Bulletin No. 21. (B. a. i. no.)
U. S. DEPARTMENT OF AGRICULTURE.
BUREAU OF ANIMAL INDUSTRY.
SHEEP SCAB:
ITS NATURE AND TREATMENT.
BV
D. E. SALMON, D. V. Tvl.,
Chief of Bureau of Animal Industry,
AND
CH, WARDELL STILES, Ph. D.,
Zoologist of the Bureau.
WASHINGTON:
GOVERNMENT PRINTING OFFICE.
I898.
Historic, archived document
Do not assume content reflects current
scientific knowledge, policies, or practices.
Bulletin No. 21. (B. a. i. no.)
U. S. DEPARTMENT OF AGRICULTURE.
BUREAU OF ANIMAL INDUSTRY.
SHEEP SCAB:
ITS NATURE AND TREATMENT.
BY
D. E. SALMON, D. V. JVL,
Chief of Bureau of Animal Industry,
AND
CH. WARDELL STILES, Ph. D.,
Zoologist of the Bureau.
WASHINGTON :
GOVERNMENT PRINTING OFFICE.
1898.
LETTER OF TRANSMITTAL.
U. S. Department of Agriculture,
Bureau of Animal Industry,
Washington, D. C, March 15, 1898.
Sir: I have the honor to transmit herewith, for publication as a
bulletin of this Bureau, a discussion of "Sheep Scab: Its Nature and
Treatment." The disease known as scab is one of the most serious
drawbacks to the sheep industry and results in enormous financial
losses. Yet, despite its insidious nature, its ease pf transmission, its
severe effects, and its prevalence in certain localities, it is a disease
which yields readily to proper treatment. If all of the sheep owners
of the country would dip regularly and thoroughly, there is no reason
why this scourge should not be totally eradicated from the United
States. There should be stringent scab laws in every State, with State
inspectors to see that those laws are carried out.
The sheep raisers of this country are intelligent and progressive men,
and most of them fully recognize the necessity of combining to eradi-
cate this disease. In many cases, however, more particularly among
owners of small flocks, there are many erroneous ideas prevalent
regarding the exact nature of the disease and the methods by which
it may be eradicated. It is to meet the demand for exact information
on this subject that this bulletin has been prepared. In it will be
found a description of the various kinds of scab, references to condi-
tions which may be mistaken for scab, a description of various kinds of
dipping plants suitable for use on small and on large farms, directions
for preparing certain homemade dips, and directions for dipping. The
investigation of various kinds of dips will be continued by this Bureau,
and supplementary circulars will be published if necessary.
In the preparation of the bulletin the writers have received valuable
assistance from Dr. Schroeder, Director of our Experiment Station.
Respectfully,
D. E. Salmon,
Chief of Bureau of Animal Industry.
Hon. James Wilson,
Secretary.
3
CONTENTS.
Page.
Historical introduction 7
Losses caused by scab 8
Losses in home industry 8
Losses in export trade 9
Cause of scab 9
Common sort 9
Other forms 10
Description of sheep scab 11
Common scab, body scab, or psoroptic scab 11
Head scab, black muzzle, or sarcoptic scab 15
Foot scab, or chorioptic scab 17
Follicular scab, or demodectic scab 17
Conditions which may be mistaken for scab 17
Treatment of scab 18
Hand applications 18
Dipping ; 19
Choice of a preparation for dipping 20
Kinds of dips 23
Tobacco-and-sulphur dip 23
Lime-and-sulphur dips 24
Potassium sulphide dip 30
Tobacco dips 30
Arsenical dips 32
Carbolic dips 33
Setback to the sheep from dipping 35
Dipping plants . 36
Small portable vats for small flocks 38
More permanent plants for larger flocks 39
Receiving and forcing yards. . ; 39
Chutes, or slides 44
The dipping vat 45
The incline to the dripping pens 52
The dripping pens : 53
Shelter for the dipping plant 54
Arrangements for cleaning 54
Boiling, infusing, and settling tanks 54
Measures 56
Pumps 56
Federal laws and regulations relative to sheep scab 58
Notice of enforcement of the law 60
Effect of meat inspection regulations 61
5
ILLUSTRATIONS.
Plates.
Page.
Plate I 10
II 10
III 10
IV • 10
V 10
VI 10
Figures.
Fig. 1. A comparatively early case of common scab, showing a bare spot and
a tagging of the wool 10
2. Adult sheep tick (Helophagus ovinus) 11
3. Sheep louse (Trichoccphalm spluerocephahts) 15
4. Sheep-foot louse (Hcematopinus pedalis) 16
5. A Rimple caldron which may be used for boiling dip 36
6. A caldron with stove 37
7. A floating dairy thermometer 38
8. A crutch or dipping fork 39
9. Another style of crutch or dipping fork 39
10. Dipping sheep in a tub 39
11. Trough for dipping lambs 40
12. A small portable dipping vat for small flocks 40
13. A small portable dipping vat, with attached dripping platform 41
14. Detachable skeleton box, with gate, to fit over the dripping platform. 41
15. A small patented portable vat arranged as a cart 42
16. A small patented portable vat arranged as a cart, unfolded and in nse. 42
17. A small dipping plant 43
18. Receiving and forcing yards, with attached Btage, decoy pen, vat,
draining yards, etc 43
19. Australian circular receiving and forcing yards, with straight race or
drive, the incline chute, straight vat, incline, two draining pens,
etc 43
20. Argentine semicircular receiving and forcing yards, with a straight
vat, draining pens, etc 44
21. Dipping plant provided with an endless chain or treadmill chute 4"*
22. Dipping plant 45
23. Dipping plant 46
24. A straight vat known as the Australian sheep-dipping tank 46
25. A straight swim somewhat similar to fig. 24 47
26. A dipping plant 47
27. A dipping plant in use in Millard County, Utah 48
28. A triple vat 48
29. A circular dipping tank 49
30. A circular dipping tank, with drive and slide 50
31. View of a double oblong swim 51
32. A double oblong swim 52
33. Ground plan of yards and vat 53
34. Ground plan of yards and vat 54
35. View of the dipping plant at the Stock Yards, South Omaha, Nebr. .. 55
36. View of the dipping plant at the Union Stock Yards, Chicago, 111 57
6
SHEEP- SCAB: ITS NATURE AND TREATMENT.
HISTORICAL INTRODUCTION.
The disease commonly called sheep scab is the mange, or scabies,
of the sheep. It is a contagious skin disease caused by a parasitic
mite. This disease is one of the oldest known, most prevalent, and
most injurious maladies which affects this species of animals. It has
been well known for many centuries, and references to it are found in
the earlier writings, including the Bible, where we find, in Leviticus,
xxii: 22, the use of scabbed sheep forbidden in sacrifices. Some think
that the mite which causes the disease was known to Aristotle, 322
B. C; but it appears that Wichmann^ writing in 1786, was one of the
first authors of modern times to suspect that sheep scab was of the same
nature as the scabies of man. Wichmann held the erroneous view,
however, that both diseases were produced by the same parasite.
The prevailing opinion concerning scab prior to and during the first
years of the present century was that it was caused by some special
condition of the sheep's system, a "humor of the blood," which led to
a skin eruption. The parasites were in some cases known and recog-
nized, but they were supposed to be either an accidental occurrence or
to have arisen by spontaneous generation as a result of the disease,
and because the affected skin offered conditions favorable to their devel-
opment and existence.
As a result of diligent research, certain investigators reached the con-
clusion that the malady was due directly to the mites which were found
inhabiting the diseased parts of the skin. Their opinion was not at
once adopted, however, but, on the contrary, met with strong opposi-
tion from those who held that scab was due to a diseased condition of
the blood and from others who held a modified view to the effect that
the mites carried poisonous or diseased material from one animal to
another and in that manner communicated the disease. The errors and
uncertainties which came down to us through centuries of controversy
were finally and for all time dispelled by conclusive experiments upon
animals made during the first half of this century. It was shown that
scab does not develop and can not be produced without the parasites.
The complete life cycle of the mites was studied and demonstrated from
the eggs to the adult parasites. It was shown that mites are always
the offspring of ancestors, the same as are the larger animals, and it
has in later years come to be admitted that there is no such thing known
7
8
BUREAU OF ANIMAL INDUSTRY.
as spontaneous generation of any living thing under any circumstances.
The demonstration was repeatedly made that the disease always devel-
oped if mites were taken from diseased sheep and placed upon healthy
ones, and that diseases of the skin resembling scab are not contagious
unless the mite is present.
Questions are still frequently asked, by persons not conversant with
the investigations of the subject, as to whether the scab is the cause of
the mite or the mite is the cause of the scab, and also whether the dis-
ease can develop without the presence of the scab mite. The investiga-
tions which have been referred to answer these questions and also show
that the treatment must consist in external applications for the destruc-
tion of the parasites and not internal remedies to "purify the blood."
Is scab hereditary? — An impression has arisen among some sheep
raisers that scab is hereditary. This impression is, however, erroneous.
Scab is no more hereditary than are sheep ticks or sheep lice, for the para-
sites which cause it live on the external surface of the body and do not
reach the womb. It is possible, however, for a lamb to become infected
from a scabby mother at the moment of birth or immediately after.
Lambs are occasionally born with white spots on their skin, and this
possibly has given rise to the idea that scab is hereditary.
LOSSES CAUSED BY SCAB.
Losses in home industry. — The losses from sheep scab have been and
are still very severe in most sheep raising countries. They are due to
the shedding of the wool, the loss of condition, and the death of the
sheep.
Although laws were made for the control of the disease as early as
the beginning of the eleventh century, general ignorauce in regard to
its nature and proper treatment has prevented the successful adminis-
tration of such laws even to the present day. The disease exists in
most of the countries of Europe, and also in Asia and Africa, and until
recently in Australia. Most civilized countries now control the disease
to a certain extent, and limit the losses by the enforcement of stringent
sanitary regulations; but the extent of its prevalence is nevertheless
surprising. It is a disease not difficult to cure and eradicate, and an
accurate knowledge of its characteristics with attention to details are
all that is needed to secure this result.
In the United States some sections have been overrun with sheep
scab, and many persons engaged in the sheep industry have been forced
to forsake it because of their losses from this disease. It is probable
that in its destruction of invested capital sheep scab is second only to
hog cholera among our animal diseases. The large flocks of the Plains
and Eocky Mountain region and the feeding stations farther east have
-suffered severely and are constantly sending diseased animals to the
great stock yards of this country. As a consequence of this market-
ing of affected sheep, the stock yards are continually infected, and any
SHEEP SCAB: ITS NATURE AND TREATMENT. 9
sneep purchased in these markets are, unless properly dipped, likely
to develop the disease after they are taken to the country for feeding
or breeding. There is in this way a constant distribution of the con-
tagion, and thousands of persons who know little of its nature or the
proper methods of curing it find that they have introduced it upon
their premises.
Losses in export trade. — In addition to the direct losses in wool, in
flesh, and in the lives of our sheep, we have suffered immensely in our
foreign trade because of the prevalence of this disease. Great Britain
appears to have been the first country to prohibit live sheep coming
from the United States, by an order issued in 1879. Upon representa-
tions that there was no foot-and-mouth disease in the United States
this order was rescinded in 1892, but only to be again enforced in 1896
on account of the many scabby sheep sent abroad by our exporters.
Our sheep are consequently slaughtered on the docks where landed,
the market being restricted and the prices much less favorable than
would otherwise be obtained. The markets of Continental Europe
have been entirely closed to American sheep, as even the privilege of
slaughtering at the landing places is denied. For a long time it was
impossible to send our pure-bred sheep to Australia, where there is a
demand for them for breeding purposes, because the Australian law
required them to be transshipped and quarantined in British ports,
and the British authorities declined to grant this privilege. Arrange-
ments have since been made for the direct shipment of sheep to Aus-
tralia, if accompanied by the certificate of a veterinarian appointed by
the Australian authorities.
On the whole, it is seen that the existence of this disease in our
flocks has prevented the development of our export trade in many
directions, and has caused no end of trouble and loss to our exporters.
CATJSE OF SCAB.
Sheep scab is a strictly contagious disease.
Common sort. — Common sheep scab is caused by that species of mites
technically known as Psoroptes communis. 1 Parasites of tbis species
cause scab in horses, cattle, sheep, goats, and rabbits ; but for each
of these species of animals there appears to be a distinct variety of
this parasite. Although it is more or less difficult to distinguish
between these varieties, they differ somewhat in size, and it is found
that the Psoroptes communis of the sheep does not cause scab of the
horse, ox, or rabbit; nor, on the other hand, does the Psoroptes com-
munis of the horse, ox, or rabbit cause scab of the sheep. Natural-
'The technical term Psoroptes is derived from the Greek, and meaDS that the mites
hide under the crusts. The parasite is sometimes called Dermatocoptes, which means
that the mites wound the skin. A third name, Dermatodectes, indicates that the
mitea bite the skin.
10
BUREAU OF ANIMAL INDUSTRY.
ists, therefore, distinguish the parasite of sheep scab by the name
Psoroptes communis var. ovis. 1
The parasite of this disease is one of the larger mites, and is quite
easily seen with the naked eye. The adult female is about one-fortieth
inch long and one-sixtieth inch broad ; the male is one-fiftieth inch long
and one-eightieth inch broad. These mites are discovered more readily
and more clearly on a dark than on a light background, and for that
reason the crusts from the affected skin are often placed upon black
paper and kept in the sunshine for a few minutes in order to reveal the
parasites crawling about.
JTig. 1 — A comparatively early case of common scab, showing a bare spot and a tagging of the wo< I.
The psoropt inhabits the regions on the surface of the body which
are most thickly covered with wool; that is, the back, the sides, the
rump, and the shoulders. It is the most serious in its efl'ects upon
sheep of any of the parasitic mites, and it is the cause of the true body
scab.
Other forms. — Sheep are also affected with three other forms of
scab, likewise caused by parasitic mites. One of these is the sar-
coptic scab (head scab, or black muzzle), which is limited almost
entirely to the head, and is caused by the mite known as the Sarcoptes
1 Var. is the abbreviation of the Latin word varietas, meaning variety.
BULLETIN NO. 21 , B. A. I.
PLATE II.
ikmM
FIQ. 4. AN ADVANCED CASE OF COMMON SCAB.
A.Hosti & Co.
BULLETIN NO. 21, R. A. I.
PLATE HI.
FIG. S. ADULT MALE PARASITE OF OOMMON SHEEP SCAB. DORSAL VIEW. FlQ. 6 VENTRAL VIEW OF SAME FIG. B A. HEAD
OF FEMALE. 6 B. LEG OF FEMALE. ALL GREATLY ENLARGED.
A. Hoen &■ Ct».
TIG. 7. ADULT FEMALE PARASITE OF COMMON SHEEP SCAB, DORSAL VIEW.
PLATE tV.
FIG. 8. VENTRAL VIEW OF SAME.
A.Hoen t-Go.
BULLETIN No. 21, B. A. I.
PLATE V.
FIQ. 9. EGG OF MITE WHICH CAUSES COMMON SHEEP SCAB. FIG, 10. SIX-LEGGED STAGE Of-' SHEEP SCAB MITE. FIG. II. YOUNG
FEMALE BEFORE MOULTING FOR THE LAST TIME, DORSAL VIEW. FIG. 12. ADULT MALE PARASITE OF SARCOPTI C SCABIES
OF MAN '.THE CORRESPONDING PARASITE OF SHEEP IS VERY SIMILAR/, VENTRAL VIEW, X 360 (aFTER BLANCHARd).
FIG. 13. ADULT FEMALE PARASITE OF SARCOPTIC SCABIES, DORSAL VIEW. X Zfto (aFTER BLANOHARd). FIG. 14. SAME,
VENTRAL VIEW (aFTER BLANCHARd). ALL GREATLY ENLARGED.
A.Hoen&-Co.
BULLETIN NO. 21, B. A. I.
PLATE VI.
SHEEP SCAB: ITS NATURE AND TREATMENT.
11
scabiei var. ovis. 1 The second is the symbiotic scab (foot scab), which
affects the limbs, scrotum, and udder, and is caused by the Ghorioptes
communis var. ovis. 2 Lastly may be mentioned an extremely rare affec
tion, the so-called follicular, or demodectic, scab, affecting the eyelids,
caused by a mite known as Demodex folliculorum var. ovis. 3
The sarcoptic, symbiotic, and demodectic forms of scab are with
sheep mild diseases compared with common scab, and appear to be
rather rare.
DESCRIPTION OP SHEEP SCAB.
(1) COMMON SCAB, BODY SCAB, OR PSOROPTIC SCAB.
Although the symptoms of common scab are familiar to most farm-
ers, they will here be briefly reviewed.
The mites of common, or body, scab — that is, the Psoroptes — prick
the skin of the animal to obtain their food, and probably insert a poi-
sonous saliva in the wound. Their bites are followed by intense itch-
ing, with irritation, formation of papules, inflammation, exudation of
serum, and the formation of
crusts, or scabs, under and near
the edge of which the parasites
live. As the parasites multi-
ply they seek the more healthy
parts, spreading from the edges
of the scab already formed,
thus extending the disease.
The sheep are restless; they
scratch aud bite themselves,
and rub against posts, fences,
stones, or against other mem-
bers of the flock. This irrita-
tion is particularly noticeable
after the animals have been FlQ - 2 — Atlult 8hee P tick < a) an(l pop*™™ <*) (Me-
. . lophagusovinu8). Enlarged. (AfterOsborn, 1896;
driven, for the Itching IS more Bui. No. 5, Div. Entomology, Dept. Agr.)
intense when the sheep become
heated. The changes in the skin naturally result in a falling of the
wool; at first slender "tags" are noticed; the fleece assumes the condi-
tion known as "flowering;" it looks tufty or matted, and the sheep
pulls out portions with its mouth,.or leaves tags on the objects against
which it rubs. Scabs fall and are replaced by thicker and more adher-
ent crusts. The skin finally becomes more or less bare, parchment-
like, greatly thickened, furrowed, and bleeding in the cracks. With
shorn sheep especially a thick, dry, parchment-like crust covers the
greatly tumifled skin. Ewes may abort or bear weak lambs.
1 Sareoptes, from the Greek, means that the mites wound the flesh.
2 Chorioptes signifies that the mites hide in the skin. Another name, Symbiotes,
signifies that a number of the mites live together; and a third name, Dermatophagm,
means that the mites eat the skin.
3 Demodex signifies that the mites have a worm-like body.
12
BUREAU OF ANIMAL INDUSTRY.
Parts of iody affected. — When sheep are kept in large numbers the
chances for infection are naturally greater, and the disease may begin
on almost any part of the body. Generally, however, it affects the
parts which are covered with wool. When the sheep are fat and the
wool has a large amount of yolk, the progress of the disease may be slow ;
usually beginuing on the upper part of the body, withers, and back, it
extends slowly, but none the less surely and in ever-increasing areas,
to the neck, sides, flanks, rump, etc. In two or three months the entire
body may be affected.
Contagion. — Common scab is exceedingly contagious from one sheep
to another, and may in some cases show itself within about a week
after healthy sheep have been exposed to infection. The contagion
may be direct, by contact of one sheep with another; or indirect, from
tags of wool, or from fences, posts, etc., against which scabby sheep
have rubbed, or from the places where the sheep have been " bedded
down." One attack of scab does not protect sheep from later attacks.
Transmitted to man, sheep scab may produce a slight spot on the skin,
a point which is sometimes taken advantage of for the purpose of
diagnosis. In case of suspected scab, one of the crusts is bound lightly
on the arm. After a short time an itching sensation is felt and the mites
are found on the skin. Transmitted to horses, cattle, or goats, common
sheep scab fails to develop.
Chances for recovery. — Cases of apparent spontaneous recovery are
rare. Usually when proper methods of treatment are not adopted the
disease increases, leads to anaemia, emaciation, exhaustion, and death,
and may result in a loss of from 10 to 80 per cent of the flock. Scab is
favored by seasons when the wool is lougest, and by huddling or over-
crowding the animals; also race, energy, temperament, age, state of
health, length, fineness, and abundance of wool, and the hygienic con-
ditions of the surroundings influence the course and termination of the
disease. Young, weak, closely inbred animals, and those with long,
coarse wool will most quickly succumb. Unhealthy localities, damp
climate, and poorly ventilated sheds favor the disease. Pure or mixed
Merino sheep succumb sooner than certain other breeds. The mortality
varies according to conditions, but is highest in autumn and winter.
When owners are careless the death rate may be very high; if untreated
the sheep may die in two to three months. Hygienic conditions, good
food, and cool dry atmosphere tend to check the disease. Sheep sheds
should accordingly be well ventilated and open to light and sunshine.
With proper attention to hygienic conditions and thorough dipping,
a positive cure can be guaranteed.
Vitality of the parasite. — Taken from the sheep, the mites possess a
remarkable vitality. It is generally stated that, kept at a moderate
temperature on portions of scab, the adults may live from four to
twenty days, but they will occasionally live much longer; cases are on
record where they have lived three, four, or even six weeks when sepa-
SHEEP SCAB: ITS NATURE AND TREATMENT.
13
rated from sheep; if the atmosphere is dry they will generally die in
about fifteen days; but death is often only apparent, for the mites may
sometimes be revived by warmth and moisture even after six or eight
weeks; the fecundated females are especially tenacious of life. Vari-
ous rather contradictory statements may be found regarding their
resistance to cold: Krogmann states that they may live at a tempera-
ture of minus 10° 0. (+14° P.) for twenty-eight days; other authors
claim that the mites die in two hours at 47° F. ; still other authors, that
they die at 50° C. (122° F.). They are said to have been kept alive in
cold water for six days and in warm water for ten days. Several
authors admit, however, that the parasites are usually killed by a soak-
ing rain; though it is claimed that in damp, dark stables they "may
live for months."
Experience has shown that in some cases apparently healthy sheep
have become infected in places where no sheep have been kept for four,
eight, twelve, or even twenty-four months. The conditions underlying
this infection are not thoroughly understood. Possibly some of the
eggs have retained their vitality a long time and then hatched out;
possibly the vitality of the fecundated female has also played a role;
while it is not at all improbable that an entirely new infection has
accidentally been introduced by birds or other animals. Certain
authors of high standing scout the idea that birds can introduce an
infection of scab, but there is no reason why birds should not do this,
and there are some reasons for believing that they do. It has been
noticed on the Experiment Station of the Bureau, for instance, that
crows delight in perching on the backs of scabby sheep and picking at
the scab; while so doing it is only natural that small tags of wool would
adhere to their feet, and thus scatter scab. The fact that snails cling
to birds' feet and are carried long distances is too well established to
need discussiou, and it is very probable that many of the cases where
sheep are supposed to have become infected with scab on pastures
which have not been occupied for one or two years are in reality cases
of fresh infection by means of birds. From the data at hand, while it
may be admitted that in some cases, under favorable conditions, the
mites may live from spring to fall, it is scarcely within the limits of
probability that either the scab mites or their eggs will live through a
winter when separated from the sheep and exposed to the elements.
All matters connected with the vitality of the scab mite have an
important bearing iu explaining cases of indirect infection on roads
over which scabby sheep have been driven, or in fields and sheds where
they have been kept. From the facts now at our disposal we can lay
down the following important rules:
(1) Scabby sheep should never be driven upon a public road ; (2)
sheds in which scabby sheep have been kept should be thoroughly
cleaned, disinfected, and aired, and should be left unused for at least
four weeks Abetter two months) before clean sheep are placed in them;
14
BUREAU OP ANIMAL INDUSTRY.
(3) fields in which scabby sheep have been kept should stand vacant
at least four weeks (better six or eight) before being used for clean
sheep; (4) a drenching rain will frequently serve to disinfect a pasture,
but it is well to whitewash the posts against which scabby sheep have
rubbed. Even after observing the precautions here given it is not pos-
sible to absolutely guarantee that there will be no reinfection, but the
probabilities are against it.
Life history of the parasite. — A study of the life history of the scab
parasite is necessary in order to determine several important points of
practical value, such as the proper time for the second dipping, etc.
The female mite lays about 15 to 24 eggs on the skin, or fastened to
the wool near the skin; a six-legged larva is*hatched; these larvse
cast their skin and become mature; the mites pair and the females lay
their eggs, after which they die. The exact number of days required
for each stage varies somewhat, according to the writings of different
authors, a fact which is probably to be explained by individual varia-
tion, and by the conditions under which theobservations and experiments
were made. Thus Gerlach, in his well-known work (1857), estimates
about fourteen to fifteen days as the period required for a generation of
mites from the time of pairing to the maturity of the next generation.
He divides this time as follows: Under ordinary conditions the eggs
hatch in three to four days, although two authors allow. ten to eleven
days for the egg stage; three or four days after birth the six-legged
larvse moult and the fourth pair of legs appears; this fourth pair is
always present when the mites are two-thirds the size of the adults;
when 7 to 8 days old the mites are mature and ready to pair; several
(three or four) days are allowed for pairing; another generation of eggs
may be laid fourteen to fifteen days after the laying of the first genera-
tion of eggs. Without going into all of the other observations on these
points, it may be remarked that the eggs may not hatch for six or seven
days; the six-legged larva; may moult when three to four days old, and
become mature; after pairing a second moult takes places, lasting four
to five days; a third moult follows immediately, then eggs are laid and
the adults die; in some cases there is a fourth moult, but apparently
without any further production of eggs. Accepting Gerlach's estimate
of fifteen days as an average for each generation of 10 females and 5
males, in three months' time the sixth generation would appear and
consist of about 1,000,000 females and 500,000 males.
Several practical lessons are to be drawn from these figui'es: First,
it is seen that the parasites increase very rapidly, so that if scab is dis-
covered in a flock, the diseased sheep should immediately be isolated;
second, if new sheep are placed in a flock, they should either first be
dipped, as a precautionary measure, or they should at least be kept
separate for several weeks to see whether scab develops; third, since
the chances for infection are very great, the entire flock should be
treated, even in case scab is found only in one or two animals; fourth,
SHEEP SCAB: ITS NATURE AND TREATMENT.
15
as dipping is not certain to kill the eggs, the sheep should be dipped a
second time, the time being selected between the moment of the hatch-
ing of eggs and the moment tbe next generation of eggs is laid. As
eggs may hatch between three and seven, possibly ten or eleven, days,
and as fourteen to fifteen days are required for the entire cycle, the
second dipping should take place after tbe seventh day, but before the
fourteenth day; allowing for individual variation and variation of con-
ditions, the tenth, eleventh, or twelfth day will be the best time to
repeat the dipping.
(2) HEAD SCAIS, BLACK MUZZI.K, OR SAKCOI'TIC SCAli.
Head scab is less frequent and less important than body scab. No
case of it has ever been reported by the inspectors of this Bureau, and
many extensive sheep breeders and professional sheep dippers state
that they have never heard of a case.
Fig. y. — Sheep louae (Trichocephalus sphterocephalus) : a, female ; b, antenna ; c, rf, dorsal and side view
of leg. Enlarged. (After Osborn, 1896; Bui. No. 5, Div. Entomology, Dept. Agr.)
In this disease the parasites are much smaller than the psoropt of
body scab. They are almost invisible to the naked eye, but may be
seen with a magnifying glass. They are found on the moist uuder-
surface of the crusts, and live on the fluids of the sheep. They give
rise to a violent itching, causing the sheep to rub and scratch their
heads and , lick their lips ; in advanced stages the eyes may be partly
closed, and consequently the sight impaired; breathing and even eat-
16
BUREAU OP ANIMAL INDUSTRY.
ing may become difficult because of the formation of crusts the
mouth and nostrils. Small papules form, with soft centers; usually
the rubbing causes them to break, and they exude a fluid which
hardens and forms a scab; the scabs, increasing in number, may run
together; they become thicker and harder, until almost the entire head
is merged into one crust. Rubbing causes the crusts to break; the
wounds heal and form scars; the skin thickens and is raised in folds,
in which cracks appear and from which there may be bleeding. When
affecting lambs the disease may assume an ulcerative character.
Parts of body affected. — This form of scab appears on parts of the
body where the wool is scarce; usually beginning about the nostrils
FIG. 4. — Slieep foot louse (Hcematopinus pedalin): a, adult female; 6, ventral view of terminal seg-
ment of Bame, showing brushes ; c, terminal segments of male; d, egg. Enlarged. (After Osborn,
18116; Bui. No. 5, Div. Entomology, Dept. Agr.)
and on the upper lip, more rarely about the eyes and ears, it spreads
to the cheeks, eyes, forehead, and under the jaws; in severe cases it
may extend to the belly, front legs, knees, hocks, and pasterns. Coarse
dry wool favors it more than fine oily wool. The line between the dis-
eased and the healthy skin is quite sharply defined.
Contagion. — Head scab is contagious from sheep to sheep, from sheep
to goats, and rarely from sheep to man; when transmitted from sheep
to horses, cattle, and dogs the disease remains local and does not spread.
Head scab is also contagious from goats to sheep. Viborg states that
the sarcoptic scab of pigs is contagious to sheep, but this is denied
by Am-Pach. Chabert maintained that sarcoptic scab of dogs is trans-
missible to sheep, but this is doubtful.
SHEEP SCAB: ITS NATURE AND TREATMENT.
17
Chances for recovery. — Head scab can be easily treated if taken in
time, but if neglected it will cause inflammation of the eyes and exten-
sive alterations in the skin, and will prevent the sheep from fattening.
(3) FOOT SCAB, OK CHORIOPTIC SCAB.
Foot scab is rare, if present at all, in this country, but a number of
cases have recently been reported from England. It is not impossible
that some of the cases supposed to be foot rot are in reality foot scab.
The minute parasitts, which are much smaller than those of common
scab, cause an intense itching, which leads the sheep to stamp their feet
and scratch and bite the infected parts. There is a reddening of the
skin, followed by scaling, and later by the formation of yellowish white
crusts; the crusts thicken, cracks may form in the folds of the pas-
terns, and the legs may become quite unsightly.
Parfs of the body affected. — The disease appears on the feet and legs,
spreading slowly to the upper parts of the legs and the adjoining parts
of the body, scrotum, or udder.
Contagion. — This disease is contagious from sheep to sheep, but not
so actively as common scab.
(4) FOLLICULAR SCAB, OR DEMODKCTIC SCAB.
The glands of a sheep's eyelids are occasionally infected with a fourth
kind of microscopic mite, which is elongate and much like a worm. It
lias been recorded but a few times, and for the present, at least, is of
no importance to the American sheep raiser.
CONDITIONS WHICH MAY BE MISTAKEN FOR SCAB.
Any parasite or condition which causes an itching, and thus leads
the sheep to scratch themselves, or any abnormal condition of the skin,
may be temporarily mistaken for scab; but if the rule is held in mind
that no scab is possible without the presence of the specific parasites,
it will be easily determined whether scab is present or not. The fol-
lowing are the more important cases to be considered :
(1) Itching due to other parasites, such as the common "sheep tick,"
true ticks, and lice, may be distinguished from scab by finding the
parasites. The dipping used for treating scab will also kill sheep ticks
and lice.
(2) Inflammation of the sebaceous glands. — This may be mistaken for
common scab. It appears most frequently in autumn. There is a
severe itching, the skin is red and sensitive, and is covered with a
strong-smelling, yellowish, viscid yolk; tufts of wool may be shed. It
may be cured, after shearing, with any starchy lotion.
(3) Bain rot. — In rainy weather an eruption may appear on the skin
which might be mistaken for scab. There is, however, no parasite
present; itching is absent, and the trouble disappears when dry
weather comes.
3227— No. 21 2
18
BUREAU OF ANIMAL INDUSTRY.
THE TREATMENT OF SCAB.
In the foregoing discussion attention has been called to the necessity
of keeping sheep under proper hygienic conditions. That alone, though
of importance in connection with the subject of treatment, can not be
relied upon to cure scab. The only rational treatment consists in using
some external application which will kill the parasites. Formerly med-
icines were given internally, and even within a few years past it has
been claimed that feeding sulphur to sheep will cure the disease. The
statements regarding sulphur were such as to lead us to try the exper-
iment, which, however, was soon abandoned as unsuccessful. The
external application of scab cures is in various ways made known as
hand dressing, hand curing, spotting, pouring, smearing, and dipping.
Of these methods, dipping is by far the most satisfactory.
Hand Applications.
In case of head scab, or in light cases of foot scab, hand applications
may be resorted to, and will frequently suffice. A nonpoisonous oint-
ment may be made by taking 4 ounces of oil of turpentine, 6 ounces of
flowers of sulphur, and 1 pound of lard. Mix the ingredients at a
gentle heat, and rub in well with the hands or with a brush, at the
same time breaking the crusts. The simple sulphur ointment may be
made of 1 part of sulphur and 4 parts of lard; one-fourth part of
mercurial ointment may be added. Few remedies are so useful in
mange in dogs, ringworm, and other itching complaiuts as sulphur
iodide, and it may well be given a trial on head scab. It is prepared
as follows: Mix in a nonmetallic vessel, as a porcelain mortar, 4 ounces
of iodine with 1 ounce of sublimed sulphur, gently heating the mixture
until it liquefies; the red-brown liquid upon cooling becomes a gray-
black crystalline mass, insoluble in water, but soluble in glycerine and
fats, with 8 or 10 parts of which it is mixed for ointments or liniments.
An ointment of flowers of sulphur and carbolated vaseline would also
probably give good results. One author advises for head scab and foot
scab a mixture consisting of 1 part of mercurial ointment and 11 parts
of sulphur ointment. Foot scab and head scab would also probably
respond to treatment with the various dips used for common scab.
Hand dressing is not recommended for common scab; in fact, it must
be looked upon as directly responsible for a considerable amount of the
disease, since it is too often relied upon to cure the disease, while in
reality it is only a palliative. The only condition under which hand
dressings can be advised is in case scab is discovered in one or two
sheep of a flock during severe winter weather, when dipping would be
impracticable. In that event, the infected sheep should be immediately
isolated from the flock; and they might be hand dressed, if desired, in
order to hold the disease in check. It can not be too strongly insisted
upon that "pouring," " spotting," etc., are only expensive and temporiz-
ing methods of dealing with scab.
SHEEP SCAB: ITS NATURE AND TREATMENT. 19
''Pouring" is done as follows: Part the wool on the back by mak-
ing a furrow with the finger from the head to the tail ; furrows are also
made along the shoulders and thighs to the legs, and on the sides; pour
the ointment or dip in these furrows. A still better plan is to pour the
warm dip from a coffeepot or teapot directly on the affected parts,
rubbing it well iu with the hand, a brush, or a corncob. It must be
repeated for emphasis, however, that such treatment can not be relied
upon, and should be used only in emergency cases when dipping is
impracticable.
A mercurial ointment may be made as follows: (A) dissolve 1 pound
of resin in one-half pint of oil of turpentine; (B) mix 1 pound of mer-
curial ointment with 6 pounds of lard, with gentle heat, and (C) when
cool mix the two compounds, A and B. It should be remembered that
mercurial ointments are not unattended with danger, and on this
account it is better to prepare a small amount of dip and pour it on the
affected part as described above.
Dipping.
By far the most rational and satisfactory, and the cheapest method
of curing scab is by dipping the sheep iu some liquid which will kill
the parasites. The dipping process is as follows :
(1) Select a dip containing sulphur. If a prepared "dip" is used
which does not contain sulphur, it is always safer to add about 1CJ
pounds of sifted flowers of sulphur to every 100 gallons of water,
especially if, after dipping, the sheep have to be returned to the old
pastures.
(2) Shear all the sheep at one time, and immediately after shearing
confine them to one half the farm for two to four weeks. Many persons
prefer to dip immediately after shearing.
(3) At the end of this time dip every sheep (and every goat also, if
there are any on the farm).
(4) Ten days later dip the entire flock a second time.
(5) After the second dipping, place the flock on the portion of the
farm from which they have been excluded during the previous four or
five weeks.
(C) Use the dip at a temperature of 100° to 110° F.
(7) Keep each sheep in the dip for two minutes by the watch— do not
guess at the time — and duck its head at least once.
(8) Be careful in dipping rams, as they are more likely to be over-
come in the dip than are the ewes.
(9) Injury may, however, result to preguant ewes, which must, on this
account, be carefully handled. Some farmers arrange a stage, with
sides, to hold the pregnant ewes, which is lowered carefully into the
vat, and raised after the proper time.
(10) In case a patent or proprietary dip, especially an arsenical dip,
is used, the directions given on the package should be carried out to
the letter.
20
bureau of animal industry.
Choice op a Preparation for Dipping.
Numerous different sheep dips are recommended by various parties,
and undoubtedly many of them are efficacious; few dips can be named
which some persons do not consider far superior, and other persons
consider far inferior to all other dips known ; few dips can be found
which have not cured cases of scab, and probably no dip can be named
with which failures have not been reported. Under these circum-
stances the farmer should not be deceived by exaggerated statements
in either extreme; he should recall that it lies in the business interest
of the manufacturers of every proprietary, or patent, dip to advertise
their own particular dip in every way possible, but that too often these
merchants pursue the method of deprecating the use of homemade
dips as "dangerous," "ineffective," "liable to produce blood poisoning,"
etc., and of citing the accidents, failures, and dangers of other propri-
etary dips rather than of giving exact and reliable statements regard-
ing the successes of their own compounds.
proprietary articles.
The Department can not properly advertise or recommend the use of
any dip which is made from a secret formula. It can not be said that
no such dip has any value as a scab cure, or that such dips have never
met with any success, for that would be a misrepresentation of facts.
The farmer should, however, know the composition of the material he
is using. If he desires to use a ready-made dip, let him inform him-
self of the exact nature of that dip in order to prevent impositions
and guard against dangers. He would do well to refuse to pur-
chase any prepared dip which does not bear on each package a printed
statement of the ingredients and their proportions, which the manu-
facturer guarantees are to be found in that package; he would also do
well to avoid any dip which irresponsible parties advertise as "the
only sure cure for scab," etc. Proprietors thus advertising are either
showing gross ignorance of the history and nature of scab, and hence
are not to be taken as advisers, or they are intentionally misrepresent-
ing established facts.
In case of more than one proprietary dip, it seems quite clear from
the circulars and advertisements distributed by the manufacturers that
the firms have had little or no practical experience with scab, and that
the extravagant claims set forth by them for their mixtures are little
less than artful methods of advertising, rather than statements based
upon any tests or experiments. Good examples of worthless or almost
worthless dips are cited by Bruce, who quotes the treatment of 80,021
cases of scab with Allen's Specific, with not a single case of cure!
Hayes's Specific cured 6,255 cases and failed in 80,931 cases !
SUCCESS with homemade dips.
While a dip should not be condemned simply because it is prepared
ready for use— for it may be frankly admitted that there are some excel-
SHEEP SCAB: ITS NATURE AND TREATMENT.
21
lent proprietary dips — the value of homemade dips must be insisted
upon, and attention is called to the fact that it was almost entirely
through homemade dips that scab was eradicated from certain of the
Australian colonies, and that year after year, in the reports of the scab
inspectors of Capetown Colony, the first and third places are accorded
to homemade dips, while second place is accorded (with some qualifi-
cation) to a secret dip. In this connection the following significant
remarks, made in 1892 by the chief inspector of stock in Queensland,
will be of interest :
Our Australian experience of tobacco and sulphur and of lime and sulphur as the
only effectual means of curing scab is such that at the stock conference held in
Sydney in 1886, and again in Melbourne in 1889, attended by the chief and Govern-
ment veterinarians of all the colonies, it was on both occasions decided that none
but these two dips be recognized in the colonies, and this has now been embodied in
regulations under the " Stock disease acts " of all the colonies.
The stamping out of scab in these colonies has been more retarded by venders of
patent dips than by any other cause; hence the determination of the governments
of all the colonies to forbid the use of any specific except tobacco and sulphur or
lime and sulphur for scab or for the (precautionary) dressing of imported sheep
while in quarantine.
In view of the more or less frequent statements that scab was eradi-
cated from the English colonies by killing the scabby sheep or by the
use of prepared dips it may be well to say that these statements are
erroneous. "It is true an act was passed in New South Wales about
1851 compelling the slaughter of scabbed sheep, and a few remaining
straggling flocks were destroyed under that act, but later, on the reap-
pearance of scab in that colony in 1863 by infection from Victoria, the
act was repealed, and the whole of the scabbed sheep, about 400,000,
were completely cured by means of tobacco and sulphur." 1
IMPORTANCE OF PROPER USE OF DIP.
Whatever dip is selected, the farmer should not forget that there
are two ways to use that dip. One way is to prepare and use it in
accordance with the directions given; the other way is to attempt to
economize time, labor, or money by using the dip in weaker proportion
than advised, by hurrying the sheep through the swim, or by later
placing the dipped sheep under unfavorable conditions. If the former
method is adopted with any of the established dips, the treatment
ought to be followed with favorable results; if the latter method is
adopted, the farmer himself must assume the responsibility of failure,
no matter which dip he decides to use. Every farmer should therefore
remember that when he has decided upon the dip he is to use his work
has only begun; to use the dip properly is fully as important as to use
a dip at all.
1 Statement made by P. A. Gordon, chief inspector of stock, Queensland.
22
BUREAU OF ANIMAL INDUSTRY.
PRELIMINARY QUESTIONS IN CHOOSING A DIP.
The homemade dips which are most commonly used have either
tobacco or sulphur as their basis, while the prepared dips contain
tobacco, sulphur, arsenic, carbolic acid, etc., as curative agents.
In selecting a dip several points should be considered : First of all,
the question of expense will naturally arise; next, the question as to
whether or not scab actually exists in the flock to bo dipped, or whether
or not the dipping is more of a precautionary matter, or for the sake
of cleansing the animal's skin. The facilities at hand, the setback to
the sheep, and the length of the wool are also matters for consideration,
as well as the pastures into which the dipped sheep are to be placed.
Notwithstanding statements to the effect that a given dip can be used
under all conditions, the above questions are evidently important.
Expense. — In estimating the expense one should consider not only
the actual outlay for the ingredients of the ooze, but the cost of fuel
and labor, the injury, if any, to the sheep, and the liability of not curing
the disease. It is much more economical to use an expensive dip and
cure scab than it is to use a cheap dip and fail to cure it. To'illnstrate
with a well-known homemade dip: A lime and-sulphur dip may be
made in ten to thirty minutes, with but little fuel and little labor, which
may or may not cure the disease, and which will surely do great injury
to the wool; or a lime-and-sulphur dip may be made in several hours'
time, at the expense of considerable fuel, labor, and patience, which can
be relied upon to cure scab, and which will do little or no injury to the
wool. The first dip is cheap, but not economical; the second dip is
more expensive, but more economical.
Does scab exist in the flock f — Every farmer should ask himself this
question before he selects his dip. If scab does not actually exist and
the wool is long, the dipping in this case simply being a matter of pre-
caution, it is best not to select a dip containing lime. The use of the
lime-and-sulphur dips is therefore not advised simply as precautionary
dressing for healthy long-wooled sheep. On the contrary, the use of
any dip containing lime, as a precautionary measure, should be avoided.
The facilities at hand for preparing dip. — If fuel is very scarce, so that
it is impracticable to boil the mixture for at least two hours, the lime-
and-sulphur dips should not be selected. A tobacco-and-sulphur dip,
as well as many of the better proprietary dips, can be made without
the necessity of lengthy boiling, and should be given preference when-
ever facilities for boiling are not at hand.
The length of the wool. — See remarks upon this subject in discussion
of lime and sulphur, page 26.
The pastures. — In case it is necessary to place the dipped sheep on
the same pastures they occupied before being dipped, it is always best
to use a dip containing sulphur. If a proprietary dip is selected under
those circumstances, it is suggested that sulphur be added, about 1
pound of flowers of sulphur to every 6 gallons of dip. In case it is
SHEEP SCAB: ITS NATURE AND TREATMENT.
23
possible to utilize fresh pastures after dipping, the use of sulphur is not
so necessary, but is always advisable. The object in using sulphur is
to place in the wool a material which will not evaporate quickly, but
will remain there for a longer period of time than the scab parasites
ordinarily remain alive away from their hosts. By doing this the sheep
are protected against reinfection.
Sulphur is one of the oldest known remedies for scab, its use dating
back to Columella in the early part of the Christian era. As a scab
eradicator. it must be placed among the best substances at our disposal.
It is one of the constituents of certain proprietary dips, but its use to
the farmer is best known in the tobacco and-sulphur dip and in the lime-
and-sulphur dip. These homemade mixtures are the two dips which
have played the most important roles in the eradication of scab from
certain English colonies, and their use, especially the use as well as the
abuse of lime and sulphur, is quite extensive in this country.
The formula, as given here and as adopted by the New South Wales
sanitary authorities, appears to have first been proposed in 1854 by
Mr. John Rutherford. Regarding its success in Australia, Dr. Bruce,
chief inspector of sheep for New South Wales, makes the following
statements :
Ou the Hopkins Hill Station Mr. Rutherford, with two dressings of these ingredi-
ents, then cured over 52,000 sheep which had been infected for eighteen months; and
he also subsequently cured with two dippings the sheep on Mount Fyans Station,
where they were in a most wretched state, and had been scabby for more than three
years, and that, too, in both cases, without destroying a single hurdle or yard or
renioviug any of the sheep from their old runs.
Since then millions of scabby sheep have been permanently cured iu Victoria in
the same way, and in South Australia and New South Wales hundreds of thousands
of scabby sheep have also been cleansed with tobacco and sulphur. In fact, this
dressing has the credit of having eradicated scab from the flocks of both the latter
colonies, and there are good grounds for asserting that had this remedy not been
known and used neither colony would be, as they both are now, almost entirely free
from the scourge. Judging therefore from the experience of the three colonies,
there is no medicament or specific yet known [1884] that can be compared with
tobacco and sulphur as a thorough and lasting cure for scab in sheep.
The proportions adopted by Rutherford, and afterwards made official
by the scab sanitary authorities, are:
Tobacco leaves pound.. 1
The advantage of this dip lies in the fact that two of the best scab
remedies, namely, tobacco (nicotine) and sulphur, are used together,
Kinds of Dips.
THE TOBACCO-AND-SULPHUR DIP.
Flowers of sulphur
Water
...do.... 1
gallons.. '6
1 The original formula reads 5 gallons (imperial) which are equivalent to 6 United
States gallons.
24
BUREAU OF ANIMAL INDUSTRY.
both of which kill the parasites, while the sulphur remains in the wool
and protects for sometime against reinfection. As no caustic is used
to soften the scab, heat must be relied on to penetrate the crusts.
Directions for preparing the dip. — A. Infusing the tobacco: Place 1
pound of good leaf or manufactured tobacco for every 6 gallons of dip
desired in a covered boiler of cold or lukewarm water and allow to
staud for about twenty- four hours; on the evening before dipping bring
the water to near the boiling point (212° F.) for an instant, then remove
the lire and allow the infusion to stand over night.
B. Thoroughly mix the sulphur (1 pound to every C gallons of dip
desired) with the hand in a bucket of water to the consistency of
gruel.
C. When ready to dip, thoroughly strain the tobacco infusion (A)
from the leaves by presure, mix the liquid with the sulphur gruel (B),
add enough water to make the required amount of dip and thoroughly
stir the entire mixture.
All things considered, the tobacco-and-sulphur is as good a dip as is
known at the present time.
See also the discussion of the tobacco dip on page 30.
Under the term " liine-and-sulphur dips" is included a large num-
ber of different formula? requiring lime and sulphur iu different pro-
portions. In general practice all of these dips are spoken of as "the
liine-and-sulphur dip," but in reality each separate formula represents
a separate dip.
To give an idea of the variety of the lime-and-sulphur dips, the fol-
lowing list is quoted, the ingredients being reduced in all cases to
avoirdupois pounds and United States gallons:
1. The original "Victorian lime-and-sulphur dip" proposed by Dr.
Eowe, adopted as official in Australia:
Flowers of sulphur pounds.. 20j
Fresh slaked lime do 10^
Water gallons. . 100
2. South African (Cape Town) official lime-and-sulphur dip:
Flowers of sulphur (minimum) pounds.. 15
Unslaked lime do 15
Water gallons.. 100
3. South African (Cape Town) official lime-and-sulphur dip, February
4,1897: •
LIME-AND-SULPHUR DIPS.
Flowers of sulphur
Unslaked lime
Water
pounds
...do.,
gallons
20|
16f
100
4. Nevada lime-and-sulphur dip:
Flowers of sulphur
Lime
Water
pounds
...do...
gallons
m
33*
100
SHEEP SCAB: ITS NATURE AND TREATMENT. 25
5. Fort Collins lime-and-sulphur dip:
Flowers of sulphur pounds.. 33
Unslaked lime do 11
Water gallons.. 100
6. A mixture which, used to some extent by this Bureau, contains
tlie same proportions of lime and sulphur (namely, 1 to 3) as the Fort
Collins dip, but the quantities are reduced to:
Flowers of sulphur pounds.. 24
Unslaked lime do 8
Water gallons.. 100
Dangerous formula. ' .
7. California lime-and-sulphur dip :
Flowers of sulphur pounds.. 100
Lime do 25
Water gallons.. 100
8. A very dangerous misprinted formula to be found in several books
and journals, probably due to a typographical error:
Flowers of sulphur pounds.. 100
Lime do 150
Water gallons.. 100
In case of fresh scab formula No. 6 will act as efficaciously as the
dips with a greater amount of lime, but in cases of very hard scab a
stronger dip, as the Fort Collins dip, should be preferred, or, in unusu-
ally severe cases, an ooze with more lime in proportion to the amount
of sulphur, such as the Victorian (No. 1), the Nevada (No. 4), or the
South African (No. 3) dip might be used.
Many other formulae might be cited, but these are enough to show
the great variations in the dips which have been used; and to prove
that when a party simply states that "lime and sulphur" is an excel-
lent dip, or that it is a dangerous dip, or that he has succeeded or
failed with it, or that the lime-and-sulphur dip is injurious to the wool,
his statements can not be taken as definite, unless he also states which
lime and-sulphur dip he used and how he used it.
Prejudice against lime-and-sulphur dips.
There is at present great prejudice (a certain amount of it justified
no doubt) against the use of lime and sulphur, emanating chiefly from
the agents of patent or proprietary dips and from the wool manufac-
turers. It will be well therefore to consider the points brought forward
by them against its use.
In the first place, it is frequently asserted that lime and sulphur
does not cure scab. This statement is, of course, in the interest of pro-
prietary dips, but it is based either upon an absolute ignorance or a
misrepresentation of facts. Experience in Australia and South Africa,
as well as in this country, has shown beyond any doubt that a lime-
and-sulphur dip, when properly proportioned, properly prepared, and
properly used, is one of the best scab eradicators known. Cases of its
26
BUREAU OP ANIMAL INDUSTRY.
failure have been due to careless or improper methods of its prepara-
tion and use.
It is claimed by some that it produces " blood-poisoning." But the
cases of death following the use of lime-and-sulphur dips have been
infinitesimally few when compared with the number of sheep dipped iu
these solutions and when compared with the deaths which have been
known to follow the use of certain proprietary dips. The details of
such accidents so far as they have been reported have not shown that
death was due to any properly prepared and properly used lime and-
sulphur dip. If the formula of 100 pounds of sulphur, 150 pounds of
lime, and 100 gallons of water has killed animals, that surely is no argu-
ment against the formula 33 pounds of sulphur, 11 pounds of lime, and
100 gallons of water, but simply shows that the former formula is too
strong; if any other conclusion than this is drawn, consistency would
compel us to reject many of our most valuable remedies because some
parties had used them in overdose. The argument frequently raised
against lime and sulphur — namely, that "shear-cut" sheep die when
dipped immediately after shearing in a lime-and-sulphur dip which has
stood for some time — can be used equally well against other dips, and
simply shows that it is safer to use a fresh supply of dip and to allow
a short time to elapse after shearing before dipping. It is highly prob-
able that the cases of so-called " blood-poisoning" of shear-cut sheep
are generally due to an infection with bacteria in stale dip contain-
ing putrefying material. Some cases of death are also said to have
occurred after using a lime-and-sulphur dip made in brass kettles.
In au experiment by this Bureau, 5 cc. of a clear lime-and-sulphur
ooze (Formula No. 0) has been injected under the skin of a sheep with-
out producing any evil effects.
The greatest objection raised against the use of lime-and-sulphur dip
is that it injures the wool. This objection is raised by many wool man-
ufacturers, and echoed with ever-increasing emphasis by the manufac-
turers of prepared dips; while, after years of extensive experience with
properly prepared dip, its injury to the wool is strongly and steadfastly
denied by the agricultural department of Cape Colony.
It is believed that a certain amount of justice is attached to this
objection to lime and sulphur as generally used; unless, therefore, lime
and sulphur can be used in a way which will not injure the wool to an
appreciable extent, we should advise against its use in certain cases ;
in certain other cases the good accomplished far outweighs the injury
it does. Let us, therefore, examine into this damage and its causes.
The usual time for dipping sheep is shortly after shearing, when the
wool is very short; whatever the damage at this time, then, it can be
only slight, and the small amount of lime left in the wool will surely do
but little harm.
In full fleece, lime and sulphur will cause more injury. In Australia
the deterioration was computed by wool buyers at 17 per cent, although
in Capo Colony the department of agriculture maintains that if prop-
SHEEP SCAB: ITS NATURE AND TREATMENT.
27
erly prepared, and if only the clear liquid is used, the sediment being
thrown away, the official lime-and-sulpbur formula will not injure the
long wool. In our own experiments we have found some samples of
wool injured by dipping, while on other samples no appreciable effect
was noticeable.
It must not be forgotten that other conditions, such as variations in
the feed, pasturing on alkaline land, ill health from any cause, etc.,
may cause brittleness of the wool, which might be mistaken for the
effects of lime and sulphur.
If a lime-and-sulphur dip is used, care must be taken to give the solu-
tion ample time to settle, then only the clear liquid should be used,
while the sediment should be discarded. In some of our tests on sam-
ples of wool we have found that the dip with sediment has produced
very serious effects even when no appreciable effects were noticed on
samples dipped in the corresponding clear liquid.
Experience lias amply demonstrated that a properly made and prop-
erly used lime and-sulphur dip is one of the cheapest and most efficient
scab eradicators known, but its use should be confined to flocks in
which scab is known to exist, and to shorn sheep, with the exception
of very severe cases of scab in unshorn sheep. It should only be used
when it can be properly boiled and settled. The use of lime and-sul-
phur dips in flocks not known to have scab, especially if the sheep are
lull fleeced, can not be recommended; in such cases tobacco, or sulphur
and tobacco, is safer and equally good.
If a lime-and-sulphur dip is chosen, it is better for ordinary cases to
use the solutions containing a small amount of lime and three times as
much sulphur as lime, as the Fort Collins formula (33 pounds of sul-
phur and 11 pounds of lime to every 100 gallons of water) or the Bureau
of Animal Industry formula (No. 6) (24 pounds of sulphur aud 8 pounds
of lime to 100 gallons of water), rather than the formula with a greater
proportion of lime.
If the stronger solutions, as the Victorian formula (No. 1), or the
present South African formula (No. 3), or the Nevada formula (No. 4)
are used at all, their use should be confined to unusually severe out-
breaks. Under no circumstances should the Oalifornian formula (No. 7)
or formula No. 8 be used. They are too strong, and the latter is espe-
cially liable to kill the sheep.
Another objection raised to the use of lime and sulphur is the claim
that the "shrinkage" in the sheep after the use of these dips is greater
than after the use of other dips. In reply to this objection, raised
chiefly by patent-dip manufacturers, it can only be repeated that such
has not been the experience of this Bureau (see p. 35), nor was it the
experience of Professor Gillette in his experiments in Colorado. The
burden of proof for the opposite statement, with exact statistics, rests
upon those who raise this objection.
Still another objection advanced against lime and sulphur is that
its continued use year after year will gradually decrease the annual
28
BUREAU OP ANIMAL INDUSTRY,
clip. Whether this objection be valid or not, it is scarcely necessary
to discuss it in detail in this place; for, in the first place, the average
sheep raiser of this country does not keep the same sheep "year after
year," but sends most of his sheep (breeding ewes and the rams
excepted) to market. Hence there will usually be little opportunity
to injure the wool of a given animal "year after year." In the next
place, if lime and sulphur are properly used one year, so that the flock
is freed from scab and if reinfection be guarded against, it will not be
necessary to resort again to lime and sulphur.
These objections have been reviewed somewhat in detail in order to
place the facts, so far as obtainable, before the farmer. It is not par-
ticularly advised by the Bureau that lime and sulphur be used in this
country in preference to sulphur and tobacco, or tobacco alone, or any
other effective dip. In fact, it is hoped that within ten years there will
be no further use for the lime-and-sulphur dips. At the same time,
where it is a choice, on the one hand, between lime and sulphur, with a
temporary slight deterioration in the value of wool, but an absence of
scab, and, on the other hand, the use of a secret and ineffective patent
dip, with the continual presence of scab, and hence permanent deterio-
ration in wool, there can be no doubt that the decision should be in
favor of lime and sulphur (properly prepared and properly used).
All things considered, where it is a choice between sacrificing the
weight of sheep, aud to some extent the color of the wool, by using
tobacco and sulphur, and sacrificing the staple of the wool by using
lime and sulphur, the farmer should not hesitate an instant in selecting
tobacco in preference to lime. The loss in weight by using tobacco
and sulphur is not much greater than the loss iu using lime and sul-
phur, while the loss in staple is of more importance than a slight
discoloration.
Preparation of the mixture. — Almost as many different methods of
preparing the liquid exist as there are different formulte, some of the
methods laying great stress upon sifting both the lime and the sulphur,
others laying great stress upon allowing the liquid to settle, others
leaving out of consideration both of these points. The method which
has been found in the Bureau to be the easiest and most satisfactory
is as follows:
A. Take 8 to 11 pounds of unslaked lime, place it in a mortar box or
a kettle or pail of some kind, aud add enough water to slake the lime
and form a "lime paste" or "lime putty." 1
B. Sift into this lime paste three times as many pounds of flowers of
sulphur as used of lime, and stir the mixture well.
1 Many persons prefer to slake the lime to a powder, which is to be sifted and
mixed with sifted sulphur. One pint of water will slake three pounds of lime if the
slaking is performed slowly and carefully. As a rule, however, it is necessary to
use more water. This method takes more time and requires more work than the one
given above, and does not give any better results. If the boiled solution is allowed
to settle the ooze will be equally as safe.
Sheep scab: its nature and treatment.
29
Be sure to weigh both the lime and the sulphur. Do not trust to
measuring them in a bucket or to guessing at the weight.
0. Place the sulphur -lime paste in a kettle or boiler with about 25 to
30 gallons of boiling water, and boil the mixture for two hours at least,
stirring the liquid and sediment. The boiling should be continued
until the sulphur disappears, or almost disappears, from the surface;
the solution is then of a chocolate or liver color. The longer the solu-
tion boils the more the sulphur is dissolved, and the less caustic the
ooze becomes. Most writers advise boiling from thirty to forty min-
utes, but we obtain a much better ooze by boiling from two to three
hours, adding water when necessary.
D. Pour the mixture and sediment into a tub or barrel placed near
the dipping vat and provided with a bunghole about four inches from
the bottom and allow ample time (two to three hours, or more if neces-
sary) to settle.
The use of some sort of settling tank provided with a bunghole is an
absolute necessity, unless the boiler is so arranged that it may be used
both for boiling and settling. An ordinary kerosene oil barrel will
answer very well as a small settling tank. To insert a spigot about
three to four inches from the bottom is an easy matter. Draining off
the liquid through a spigot has the great advantage over dipping it out
in that less commotion occurs in the liquid, which therefore remains
freer from sediment.
JE. When fully settled, draw off the clear liquid into the dipping
vat and add enough warm water to make 100 gallons. The sediment
in the barrel may then be mixed with water and used as a disinfectant,
but under no circumstances should it be used for dipping purposes.
A double precaution against allowing the sediment to enter the vat
is to strain the liquid through ordinary bagging as it is drawn from the
barrel.
In watching the preparation of lime-and-sulphur dips by other
parties the Bureau investigators have found some persons who laid
great stress upon stirring the sediment well with the liquid before
using the ooze. This custom is undoubtedly responsible for a great
deal of- the prejudice which exists at present against lime-and sulphur
dips; and considering the preparation of these dips in this way there is
no wonder at the immense prejudice against them in certain quarters.
To summarize the position of the Department ou the lime-and-sul-
phur dips: When properly made and properly used, these dips are
second to none and equaled by few as scab eradicators. There is
always some injury to the wool resulting from the use of these dips,
but when properly made and properly used upon shorn sheep it is
believed that this injury is so slight that it need not be considered; on
long wool the injury is greater and seems to vary with different wools,
being greater on a fine than on a coarse wool. This injury consists
chiefly in a change in the microscopic structure of the fiber, caused by
the caustic action of the ooze. When improperly made and improperly
used the lime-and-sulphur dips are both injurious and dangerous, and
30
BUREAU OP ANIMAL INDUSTRY.
in tliese cases tlie cheapness of the ingredients does not justify their
use. In case scab exists in a flock and the farmer wishes to eradicate
it, he can not choose a dip which will bring about a more thorough cure
than will lime and sulphur (properly made and properly used), although
it will be perfectly possible for the farmer to find several other dips
which will, when properly used, be nearly or equally as effectual as any
lime and-sulphur dip. There is no dip to which objections can not be
raised.
It has been proposed by several parties to use a potassium sulphide
dip, and such a dip has been tried to some extent. As yet, however,
judgment upon it must be reserved. Gillette tried a dip composed of
4£ pounds of potash lye, 16 pounds of flowers of sulphur, and 100 gal-
lons of water, and promises further reports on its effectiveness. Sheep
dipped in this liquid gained but 6 pounds, namely, the same as the
sheep treated with carbolic dip.
The active principle of tobacco, upon which the tobacco dips depend
for their action, is a poisonous substance known as nicotine. This
poison when applied to animals externally in too strong solutions may
cause nausea, fainting, and even death. The dog and the rabbit are
particularly susceptible to its effects. Diluted to about thirty- three
one-thousandths to sixty one-thousandths of 1 per cent it makes a slow
but sure- acting and excellent sheep dip.
Unfortunately the percentage of nicotine varies greatly, not only in
different kinds of tobacco, but also in different parts of the plant, in
different years, and even in different parts of the same package. There
is more nicotiue in the leaves, for instance, than in the stems. In fer-
mented tobacco there seems to be a certain relation between the
amount of nicotine and the amount of juice present, so that in general
dry, thin leaves do not contain so much nicotine as thick, u fat " leaves.
The variation in percentage of nicotine in different kinds of tobacco
may be seen from the following table of determinations taken from
Kissling, 1893 :
Statemen t giving the name of tobacco and amount of nicotine in percentage of dry substance.
POTASSIUM SULPHIDE MP.
TOBACCO DIPS.
Per cent.
Per cent.
Virginia .
Virginia .
Kentucky
Sumatra .
Seedleaf . .
Seedleaf . .
Havana .
Havana . .
Brazil
4. 80
4.30
4.50
4.10
3.70
3.00
3.00
1.90
2.78
2.73
1.25
2.61
Brazil
Turkish
Elsace
Elaace
Maryland
Maryland scrubs
Carman
Ohio Bay
Ambalrma
Domingo
Ohio
1. 14
2.51
1. 91
0.92
1. 26
1. 17
1.18
1.06
1. 17
0. 82
0.68
Brazil Felix
Brazil Felix
Java
SHEEP SCAB: ITS NATURE AND TREATMENT.
31
In four carloads of stems, aggregating 127,273 pounds, one American
firm extracted 1,405.43 pounds of nicotine, or 1.104 per cent.
While the above figures represent the percentages extracted in the
chemical and manufacturing laboratories, they do not necessarily repre-
sent the amount which the farmer would be able to extract with the
methods and apparatus at his disposal. On account of the variation
in the amount of nicotine in the different samples of tobacco, it is prac-
tically impossible for the farmer to make up an exact desired strength
of tobacco dip if he prepares his own mixture from the leaves. He
can, however, prepare a mixture which will come within the limits
necessary to kill the scab parasites. If a solution of an exact given
strength is desired, it will be necessary to buy prepared nicotine, or
prepared tobacco dips of a guaranteed strength and reduce them to
the strength determined upon.
To prepare the tobacco dip from the leaves, it is best to use at least
21 pounds of leaves to every 100 gallons of water. Assuming that a
tobacco leaf is used from which the farmer might extract 2 per cent
of nicotine, the 100 gallons of ooze would contain slightly more than
five hundredths of 1 per cent; to obtain 100 gallons of ooze of thirty-
three one-thousandths of 1 per cent strength, it would be necessary to
use 21 pounds of tobacco yielding nearly 1.3 per cent nicotine.
Directions for preparing the dip. — For every 100 gallons of dip desired,
take 21 pounds of good prepared tobacco leaves; soak the leaves in
cold or lukewarm water for twenty-four hours in a covered pot or
kettle; then bring the water to near the boiling point for a moment
and, if in the morning, allow the infusion to draw for an hour; if in
the evening, allow it to draw over night; the liquid is next strained
(pressure being used to extract as much nicotine as possible from the
wet leaves) and diluted to 100 gallons per 21 pounds of tobacco. This
dip should be used as fresh as possible as it contains a large amount of
organic material which will soon decompose.
The proportions here given, 21 pounds of prepared tobacco leaves to
100 gallons of water, have given very satisfactory results, especially in
Gape Town colony, where the reports of the scab inspectors accord this
homemade tobacco dip third place among the dips officially recognized.
In regard to one of the proprietary tobacco dips the Cape Town agri-
cultural department reports as follows: "Highly spoken of by several
inspectors. Very efficacious, and improves the quality of the wool,
making it soft and pliable. The one thing which militates against its
general use is its expense, hindering the poorer farmers from using it.
It is allowed to be one, if not the best, of the patent dips in use, and
also the safest." By all means the use of a tobacco dip, or of the
tobacco-and-sulphur dip, in preference to the lime-and-sulphur dips is
advised in case the sheep to be dipped show no unmistakable signs of
scab.
The advantages of the tobacco dip are that it is comparatively cheap,
32
BUREAU OF ANIMAL INDUSTRY.
since the farmer can grow his own tobacco ; that it is effectual and at
the same time not injurious to the wool. The disadvantages of* the dip
are that it sometimes sickens the sheep; that it also occasionally
sickens the persons who use it, especially if they are not smokers; it
spoils very rapidly ; it causes a greater setback than lime and sulphur,
but less of a setback than carbolic dips.
ARSENICAL DIPS.
There are both homemade arsenical dips and secret proprietary arsen-
ical dips. It is well to use special precautions with both because of the
danger connected with them. One of the prominent manufacturers of
dips, a firm which places on the market both a powder arsenical dip
and a liquid nonpoisouous dip, recently summarized the evils of arsen-
ical dips in the following remarkable manner:
The drawbacks to the use of arsenic may be summed up somewhat as follows :
(a) Its danger as a deadly poison. (if) Its drying effect on the wool, (c) Its weak-
ening of the fiber of the wool in one particular part near the skin, where it comes in
contact with the tender wool roots at the time of dipping. (<i) Its not feeding the
wool or stimulating the growth, or increasing the weight of the fleece, as good
oleaginous dips do. (e) The danger arising from the sheep pasturing, after coming out
of the bath, where the wash may possibly have dripped from the fleece, or where
showers of rain, after the dipping, have washed the dip out of the fleece upon the
pasture. (/) Its occasionally throwing sheep off their feed for a few days after
dipping, and so prejudicing the condition of the sheep, (g) Its frequent effect upon
the skin of the sheep, causing excoriation, blistering, and hardness, which stiffen and
injnre the animal, sometimes resulting in death.
Although this manufacturer has gone further in his attack upon
arsenic than this Bureau would have been inclined to do, it must be
remarked that when a manufacturer of such a dip can not speak more
highly of tbe chief ingredient of his compouud than this one has done
in the above quotation, his remarks tend to discredit dips based upon
that ingredient. It might be added that Bruce, the chief inspector of
live stock for New South Wales, pays his respects to arsenical dips
with the statement, "Arsenic and arsenic and tobacco (with fresh runs)
cured 9,284 and failed with 9,271."
It may be said, on the other hand, that arsenic really has excellent
scab-curing qualities ; it enters into the composition of a number of the
secret dipping powders and forms the chief ingredient in one of the old-
est secret dips used. This particular dip has been given second place
(with some qualifications) among the officially recognized dips in South
Africa. In deference to the opinion of those who prefer an arsenical
dip several formulae are quoted here.
Formulae for arsenical dips. — Finlay Dun recommends the following:
Take 3 pounds each of arsenic, soda ash (impure sodium carbonate) or
pearl ash (impure potassium carbonate), soft soap, and sulphur. A
pint or two of naphtha may be added if desired. The ingredients are
best dissolved in 10 to 20 gallons of boiling water and cold water is
SHEEP SCAB: ITS NATURE AND TREATMENT.
33
added to make up 1 120 gallons. The head of the sheep must, of course,
be kept out of the bath.
A mixture highly indorsed by certain parties consists of the following
ingredients:
The arsenito of soda is thoroughly mixed with the sulphur before
being added to the water.
Precautions in use of arsenical mixtures. — Any person using an arsen-
ical dip should bear in mind that he is dealing with a deadly poison.
The following precautions should be observed:
(1) Yards into which newly dipped sheep are to be turned should
first be cleared of all green food, hay, and even fresh litter; if perfectly
empty they are still safer. (2) When the dipping is finished, the yard
should be cleaned, washed, and swept, and any unused ooze should at
once be poured down a drain which will not contaminate food or
premises used by any animals. (3) Dipped sheep should remain in an
open, exposed place, as on dry ground. (4) Overcrowding should be
avoided, and every facility given for rapid drying, which is greatly
facilitated by selecting fine, clear, dry weather for dipping. (5) On
no account should sheep be returned to their grazings until they are
dry and all risk of dripping is passed.
Suggestion as to danger. — The formula? given above are copied from
the writings of men who have had wide experience in dipping, but this
Bureau assumes no responsibility for the efficacy of the dips given or
for their correct proportions. Furthermore, as long as efficacious non-
poisonous dips are to be had, we see no necessity for running the risks
attendant upon the use of poisonous dips.
A carbolic-acid dip may be made at home or may be purchased as a
proprietary article. This class of dips kills the scab mites very quickly,
but unfortunately the wash soon leaves the sheep, which is conse-
quently not protected from reinfection in the pastures. If, therefore,
a carbolic dip is selected, it is well to add flowers of sulphur (1 pound
to every 6 gallons) as a protection against reinfection.
The advantages of carbolic dips are that they act more rapidly than
the tobacco or sulphur dips, and that the prepared carbolic dips are
very easily mixed in the bath. They also seem, according to Gillette,
to have a greater effect on the eggs of the parasites than either the
sulphur or the tobacco dips. The great disadvantages of this class of
dips are, first in some of the proprietary dips, that the farmer is uncer-
tain regarding the strength of material he is using; second, the sheep
1 The original formula reads 100 (imperial) gallons, which equal 120 United States
Commercially pure arsenite of soda
Ground roll sulphur
Water
pounds.. 14
do.... 3ii
gallons (U. S.).. 432
CARBOLIC DIPS.
gallons.
3227— No. 21
3
34
BUREAU OF ANIMAL INDUSTRY.
receive a greater setback than they do with either lime and sulphur or
tobacco.
Gillette reports most excellent results from the use of a certain pre-
pared carbolic dip. The Bureau purchased the same dip upon the
open market and tested its effects upon the sheep in the proportion
recommended by the manufacturer on the label of the package and
also in one-half and one-third that strength. In the first and second
tests the dip was severe both on the sheep and on the operators. In
one case it caused a considerable, though temporary, eruption on the
hands and arms of an operator. In all three cases the dipped sheep
were almost overcome in the dipping tank, and upon recovering them-
selves ran around the field iu an excited mauner, bleating loudly and
shaking their heads and tails. The eyes were more congested than we
have ever seen them to be after a lime-and-sulphur or a tobacco dip.
An objection to some of the proprietary carbolic dips is that the
manufacturers themselves apparently are little acquainted with their
own mixtures. Their claims are extravagant and their directions often
contradictory. It may be admitted that the carbolic dips are promis-
ing and that they may have a brilliant future, but they have not had
a very brilliant past, and this Bureau is inclined to be extremely con-
servative in regard to them and to advise their manufacturers to pre-
pare them in a guaranteed strength with more explicit directions for
use than are to be found in the present circulars. The dip just referred
to was certainly more severe in its effects on the sheep than can be
justified by its quick action in killing the scab parasites, considering
that other equally effective but milder solutions are to be had.
We also found in our tests (which are not yet fully completed) that
the sheep have gained less in weight when dipped in certain two ot
these washes than when dipped in lime and sulphur, or in sulphur and
tobacco, or in tobacco.
If a carbolic dip is used care must be taken that the ingredients
form a thorough emulsion ; if a scum arises to the top, a softer water
should be used.
In justice to this class of dips it is only fair to state that while the
views here expressed are entirely in accord with the opinions of some
authorities, they do not agree with the views held by others ; but they
are based upon the material purchased in open market, and probably
represent the experience of many who have used these dips. The
investigations of the Bureau certainly show that more tests are neces-
sary before this class of dips can be indorsed. It is hoped that these
tests may be made in the near future.
One of the prominent proprietary carbolic dips was formerly recog-
nized as one of the three official dips in New South Wales, but it has
now been stricken from the list. In Cape Town carbolic dips are not
much used, and in the official reports little is said concerning them.
SHEEP SCAB: ITS NATURE AND TREATMENT.
35
Setback to the Sheep from Dipping.
Dipping often results in a slight setback. If sheep are weighed
immediately before dipping, and again at the same hour the following
day, it will be noticed that the weight has changed. There may be a
gain, but usually there is a loss varying from | to 3£ pounds. The sec-
ond day there may also be either a gain or loss. As the weight of
sheep varies from day to day, from 1 to 5 pounds in loss or gain, due
chiefly to the increase or decrease of the amount of fodder and water
in the stomach, the effects of dipping can not be estimated in twenty-
four or forty-eight hours. In order to meet statements made concern-
ing loss or gain iu weight, this Bureau had sheep dipped at stated
intervals, aud the weights taken from week to week; all the sheep were
kept under exactly the same conditions; the dips used were lime and
sulphur, tobacco and sulphur, and two proprietary carbolic dips.
At the end of about two months, after three dippings, all of the
sheep showed a gain, with the exception of one of the sheep from
the carbolic dip, which lost slightly. The lowest gain among the sheep
treated with tobacco dip was 3£ pounds, the highest 11J pounds. The
lowest gain among the sheep treated with lime and sulphur was 7
pounds, the highest 8£ pounds. The lowest gain among the sheep
treated with the carbolic dip was 1£ pounds, the highest 3| pounds,
while one animal lost £ pound. The sheep were given a fourth dipping,
and at the end of another month showed the following gains aud losses
over their original weight at first dipping : Sheep treated with tobacco,
9 to 15 pounds gain; sheep treated with lime aud sulphur, 11^ to 14
pounds gain ; sheep treated with carbolic dip, 1 to 6 J pounds gain, in
one case 13£ pounds lost.
The experiment was then repeated, the lime aud sulphur being used
on sheep previously dipped in carbolic or tobacco dips, and vice versa.
After ten days the sheep treated with lime and sulphur had gained
from 2 to 3 pounds; the sheep treated with tobacco had remained sta-
tionary or had lost from 1 to 1J pounds; the sheep treated with car-
bolic dip had gained as high as 1 pound, or remained stationary, or
had lost as much as 2£ pounds. At this point circumstances inter-
vened which closed the experiments for the season.
Gillette has also made determinations of tbe loss of weight of sheep
from dipping. Part of his results agree with ours and part differ.
The chief point of difference in opinion is that Gillette considers that
the best conclusion can be based upon weights taken a few days after
dipping, while we consider the weight at a later period as the better
criterion. Gillette gives weights from November 17 to December 22,
and, taking the cases where the sheep bave been dipped twice, we see
from his tables that the carbolic sheep gained on an average G pounds,
the sheep treated with tobacco gained 8 pounds, the sheep treated
with arsenical dip gained 8 pounds, the sheep treated with lime and
36
BUREAU OF ANIMAL INDUSTRY.
sulphur 1 gained 9 pounds, while the sheep which were not dipped, in
order to give a basis for comparison, gained 6 pounds.
Holding in mind that sheep may apparently gain or lose about 3
pounds per day when not dipped, it is seen from the experiments by
Gillette, in Colorado, and by this Bureau, in the District of Columbia,
that the oft-repeated claim that lime-and-sulphur dips give a greater
setback than other dips is erroneous. In both the Western and the
Eastern experiments the sheep treated with lime and sulphur averaged
the greatest gain, the sheep treated with tobacco the second highest
gain, while the carbolic sheep showed the lowest gain.
DIPPING PLANTS.
There are numerous kinds of dipping plants in use, the size and style
varying according to the conditions which are to be met and the indi-
vidual taste of the owner.
The farmer who has but a small flock can use a small portable vat
for dipping, turning a part of his barn or some shed into a catching
pen ; by holding the sheep a moment at the top of the incline, as the
animals emerge from the vat, and allowing them to drain, he can do
away with the necessity of a drain-
(6) draining yards.
Iro. 5.— A simple caldron which may be used for * ' . . ,
boiling dip. Heating tanks or boilers are also
necessary. For a small vat any
portable caldron (figs. 5 and (>) with a capacity of 30 to 100 gallons
will answer, and the proper temperature may be maintained by pouring
fresh hot ooze into the vat as the supply is exhausted by the dipping.
In the large permanent plants the temperature can best be regulated
by means of a steam pipe or hot water coil close to the floor of the tub.
Thermometers are an absolute necessity. The floating dairy ther-
mometer (fig. 7) will be found to be most convenient, and several extra
thermometers should be kept on hand to replace broken instruments.
The thermometer is dropped into the vat and allowed to float for a
short time, then quickly removed and the temperature determined. It
is well to make paint marks at the side of the 100° and 110° points.
'Unfortunately for the comparison this lot did not receive the same fodder as the
others.
SHEEP SCAB: ITS NATURE AND TREATMENT.
37
Building material. — The yards and vat may be built of wood, concrete,
cemented stone, or brick, according to the individual taste of the owner
and the facilities at hand.
Dimensions. — The dimensions of the various parts given in the follow-
ing descriptions may be varied according to the breed and the number
of sbeep to be dipped. Dipping liquid will be saved by making the
tub much narrower on the bottom than at the top. On top, simple
oblong dipping tanks vary from 1 foot 9 inches to 3 feet in breadth, 2
feet or 2 feet 6 inches forming a convenient medium. Floors vary from
Cinches to 3 feet in width, 9 inches forming a good working medium.
Depth varies from 3 feet to 5 feet 0 inches, 4 feet to 5 feet forming a
convenient medium. If calves are to be dipped in the same vat it will
be best to make the tub 5 feet or 5 feet 6 inches deep.
In sinking the tub in the ground it is always well to have the top of
the tub 9 inches above the ground line. It is also well to sink one end
(where the sheep are thrown in) slightly lower than the other end, as
this will make it easier to empty and clean the vat.
Crutches, or forks. — In using large vats crutches, or dipping forks,
are necessary, and even with small vats they are useful. Crutches
should be 5 or 6 feet long. The handle should be strong (rake handles
are a little too light). One end is provided with an iron ferrule, into
which the bent iron is inserted. The iron should be one-half inch round
Fig. 6.— A caldron with otove.
BUREAU OF ANIMAL INDUSTRY.
or three-quarters inch half round. The form of the crutches
is shown in figs. 8 and 9.
Gauges. — The capacity of tabs should be plainly marked
on the side every 3 or (! inches, in order to correctly measure
the amount of liquid.
Small Portahi.e Vats for Small Flocks.
If no regular dipping vat is at hand a good-sized tub
may be used, as shown in fig. 10. Dipping in this manner
is slow and tedious, but may be resorted to in case of neces-
sity, as, for instance, when a few sheep are bought from
another flock which is not known to be absolutely free from
scab. If care is taken to dip thoroughly the dipping may
be done as effectually in such a tub as it could be done in
a large vat. llecourse to ordinary tubs is not advised,
however, when it is possible to use regular dipping vats.
Lambs may, in case of necessity, be dipped in troughs, as
shown in fig. 11.
A small portable vat, suitable for use in dipping small
flocks, is shown in fig. 12. When not in use this vat may
be conveniently stored away. An advantage connected
with this vat is that it may be drawn from place to place as
desired. The dimensions here given may be varied, accord-
ing to individual taste, by making the vat longer, broader,
or deeper. A convenient size will bo 9 feet long by 2^ feet
broad at the top, 9 inches broad at the bottom, and 3£ to 5
feet deep; the floor measures 9 inches broad by 4 feet long;
from 1 foot above one end of the floor a slant with cross
cleats rises to the top and end of the vat. The sheep are
dropped in by hand, one at a time, at the deep end, and after
being held in the dip for two minutes are allowed to leave
the vat at the slanting end. They are held a moment on
the slant to allow them to drain off, thus economizing in
dip. A gate may be placed at the deeper part of the slant
if desired, in order to save labor. This gate should swing
toward the exit of the vat. Such a tank may be made of
1^-inch pine boards, with tongue and groove, and should
be well pitched or painted.
This plan of vat may be easily modified, if desired, so as to
have a small dripping pen attached, as shown in figs. 13 and
14. In this modified plan an inclined platform is added to
the vat shown infig. 12 and aremovable skeleton boxis made
to fit over it. While one sheep is being dipped another
sheep is allowed to ascend the incline into the small dripping
pen. When the sheep is sufficiently drained the gate is
opened, it leaves the pen, the gate is closed, the sheep in the
vat enters the pen, and another sheep is placed in the vat.
SHEEP SCAB: ITS NATURE AND TREATMENT.
39
A small portable vat used in some places is shown in figs. 15 and 16.
Dipping in a vat of this kind may be thorough, but is tedious.
Another style of small vat suitable for holding three sheep at a time
is shown in fig. 17. It is estimated that 1,500 sheep may be dipped in
this tub in a single day. The dimensions of the plant are given in the
diagram, and need no further explanation.
FiQ. 8.— A cratch, or (lipping fork. (Copied Fia. 9.— Another style of crutch, or dipping
from the Agricultural Journal, 1894, p. 261.) fork.
More Permanent Plants for Larger Flocks,
receiving and forcing yards.
Where large numbers of sheep are to be dipped, it is necessary to
build receiving pens close to the dipping vat. The number aud size of
the pens vary with the number of sheep to be handled. The yards
Fio. 10 Dipping Bhcep in a tub. (Copied from Stewart's The Shepherd's Manual, 1882, p. 47.)
40
BUREAU OF ANIMAL INDUSTRY.
may be either square or oblong, as shown in figs. 17 and 18, or they may
be circular, as shown in fig. 19. The square or oblong yards are the
more simple in construction and need no detailed description, as all
details may be seen by consulting the diagrams. The circular yard,
however, needs a word of explanation.
Fig. 11. — Trough lor dipping lambs. (Copied from Stewart's The Shepherd's Maunal, 1882, p. 48.)
In using the circular yards (fig. 19) two natural habits of the sheep
are turned to practical account, so as to lessen the work of driving,
namely, the habit sheep have of "ringing" when disturbed in a yard,
and the tendency they show to escape at the point where they enter an
inclosure.
Fig. 12. — A small portable dipping vat for small Hooks.
The flock is yarded at AB and find its way into yards 1 and 2
through the openings CD and GJS. When these yards are full the
gates CD and AB are closed to form yard 6. The sheep then circle
through yards 3, 4, 5, and G, comin? t i the point at which they entered
SHEEP SCAB: ITS NATURE AND TREATMENT.
41
and expecting to escape. When yards 3, 4, 5, and C are filled the other
gates are closed, so that the sheep can not return to yards 1 and 2. If
Fio. 13 A small portable dripping vat with attached dripping platform.
the animals hesitate to enter yards 3, 4, 5, and G, another natural tend-
ency of the sheep may here be turned to account. A man jumps over
the fence and runs through the flock in the opposite direction (6; 5, 4, 3)
Fig. 14. — Detachable skeleton box, with gate, to nt over the dripping platform shown in fig. 13.
to that in which the animals are wanted to move. This will generally
result in starting the sheep in the desired direction.
42
BUREAU OP ANIMAL INDUSTRY.
Prom the exit of yard 6 (BG) there should be built a narrow run
extending to the dipping vat. This run should be about 20 feet long
by 21 feet wide, and should be provided with sides high enough, espe-
Fig. 15.— A small patented portable vat arranged as a cart.
Doctor, p. 491.)
(Copied from Armatage, 1895, The Sheep
cially near the vat, to prevent the sheep from jumping over and thus
escaping. These sides should be continued a short distance along both
sides of the vat. The last 5 feet of this run should slant down-
ward toward the vat at an incline of 25 to 30 degrees, and should be
Fig. Mi.— Portable vat unfolded and in use. (Copied from Armatage, 1895, The Sheep Doctor, p. 491.)
smooth. By pouring upon it some of the dip it may be made slippery
so that the sheep will slide into the vat. If there is no natural incline
toward the vat, an incline may easily be made by raising the floor of
SHEEP SCAB: ITS NATURE AND TREATMENT.
43
Fig. 17.— A small dipping plant: A, collecting yard; J»\ dipping vat; (7, place for man with fork; D,
incline, with cross cleats, to draining pons E and F. Lower diagram gives dimensions of the
vat. (Copied from Sutherland's Sheep Farming, 1892.)
Fig. 19.— Australian circular receiving and forcing yards, with straight race or drive, the incline
chute, straight vat, Incline, two draining pens, etc. Scale 50 feet to 1 J inches, making the outer
circle of the yards about 66 feet in diameter. (Copied from Brace's Scab and Its Cure, 1894, p. 17.)
44
BUREAU OF ANIMAL INDUSTRY.
the run at a point 5 feet from
incline x to the highest point
Much time will be saved in
in such a way that the sheep
This can be accomplished by
run, instead of being straight
point y (see fig. 19); the va
RISTINS VATO
1,600
the vat. The sheep will then pass up the
y, then down the incline chute z.
dipping if the yards and run are arranged
in the race can not see the dipping vat.
either of two simple methods: First, the
, may be built with a sudden angle at the
t will then not be visible to the sheep
ascending the incline x; or, second,
if a straight run is built as shown
in fig. 19 a loose curtain of bagging
may be hung at the point where the
run joins with the vat. This curtain
will fall back into place as the sheep
drop into the vat.
A modification of the circular pen
is seen in fig. 20, taken from Gibson's
(1893) History and Present State of
the Sheep Breeding Industry iu the
Argentine Republic.
CHUTES, OR SLIDES,
The most simple kind of chute is
made by using an incline at the end
of the run, as shown in fig. 19.
A second kind of chute in use is
the endless-chain or treadmill chute,
shown in fig. 21. Its construction
can be seen from the diagram and
need not be described in detail.
This chute may be improved by
building it on a slant toward the vat,
in which case a bolt or other arrange-
ment must be attached to stop the
chute when desired; the weight of
the sheep on the movable chute will
help to carry the animals toward the
vat.
A third chute in use is a pivo'ted platform, shown in fig. 22. The
sheep walk out on the platform until they overbalance its free end, and
then, when a sliding bolt is removed, fall into the tank. The structure
of the chute may be seen from the figure. Accidents are more likely
to result from using this chute than from using the slant or the chain
chute.
For dipping pregnant ewes some persons build a movable platform
which can be lowered into the vat and raised at will.
Fio. 20.— Argentine semicircular receiving and
forcing yards, with a straight vat, draining
pens, otc. The dimensions arc given in the
metric system: 1 m. (meter) equals 39.30
inches. (Copied from Gibson's History and
Present State of the Sheep-Breeding In-
dustry in the Argentine Eepuhlic, 1893.)
SHEEP SCAB: ITS NATURE AND TREATMENT.
45
THK DIPPING VAT.
The dipping vat may be made on several different plans: The single
oblong straight vat; the double or triple, with turns at the ends; the
Fig. 21.— Dipping plant provided with an endless-chain or treadmill chute. (Copied i'roin the Amer-
ican Sheep breeder, 1891.)
square; or the circular. In case of single oblong vats, time will be
saved in dipping if a long vat is used, so that the animals may swim
22. — Dipping plant illustrating: A, collecting anil forcing yards; H, straight drive; O, decoy pen
in which several sheep are kept; -Z>, dipping pen with pivoted rioor M, secured hy a holt; by with-
drawing the holt the sheep are precipitated into the square tuh F; O, sliding gate through which
the sheep pass from the tuh to the draining peus, J and K; L, channel for drip, conducting the
ooze back to the vat. The lower diagram gives a surface view of the upper figure. (Copied from
the Veterinarian, 1862, p. 333.)
directly through without stopping, and then leave the tank. Very nat-
urally the longer the vat the more building material and ooze will be
required. Vats are in use varying from 10 to 120 feet long.
46
BUREAU OF ANIMAL INDUSTRY.
The single oblong vat. — Single oblong dipping vats are shown in figs.
18, 19, 20, 21, 23. These tanks should be made about 2£ feet broad at
GROUND PLAN.
\
SECTION.
\
Via. 23 A, collecting yard for the sheep which are to ho dipped; II, 71, 71, small pens leading to O,
an inner pen with an inclined chute, or in which a man may stand to pass the sheep one at a time
into the vat; D 7>, tho tub, which should measure from 20 to 120 feet long, 21 to 30 inches hroad at
the top, 6 to 9 inches hroad at the hottom ; M , hoard 2 feet high on each side of the entrance of the
vat to catch the splash and to prevent the sheep from escaping ; E, E, draining, or dripping, pens ;
F, swinging gate; O, cross section of the tub ; J, crutch for keepiug the hacks of the sheep under
the surface, and for catching or holding sheep in the dip. (This drawing is taken from the Agri-
cultural Journal, in, 1891, p. 238 ; it was also published in tho American Sheep Breeder, Feb. 15,
1892.)
the top, 9 inches broad at the bottom, and 4 to 5 feet deep ; the length
may be 20 to 120 feet, as desired. One end (the entrance) should be
straight, as shown in figs. 24 and 26, or with a steep
slant, as shown in figs. 21, 23, and 25, while the last
5 to 14 feet at the other end (exit) should have a
gradual slant with cross cleats.
The square vat. — A square vat is shown in fig. 22.
This tub should be 5 feet deep, and large enough to
hold 10 or 12 sheep at a time. The square vat does
not present any particular advantages over nar-
row oblong vats, except that it gives the sheep
an opportunity to swim around. This kind of a
vat is not in very general use among large herders.
The triple vat. — In the triple vat (fig. 28) the sheep
come through the run, or drive, and slide into the
first vat at A; swimming in. the direction of the
arrows they round the turns B and 0, ascend the
incline I), and enter the draining pens. The theory
upon which this triple vat is used is that upon
rounding the point B the sheep bend toward the
left, thus crumpling the scabs on the left side and
opening the wool on the right; upon rounding the point G they bend
toward the right, crumpling the scabs of that side and opening the
TOP SECTION.
.SIKSECTWI*
Fig. 24. — A straight vat
known as the Aus-
tralian sheep dipping
tank. 1
1 This vat is in use at Tnlcumbah station. New South Wales, and gives much sat-
isfaction. Tho swimming race is 29 feet 3 inches long, 1 foot 10 inches wide at top,
with gradual inward slope to 11 inches at the bottom, and 5 feet 9 inches deep; the
landing stage (slant) is 14 feet 3 inches long (surface measurement), with a rise of
5 feet 9 in 14 feet 3 inches. To allow for any weak sheep, which stand in the way
aud block the others at the end of the swim, the landing stage opens out from 1 foot
SHEEP SCAB: ITS NATUEE AND TREATMENT.
47
wool on the left. This is evidently a more theoretical than practical
consideration.
□RDUND PLAN.
FlG. 25.— A somewhat similar straight swim taken from Sutherland's Sheep Farming: A, collecting
pens; B, B, smaller pens O, small pen at the side of the vat; Ji, decoy pen in which several
sheep are placed to induce the sheep in pen B to enter pen C; Z), Z>, a tub 50 to 60 feet long, 5 feet
deep, 21 inches broad mitii 3 'eet from the top, then narrowing to G or 8 inches at the bottom, as
shown in the cross section, G; M, a hoard 2 feet high to catch the splash; the last 18 feet of the
swim slants gradually, with cross cleats, to the draining pens, as seen in H; E, JE, draining pens,
worked alternately with the swinging gate, F; each pen measures 24 by 15 feet, and should slant
toward the vat ; J, crutch 5 or 6 feet long ; TV, mixer for stirring the liquid.
Each run should be about 15 to 30 feet long and 2£ feet broad; the
tank should be 4£ to 5 feet deep and 4 to 7£ feet wide at the bottom.
CATCHING KFWVL
floor where ruanwifli forVvwrta
TANK
HI
DRAINING KRAAL.
Kiq. 26. — A dipping plant figured in the Agricultural Journal, 1894, p. 620, in use in South Africa.
At the point J., where the sheep fall into the swim, it is best to have
the floor of the first run 2£ feet wide for a distance of 6 feet, in order
10 inches at top and 11 inches at bottom to a width (top and bottom) of 6 feet at a
distance of 6 feet 3 inches (longitudinally) from the end of the swimming race,
and gradually widens for the remaining 8 feet of length to a width of 7 feet at
the end.
48
Fio. 27.— A dipping plant in uso in Millard County, Utah. A, chute from the large corral ; B, a slop-
ing hoard over which the sheep in attempting to pass to the decoy pen, C, slide into the tank, D;
K, Jf, two pieces, 2 by ii inches and 12 feet long, bolted lengthwise of the tank, leaving a 12-iuch
space in the middle of the dip through which the sheep must put their heads, preventing those in
rear from riding those in front, at the same time keeping their backs under the dip. (Copied from
Powers' The American Merino, 1887, p. 308.)
ISTt. t« 3D Ft.
Fig. 28.— A triple Tat. The various diagrams give surface view, cross section, vertical section of
entrance to the vat, and vertical section of the incline and dripping pens.
SHEEP SCAB: ITS NATURE AND TREATMENT.
49
to prevent accidents, but beyond tbat distance the floor may be nar-
rowed in order to save the dipping flaid. If the partitions E and F
are not made solid the ooze will circulate more easily and thus remain
at a more even temperature ; the boards should be close enough
together, however, to prevent the sheep from catching their feet in the
cracks. A gate should be arranged at D, so that the animals may be
delayed in the ooze, if desired. (See also fig. 36 of the triple vat in use
at the Chicago Stock Yards.)
The circular vat. — Some parties prefer a circular vat (fig. 29). The
advantages set forth in favor of this are, first, a fewer number of men
are required to attend to the animals in the tub; second, where it is
Fig. 29. — A circular dipping tank. (Copied f rom the Agricultural Journal, 1895, p. 119.)
desired to give any particular sheep an extra long swim, this may be
done by quickly closing the gate D at the exit, thus compelling the
animal to swim around again, without delaying the other sheep; third,
by building a circular vat with a circumference of 30 feet the animals
may be made to swim around two, three, or four times, thus gaining
the advantage of a tank GO, 90, or 120 feet long, yet with a much smaller
amount of building and dipping material.
The vat should be 2| feet broad art the top, 9 inches broad at the bot-
tom, and 5 feet deep. To determine the circumference multiply the
diameter by 3.141G.
Despite the advantages of the circular tank in saving material and
obtaining tuo advantages of a long swim, there are two rather serious
3227— No. 21 4
50
BUREAU OF ANIMAL INDUSTRY.
objections to it: First, in the vat as shown in fig. 29, it is necessary to
throw the animals in by hand, since a chute directed into the circle
would lead to accident; second, the circular vat is much more difficult
of construction than the straight vat.
These objections may, however, be overcome in several ways, still
preserving all the advantages. If a circular vat is preferred and a
Fig. 30.— A circular dipping tank, with drive and slide.
chute is desired, the object may be attained by building a short, straight
vat on a tangent to the circle, as shown in fig. 30. In this case, two
swinging or sliding gates, A and B, will be required.
The double vat. — All of the advantages of the circular vat may be
combined with the easy construction of the straight vat by building a
straight tub with a double channel, as shown in figs. 31 and 32, the
SHEEP SCAB: ITS NATURE AND TREATMENT.
51
second swim being prolonged in an incline to the draining pens. Such
a vat may be constructed as follows :
Build an oblong tub 15 feet long, 5 feet deep, 5 feet wide at the top,
and 3 to 5 feet wide at the bottom. Running lengthwise through the cen-
ter, build an upright, partially open, partition 10 feet long and 4£ feet
deep (measured from the top of the tub), leaving an open space of 2£ feet
at each end and 0 inches at the bottom; this partition is supported by
three uprights running to the floor of the tub, and cross supports may be
placed on top of the tub at any point except near the entrance of the
Flo. 31 View of double oblong swim. (Consult also fig. 32.)
swim. A gate is hung at one end between the slide (entrance) and the
incline (exit), and should extend above the tub, in order to prevent the
slieep from jumping over the middle partition into the second swim;
it should extend down to within about 6 or 12 inches of the floor of the
tub. When this gate is closed against the middle partition the sheep
will leave the vat by the incline to the draining pens; when it is closed
against the incline, the sheep can be forced to swim around the tub two
or three times, as desired. Or, in place of a swinging gate, two sliding
gates may be arranged to run up and down in grooves, balancing each
52
BUREAU OF ANIMAL INDUSTRY.
other or each balanced separately by weights. One of these gates is
placed between the end of the vat aud the end of the middle partition,
the other is placed at the entrance of the incline to the draining pens.
By constructing the double vat and sending the sheep around three
times there would result, first, a saving in the original cost of the
tank when compared with a 90-foot straight swim ; second, a saving in
space; third, less than half as much dip would have to be kept warm
at a time; fourth, less than half as much dip would have to be made
Fig. 32.— A double oblong swim : A, ground plan; B, side view of the middle partition ; O, longitudi-
nal section of the first swim ; J), longitudinal seotion of the second swim, with incline; E, cross
section of the entire vat, with partition in the center.
up at a time; fifth, the residue after dipping would be reduced and
thus the loss decreased. It would, however, take a longer time to dip
a large flock of sheep in such a vat than in a straight vat 90 feet long.
The Incline to the Dripping Pens.
At the end of the vat an incline, with cross cleats, is built so that
the sheep may leave the dip of their own accord and enter the draining
pens. A board fence, 2 feet high above the top of the vat, should run
SHEEP SCAB : ITS NATURE AND TREATMENT.
53
a few feet each side of this incline to prevent the sheep from escaping.
These inclines are shown in figs. 21, 23, 25, and 20 ; the rise for fat heavy
wool sheep must not be too steep, otherwise the exertion will be too
great. In fig. 24 the incline is 5 feet 9 iuches in a surface distance of
14 feet 3 inches. At the Chicago Stock Yards the incline is 9 feet.
Much labor will be saved if a hinged or, still better, a sliding gate
Fig. 33. — Ground plan of yards and vat. (Copied from Arraatage, 1895, The Sheep Doetor.)
is placed at the deepest portion of the incline. The sheep may thus be
held in the dip as long as desired; when the time is up the gate is
opened and the sheep enter the draining pens.
The Dbippino Pens.
There should be two dripping pens side by side (figs. 17, 18, 21, 23, and
33) with a swinging gate at the entrance; one is filled, the gate is then
closed, opening the other pen ; when the second pen is filled the first
pen is emptied; or the pens may be in direct line with the vat (figs. 17
and 22).
These pens should have a slight incline toward the tub so that the
dripping ooze will run back to the tub. A good plan is to build the
incline from the sides toward the center fence; under the fence build
a partially covered gutter inclining to the tub ; the cover of the gutter
should be removable to allow cleaning; at the end of the gutter nearest
the tub place a grating to catch the wool and droppings, thus prevent-
ing these materials from being washed into the dip.
54
BUREAU OF ANIMAL INDUSTRY.
Shelter for the Dipping Plant.
The vat, boilers, and dripping pens should be under cover, and it will
be well to extend the cover over the drive and the forcing pens.
Arrangements for Cleaning.
Cleaning the plant may be facilitated if the following suggestions
are observed: It is well to have one end of the vat slightly lower than
the other end, so that the ooze will run toward that point when the
tub is being emptied. If the entire floor of the collecting pens is made
of brick, cement, or boards, and inclines slightly toward one or two
points, the yards may be more easily cleaned by means of a hose and
Fig. 34.— Ground plan of yards and vat. (Copied from Powers' Tho American Merino, 1887, p. 304.)
stream of water. If this plan is adopted there should be an upright
baseboard or a solid wall of concrete or brick a few inches in height
running around the edge of the entire pen. If there is direct sewer
connection for the vat a trap or manhole should be made to catch the
droppings and the tags of wool, otherwise the sewer pipe will become
obstructed.
Boiling, Infusing, and Settling Tanks.
The arrangemeut of the boiling tanks depends upon two factors in
particular: First, upon the kind of dip used; second, upon the arrange-
ment adopted for keeping the bath at the proper temperature.
In case a steam pipe is placed near the floor of the dipping vat in
order to keep the ooze at its proper temperature while dipping, the vat
itself may be used for heating water. Clear water is run into the vat
and tho steam turned on full force until the proper temperature is
obtained. If a carbolic or a prepared tobacco dip is used, the material
may then be mixed in the vat if desired. Even in this case, however,
it is best to provide a separate boiling tank for heating and preparing
fresh ooze to replace the dip as it is used up.
These boiling tubs may be made of wood or iron, according to the
facilities at hand. If steam is to be had, the square or round wooden
boiling tub may be used, and an open steam pipe run into it to heat
the water. If the steam pipe can not be used, either iu the vat or in
Fig. 35.— "View of the dipping plant at the stock yards, South Omaha, Nebr.
56
BUREAU OF ANIMAL INDUSTRY.
tlio boiling tanks, iron tanks should be provided. The iron tanks are
set iu brick or stone frames, with a fireplace below. It is best to have
two tiinks, each with a capacity of about 400 gallons.
If a homemade tobacco dip is prepared from the leaves there should
also be provided two iron infusing caldrons, each with a cover and with
a capacity of 80 to 120 gallons. The infusion is prepared in these
smaller tanks, while the bulk of the water is heated in the boiling
tanks or in the swim itself.
If a lime-and-sulphur dip is used it is absolutely necessary to pro-
vide some means for settling the mixture, in order that the bath may
be free from sediment. This may be done in two Ways. The better
way is to have separate settling tubs provided with bunguoles or pipes
three or four inches from the bottom. After the mixture is thoroughly
boiled it is pumped into the settling tubs and allowed to remain there
until it is perfectly free from sediment; the clear liquid is then run
into the dipping vat and diluted with warm water to the proper
strength. Or the boiling tanks may also be used as settling vats. A
pipe with elbow joint is run into the boiling tank three or four inches
above the bottom ; the opening of the pipe should point sidewise, not
up. After boiling the proper length of time the fire is removed and
the liquid allowed to stand uutil clear; ouly the clear ooze is drawn
off, the sediment remaining on the floor of the boiling tank.
Measures.
The capacity of the vat should be marked at different depths. The
capacity of the boilers should also be marked in the same way. If
these are marked for every 100, 200, 300, or 500 gallons (according to
the amount of dipping to be done), separate measuring tanks will be
unnecessary. In case the tanks are not marked a separate measuring
tank should be provided.
If a homemade tobacco dip or a lime and-sulphur dip is used a set
of scales is necessary. To guess at weights in mixing lime and sulphur
may result in too strong a dip.
Pumps.
A portable pump will be found of great use in filling and emptying
tanks.
Fig. 36 View of the dipping plant at tho Union Stock Tarda, Chicago, 111. (This dipping plant, including vat, boiler, etc., cost about $2,500.)
FEDERAL LAWS AND REGULATIONS RELATIVE TO
SHEEP SCAB.
As the scab of the sheep is unquestionably a contagious disease, it
is unlawful to ship sheep so affected from any State, Territory, or the
District of Columbia into any otber State, Territory, or the District of
Columbia. The penalties for such shipment of diseased sheep are
heavy, as will be seen from an examination of sections 0 and 7 of the
act approved May 29, 1884, which are as follows :
Sec. 6. That no railroad company within the United States, or the owners or
masters of any steam or sailing or other vessel or boat, shall receive for transpor-
tation or transport, from one State or Territory to another, or from any State into
the District of Columbia, or from the District into any State, any live stock affected
with any contagions, infectious, or communicable disease, and especially the disease
known as plenro-pnenmonia ; nor shall any person, company, or corporation deliver
for such transportation to any railroad company, or master or owner of any boat or
vessel, any live stock, knowing them to be affected with any contagious, infectious,
or communicable disease; nor shall any person, company, or corporation drive on
foot or transport in private conveyance from one State or Territory to another, or
from any State into the District of Columbia, or from the District into any State, any
live stock, knowing them to be affected with any contagious, infectious, or communi-
cable disease, and especially the disease known as pleuro-pneumonia: Provided, That
the so-called splenetic or Texas fever shall not be considered a con tagious, infectious,
or communicable disease within the meaning of sections four, five, six, and seven of
this act, as to cattle being transported by rail to market for slaughter, when the
same are unloaded only to be fed and watered in lots on the way thereto.
Sec. 7. That it shall be the duty of the Commissioner of Agriculture to notify, in
writing, the proper officials or agents of any railroad, steamboat, or other transpor-
tation company doing business in or through any infected locality, and by publica-
tion in such newspapers as he may select, of the existence of said contagion; and
any person or persons operating any such railroad, -or master or owner of any boat
or vessel, or owner or custodian of or person having control over such cattle or other
live stock within such infected district, who shall knowingly violate the provisions
of section six of this act, shall be guilty of a misdemeanor, and, upon conviction,
shall be punished by a fine of not less than one hundred dollars nor more than five
thousand dollars, or by imprisonment for not more than one year, or by both such
fine and imprisonment.
The provisions of this statute are very specific and clear, and there
can be no possible doubt of their application to the disease under con-
sideration. Congress has, nevertheless, gone still further by way of
emphasizing this application, and has particularly directed the atten-
tion of the Department of Agriculture to a few important diseases,
including sheep scab, by the following clause, which has been repeated
in the appropriation act for a number of years : ,
* * * and the Secretary of Agriculture is hereby authorized to use any part of
this sum he may deem necessary or expedient, and in such manner as he may think
58
SHEEP SCAB: ITS NATURE AND TREATMENT.
59
best, in the collection of information concerning live stock, dairy, and other animal
products, and to prevent the spread of pleuro-pneunionia, tuberculosis, sheep scab,
and other diseases of animals, and for this purpose to employ as many persons as he
may deem necessary.
Acting in accordance with this legislation, the following orders have
been made and promulgated by the Secretary of Agriculture :
REGULATIONS PROHIBITING THE TRANSPORTATION OF ANIMALS AFFECTED WITH HOG
CHOLERA, TUBERCULOSIS, OU SHEEP SCAB.
U. S. Department of Agriculture,
Office of the Secretary,
Washington, D. C, Decemher IS, 1S05.
Notice is hereby given that under the law relating to control of contagious and
infectious diseases of animals, tho regulations of the Bureau of Animal Industry
dated April 15, 1887, are hereby amended by additional section, as follows :
Sec. 15. Animals affected with hog cholera, tuberculosis, or sheep scab shall be
considered animals affected with contagious or infectious diseases as designated by
the law and the regulations of the Bureau of Animal Industry, and shall not enter
into interstate trade nor be brought into contact with other animals intended for
such trade. Such affected animals shall not be permitted to enter any stock yards or
other places where animals are handled for interstate trade, and when so found at
such places shall be condemned, tagged, and placed in quarantine by inspectors or
employees of said Bureau until proper disposition is made of same.
Stock-yard companies, transportation companies, or others receiving or handling
such diseased animals are hereby required to thoroughly disinfect such portions of
their premises or property as contained such diseased animals, subject to the approval
of the inspectors of said Bureau.
Such diseased animals so quarantined shall not be removed therefrom except by
written permit of the inspector in charge. When such diseased animals are found,
inspectors shall make careful inquiry as to shipper and owner of same, and trans-
portation company handling same, for the purpose of instituting prosecution under
the law provided in such cases.
All animals entering stock yards where inspection exists shall be carefully inspected
and those affected with the contagious diseases abovo mentioned shall be condemned
and tagged, and when so condemned shall not be shipped therefrom or enter into the
interstate trade ; and all violations of this regulation should be immediately reported
to the Chief of the Bureau of Animal Industry for institution of prosecution accord
ing to law.
J. Sterling Morton, Secretary.
(B. A. I. Obdeb Ho. 5.)
TRANSPORTATION OF SHEEP AFFECTED WITH SCABIES.
U. S. Department of Agriculture,
Office of the Secretary,
Washington, D. C, June 18, 1897.
To the Managers and Agents of Railroads and Transportation Companies of the United
States, Stockmen, and Others :
In accordance with section 7 of the act of Congress approved May 29, 1884, entitled
"An act for the establishment of a Bureau of Animal Industry, to prevent the
exportation of diseased cattle, and to provide means for the suppression and extirpa-
tion of pleuro-pneumonia and other contagious diseases among domestic animals,"
and of the act of Congress approved April 23, 1897, making appropriation for the
Department of Agriculture <or the fiscal year ending June 30, 1898, you are hereby
notified that the contagious disease known as sheep scab, or scabies of sheep, exists
among sheep in the United States, and that it is a violation of the law to receive for
60
BUREAU OF ANIMAL INDUSTRY.
transportation or transport any stock affected with said disease from one State 01
Territory to another, or from any State into the District of Columbia, or from the
District into any State. It is also a violation of the law for any person, company,
or corporation to deliver for such transportation to any railroad company, or master
or owner of any boat or vessel, any sheep, knowing them to he affected with said
disease ; and it is also unlawful for any person, company, or corporation to drive on
foot or transport in private conveyance from one State or Territory to another, or
from any State into the District of Columbia, or from the District into any State,
any sheep, knowing them to be affected with said disease. All transportation com-
panies and individuals shipping, driving, or transporting sheep are requested to
cooperate with this Department in enforcing the law for preventing tho spread of
the said disease. Inspectors of the Bureau of Animal Industry are directed to
report all violations of this act which come to their attention.
In order to-more effectually accomplish the object of the above-mentioned laws,
it is hereby ordered that any railroad cars, boats, or other vehicles, which have been
used in the transportation of sheep affected with said disease, shall be immediately
cleaned and disinfected by the owners or by the transportation companies in whose
possession said cars or vehicles may be at the time the animals are unloaded, by first
removing all litter and manure which they contain, and then saturating the wood-
work with a 5 per cent solution of crude carbolic acid in water. Inspectors of
the Bureau of Animal Industry are directed to see that this order is carried into
effect.
James Wilson, Secretary.
NOTICE OF ENFORCEMENT OF THE LAW.
These orders constitute the notice as to tbe existence of the disease,
and call the attention of transportation companies, stockmen, and others
to the provisions of the law. Any one who violates this law or the reg-
ulations made in accordance therewith will be subject to the penalty,
and can no longer plead ignorance or lack of notice. Owing to an
insufficent number of inspectors during the past years, the Department
has not been as active in seeking out and prosecuting offenders against
this statute as the importauce of the matter demands. There have
undoubtedly been many shippers, as well as transportation companies,
who have rendered themselves liable to prosecution and who have not
been proceeded against, but it sbould not be concluded that, because the
penalty has been escaped in a few instances, this immunity will con-
tinue. The inspection force is now competent to deal with this subject,
and the Department of Agriculture will hereafter take such steps as
may be required to stop the dissemination of this contagion through the
channels of interstate commerce. In such action the Department will
liave the assistance and cooperation of all good citizens, and partieu
larly of all of those who are interested in the sheep industry. There
is probably no disease in this country, with the exception of hog cholera,
which causes greater losses among the domestic animals than does sheep
scab, and at the same time none which is so easily, cheaply, and certainly
cured. It is, therefore, discreditable to the intelligence and practical
qualities of our people that this contagion should still be rampant and
continually distributed through the channels of commerce.
All sheep owners who expect to ship or drive their sheep across State
SHEEP SCAB: ITS NATURE AND TREATMENT.
61
lines should assure themselves before the animals are started that scab
does not exist among them. In case symptoms of the disease are discov-
ered, the animals should be dipped and cured before they leave the
farm. The information in this bulletin is sufficient to enable anyone
to cure this disease with a minimum of trouble and expense. There
will hereafter be no excuse for those who claim that they are unac-
quainted with the nature of the disease or with the methods of treat-
ment.
EFFECT OF MEAT-INSPECTION REGULATIONS!
Sheep suffering from scab are affected by the meat-inspection law
and regulations, as well as by those mentioned above. Section G of
these regulations provides as follows :
6. The inspector in charge of said establishment shall carefully inspect all animals
in the pens of said establishment about to bo slaughtered, and no animal shall be
allowed to pass to the slaughtering room until it has been so inspected. All animals
found on either ante-mortem or post-mortem examination to be affected as follows
are to be condemned and the carcasses thereof treated as indicated in section 7 :
(1) Hog cholera.
(2) Swine plague.
(3) Charbon, or anthrax.
(4) Rabies.
(5) Malignant epizootic catarrh.
(6) Pysemia and septicaemia.
(7) Mange, or scab, in advanced stages.
(8) Advanced stages of actinomycosis, or lumpy jaw.
(9) Inflammation of the lungs, the intestiues, or the peritoneum.
(10) Texas fever.
(11) Extensive or generalized tuberculosis.
(12) Animals in an advanced state of pregnancy or which have recently given birth
to young.
(13) Any disease or injury causing elevation of temperature or affecting the system
of the animal to a degree which would mako the flesh unfit for human food.
Any organ or part of a carcass which is badly bruised or affected by tuberculosis,
actinomycosis, cancer, abscess, suppurating sore, or tapeworm cysts must be con-
demned.
Instructions have been issued to inspectors to rigidly enforce these
regulations. Sheep in an advanced stage of scab are feverish and unfit
for food, and their carcasses will be condemned. Shippers who forward
animals for slaughter in this condition will be likely to lose heavily upon
them, as they will be subject to quarantine and condemnation. This
is an additional and important reason for curing affected animals before
they leave the feeding place.
Failure to observe the laws and regulations as they relate to this dis-
ease will in many cases result in hardship and loss. In order to avoid
such unpleasant results so far as possible and to facilitate the control
of the disease this article has been prepared. It is believed that there
has been brought together herein all the information needed by the
sheep owner to successfully combat this scourge of American flocks.
INDEX.
Page.
African, South, lime-and-sulphur dip, formula 24
Animal Industry, Bureau, lime-and-sulphur dip, formula 25
Arsenical dips, formulae and remarks ' 32
mixtures, precautions to be observed 33
Black muzzle of sheep, description 15
notes 10
Bruce, Dr., remarks on tobacco-and-sulphur dip 23
Bureau of Animal Industry lime-and-sulphur dip, formula 25
Californi,*! lime-and-snlphur dip, dangerous formula 25
Cape Town lime-and-sulphur dip, formula 24
Carbolic dips, description and tests 33
Ckoriopte8 communis var. ovie, cause of foot scab of sheep 11
Chorioptic scab, description 17
Chutes, or slides, description and use 44
Crutches, or forks, description and use 37
Demodectic scab, description 17
Demodex folliculorum var. ovis, cause of scab of eyelids of sheep 11
Dip, facilities at hand for preparing 22
importance of proper use 21
preliminary questions in choosing 22
tobacco-and-sulphur, preparation 24
Dips, homemade, successful 20
lime-and-sulphur „ 24
remarks on kinds 23
suggestions as to danger 33
Dipping a setback to sheep 35
choice of a preparation 20
for sheep scab, remarks 19
plants, arrangements for cleaning 54
description 36
permanent, for large flocks 39
shelter a requisite 54
vat, description of different kinds 45
Dripping pens, description 53
of incline 52
Eyelids of sheep, scab caused by Demodex folliculorum var. ovis 11
Federal laws and regulations relative to sheep scab 58
Flock, ascertain if scab exists 22
Follicular scab, description 17
Foot scab, description 17
caused by Chorioptes communis var. ovis 11
Forks, or crutches, description and use 37
Fort Collins lime-and-sulphur dip, formula 25
Great Britain first to prohibit United States sheep. 9
Hand applications for sheep scab 18
Head scab, description 15
notes ' » 10
Itching sometimes mistaken for sheep scab 17
Laws, Federal, and regulations relative to sheep scab 58
Lime-and-sulphur dips, how to use 27
prejudice against 25
preparation 28
Measures for vats 56
Meat inspection regulations, effect 61
Nevada lime-and-sulphur dip, formula 24
Nicotine, percentage in different varieties of tobacco 30
63
64 INDEX
Page.
Parasite of sheep scab, life bistory 14
vitality 12
Pastnres and (lipped sheep, remarks 23
Pens, dripping, description 53
of incline 52
Potassium sulphide dip, description 30
Proprietary articles for sheep dip 20
I'soroptes communis var. ovis, cause of common sheep scab 9
description 10
Pumps for tanks 56
Rain rot mistaken for sheep scab 17
Regulations and Federal laws relative to sheep scab 58
for meat inspection, effect 01
Rot, rain, mistaken for sheep scab 17
Sarcoptes scabiei var. ovis, cause of head scab of sheep 10
Sarco'ptio scab, description 15
notes 10
Sebaceous glands, inflammation, mistaken for sheep scab 17
Scab of sheep. (See Sheep scab.)
Sheep, ascertain if scab exists in the flock 22
different forms of scab affectiug 10
t-cab, cause 9
description of different forms 11
expense of a dip 22
Federal laws and regulations relative thereto 58
historical sketch 7
is it hereditary? 8
losses resulting 8
mistaken conditions 17
treatment 18
setback from dipping 35
shipment from United States to Australia, if certified 9
Slides, or chutes, description and use 44
South. African lime-and-sulphur dip, formula 24
Snlphnr-and-lime dips. (Sen Lime-and-sulphur dips. )
Snlphur-and-tobacco dips. (See Tobacco-aud-sniphur dips) 23
Symbiotic scab of sheep caused by Chorioptes communis var. oris 11
Tanks, infusing, boiling, and settling 51
Thermometer, use necosary , 35
Tobacco-and-sulphur dips, preparal ion 24
remarks 23
Tobacco dips, description 30
directions for preparing 31
percentage of nicotine in different varieties 30
Vats and yards, building material and dimensions 37
measures of capacity 56
small, portable, for small flocks 38
Victorian liine-and-sulphur dip, formula 24
Yards and vats, building material and dimensions 37
receiving and forcing, for dipping plants 39
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