132
Common Diseases of Young Calves
smaller and thinner than the female, measuring 6 to 10 inches in length and
1/6 to 1/5 inch in thickness. The female (Plate XII, fig. 8) has a straight tail
and measures 8 to 12 inches in thickness. The worm eggs (Plate XII, fig. 9)
are passed out in the faeces and under suitable conditions of temperature and
humidity embryos appear in them in about three weeks, after which they
are infective. On ingestion with contaminated food or drinking water the
larval worms are liberated in the digestive canal, thence enter the blood vessels
and reach the various organs, e.g. heart, lungs and liver. In about two weeks
from the time that they first enter the host they reach the digestive canal
a second time.
These parasites do not affect the health of the animal unless they are
numerous. Heavy infestation may result in chronic inflammation of the
intestine, and continued diarrhœa or diarrhœa and constipation may alter-
nate. The affected animals lose condition, appear dull and their coats become
dry and harsh. Their development is arrested and they become pot-bellied.
Occasionally the parasites may cause intestinal obstruction. The condition
can be diagnosed by the clinical symptoms, detection of the worm eggs in the
faeces and the parasite in the intestine on post-mortem examination.
The treatment of affected animals with ordinary vermicides, e.g. turpen-
tine oil (one ounce in about half a pint of linseed oil) gives quite satisfactory
results. This treatment should be followed in about 12 hours by a dose of
about 4 ounces of castor oil.
(iv) Intestinal infestation with tape worms.—The common tape worm
which infests the intestine of calves in India is Moniezia expansa (Plate XII,
fig. 11) measuring 3 to 20 feet in length and about half an inch in breadth.
The tape worm possesses a globular head, a narrow neck and a segmented body
in which each segment is a sexually complete individual possessing both male
and female organs. The terminal segments containing large number of eggs
constantly break off and are passed out with the faeces. Probably under
suitable conditions these eggs undergo further development for about two
months and become infective. Calves may get infected soon after birth and
the worm attains the adult stage inside the intestine in about six weeks' time.
When the parasites are present in small numbers no marked symptoms
may be observed but when they are in large numbers the animal appears dull,
the visible mucous membranes are pale and digestive disturbances set in.
Rumination becomes irregular. At first there is constipation but it is soon
followed by diarrhœa and mature segments of the parasites containing the
eggs are passed out in the faeces. There are indications of colic and the worst-
affected animals will follow the herd with difficulty. There is progressive
weakness and exhaustion and the affected calves remain stunted in their
growth. The condition can be definitely diagnosed by the detection of the
worm segments or eggs (Plate XII, fig. 10) in the faeces and the entire parasites
in the intestine on post-mortem examination.
A drug should be considered to have produced the desired effect only when
the heads of the parasites are passed out in the faeces and one should look for
these after a vermicide drench has been given. One per cent solution of copper
sulphate, as recommended in parasitic gastritis, also proves effective against