be varied as desired, provided the above-given proportions of the
ingredients are adhered to. But one should attempt to work the S-B formula
on a larger scale only after skill and experience have been acquired.
_The boiled dip_ is less convenient than the S-B dip, but the final
composition and effect of dipping baths prepared from the two are the same.
To make a 500-gallon bath provide:
Sal-soda crystals 24 pounds.
White arsenic 8 pounds.
Pine tar 1 gallon.
Put 25 gallons of water into a kettle or tank of from 40 to 50 gallons'
capacity, heat to boiling, and add the sal soda. When this has dissolved
add the white arsenic, then boil and stir for 15 minutes or longer, until
the white arsenic has entirely disappeared. If intended for immediate use
cool to 140∞ F. (by addition of cold water if desired), then pour in the
pine tar in a thin stream while constantly and vigorously stirring the
solution. Immediately empty the liquid into the dipping vat, which has
already been three-fourths filled with water, and stir thoroughly.
All the utensils must be free from greasy or oily matter which would coat
the arsenic and hinder its solution. The operation of boiling requires
constant attention to avoid loss by foaming. Hard water may be used, but in
that case considerable undissolved material, which, however, does not
contain any arsenic, may be left after boiling.
For a stock solution to be kept on hand and used when needed add no tar,
but after the solution has become cold make it up to 25 gallons, stir well,
let settle, and draw off into containers which can be well closed. In this
case the tar stock previously described is also required.
_Diluting the dip._--First run water into the vat about three-fourths up to
the dipping line, at which its capacity must be known. If tar stock is to
be used the necessary amount will be one-third of a gallon for every 100
gallons of vat capacity. Measure it out, mix it with 2 or 3 times its
volume of water and pour it along the surface of the water in the vat,
stirring a little.
Every 100 gallons of standard-strength bath calls for 1-3/5 pounds white
arsenic, which quantity is contained in four-fifths of a gallon of S-B
stock or in 5 gallons of boiled stock. From these figures the quantity of
arsenic or stock needed to charge the vat may be calculated. Or one may
base the calculation on the following facts:
One pound of white arsenic will make 62-1/2 gallons of bath.
One gallon of S-B stock will make 125 gallons of bath.
One gallon of boiled arsenic stock will make 20 gallons of bath.
All solutions of arsenic are considerably heavier than water and if
carelessly put into the vat they may plunge to the bottom and be difficult
to mix. Therefore always pour the arsenic stock or a proprietary dip in a
thin stream evenly along the vat except at the shallow exit end. Another
precaution to be taken in handling proprietary dips is never to mix them
first with small quantities of water, which may "break" them. Pour them
directly into the water in the vat.
Finally, add water up to the dipping line and stir well. An excellent way
to stir is by a pail tied to a rope. Sink it at the entrance end of the vat
and haul it along the bottom to the exit. Then raise it, throw it back to
the entrance end, and haul through again, repeating as many times as
necessary but always hauling through in the same direction.
The standard-strength bath prepared as above contains practically 0.19 per
cent arsenious oxid when fresh. After use oxidation may set in and weaken
it, but it will not need to be strengthened so long as it tests not less
than 0.175 per cent arsenious oxid.
To make up small quantities for spraying, to each 5 gallons of water
measured out add first 2 fluid ounces (4 tablespoonfuls) of tar stock, and
then 5-1/8 fluid ounces of S-B stock or 2-1/8 pints of boiled arsenic
stock.
The standard strength of bath should be adhered to so far as possible
because its effectiveness against ticks will effect eradication in the
least time and with fewest dippings. But if time is not pressing it is
sometimes best to begin with a lower strength, say 0.14 or 0.15 per cent,
and gradually work up to full strength as the cattle become accustomed to
the treatment. This is certainly a wise method for the individual cattle
owner who is outside the area of cooperative work and who lacks aid and
advice from experts. Weather conditions also need to be considered. Hot or
moist weather is more trying to the cattle than cool or dry weather. The
longer the time needed for the cattle to dry off after dipping, which of
course primarily depends on the proportion of moisture in the air, the more
liable they are to show blistering or other injury through the continued
absorption of arsenic by the skin. The combination of heat and moisture is
particularly bad, and under such conditions it may be desirable, unless
other conditions prohibit, to use the bath somewhat weaker than standard
strength. The following table shows the quantities of arsenic and stock
solutions contained in 100 gallons of bath of different strengths, so that
the quantities necessary to charge a vat of any size at any strength can be
found by simple multiplication.
_Composition of dipping baths._
+-----------+------------------------------+
| Actual | Per 100 gallons of bath. |
| arsenious +------------------------------+
| oxid. | White | S-B | Boiled |
| | arsenic. | stock. | stock. |
+-----------+----------+---------+---------+
| Per cent. | Pounds. | Gallons.| Gallons.|
| 0.05 | 0.42 | 0.21 | 1.3 |
| .06 | .50 | .25 | 1.6 |
| .07 | .58 | .29 | 1.8 |
| .08 | .66 | .33 | 2.1 |
| .09 | .75 | .38 | 2.3 |
| .10 | .83 | .42 | 2.6 |
| .11 | .91 | .46 | 2.8 |
| .12 | 1.00 | .50 | 3.1 |
| .13 | 1.08 | .54 | 3.4 |
| .14 | 1.16 | .58 | 3.6 |
| .15 | 1.25 | .63 | 3.9 |
| .16 | 1.33 | .67 | 4.2 |
| .17 | 1.41 | .71 | 4.4 |
| .18 | 1.49 | .75 | 4.7 |
| .19 | 1.58 | .79 | 4.9 |
| .20 | 1.66 | .83 | ... |
| .21 | 1.74 | .87 | ... |
| .22 | 1.83 | .92 | ... |
| .23 | 1.91 | .96 | ... |
| .24 | 2.00 | 1.00 | ... |
+-----------+----------+---------+---------+
As dipping goes on the bath naturally needs replenishing, and its strength
probably needs correction from time to time. Full directions on these
points may be found in Farmers' Bulletin 1057.
_Prepared dips._--Proprietary arsenical cattle dips appear now to have
passed the experimental stage and to have become established as reliable
and useful products. At any rate this can be said of the brands which have
received permission for use in official dipping in place of the homemade
dip. The formulas and standard samples of all such brands are in possession
of the Bureau of Animal Industry and the manufacturers are required to
guarantee that their products as placed on the market will be kept up to
standard and that all requirements of the bureau will be observed. Like the
homemade dip they all contain sodium arsenite as the active tick-killing
agent. They do not all contain pine tar, because that substance is
difficult to blend into a highly concentrated product, but they all contain
some other substance or mixture of substances of such character and in such
quantity as field trials have proved will produce the same effects.
They are not regarded as any more effective or any milder on the cattle
than properly prepared homemade dips. None the less they are undoubtedly
safer for general use because they offer decidedly fewer opportunities for
making mistakes in the quantities used or in the operations gone through
and also fewer chances for accidental poisoning or other injury from the
handling of powerful chemicals. Whether their higher cost is sufficiently
outweighed by these considerations is necessarily a matter for individual
decision.
_Precautions in the use of arsenic and arsenical dips._--The fact that
arsenic is a violent poison is what renders it valuable, for the fever tick
is hard to kill. But, like a keen-edged tool, it may be decidedly dangerous
if ignorantly or carelessly handled. Three possibilities of danger must be
kept constantly in mind; danger to oneself, danger to other persons, danger
to animals.
The dry, powdered white arsenic should be kept in a tightly covered pail,
plainly labeled. Paper bags are unsafe because they easily burst, and
arsenic so scattered about looks harmless enough. In weighing or otherwise
handling the arsenic avoid raising dust or breathing it in, if raised, and
keep it off the skin and clothing. In mixing or boiling stock solutions
work only in a well-ventilated place, and on the windward side of the
kettle so that steam arising from it will not be inhaled.
The stock solutions are in some respects more dangerous than the original
substance because the arsenic in them is already in solution and can act
very quickly. If any gets on the skin or clothing it must be washed off
without delay. Cattle must be kept away from such solutions or from
anything that has been in contact with them, for cattle craving salt have
been poisoned by licking the outside of leaky barrels and by licking the
earth around dipping vats where a little concentrate had been carelessly
spilled in charging the vat. All such poisoned earth must be removed,
buried, and replaced by fresh.
The diluted bath is naturally much less dangerous, but no chances can be
taken with it. No puddles from which animals may drink should be allowed to
accumulate. The persons who do the dipping should not allow the skin or
clothing to be wet by the dip any more or any longer than absolutely
necessary. When spraying, the operator should see to it that neither he nor
the animals inhale any of the spray.
When a vat is to be emptied the approved practice is to run the waste bath
into a pit properly guarded by a fence, where it will gradually seep away
under the surface and do no harm, provided only that seepage can not be
carried to a well, stream, or spring from which any person or domestic
animal may drink.
The symptoms of arsenical poisoning are rather variable and also depend on
the size of the dose and the method of administration. If an animal sickens
or dies shortly after dipping it by no means follows that arsenical
poisoning or any other effect of the dipping is the cause. Very few cattle
relative to the total number dipped have suffered undoubted arsenical
poisoning and in most of the cases the cause could be traced to somebody's
error or carelessness.
In regard to arsenical poisoning of human beings there is a standard
antidote, which may be obtained at any drug store with directions for use.
It should be kept on hand for emergencies. If the antidote is not at hand
the poison must be removed from the stomach by encouraging repeated
vomiting, and soothing drinks such as milk, white of eggs and water, or
flour and water must be freely given meanwhile. A suspected case of
arsenical poisoning must have the attention of a physician at the earliest
possible moment, as sometimes the poison works very quickly.
_Crude petroleum._--Various kinds of crude petroleum and emulsions of it
have been used with more or less success in destroying ticks, but on
account of the difficulty of obtaining suitable grades of oil and the
liability of injury to cattle, their use has been practically abandoned.
_Method of dipping._--The method usually adopted in dipping cattle is to
construct a narrow swimming tank with a chute at one end for the entrance
of the cattle, and a sloping exit at the other end when the cattle emerge
after passing through the vat. (See Pl. XLIX, fig. 2.) A drip chute, or
floor, is connected with the exit, where the excess of dip is allowed to
drip off the animals and to drain into the vat. Plans and specifications
for installing dipping plants may be obtained from the Bureau of Animal
Industry, Department of Agriculture, Washington, D. C.
TREATMENT.
When Texas fever has broken out, all animals, the sick as well as the
healthy, should at once be removed to a noninfected pasture. While this may
not cut short the disease, it may save the lives of some by removing them
from the possibility of attack by more young ticks. Removal from infected
pastures likewise prevents a second attack, in October or early in
November, which is caused by another generation of ticks. Sick native
cattle infect with a new generation of ticks the pasture to which they are
removed, but these usually appear so late that they have but little
opportunity to do any damage; hence, sick natives do not, as a rule, cause
visible disease in other natives.
It is of importance to remove all ticks, so far as this is possible, from
sick animals, since they abstract a considerable quantity of blood and
thereby retard the final recovery.
Medical treatment of the sick has generally been unsatisfactory, although
in chronic cases and those occurring late in the fall beneficial results
have followed. If the animal is constipated, a drench containing 1 pound of
Epsom salt dissolved in 1 quart of water should be administered, followed
by sulphate of quinin in doses of 30 to 90 grains, according to the size of
the animal, four times a day until the system is well saturated with it.
Tincture of digitalis one-half ounce and alcohol 2 ounces may be combined
with the quinin, according to indications of individual cases. An iron
tonic containing reduced iron 2 ounces, powdered gentian 4 ounces, powdered
nux vomica 2 ounces, powdered rhubarb 2 ounces, and potassium nitrate 6
ounces will be found beneficial in the convalescent stage when the fever
has run its course. This tonic should be given in heaping teaspoonful doses
three times a day in the feed. Good nursing is essential in treating these
cases, and the animal should be given a nutritious, laxative diet with
plenty of clean and cool drinking water and allowed to rest in a quiet
place. If the stable or pasture is infested with ticks, the animal should
be placed in a tick-free inclosure to prevent additional infestation with
these parasites and the introduction of fresh infection into the blood.
Furthermore, all ticks that can be seen should be removed from the sick
cattle, as they keep weakening the animal by withdrawing a considerable
quantity of blood, and thereby retard recovery.
QUARANTINE REGULATIONS.
The sanitary regulations issued by the Department of Agriculture for the
control of cattle shipments from the infected districts have for their
initial purpose the prevention of the transportation of ticks from infected
regions to those that are not infected, either upon cattle or in stock cars
or other conveyer. They are based upon the fact that Texas fever is carried
north only by the cattle tick, and the exclusion of this parasite from the
noninfected territory has in every instance been found a certain method of
excluding Texas fever. The regulations governing the movement of cattle
from below the quarantine line are made yearly by the Secretary of
Agriculture, and they define the boundary of infected districts. The
infected area as now determined is shown in maps issued periodically.
In consequence of the enforcement of these quarantine regulations, Texas
fever has been practically prevented in the noninfected districts for
several years, and little or no hardship has been caused to stockmen
handling cattle from the infected areas. Prior to the adoption of these
regulations the tick-infested district was rapidly extending northward, but
since the quarantine line was established and rational regulations enforced
it has gradually been moved farther south. This problem of still further
reducing the infested area is of the greatest importance to the cattlemen
of the South--in fact, to those on both sides of the line--and one which is
receiving special consideration by this department as well as by many of
the interested States.
TICK ERADICATION.
Systematic cooperative work by the Federal Government and the affected
States for the eradication of the cattle ticks which transmit Texas fever
was begun in the summer of 1906 under authority given by Congress in the
appropriation act for the Department of Agriculture. The first Federal
appropriation for the fiscal year ended June 30, 1907, was $82,500, and for
the fiscal year 1908 an appropriation of $150,000 was made, then for
several years $250,000, and this has been increased to $660,000 for 1922.
Funds have also been provided by States and counties.
The original infected area amounted to 728,543 square miles. Of this
territory there has been released from quarantine as a result of the work
above mentioned 523,837 square miles (up to July 1, 1922). In other words,
72 per cent of the area has been freed from ticks in 16 years.
Great improvement has resulted from this work in the released territory.
More cattle are being raised, and a better grade of breeding stock is being
introduced; calves grow faster, and cattle put on flesh more rapidly during
the grazing season and go into the winter in better condition because of
the absence of the ticks; they can be marketed without quarantine
restrictions, and higher prices are being obtained; dairy cows give a
larger yield of milk; and values of farm lands are enhanced.
The difference between the prices realized for cattle from the
tick-infested region and the prices of cattle of similar grades from above
the quarantine line has ranged from $2.25 to $5 a head at the principal
northern live-stock markets, without taking into account the improvement in
quality and weight of cattle because of the eradication of the ticks. It
can easily be seen that the extermination of the ticks means a large total
annual increase in the prices obtained for southern cattle sold in northern
markets. In addition to this, the increase in prices of cattle sold locally
in the South would represent a large sum. This local increase has been
found to amount to from $3 to $15 a head in territory freed from ticks. An
agricultural official of one of the Southern States has reported that
calves in the tick-free area bring double the prices that can be obtained
for similar calves in the tick-infested region.
Heretofore it has been impracticable to improve the quality of southern
cattle by introducing fine breeding animals from other sections, because
such animals were liable to contract Texas fever and die unless protected
by inoculation. Furthermore, it is impossible for animals to attain good
growth and to thrive when they are heavily infested with ticks. With the
eradication of the ticks, however, the southern farmers are enabled to
introduce good breeding animals and to improve the grade of their stock.
There is no longer any doubt that it is entirely practicable to exterminate
the ticks throughout the entire region, and the accomplishment of this
result will be of tremendous economic advantage not only to the South but
to the whole country. The rate of progress depends mainly on two factors--
the amounts appropriated by the Federal and State Governments, and the
cooperation of the people.
* * * * *
SOUTHERN CATTLE FEVER (TEXAS FEVER, TICK FEVER).
DESCRIPTION OF PLATES.
PLATE XLIV. Normal spleen and spleen affected by Texas fever.
Fig. 1. Spleen of an acute, fatal case of Texas fever. The narrow end of
the spleen is here represented.
Fig. 2. Spleen of healthy steer. Though the latter animal weighed one-half
more than the former, the weight of the diseased spleen (6-7/8 pounds) was
nearly three times that of the healthy spleen (2-3/8 pounds).
PLATE XLV. Texas fever.
Fig. 1. The cut surface of a healthy liver taken from a steer slaughtered
for beef.
Fig. 2. The cut surface of the liver in Texas fever.
Fig. 3. Appearance of the urine in an acute, fatal case of Texas fever.
Fig. 4. Red corpuscles, magnified 1,000 diameters, containing the parasite
of Texas fever. This appears as a blue point _a_ near the edge of the
corpuscle. The blood was taken from a skin incision. The case was nonfatal
and occurred late in the fall.
Fig. 5. Red corpuscles from the blood of an acute, fatal case, 20 hours
before death. The Texas-fever microbes _a_ are shown as pear-shaped bodies,
stained with methylene blue, within the red corpuscles. The larger body on
the right _b_ is a white blood corpuscle, also stained with methylene blue.
(Magnified 1,000 diameters.)
PLATE XLVI. The cattle tick (_Margaropus annulatus_), the carrier
of Texas fever.
Fig. 1. A series of ticks, natural size, from the smallest, just hatched
from the egg, to the mature female, ready to drop off and lay eggs.
Fig. 2. Eggs, magnified 5 times.
Fig. 3. The young tick just hatched (magnified 40 times).
Fig. 4. The male after the last molt (magnified 10 times).
Fig. 5. The female after the last molt (magnified 10 times).
Fig. 6. A portion of the skin of the udder, showing the small ticks. From a
fatal case of Texas fever produced by placing young ticks on the animal.
(Natural size.)
Fig. 7. A portion of the ear of the same animal, showing same full-grown
ticks ready to drop off. (Natural size.)
PLATE XLVII. The cattle tick (_Margaropus annulatus_).
Fig. 1. Dorsal view of male. (Greatly enlarged. Original.)
Fig. 2. Ventral view of male. (Greatly enlarged. Original.)
Fig. 3. Dorsal view of replete female. (Greatly enlarged. Original.)
Fig. 4. Ventral view of same.
PLATE XLVIII. Portion of a steer's hide, showing the Texas-fever
tick (_Margaropus annulatus_). (Natural size. Original.)
PLATE XLIX. Fig. 1. Tick-infested steer.
Fig. 2. Dipping cattle to kill ticks.
PLATE L. Facsimile of poster used to show the difference between
cattle of similar breeding raised on a tick-free farm in one case and on a
ticky farm in the other.
* * * * *
CHRONIC BACTERIAL DYSENTERY.
Chronic bacterial dysentery is a chronic infectious disease of bovines
caused by an acid-fast bacillus simulating the tubercle bacillus and
characterized by marked diarrhea, anemia, and emaciation, terminating in
death.
This disease was observed in the United States for the first time by
Pearson in Pennsylvania cattle, and later by Mohler in Virginia cattle, and
in an imported heifer from the island of Jersey at the Athenia quarantine
station of the Bureau of Animal Industry.
Pearson proposed the name chronic bacterial dysentery for this affection,
and it has also been termed Johne's disease, chronic bacterial enteritis,
chronic hypertrophic enteritis, and chronic bovine pseudotuberculous
enteritis by various European investigators. The disease was first studied
in 1895 by Johne and Frothingham in Dresden, but they were inclined to
attribute to the avian tubercle bacillus the cause of the peculiar lesions
of enteritis which they observed. In 1904 Markus reported this disease in
Holland, and subsequently it was observed in Belgium, Switzerland, Denmark,
and Great Britain.
_Cause._--The bacillus, which has been invariably demonstrated in the
intestinal lesions and mesenteric lymph glands in this disease, is a rod
about 2 to 3 microns long and 0.5 micron wide. It stains more or less
irregularly, like the tubercle bacillus, and moreover the similarity goes
further, in that the organism is also strongly acid-fast, which facts led
Johne and Frothingham to surmise that the disease was caused by avian
tubercle bacilli. However, it has now been plainly demonstrated that the
bacillus of chronic bacterial dysentery is readily distinguished from the
latter organisms, for while it resembles the tubercle bacillus in form and
staining qualities, no one has succeeded in growing it in culture media or
in reproducing the disease by injecting experiment animals.