The prevention of roundworms in pigs

Historic, archived document

Do not assume content reflects current
scientific knowledge, policies, or practices.

Issued May 1927; Revised March 1935
Slightly revised December 1946

- % PREVENTION of

ROUNDWORMS PIGS

B-H- RANSOM” CHIEF, ZOOLOGICAL DIVISION
BUREAU OF ANIMAL INDUSTRY

LEAFLET ee oe NUMBER 5

UNITED STATES DEPARTMENT OF AGRICULTURE

CONTENTS
Page | Page
Damage done by worms________.__=__-- 1 Permanent hog lots dangerous_______ eee 7
pourcesioh infection» 25 — 0 au 2 Skim-milk diet supplements sanitation - 7
Development of a system for prevent- Benefits from the system_______._______ 7
ines iniechion = =o eee 3 Summary of the swine - sanitation
The swine-sanitation system____________ 4 SVSUCIINS Sim bk OE PS ae hoe Sie Rete 8

Damage Done by Worms

The common intestinal roundworm or ascarid? is one of the most
injurious of the various kinds of parasites that infest the pig. It
causes digestive troubles, retards growth and development, and in
other ways interferes with the well-being of pigs, especially the
younger animals. Furthermore, scientific investigations have shown
that this parasite can cause a great deal of damage otherwise than
merely as an intestinal parasite. In its early stages of development
in the pig, and while still too small to be seen by the naked eye, the
worm travels in the blood stream from the intestine to the lungs and
then back to the intestine by way of the windpipe and esophagus.
This curious journey (fig. 1) requires about 10 days for its comple-
tion, after which the young worm settles down in the intestine and
grows to maturity in about 214 months. If many of the young
worms take this trip at the same time, as often happens, the injury
that results is liable to be serious.

When the lungs of a young pig are thus invaded by numerous
young worms, the pig often shows symptoms commonly known as
thumps, and may die of pneumonia. Probably most of the cases
of thumps in little pigs are caused by worm infection, though the
characteristic thumping cough in young pigs has sometimes been
attributed by some hogmen to an overfat condition, or cold weather
with resulting lack of exercise. Pigs that survive a severe invasion
of the lungs by the young worms frequently do not recover fully
and fail to grow and develop at a normal rate. Bacterial compli-

1 Died Sept. 17, 1925. This is a revision by M. C. Hall and H. B. Raffensperger of a
mimeographed article by Doctor Ransom issued by the Bureau of Animal Industry July 1,
1921. The revision incorporates some minor additions which are regarded as desirable in
the light of later developments.

2 Ascaris lumbricoides or Ascaris suum.

695896 O - 46 1

2 LEAFLET NO, 5, U. S. DEPARTMENT OF AGRICULTURE
cations, often with pus production, sometimes follow the invasion
of the lungs by the young worms, and these infections share the
responsibility for stunted growth of pigs.

Investigations and experiments have also shown that pigs are most
susceptible to infection and suffer most seriously from the infection
during the first few weeks of life. As they grow older they become
more resistant, have fewer worms, and suffer less from both the young
worms in the lungs and the older ones in the intestine. Little pigs,
therefore, require special protection.

Sources of Infection

Pigs become infected by swallowing the eggs of the parasite.
_ These worm eggs are of microscopic size and are found in the manure

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Fic. 1.—The course traveled by the roundworm in the pig. The worm eggs are swal-
lowed by the pig and hatch in the intestines; the young worms go by way of the
blood vessels to the liver and then to the lungs; here they leave the blood vessels
and enter the air passages; go up the windpipe to the mouth and are swallowed;
return to the intestines where they develop to adult worms; and the female worms
produce eggs which pass out in the manure and start a new journey through the
pig which swallows them

of infested hogs or on and in the soil of places that have been occu-
pied by infested hogs and hence contaminated by their droppings.
It has been estimated that one full-grown female worm in the intes-
tine of a hog may contain as many as 26,000,000 to 27,000,000 eggs.
At the time they are passed out of the body of the hog in the drop-
pings the eggs are not infective. But in a few weeks or months,
depending on the weather and various other conditions, the egg
develops to a stage at which it contains a tiny worm, and it is then
ready to infect the pig which swallows it. The eggs are very resist-
ant to cold weather and drought; they are not killed by most chemical
disinfectants, and are very long-lived (some may live as long as five
years). Not all adult hogs harbor intestinal worms, even though ex-
posed to infested soil; commonly, however, the parasites may be
found in one out of three hogs of breeding age. Worms which can not
be distinguished from the swine ascarid are also not uncommon in

PREVENTION OF ROUNDWORMS IN PIGS 3

human beings, especially children, in some localities. It is still a
debatable point whether swine ascarids can develop to maturity in
man, or vice versa, either regularly or occasionally, but both go
through the lung-invading stage in man and swine.

From the foregoing it is evident that the soil of places occupied by
hogs is likely to be heavily laden with the eggs of intestinal worms,
and it is readily understood, in view of their food habits, how pigs
kept in such places may become infested with large numbers of the
) worms. Worm-infested places (fig. 2) are especially dangerous for
| young pigs. It is largely on account of worm infestations that so
many young pigs are lost or fail to grow properly when reared
under ordinary methods of hog management. Unthriftiness usually
is caused by poor breeding, poor feeding, or parasites, and if the
first two factors can be ruled out, the trouble is probably caused by
parasites. (Fig. 3.)

Fic. 2A dirty hog lot, a paradise for worms and a source from which susceptible
ae pigs may pick up worm eggs directly or by transfer from the skins and udders
of the sows

Development of a System for Preventing Infection

On the basis of the results obtained from laboratory study and

- experiments on a small scale a system of raising pigs to avoid worm
infestation, or at least to reduce the infestation to a point at which
it will cause little or no damage, has been worked out by the Bureau
of Animal Industry. Through the cooperation of the farm bureau
and public-spirited hog raisers of McLean County, IIl., this system
was carefully tested on a considerable number of farms in that
county for seven years. The results of these tests were so successful
from the start that the use of this system has spread rapidly and con-
tinues to spread. It is now widely used, especially in the Middle
West. Because it was first developed in McLean County it has
been called the McLean County system of swine sanitation. The
system not only prevents losses from worms, but also more or less
erably prevents various diseases that may be termed filth dis-
eases, such as bullnose, sore mouth, and certain forms of diarrhea.

4 LEAFLET NO. 5, U. S. DEPARTMENT OF AGRICULTURE

It is not to be depended on as a preventive of hog cholera and, even
though this system is followed, hog-cholera immunization should
still be continued in accordance with approved methods of hog-
cholera control.

The Swine-Sanitation System

Essentially the swine-sanitation system consists in handling young
pigs from the time of birth until they are several months old in a
manner that avoids or reduces to a minimum the chances of infection
with worms, or, in other words, that keeps young pigs entirely away
from old hog lots or other places exposed to fecal contamination.

Fie. 3.—Two pigs of about the same age. The one in front is the typical runt, show-
ing the effects of worm infestation and other troubles caused by dirty hog lots.
The other pig is normal and healthy

Spring Pigs
Farrowing Pens

Before farrowing time the farrowing pens, which should be of
sanitary construction, are thoroughly cleaned. (Fig. 4.) All litter
is removed, and the concrete and wooden floors, troughs, guard rails,
and sides of the pens are thoroughly scrubbed with boiling water and
lye. The heat of the water (if applied liberally and very hot) is
destructive to worm eggs and the lye helps to remove the dirt. The
indoor pens are shut off from the outside pens, which are commonly
built in connection with permanent hog houses, unless these outside
pens are of sanitary construction with concrete or wooden floors and
are thoroughly cleaned before the sows and pigs have access to them.
If the building is not artificially heated, the cleaning should be done in
the fall before freezing weather, as it may be found almost impossible
to clean the pens properly during the cold weather of early spring or
late winter.

Sows

The sows are placed in the clean pens a few days before farrowing
but not until the mud and dirt on their skins have been removed.

PREVENTION OF ROUNDWORMS IN PIGS 5

The udders particularly should be well washed with soap and water,
and the feet should not be neglected. If this precaution of cleaning
the skin of the sows is not taken they are likely to carry with them
into the farrowing pens a multitude of worm eggs and other disease
aad found in the soil of the hog yards, so that even with the first
ew mouthfuls of milk the newborn pigs may swallow: hundreds or
possibly thousands of worm eggs and germs of disease. It has been
found advantageous to oil the sow two or three days before farrowing
as a control measure for mange and lice infestation. This is accom-
plished by hand applications of crude petroleum or crank-case oil.
Further information on the control of swine parasites may be found
in Farmers’ Bulletin 1085, Hog Lice and Hog Mange.®
After farrowing, the sow and pigs are not allowed out of the
farrowing pen until they are taken to pasture for which previous

Fic. 4.—Cleaning the farrowing pen.. This is a matter calling for a shovel, broom or
brush, plenty of hot water, soap and lye, and vigorous work

arrangements have been made. The sow and her litter, in from a
few days to two weeks after farrowing, are moved to pasture by
means of a barnyard “Pullman” consisting of a double crate on
a sled which may be backed up to the door of the pen and hauled
away. (Fig. 5.) The lower compartment of the crate is for the
sow, the upper is for the pigs. 3

Pastures

A special pasture for the sows and young pigs is provided. This
should not be a permanent pasture which has been much used by
hogs and thereby more or less badly contaminated by their drop-
pings, but a field that has been under cultivation and sown at. the

SImMES, M. HOG LICH AND HOG MANGE. METHODS OF CONTROL AND ERADICATION, U. S,
Dept. Agr. Farmers’ Bul. 1085, 28 p., illus. 1920.

6 LEAFLET NO. 5, U. S. DEPARTMENT OF AGRICULTURE

roper time to a suitable forage crop. Legume pastures available
in the normal course of crop rotation may be utilized, devoting a
different field each year to this purpose. Individual shelter houses
for each sow and her litter should be provided in the pasture, thus
tending to keep the various sows and their litters separate. Though
one house for all the sows and pigs may be used, this is not so
desirable, as it tends to concentrate any infection that may be present
in any animal. Water is supplied by piping or by tanks replenished
by hauling water to them. No other hogs should have access to this
pasture, nor should the pigs be allowed to run back from the pasture
to the barn lot or hog yards. If the latter recommendation is
strictly followed, lung-worm infestation will be greatly reduced, if
not aleagerliel eliminated. They are thus kept away from the
contaminated places until they are at least 4 months old, or until
they weigh about 100 pounds, after which they are not very liable

Fie. 5.—A barnyard Pullman consisting of a crate for hauling the sow and little
pigs from the farrowing pen to the pasture. The crate is a double-deck affair; the
sow rides below and the pigs above

to suffer seriously from worm infestation even though exposed to
infection. It is, however, much better practice to Keep the pigs
away from dirty hog lots and on clean pasture until they are turned
into the cornfield or otherwise fattened for market.

If there is much difference in the ages of the various litters, the
pigs should be placed in several pastures according to age, or the
one pasture may be subdivided. Mixing together pigs of widely
different ages commonly results in the younger ones being robbed
by the older ones, so that they do not have a fair chance to get the
nourishment they need for proper growth. Temporary shade may
be built in the pasture if natural shade is not available. Care should
be taken to keep the bedding in the shelter houses in a clean and
sanitary condition. Some hog raisers move the shelter houses from
time to time and burn the old bedding. The location of the feeding
ground should be shifted occasionally, the surroundings of the water
supply maintained in a sanitary condition, and the development of

mud wallows prevented.

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PREVENTION OF ROUNDWORMS IN PIGS 7

Fall Pigs

In the case of fall pigs, if not farrowed too late, the same system
may be followed with slight modifications. The permanent farrow-
ing house need not be used. If the sows have been running on pas-
ture and are not incrusted with mud and filth, they may be trans-
ferred directly, without washing, to the special pasture, and the
farrowing done in the individual houses in this pasture. In regions
not too far north the pigs, if farrowed at the very beginning of fall
or at the end of summer, will be past the age of greatest suscepti-
bility to worm infection before it is necessary to put them in winter
quarters that are likely to be more or less contaminated. ‘This fall
farrowing system is suitable for both spring and fall farrowing in
the South. In order to control kidnéy worms, as well as ascarids,
certain modifications of the system outlined in this leaflet must be
used. These modifications are described in Leaflet No. 108, Con-
trolling Kidney Worms in Swine in the Southern States, issued by
the United States Department of Agriculture.

Permanent Hog Lots Dangerous

It is desirable to have yards that are much used by hogs so arranged
that a change can be made every year or two to fresh ground, plowing
under the surface infection on the old ground, sowing a crop, and allow-
ing a firm surface to become reestablished before using it again for hogs.
Hog yards in any case should be selected with the view to having
proper drainage, and to being able to keep them in a sanitary condi-
tion, as free as possible from the common type of mud wallow which
usually becomes a reservoir of concentrated infection that causes
disease. It is nearly always feasible to replace mud wallows at compara-
tively slight expense with shallow, concrete, wallowing tanks so con-
structed as to be maintained in a sanitary condition. Such a tank can
also be used to apply remedies for lice and mange.*

Skim-Milk Diet Supplements Sanitation

Fluid skim milk or whey may be used to supplement -sanitary
measures for keeping pigs free of roundworms. The milk or whey
may be fed once daily in lieu of a grain feeding, or may be fed in lieu
of all other feed and water for periods of 3 days at intervals of 2 weeks.
Pigs so fed either remain entirely free of worms or the infections
acquired are so slight as to be of little consequence. Furthermore,
pigs so fed make more rapid weight gains than pigs fed only grain.

Benefits from the System

_ The following benefits resulting from the use of the swine-sanita-

tion system have been reported by farmers: By its use the farmer
can raise as many pigs from two sows as are raised from three under
the usual dirty hog-lot conditions; the pigs are ready for market
from four to eight weeks earlier, and there is the accompanying
saving in feed and care; and the, herds are of uniform size and
quality and practically devoid of runts. (Fig. 6.)

4 See footnote 3.

ae

8 LEAFLET NO. 5, U. S. DEPARTMENT OF AGRICULTURE

Summary of the Swine-Sanitation System

Remove all litter and trash from the farrowing pens and thor-

oughly clean them with hot water, soap, and lye, and the vigorous.

use of shovel and brush.

A few days before her farrowing time scrub the sow thoroughly
with a brush, using soap and warm water to remove dirt and worm
eggs, paying especial attention to the udder. But nothing should
be neglected—not even the feet. Then put the clean sow into the
clean farrowing pen. When the sow has been dried off after clean-
ing and before farrowing, oil her in order to control lice and mange.

Ten days or so.after the farrowing haul (don’t drive) the sow
and little pigs-to a.clean pasture containing a suitable forage crop
on which there have been no pigs since the crop was sown. Keep

>
“

‘ate
iit 2

Fic. 6.—The result of sanitation. Six-months-old pigs raised under the swine
sanitation system. Note the uniform size and quality

other pigs away from this pasture and keep these pigs away from

dirty hog lots.

Provide plenty of shelter and shade, and a fresh, safe, water supply
for the pigs. : ; .

Leave the pigs on the pasture until they are at least 4 months old
or have attained an average weight of 100 pounds; when possible,
leave them there until they can be turned into the cornfields or other-
wise fattened for market.

Fall pigs may be farrowed in individual houses on clean pasture,
the sows being washed if necessary before being taken to the pasture.

U. S. GOVERNMENT PRINTING OFFICE O—1946

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