebox over
night to chill. Mail this specimen to your local veterinarian or to the
Experiment 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 distinct 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
specimen 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.
A. Plant improved pastures, preferably of the taller growing grasses such
as pangola, torpedo, bahia, para, clover, etc. Low growing vegetation
such as carpet grass force animals to graze too closely to the earth.
Divide pastureE into small acreage and rotate cattle frequently, giving
the grasses an opportunity to develop, and in turn the cattle better
grazing. 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 parasites from
a given area. However, rotation of shorter 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.
A. Administer, either by bolus or drench, phenothiazine according 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 ;ust visibly sick animals, but treat all ani-
mals in that particular herd and repeat treatment in 21 days. Further-
more, it is advisable to continue this treatment in the fall and spring
each year, especially those animals under 18 months of age. (See
Circular S-78, Internal Parasites of Cattle, Their Control with Pheno-
thiazine and Management.)
B. Administer hexachloroethane, as a 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 hexa-
chloroethane treatment of cattle, drain your pastures, control water, and
treat all snail-infected areas with copper sulfate to destroy the inter-
mediate host snails. (See Bulletin 502, Liver Fluke Disease and Its
C. The combination of phenothiazine 10 grams per 100 pounds of body weight
and 10 grams hexachloroethane per 100 pounds of body weight may be given
simultaneously to all parasitized animals with very good results.
D. Piperazine, a new anthelmintic, may be given cattle, sheep and goats and
will add to the effectiveness of the drench. In addition, it will remove
the Cooperia spp. from the intestines. This chemical may be combined
with phenothiazine and hexachloroethane, or given alone in doses of 7.1
grams of anhydrous piperazine per 100 pounds of body weight.
E. Animals need not be fasted before treatment.
XVI. There are a number of parasites of cattle which are not removed by the above
drugs; 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, hookworms, tapeworms, and