occurrence in various kinds of animals besides cattle, complete eradication
is a difficult problem. The only effective treatment known is to introduce
directly into the ear passages a remedy that will kill the ticks. Later, of
course, the cattle may become reinfested from exposure to infested ranges
or inclosures. The following mixture, however, in addition to killing the
ticks in the ears, will protect against reinfestation for about 30 days:
Ordinary commercial pine tar, two parts; cottonseed oil, one part--in each
case by volume. Animals to be treated are confined in a chute, and the
mixture is injected into the ears with a syringe, after the wax and other
dÈbris in the ears have been cleaned out with a wire probe that has an
eyelet at one end. Further information concerning ear ticks and the details
of their treatment is given in Farmers' Bulletin 980.
BLOODSUCKERS OR LEECHES.
These worms are sometimes taken up by cattle when drinking from ponds. They
may attach themselves to the inner surface of the mouth or nose, and
sometimes reach the upper part of the windpipe or of the gullet. Bleeding
at the mouth or nose may be noticed, the membranes where the leech is
attached are liable to be swollen and congested, and as a result of the
loss of blood a condition of anemia may result.
_Treatment._--If the worm can be reached it may be destroyed by cutting it
in two with a pair of scissors, or it may be removed with forceps or with
the fingers after wrapping a towel around the hand so that the worm can be
held without slipping. Fumigation with tobacco or tar may cause the worm to
release its hold if it can not be removed by other means. Ponds may be rid
of infestation with bloodsuckers by the introduction of eels.
PARASITES OF THE STOMACH.
The stomach of cattle consists of four compartments, of which the first and
fourth are most likely to be the seat of parasitic infestation. The first
stomach, or paunch, contains large numbers of minute parasites known as
protozoa, which are too small to be seen with the naked eye. These small
organisms apparently are in no way injurious. A species of fluke
(_Paramphistomum cervi_ or a closely related species) is occasionally found
in North American cattle, especially grass-fed cattle, attached to the
inner surface of the first stomach (fig. 12). This worm is about one-half
inch long, and somewhat conical in shape; hence the name, conical fluke, by
which it is sometimes known. Although this parasite has been accused of
producing serious effects, it is generally considered harmless.
Several species of roundworms may occur in the fourth stomach. Two of these
are of special importance.
[Illustration: FIG. 12.--Portion of the wall of the first stomach with
conical flukes attached.]
THE TWISTED STOMACH WORM (H∆MONCHUS CONTORTUS).
The twisted stomach worm (_HÊmonchus contortus_, figs. 13, 14, 15) is
sometimes found in enormous numbers in the fourth stomach of cattle. Sheep,
goats, and other ruminants may also be infested with it. Among the symptoms
caused by this parasite may be mentioned anemia, loss of flesh, general
weakness, dullness, capricious appetite, excessive thirst, and diarrhea.
The anemic condition is seen in the paleness of the skin and mucous
membranes of the mouth and eye, and in the watery swellings which often
develop under the lower jaw ("poverty jaw"). If the fourth stomach of a
dead animal is cut open and the contents carefully examined, the parasites,
which are from 1/2 inch to 1-1/4 inches in length and about as thick as an
ordinary pin, may be seen, if present in any considerable number, actively
wriggling about like little snakes.
Cattle become infected with these parasites by grazing on pastures on which
infested cattle, sheep, or goats have grazed and scattered their droppings.
The worms in the stomach produce a multitude of eggs (fig. 14_c_) of
microscopic size, which pass out of the body in the feces. In warm weather
these eggs hatch in a few hours. If the temperature is below 40∞ F., they
remain dormant, and if below freezing, they soon die. The eggs are also
killed by dryness; moisture, on the other hand, favoring their development.
The larvÊ which hatch from the eggs are microscopic in size, and, like the
eggs, are, at first and until they have developed to a certain stage, very
susceptible to freezing and drying. In very warm weather the larvÊ complete
their development, so far as they are able to develop outside the body, in
two or three days. In cooler weather the time required for this development
is longer, and at temperatures below 70∞ F. 10 days to several weeks may be
necessary. The larvÊ are then ready to be taken into the body. The eggs and
early stages of the larvÊ apparently do not develop if swallowed, and only
the completed larval stage seems to be infectious. In this stage the larvÊ
migrate up grass stalks (fig. 15) or other objects, showing activity
whenever the air is saturated with moisture; that is, during rains, fogs,
and dews. When the air becomes dry and the moisture evaporates from the
grass the young worms cease their activity, resuming their migrations when
the air again becomes overladen with moisture. LarvÊ which have developed
to the infectious stage, unlike the eggs and early larval stages, are able
to survive long periods of freezing and dryness. In two weeks to a month
after the embryos are swallowed they reach maturity and begin producing
eggs.
_Preventive treatment._--Preventive measures are important. As moisture
favors the development of the embryos, high sloping ground is preferable
for pastures. If low ground is used, it should be properly drained. The
pasture should not be overstocked. Burning over the pasture will destroy
most of the young worms on the grass and on the ground, and this means of
disinfection under certain circumstances may be very advantageously used.
The herd should be changed to fresh pasture as often as possible. Cattle
should be supplied with water from wells, springs, or flowing streams,
preferably in tanks or troughs raised above the ground. To a slight degree
salt serves to protect cattle against infection with internal parasites,
and plenty of it should therefore be kept accessible.
Affected animals should be isolated from the rest of the herd in hospital
pens or pastures. A plentiful supply of nourishing feed is an important
factor in enabling cattle to withstand the attacks of stomach worms and
other intestinal parasites. The stabling of cattle, with the maintenance of
clean and sanitary surroundings and liberal feeding, will often stop losses
from internal parasites, even though no medicinal treatment is given.
_Medicinal treatment._--In dosing animals for stomach worms it is advisable
to treat not only the animals which are seriously affected, but the rest of
the herd as well, since the parasites with which they are infested will
remain as a source of reinfection to the others. The cattle should be
removed to fresh pasture after treatment, if possible.
The animals to be treated should be deprived of feed for 12 to 16, or even
24, hours before they are dosed, and if the bluestone treatment is used
should receive no water on the day they are dosed until several hours after
dosing. In drenching, a long-necked bottle or a drenching tube may be used.
In case the former is used the dose to be given may be first measured off,
poured into the bottle, and the point marked on the outside with a file, so
that subsequent doses may be measured in the bottle itself. A simple form
of drenching tube (fig. 16) consists of a piece of rubber tubing about 3
feet long and one-half inch in diameter, with an ordinary tin funnel
inserted in one end and a piece of brass or iron tubing 4 to 6 inches long,
of suitable diameter, inserted in the other end. In use the metal tube is
placed in the animal's mouth between the back teeth, and the dose is poured
into the funnel, which is either held by an assistant or fastened to a
post. The flow of liquid through the tube is controlled by pinching the
rubber tubing near the point of union with the metal tube. It is important
not to raise the animal's head too high on account of the danger of the
dose entering the lungs. The nose should not be raised higher than the
level of the eyes. The animal may be dosed either standing on all fours or
lying on the side.
The position on all fours is preferred by some authorities, who believe
that more of the remedy is likely to reach the fourth stomach when the
animal is dosed standing than when dosed in other positions.
Great care should be used in dosing to prevent the entrance of the liquid
into the lungs, and in the preparation and administration of the remedy to
avoid getting the solution too strong or the dose too large.
Bluestone, or copper sulphate, has been extensively used in South Africa in
the treatment of sheep and cattle for stomach worms and is recommended by
the colonial veterinary surgeon of the Cape Colony as the best and safest
remedy. To prepare the solution take 1 pound (avoirdupois) of pure
bluestone, powder it fine, and dissolve in 9-1/2 gallons of warm water. It
is better first to dissolve the bluestone in 2 or 3 quarts of boiling
water, then add the remaining quantity of cold water, and mix thoroughly.
This solution may be given to cattle in the following-sized doses:
Calves 3-1/2 to 4 fluid ounces.
Yearlings 6 fluid ounces.
Two-year-olds and over 12 to 16 fluid ounces.
In making up the solution only clear blue crystals of bluestone should be
used. Bluestone with white patches or crusts should be rejected. It is
especially important that the bluestone and water be accurately weighed and
measured, and that the size of the dose be graduated according to the age
of the animal.
The special value of medicated salts advertised under various trade names
as preventives against worms is problematical. Commonly they contain little
else than ordinary salt, the other substances being in such small quantity
that their therapeutic effect is practically negligible. Definite evidence
that they are more efficacious than plain salt is not yet available and
their use is not recommended.
[Illustration: FIG. 13.--Twisted stomach worms (_HÊmonchus contortus_).
Outlines showing natural size of male (above) and female.]
[Illustration: FIG. 14.--Twisted stomach worms (_HÊmonchus contortus_).
Male (_a_), female (_b_), and egg (_c_). Enlarged.]
[Illustration: FIG. 15.--Larva of twisted stomach worm (_HÊmonchus
contortus_) coiled on tip of grass blade. Enlarged.]
[Illustration: FIG. 16.--A drenching tube made from an ordinary tin
funnel, a piece of rubber hose, and a piece of brass pipe.]
THE ENCYSTED STOMACH WORM (OSTERTAGIA OSTERTAGI).
This parasite is as thick as a fine hair and less than half an inch in
length. It lives in small cysts in the wall of the fourth stomach (fig. 17)
and is also found free in the cavity of the stomach. When numerous, these
parasites cause a thickening of the stomach wall and disturb its digestive
functions. The symptoms caused by this parasite are very similar to those
produced by the twisted stomach worm. The life history of the encysted
stomach worm is not known in detail, but it is undoubtedly very much the
same as that of the twisted stomach worm. The same measures as recommended
above for preventing infection with the twisted stomach worm should be
used. Medicinal treatment would seem to be of little use, owing to the
protected position in which the parasite occurs.
[Illustration: FIG. 17.--Piece of lining of fourth stomach, showing
cysts of the encysted stomach worm (_Ostertagia ostertagi_).]
INTESTINAL PARASITES.
TAPEWORMS.
Two species of tapeworms (fig. 18) are known to occur in the small
intestine of American cattle. They sometimes grow to a length of several
yards and to a breadth of three-fourths of an inch. Small portions of
tapeworms, consisting of one or more segments, are occasionally seen in the
droppings of infested cattle. The life history is not known, but the
infectious stage is undoubtedly taken in with the feed or water, infection
being spread by the eggs of the parasite contained in the feces of infested
animals. The eggs are perhaps swallowed by some small creature (an insect,
worm, or snail) which acts as an intermediate host, and which when
accidentally swallowed by a cow while grazing or drinking carries with it
into her stomach the infectious stage of the tapeworm.
Adult cattle do not seem to suffer much from infestation with tapeworms,
but in calves these parasites may cause scouring and emaciation.
_Treatment._--Medicinal treatment for tapeworms in cattle is usually
unsatisfactory, but the bluestone treatment used for stomach worms and
mentioned above (p. 522) sometimes expels tapeworms. Arsenic in doses of
1-1/2 to 3 grains has been claimed to give good results in the treatment of
calves for tapeworms. From results obtained at the Oklahoma Experiment
Station in the treatment of tapeworms of sheep it would appear that the
efficacy of the bluestone treatment against these parasites may be
increased by the addition of tobacco. For use on cattle the bluestone and
tobacco mixture may be prepared as follows: 13 ounces of snuff or powdered
tobacco is soaked over night in about 8 gallons of water. To this decoction
is added 1 pound of copper sulphate which has been dissolved in 2 or 3
quarts of boiling water. Sufficient water is then added to the mixture to
make a total of 9-1/2 gallons. The doses of this solution are the same as
for the simple copper sulphate solution, described on page 522, namely:
Calves 3-1/2 to 4 fluid ounces.
Yearlings 6 fluid ounces.
Two-year-olds and over 12 to 16 fluid ounces.
[Illustration: FIG. 18.--A tapeworm (_Moniezia planissima_) which
infests cattle.]
ROUNDWORMS.
A large roundworm (_Ascaris vitulorum_) measuring 6 to 12 inches in length,
sometimes found in the intestines of cattle, especially calves, may cause
inflammation and occasionally rupture of the intestine. Infection occurs
through the swallowing of the eggs of the parasite in feed or water which
has been contaminated with the feces of infested cattle.
A number of species of small roundworms, varying in size from an eighth of
an inch to an inch or more in length, occur in the intestines. Of these may
be mentioned the hookworm (_Bunostomum phlebotomum_) and the nodular worm
(_[OE]sophagostomum radiatum_). The former is about an inch long and is found
in the small intestine. The latter is somewhat smaller and is found in the
cecum and large intestine. Hookworms, when numerous, may cause anemia and
other symptoms similar to those caused by stomach worms (see p. 519). The
injury to the mucous lining of the intestine from the bites of hookworms
may cause severe inflammation, and affords an avenue of infection with the
germs of various diseases. The adult nodular worms apparently do not attack
the wall of the intestine, but derive their nourishment from the intestinal
contents. Several species of small, very slender roundworms
(_Trichostrongylus_), less than a quarter of an inch in length, sometimes
occur in the small intestine and fourth stomach, and a severe
gastroenteritis, or inflammation of the stomach and intestines, has been
attributed to them. One species of small roundworm (_Cooperia punctata_)
burrows in the wall of the small intestine and causes caseous nodules in
the mucous lining. This parasite sometimes occurs in very large numbers in
the intestines of cattle in certain sections of the country, and apparently
does considerable damage.
_Nodular disease_ of the intestine, due to young nodular worms which burrow
in the intestinal wall during a certain stage in their life history,
sometimes apparently produces serious effects, particularly in young
cattle, but commonly has little or no perceptible influence on the general
health. It, however, often renders the intestine unfit for use as sausage
casings, and as it is widely prevalent among cattle the loss from this
source is considerable. The greenish or yellowish nodules with cheesy
contents are frequently mistaken by the inexperienced for lesions of
tuberculosis.
The life histories of the various small roundworms occurring in the
intestines of cattle, so far as they have been worked out, are very similar
to that of the twisted stomach worm as described on page 519.
_Treatment for intestinal roundworms._--The preventive measures are similar
to those recommended in the case of the twisted stomach worm (p. 521).
Medical treatment is generally not very satisfactory. According to the
Oklahoma Experiment Station, the addition of 1 per cent of tobacco to the
bluestone solution used in the treatment of stomach worms in sheep is
effective in the removal of hookworms. The bluestone and tobacco mixture
described on page 524 may be of value in the treatment of hookworms in
cattle. It is asserted by one author that 2 or 3 drams of rectified
empyreumatic oil in a mucilaginous emulsion, followed the next morning with
a purgative of 1 to 1-1/2 pounds of sulphate of soda, will expel the large
roundworms (_Ascaris vitulorum_).
PROTOZOA.
A number of species of protozoa have been reported as parasites of the
intestines of cattle. To one species has been attributed a serious disease
of cattle in Switzerland known as red dysentery, but so far comparatively
few cases of this disease have been recorded in America. It is probably
more common than is generally supposed. Calves particularly seem most
likely to be affected.
FLUKES IN LIVER AND LUNGS.
Two species of flukes occurring in the liver and lungs are known to affect
cattle in the United States. These parasites are flat, leaf-like worms;
one of them, the common liver fluke (_Fasciola hepatica_, fig. 19), is less
than an inch in length, while the other, the large American fluke
(_Fasciola magna_, fig. 20), is considerably larger when full grown. In
their life history these flukes depend on snails as intermediate hosts. At
a certain stage of development the young flukes leave the snails, become
encysted on stalks of grass (fig. 21), or fall into drinking water, and
finally may be swallowed by cattle. Stiles writes as follows:
Flukes may produce a serious, often fatal, disease, more especially in
younger animals. The symptoms are somewhat similar to those produced by
worms in the stomach. The first symptoms are generally overlooked, the
disease not attracting attention until the appetite is diminished;
rumination becomes irregular, the animals become hidebound, and the coat
dull and staring. The staring coat is due to the contraction of the
muscles of the hair follicles. The visible mucous membranes become pale,
eyes become dull, there is running at the eyes, and the animal gradually
becomes emaciated. As the disease advances the milk supply is lessened,
fever appears, there is generally great thirst, but the appetite almost
ceases; edematous swellings appear on the belly, breast, etc.; diarrhea
at first alternates with constipation, but finally becomes continuous.
The disease lasts from two to five months, when the most extreme cases
succumb.
Most of the German cattle are said to be infested with liver flukes, but
even when a large number are present the nourishment of the cattle is
not disturbed. Thickening of the gall ducts, so that a so-called
"Medusa's head" forms on the surface of the liver toward the stomach,
appears in even well-nourished animals; even in cases of a cirrhosis of
the liver it is seldom that any effect upon the cattle's health can be
noticed, and so long as a portion of the liver tissue about twice the
size of the fist remains intact, the nourishment of the animal may be
comparatively good. It is rare that one sees a generalized edema in
slaughtered cattle as a result of fluke invasion, and even in the
heaviest infections of young cattle only emaciation is noticed.
_Treatment._--Medicinal treatment is unsatisfactory. The disease may be
prevented to a considerable extent by giving animals plenty of salt,
and by introducing carp, frogs, and toads into infected districts;
these animals destroy the young stages of the parasite and feed upon
the snails which serve as intermediate hosts.
The drainage of wet pastures and the avoidance of swampy lands for grazing
purposes are important measures in the prevention of fluke diseases.
Railliet and others have recently recommended the application of lime to
fluky pastures, having discovered that very weak solutions are destructive
not only to fluke embryos but to snails. This application is to be made
during the summer months at the rate of about 500 to 1,000 pounds of lime
per acre. The same authors also recommend extract of male fern for the
treatment of fluke disease. Moussu states that the average dose for cattle
is 1 gram of the extract for each 10 kilograms of live weight; that is, 10
grams for a young animal weighing 100 kilograms (about 220 pounds) up to
50 grams as a maximum for large animals weighing 500 kilograms (about
1,100 pounds) or more. The extract is mixed with about 5 times as much
non-purgative oil and the dose is administered each morning for five
consecutive days two hours before the animal is allowed to feed after
having been fasted over night. The extract of male fern used should have a
guaranteed strength of 22 to 25 per cent of filicine and 3.5 per cent of
filicic acid.
[Illustration: FIG. 19.--The common liver fluke (_Fasciola hepatica_).]
[Illustration: FIG. 20.--The large American fluke (_Fasciola magna_).]
[Illustration: FIG. 21.--Portion of grass stalk bearing three encysted
cercariÊ of the common liver fluke (_Fasciola hepatica_). Enlarged.]
TAPEWORM CYSTS OF LIVER AND OTHER VISCERA.
Three kinds of tapeworm cysts are found in the viscera of cattle. One of
these (_Multiceps multiceps_, or _C[oe]nurus cerebralis_) will be further
referred to in the discussion of gid (p. 528). All these are the
intermediate stages of tapeworms, which live when mature in the intestines
of dogs, wolves, and other canines. The eggs of the tapeworms are scattered
over the fields in the droppings of infested dogs or wolves, and when
swallowed in food or water by cattle hatch out and the embryos migrate to
the liver, mesentery, lungs, brain, or other organs, where they develop
into cysts, variously known as hydatids, bladder worms, water balls, etc.
When organs of cattle thus infested are eaten by dogs or wolves the cystic
worms are also liable to be swallowed and then develop into mature
tapeworms. To prevent cattle from infection with these parasites stray
dogs, wolves, and coyotes should be killed wherever found, and dogs too
valuable to kill should be kept free from tapeworms. As a precaution
against infection with tapeworms, the viscera of cattle, sheep, or hogs
should not be fed to dogs unless cooked.
HYDATIDS (_Echinococcus granulosus_) form tumors (fig. 22) of varying size
(sometimes as large as 6 inches in diameter) in the liver, lungs, and other
organs. Their contents are liquid, resembling water. The presence of these
parasites can not be detected in the living animal and there is no
medicinal treatment for them. Organs containing hydatids should be
destroyed by burning in order to prevent their being eaten by dogs. This is
especially important, as dogs infested with the tapeworm stage of this
parasite are a menace to human beings on account of the danger of infecting
them with hydatids, which develop in man if the eggs of the hydatid
tapeworm are swallowed.
THIN-NECKED BLADDER WORMS (_TÊnia hydatigena_, fig. 23) are most commonly
found attached to the mesentery and omentum. There is no medicinal
treatment.
GID.--Bladder worms (_Multiceps multiceps_, or _C[oe]nurus cerebralis_),
which are occasionally found in the brain of cattle and cause gid,
"turnsick," or "staggers," deserve mention, as they are rather common among
sheep in the Northwest. As already alluded to, these worms are the
intermediate stage of a tapeworm found in dogs, and their life history and
the means of preventing infection have been briefly discussed above (see p.
527).