Veterinary Science '-S"v
'4liimeo Series No. $9-2 7
LUNG-,OH! DISEASE OF CATTLE(
LEONARD E. SWANSON, Parasitologist
A. E. WADE, Research Asst. in Parasitology
Agric. Exp. Sta., Dept. Vet. Science
Univ. of Florida, Gainesville, Florida
Lungworm disease of cattle is caused oy a long, thin, white worm, tech-
nically known as Dictyocaulus viviparus. The life cycle is direct, no inter-
mediate host is required. The larvae are passed from the animal in the feces
and become infective to calves and adult animals by the fourth day. This parasitic
disease is very prevalent throughout Florida, especially where calves and older
cattle have access to muck lands, wet areas, deep shade, swamps, or drainages
from barns or corrals. In the areas mentioned above it is nearly impossible to
raise replacement dairy heifers. Beef calves from four months to yearlings suffer
frrom the ravages of this parasite. Adult cattle may also become infected. Many
dairymen have lost their entire calf crop, and beefmen have lost up to 30 percent
of their calf crop. The biggest loss, however, is not in the actual deaths buy
rather retarding the growth of animals.
HISTORY AND SYMPTOMS
Usually the owners will report that they weaned the best crop of calves
and all of a sudden the animals begin to go off feed and lose weight. The calves
will stand out from the herd. Coughing is very prevalent, especially if excited.
The bowel passages may be normal or the animal may be constipated, and many will
show diarrhea. The mouth may be held open with a pronounced abdominal type breath-
ing. Occasionally a calf will be seen with tongue protruding, ears droopy; glaasy
eye. A frothy creamy colored mucous will be noted running from the nostrils
or mouth and the infected calf continually licking its nose. When the
animal becomes too weak to eat or stand it goes down and dies, usually
without a struggle. Death is a result of suffocation, 1dck of dtxdation
of the -. ftbq, dehydration and strrv tion.
The blood is dark red. There is bilateral pleurisy (inflammation
of chest cavity), with straw colored fluids in the thoracic and abdominal
cavities. The entire carcass is emaciated, usually showing edematous
infiltration of the lymph glands, mesentery, momentum, heart and kidneys.
The trachea and bronchial tubes are filled with a yellowish-white frothy
exudate mixed with adult worms, embryonated ova and larvae. The bronchial
lymph glands are extremely large and gelatinous in appearance. There is
heavy congestion of the lung tissue with marked lobar pneumonia. The
bronchioles and trachea may be reddish in color but usually are clear.
LONGEVITY OF ADULT WOMS
Naturally infected calves will be free of lungworm larvae in from
60 to 180 days, depending upon the severity of infection. Adult bulls
and cows, when exposed to infected areas, will carry light loads, con-
stantly reinfecting the premises, yet they will show no symptoms of the
The larvae are recovered from the feces by means of a Baerman appara-
tus. Lungworm larvae in fecal samples varies from 1 to 1000 per gram
feces depending upon the severity of the infection. Four day old larvae
given to parasite-free calves by mouth were able to establish themselves
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in the lungs, and larvae were recovered in the feces of experimentally
infected animals in from 21 to 33 days. Embryonated ova ire found in the
bronchiole, whereas free larvae are found in the trachea, stomach and
small and large intestines. The larger numbers of larvae are found in
the caecum and rectum. The highest daily output (24 hours) of larva from
any one calf on test was 1,851,000.
LIFE HISTORY OF LUNGWORMS
The lungworms of cattle are direct infectors, the adult worms live
in the bronchioles and trachea of the animal, male and females mate, the
female lays her eggs which contain a larvae. The eggs hatch in the
trachea and/or digestive tract of the host. Those larvae or eggs which
are coughed up are swallowed, pass on out the animal with the ingesta to
the ground. Upon reaching the ground in feces and in the presence of
moisture, these larvae develop into infectious larval stages in four to
seven days. The infective larvae crawl upon blades of grass where they
are eaten by grazing animals. The larvae reach the lungs by way of the
lymph and vascular systems and reach sexual maturity within 21 to 33
days after taken into the body of the host.
OTHER PARASITIC INFECTIONS
All calves observed with natural infections of lungworms were also
carrying heavy burdens of stomach and intestinal parasites. A typical
parasite infection found on necropsy is as follows:
Number Location Kind
200 Stomach Haemonchus contortus Wireworms
8,600 Stomach Ostertagia patertag Threadworms
2,400 Stomach Trichostrongyius axei Tankrupt worms
10,o00 Small Intestine Strongyloides spp. Microscopic worms
Number Location Kind
53,900 Small Intestine Cooperia spp. Threadworms
100 Small Intestine Buonostomum thlebotomum Hookworms
787 Large Intestine Oesophagostomum radiatum Nodular worms
61 Large Intestine Trichuris discolor Whipworms
5,389 Bronchial tubes Dictyocaulus viviparus Lungworms
Other calves had like infections, although many were more fortunate
and carried only light infections of the stomach and intestinal parasites.
One hears many suggestions and sees many writings on the control of
lungworms in calves. Good feeds, protection from adverse weather condit-
ions, and removing animals from low, wet, shady places are recommended.
Good management practices arei
o1 Creep feed the calves during their nursing or milk feeding
period to promote growth and to prevent the shock from sudden
change of feeds.
2. Rotate pastures frequently and do not allow animals to crop
grasses too close to the earth.
3. Use heavy muck lands and deep shaded areas for fattening older
cattle intended for slaughter.
4. Place dairy calves above barns or older cattle yards and on
well drained areas.
5. Segregate age and sex groups.
6. Remove visibly sick animals from the herd.
7. Infected calves should be placed on high, dry areas, given free
access to good hay, concentrates and minerals, and if available,
citrus or sugar cane molasses. All feeding should be done from
racks or bunkers. DO NOT FEED ON GROUND. Have your calves checked
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for parasites periodically, especially for stomach and intestinal worms.
8. Treat all infected calves with the therapeutic dosages of pheno-
thiazine, and repeat the dosage in 21 days. If necessary, con-
tinue the dosing every 21 days until stomach and intestinal para-
sites are reduced and calves show improvement. This method will
eliminate most stomach and intestinal parasites, giving the calf
an opportunity to throw off the lungworm infections. If calves
are not treated and properly fed as outlined, they will die
from parasite infections.
TREATMENT FOR REMOVAL OF LUNGWORMS
All attempts to remove these worms from the lungs of calves have
failed. Various drugs administered directly into the lungs by inhal-
ation, hypodermically or by mouth were ineffective.
Experiments are in progress studying the means of destroying the
adult parasites in the lungs, the larvae in the feces and of producing
immunity in calves.