TEXAS AGRICULTURAL EXPERIMENT STATION

f" A. B. CONNER. DIRECTOR
College Station, Texas

BULLETIN NO. 611 APRIL 1942

FERN (NOTHOLAENA SINUATA,var.C1"enata)
POISONING IN SHEEP, GOATS, AND
CATTLE—THE SO-CALLED “JIMMIES”

OF THE TRANS-PECOS

FRANK P. MATHEWS

Division of Veterinary Science

in cooperation with
Bureau of Animal Industry
U. S. Department of Agriculture

LI BRA RY
Agricultural 8» Mechanical llnllege of Texas

College Statiun, Texas

AGRICYLTYRAL AND DIECHANICiAL COLLEGE OF TEXAS
T. O. ‘VALTON, President

B-9—-442—7l\I-——L180

[Blank Page in Original Bulletin]

A disease of sheep, goats and cattle which occurs on rocky, limestone
areas of the Trans-Pecos and referred to as “jimmies” was reproduced
by feeding Notholaena, sinuata Var. crenata, a fern growing from central
Texas to California and extending into Mexico. Since the greatest loss
occurs in sheep and due to the westward movement of this industry, it is
becoming one of the leadin.g disease problems for this class of livestock
in the Trans-Pecos. The grazing of this plant causes a slight to moderate
loss in goats but probably none in cattle. The effects of grazing the plant
may appear as early as the middle 0f November. Mortalities begin the
first part of January and continue until about three weeks after other
green feed becomes available in the spring. The disease is characterized
by trembling and sudden death, both of which are induced by exercise.

In the experimental feeding of this fern to sheep and goats, evidence of
toxicity was obtained by walking the animals not earlier than 48 hours
after receiving the first dose of the plant. Recovery from the toxic effects
of the plant required from 5 to 19 days, a period which agrees with range
observations.

Infested pastures should be devoted to goat or cattle grazing. If sheep
are maintained in such areas the pastures should be small and no attempt
made to work the sheep during the winter months.

[Blank Page in Original Bulletin]

FERN (N OTHOLAENA SIN UATA, var. Cren-ata) POISONING
IN SHEEP, GOATS AND CATTLE—THE SO~CALLED
“JIMMIES” OF THE TRANS-PECOS

BY
Fran]; P. Mathews, Veterinarian in Charge
Loco \Veed Laboratory, Alpine, Texas

(In cooperation with the Bureau of Animal Industry, Pathological
Division, United States Department of Agriculture,
Washington, D. C.)

For many years ranchers in certain areas of the Trans-Pecos have
recognized a disease entity which they refer to as “jimmies.” The disease
is characterized by sudden seizures of severe trembling which may be
followed by sudden death from respiratory paralysis, both of which are
induced by exertion. Affected animals show no indication of a morbid
condition while grazing, but fatalities frequently occur as a result of the
animals’ being driven as little as 100 yards. The term “jimmies” as
applied to the disease herein described bears no relation to the same term
which is sometimes used to designate rayless goldenrod poisoning. The
two diseases have no resemblance to one another.

The disease occurs in sheep, goats and cattle, but has never been
observed by the author in horses. There are reports of its occurrence
in horses but after observing this condition on numerous ranches where
the horses were being ridden daily with no ill effects and were being
grazed in the same pastures as the affected sheep we are forced to con-
clude that horses are not affected, or that they do not graze this toxic
plant. As a rule the disease appears about the middle of December and
disappears about three weeks after green feed becomes available in the
spring, which is about the latter part of March or the first of April.
Drought conditions hasten its appearance in the fall and if continued
throughout the winter may prolong its existence well into the spring
months. It has never been observed on the igneous rocks of the Davis
hlountains, but has been confined to rocky, limestone hills and moun-
tains—a type of soil which appears to be best adapted for the growth of
the fern which was found to be the cause of this disease. The fern has
been found in sufficient quantities to produce toxic effects at elevations
ranging from 2000 to 6000 feet.

The greatest loss occurs in sheep. In a flock of goats the incidence of
the disease may be just as high as in a corresponding number of sheep
but the loss is never severe. The goat appears to be more conscious of
approaching danger and when the symptoms appear can not be forced
to continue walking. It is probably this ability of the goat to take care
of itself rather than lower susceptibility which accounts for the much
lower death rate in goats than in sheep. From reports which have reachv

6 BULLETIN NO. 611, TEXAS AGRICULTURAL EXPERIMENT STATIOX

the author it is evident that this condition occurs in cattle but authentic
reports of losses from this source have not been received. Since exercise
is required to produce the symptoms and since no sane rancher will
subject affected sheep t0 unnecessary driving or handling, there is no
accurate method for determining the extent of the morbidity; however,
flocks have been observed in which an estimate of 75 per cent would
appear conservative. In sheep the loss may vary all the way from 1 to 25

per cent, depending upon range conditions and the-management of the _

flock. Large poorly watered pastures and unnecessary handling con-
tribute materially to the loss, but the chief factors involved in this con-
nection are range conditions and the amount of fern available for grazing.

BOTANICAL DESCRIPTION OF NOTHOLAENA SIN UATA var. Crenata*
(*By V. L. Cory, Range Botanist, Texas Agricultural Experiment Station.)

Notholaena sinuata (Lag.) Kaulf., var. crenata, Lemmon, is an erect,
leafy herb, 10-15 cm. high, from a short, woody, very chaffy rootstock.
Its fronds (leaves) are narrow, elongated, once-pinnate, tufted, and
petioled. Its pinnae (leaf-divisions or segments) are 5-8. mm. broad,
nearly orbicular (as broad as long), one or more crenately toothed‘ or
lobed, numerous, short-stalked, grayish-green above, and grayish-brown
and scaly beneath. The reproductive body of this plant, as in all ferns,
is a spore and not a seed. The spores are borne in spore-cases (sporangia)
which are collected in clusters (sori) on the back and near the margin
of the pinnae. In many ferns the sori have a proper membranous pro-
tective covering which is known as the indusium, but in our plant the
indusium is lacking and the sori. are naked as also the margin of the
pinnae is not inrolled to form a false covering. This counterfeit indusium
is present in most of the other species of this genus, hence its Greek name
meaning “false cloak." The common name, where one is used, is that
of cloak fern. This fern grows in crevices and under rocks in the drier
hills and mountains from central Texas on west into southern California
and on south into northern Mexico. The species, of which this fern is a.

variety, occurs over much of this same area. It is about twice as large a

plant with pinnae as large, oblong in shape, and sinuate to several-toothed.
It requires more favorable moisture conditions for its growth.

SYIWPTOMS

During the early part of the “jimmies” season, which may be considered
as from November 15 to December 20, an affected flock has all the appear-
ance of well being, but for various reasons the owner may decide to work
a certain pasture. The sheep will be found grazing and when headed for
the corral will move off in a perfectly normal manner and may be driven
for a mile or more before the first symptoms appear. These consist of
an arched back, a peculiar stilted movement of the hind legs and usually
increased respiration. Such animals attempt to keep up with the fleck,

FERN PUISONING 1X SHEEP, fiiOAlfi, AND CA'l"l‘LE

Figure 1. Notholaena sivmalta, var. crenata.

8 BULLETIN NO. 611, TEXAS AGRICULTURAL EXPERIMENT STATION

but eventually stop and tremble violently from head to foot. By this
time both respiration and heart action are very much increased. If the
affected individuals are permitted to lie down for 15 to 30 minutes the
symptoms subside and they can be driven with the flock for some distance
before a second attack will appear. If the affected animals are “dropped
out” they frequently continue to follow and arrive at the corral shortly
after the main band. Lambs up to one year of age are the first to show
the toxic effects of the plant but as the mortality in this class of animals
is much less than in older sheep, especially in pregnant ewes, a round-up
during the early part of the “jimmies” season is not associated with the
dangers and sometimes disastrous results as would be encountered in
working the same flock by the middle of January. The number of affected
sheep and the severity of intoxication increases as the dangerous season

advances.

Thus by the first part of January a few dead sheep will be found along
the trails and it is evident that the deaths were sudden as there is no

evidence of struggle after the animal “went down.” At this time observa- g

tions on an affected flock as they drift to water will disclose a number of
stragglers behind every band of sheep. These stragglers sometimes stop,
lower the head and take two or three backward steps and trembling
usually follows. With each attack they rest for a short time and either
attempt to catch up with the original band, or are picked up by a second
band on its way to water. In a “jimmies” region, stragglers behind every
band of sheep as they drift to water is very good evidence of an affected
flock.

By the middle of January if an attempt is made to work an afiected
flock, it is invariably associated with disastrous results. Mortalities as
high as 10 per cent have been observed during the round-up of a single
pasture. In this stage of the disease the sheep still have a healthy appear-
ance as they graze around the pasture, but an affected animal may drop
dead as a result of being driven not to exceed 100 yards. In such cases
there is very little warning of approaching danger; the animal may take
three or four stilted steps with the hind legs before it drops to the ground,
gives two or three kicks, sometimes a few spasmodic gasps for air and
is dead. The heart action continues for a short time after all respiratory
efforts have ceased. Artificial respiration has no value in the restoration
of the animal. The picture is of common occurrence in pregnant ewes
as they approach the lambing season.

Less commonly noted symptoms, and generally observed during the
tail end of the “jimmies” season, is a lack of coordination in the move-
ment of the fore and hind legs. The fore legs are advanced in about the
normal manner, whereas, the advancement of the hind legs is quite
labored, each step becomes a little shorter until eventually the rear sup-
port is so far behind and the front support so far in front of the center
of gravity that the animal falls on its belly with the hind legs stretched
out behind and the fore legs sticking out in front. Another unusual

FERN POISONING IN SHEEP, GOATS, AND CATTLE 9

symptom consists of immo-
bility with a lowered head,
and if a person attempts to
approach such a case it
takes a few backward steps
and then rears up on its
hind legs several times.
However, it does not appear
to be able to avoid an ap-
proaching person. The han-
dling of such cases will very
likely result in fatal termi-
nation. It is not uncon1-
mon to find young suckling
lambs showing m a r k e d
symptoms but the mothers
showing no evidence of the
disease.

Figure 2. A field caie (taf “jiaizéiigs” sbhowirztfi
th i r u
In goats the Symptoms abgutpbgs tiliteeinaabilit‘; $10 ad$ra§ce
are much the same as in the 1111161935-

sheep. The first symptom observed is a rapid switching of the tail in a
circular motion. The stilted gait, rapid respiration and trembling soon
appear. The goat does not remain standing long after the trembling
appears but lies down to rest. In addition to these symptoms the goat
utters a bleat which has the tone of fright. When death does occur it is‘
sudden and followed by the symptoms as are observed in sheep.

From the reports obtained upon the occurrence of the disease in cattle
the symptoms are about the same as observed in sheep without the fatal
termination. Ranchers who are familiar with the disease in cattle state
that even though wild, cattle are unable to avoid an approaching person
as long as an attack of trembling continues. Recovery takes place more
quickly in cattle than it does in sheep and if left alone an affected cow
will continue to follow a moving herd and never be very far in the rear.

PATHOLOGY

Within 30 minutes to an hour after death an accumulation of blood-
streaked foam is observed around the nostrils, but upon autopsy the only
lesions are a few asphyxiation hemorrhages in the lungs and these are
lacking as often as they are observed. A thorough microscopic study of
the various organs and tissues of affected animals has revealed no micro-
scopic changes. '

EXPERIDIENTAL PROCEDURE

The leaves of the fern were fed to 10 wethers, one ewe, two wether
goats and one calf. The roots of the plant were fed to one wether. The

1O BULLETIN NO. 611, TEXAS AGRICULTURAL EXPERIMENT STATION

wethers were from 11 months to 3 years of age, the goats were three
years 0f age and the calf six months. The ewe was suckling a three
weeks old lamb during the time she was fed the fern. The usual pro-
cedure of grinding and force feeding the plant was at first practiced but
it was soon learned that the discharge of the bolus of ground plant into
the mouth was all that was required as the animals would then chew and
swallow the material with no waste. In order to determine the presence
or absence of toxic efiects the animals were driven at a walk for one hour
around a pasture, unless evidence of the disease appeared in less time.
One hour was considered suflicient to detect all but the mildly intoxicated
cases. The forced exercise was started 24 hours after the first dose of
the plant and continued daily until the animals were shown to be affected.
In most of the cases the feeding of the plant was then discontinued and
the animals were walked every second or third day in order to determine
the time required for recovery.

RESULTS OF EXPERIMENTAL FEEDING

The results of feeding the leaves and roots to sheep, goats and one calf
are summarized in Table 1. There are a few items of interest in con-
nection with the feeding of the fern, one being the regularity with which
symptoms could be produced by walking the animals on the second day
after they received the first dose of the plant. It is rather remarkable
that doses ranging from 0.5 to 1.4 per cent of the body weight of six
sheep and two goats, symptoms of toxicity could be produced, by walking,
approximately 48 hours but not 24 hours after receiving the first dose
of the plant. One sheep (No. 159) which received the equivalent of 0.5
per cent of its body weight showed no evidence of toxicity until the fourth
day after receiving its first dose of the fern, and another sheep (No. 166)
was not affected until the third day but this animal was fed but one dose
and that equivalent to 0.33 per cent of the bodvweight. Evidence of
cumulative effect was obtained by feeding 0.25 per cent doses to sheep
No. 142 for 21 days before evidence of toxicity was detected. This is
evidently approaching the minimum toxic doses as sheep No. 149 was
fed 0.2 per cent doses for 48 days with no apparent ill effects. The fact
that sheep No. 149 was fed the dry plant might be interpreted as an
indication of loss of toxicity as a result of drying the fern. However,
this is not the case, for sheep No. 142 and No. 149 were fed the same
material at the same time. Furthermore, the same batch of the plant
was found to be toxic one month after the feeding of sheep No. 149 was
discontinued. It has also recently been found that the fern retains its
toxicity after drying for 8 months. The goat is about as susceptible as
sheep, judging from the symptoms observed and the size of doses required
to produce the symptoms. The results of feeding the fern to the one calf
would indicate less susceptibility on the part of cattle. Doses equivalent
to 0.54 per cent of the body weight of the calf had no ill effects for 8 days
and when the dose was increased to 1.08 per cent of the body weight
seven more doses were required before evidence of toxicity was pr0d11Qed_

m.i-d_na\..4.n4nj..-A4JAAQ-A1Al)hAl4A-4..g. . 1

FERN POISONING’ IN SHEEP, GOATS, AND CATTLE 11

Table 1. The results of feeding Notholaena sinuata var. crenata to sheep, goats
and one calf, green leaves unless otherwise stated

‘ i
Animal   Pounds of  Per cent  Number of Days required_to  Recovery in
Number Weight  fern fed ‘ body wt. 1 days fed produce toxicity 1 days
——E 7 *1 i 1
S149 j 50 ‘ o.1* 0.2 1 48 No ill effects l ___________ __
S142 S0 02* 0.25 l 21 21 l 11
S166 75 0.25 0.33 1 1 3 i N.D.
S100 100 0.5 0.5 1 3 2 ___________ _-
0.25 0.25 3 __ ‘ 11
S130 90 0.5 0.55 5 3 2 5
S153 , 60 0.4 0.66 3 3 2 N.D.
S159 I 75 0.5* 0.66 l 3 4  19
S158 1 60. 05* 0.8 ‘l 2 2 ‘ ___________ --
0.25* 0.4 5 2 Dropped dead 0n fourth day
I .
S129 60 0. 1.0 1 3 2 ‘ 11
S151 35 0.3 1.42 \ s 2 \ N.D.
G114 70 0.5 0.7 2 2 ___________ __
0.25 0.35 4 __ 11
G124 6'5 0.5 0.77 4 2 6
C124 245 1.33* 0.54 8 N0 ill effects
2 w‘ 1.08 | 7 15 1 7
S155 so 0.5+ 0.s i e No definite 111 effects 
0.25 0.4 | 4 7—dropped dead 

*Dry plant expressed as original Weight of green.

iRoots of plant.

N.D.—not determined.

S=sheep; G=goat; C=calf. -

NOTE: Sheep No. 100, No. 158 and Goat N0. 114 were fed for a demonstration of the dis-
ease. The quick response in these animals suggested the advisability of a 50 per cent reduction
of the amount fed daily without interrupting the experiment in order to prolong intoxication
without fatal terminations until the day of the demonstration arrived. Sheep No. 155 was fed
at the same time and for the same purpose. Although this animal showed no definite ill effects
the first three days there was" a suspicion that it was affected, hence the reduction of the
amount fed daily.

The results obtained from feeding the roots of the plant to sheep No.
155 were interesting. Three days after it received the first dose the
walking of this animal produced suggestive evidence of toxicity but
nothing definite was obtained until it dropped dead after being walked
20 minutes on the 7th day. For about two minutes before it dropped
dead this sheep was showing the arched back and stilted gait of the
hing legs, but familiar as we were with the indications of the danger
point for such cases, we were not prepared for the fatal termination of
this animal. An immediate autopsy on this case proved that respiration
and heart action ceased at the same time, a deviation from the con-
sistent findings of numerous autopsies conducted immediately after the
death of range cases of the disease. '

The time required for apparent recovery varied from 5 to 19 days
after the feeding of the plant had been discontinued or an average of
10.5 days for five sheep and two goats, the shortest period 5 days and
the longest 19 days. These results coincide with the time required for

12' BULLETIN NO. 611, TEXAS AGRICULTURAL EXPERIMENT STATION

recovery from the disease under range conditions. Over a period of
years there has been opportunity to observe the effects of moving sev-
eral affected bands of sheep from infested to non-infested areas. Reliable
reports from ranchers state badly affected flocks could be Worked as
early as one week after removal to non-infested pastures without danger
of loss, although some affected animals were invariably found. Two
weeks after removal to non-infested pastures sheep have been worked with
no evidence of the disease. The calf had recovered by the seventh day.

TOXIC PRINCIPLE ELIMINATED IN MILK

A ewe which was sucking a three-weeks‘ old lamb was fed 0.3 lb. of
the dry fern (equivalent to 0.5 lb. of the green plant, 0.49 per cent of
the body weight) for 6 consecutive days. The ewe and lamb were walked
daily from the third to fifth day after receiving the first dose with no
ill effects in either animal. On the sixth day after the ewe received
the first dose the lamb developed a severe and typical case of trembling
after being walked for 10 minutes. The ewe was not affected although
she got in the lead of other sheep which were being walked at the same
time and led them around the pasture for about an hour before she could
be corraled. Walking these animals the next day was a duplication of
the results of the sixth day. The ewe went off feed about this time
and later died. The lamb recovered. The death of the ewe was prob-
ably the result of over-heating while stampeding around the pasture on
the sixth and seventh day as both were very warm days and the ewe was
certainly over-heated on both occasions.

CONTROL

Since it is not uncommon to find sheep, goats and sometimes cattle
being grazed in the same pasture with a. serious loss occurring in the
sheep but none in either the goats or cattle, the control of this condi-
tion is, therefore, principally concerned with sheep. In this connection
the occurrence and distribution of the fern should first be considered as
it is rare to find all the pastures on any given ranch infested, and quite
often there will be as many non-infested as infested pastures. The in-
fested areas should be grazed between April 1 and November 1 to 15, the
non-infested pastures should be held for winter grazing and the sheep
placed in them not later than November 15. Probably a more profitable
and simplified method would be a combination of sheep and goat rais-
ing, with the goats maintained in infested pastures and the sheep on
the fern free areas. In some areas cattle could be substituted for goats,
but as a rule infested areas are very rough and thus better adapted to
goat than to cattle grazing.

If infested pastures must be devoted to sheep raising they should be
small and well watered in order to cut down travel to and from water
as much as possible. The sheep should be placed in the pastures in the

 

FERN POISONING‘ IN SHEEP, (BOATS, AND CATTLE 13

fall and never handled again until the following spring when the danger
of the condition developing is passed. No attempt should be made to
maintain breeding ewes, which are due to lamb anywhere between Feb-
ruary 1 and April 30, on infested areas. Lambs and wethers are the
only classes of sheep which may be grazed with reasonable safety on in-
fested areas and even in these classes an important loss is liable to occur.

Grubbing of the plant might be found profitable in small areas but as
a rule the value of the land would not justify this method of control,
as the grubbing would cost more than the $3.00 to $7.00 an acre, for
which most of the infested land can be purchased. No specific treatment
can be recommended at this time.

DISCUSSION

With the increasing westward movement of the sheep industry, this is
rapidly becoming one of the leading disease problems in the Trans-Pecos
area of Texas for this class of livestock. Ranch conditions and lack of
familiarity with this disease has contributed materially to the losses from
this source. Many large cattle pastures have been converted to sheep
pastures without proper subdivision and without proper watering facili-
ties. Due to the tendency of sheep to graze against the wind until they
encounter a fence in large pastures they eventually arrive at points sev-
eral miles from water. As they are thirsty by this time they start a steady
walk back to water rather than graze much of the distance. Such
conditions invariably predispose to a serious" loss the latter part of the
“jimmies” season. The over-grazed area so frequently observed around
central watering places also contributes to the loss. In returning to
water sheep strike a steady walk when this area is reached, thus creat-
ing a hazard of considerable importance whenever the radius of this
area amounts to as‘ much as one-half mile- or more.

The grazing of this fern can not be attributed to over-stocking as
losses have been observed under excellent but dry winter ranges. Wet
mild winters, which provide other green feed tend to reduce the loss; dry
cold winters have an opposite effect. The fern appears to possess con-
siderable palatability and is grazed as soon as the more palatable for-
age is killed by frosts. Frosts and freezing weather have no effects on
the fern, thus" it generally remains the only succulent forage during the
winter months. The almost sudden disappearance of the disease in the
spring is due to two factors; first, more palatable green feed becomes
available, and second, the first few hot days of spring have a withering
effect on the fern which probably decreases its palatability.

We have been unable to find sufficient amounts of this plant growing
among the igneous rocks of the Davis Mountains to conduct a feeding
test for toxicity. It is probably the scarcity of this variety of fern which
accounts for the fact that we have not observed this disease in the Davis

14 BULLETIN NO. 611, TEXAS AGRICULTURAL EXPERIMENT STATION

Mountains. On the other hand, Notholaena sinuata is rather abundant
in this region, much more so than it is in the Glass Mountains, the region
from which the crenata variety was obtained for the present investigation.

A toxicity test on N. sinuata was conducted by feeding three sheep from
two to three times the toxic dose for N. sinuata var. crenata without pro-
ducing toxic effects. This would indicate that N. siinuata growing in the
Davis Mountains is not toxic. Its status when growing in a limestone area
has not been determined, as thus far we have not found suflicient quan-
tities in limestone areas to conduct a toxicity test, Should future investi-
gations on N. sinuata confirm the non-toxic nature of this plant, it would
appear that we have sufiicient justification for designating crenata as a
distinct species rather than a variety.

The walking of the experimental sheep for one hour as a test for
determining the presence or absence of toxic effects of the fern was not
as arbitrary a standard as might appear. It is a fact that we have observed
sheep to manifest symptoms of intoxication after being walked for more
than one hour under range conditions, but a fatal termination in such
cases is rare, therefore the degree of intoxication in such cases must be
considered mild. It would follow that in affected areas, any pasture that
requires a steady walk of one hour or more in order to return to water
is too large for sheep and should be subdivided or more watering places
provided. The same reasoning prevails in case a rancher findsit necessary
to work a pasture during the winter‘ months. The pasture should not
be large enough to require a drive of as much as an hour in order to
reach the corrals. If at the end of that time no fatalities have occurred
no serious disease problem exists.

During the years this condition has been under investigation we have
picked up many field cases and hauled them to the experimental feed pens
for further observations. Quietly picking these animals up and placing
them in a car for transportation, or the unloading upon arrival at the
pens has resulted in the death of many sheep which in all probability
would not have died if they had not been molested. In contrast to these
observations, we as well as ranchers have observed that badly affected
animals, if suddenly startled, will break into a run and continue at this
pace for as much as a mile Without a fatal termination. In other words,
sudden violent exercise does not appear to have as serious effects as a
slow steady walk. In Working with our experimental animals similar
observations were made. We have found that the best way to bring out
the symptoms of the disease was to herd the sheep around a large pasture
at a slow but steady walk. In attempting to bring out the symptoms in a
corral where the animals would have to be forced into a walk one minute
and would break into a run the next, we have never produced as clean-cut
results as we have in a pasture with a slow but steady walk maintained.
This is a peculiar observation and one for which no explanation is offered.

After a study of a number of years we are able to predict a chain of
events when an uninformed rancher encounters “jimmies” for the first

, Ah._ n- aka-shaman “t.  . .

FERN POISONINCH IN SHEEP, GOATS, AND CATTLE 15

time. The appearance of a few dead sheep along the trails attracts his
attention and he immediately decides he is dealing with hemorrhagic
septicemia. He proceeds to round up the flock and vaccinates. The
round-up is invariably associated with a serious loss. For about two weeks
after this treatment he finds no additional dead sheep, he is convinced
that he has the answer to the problem. By the beginning of the third
week the mortalitis begin again, but this time tape worms are blamed for
the trouble. Another round-up is made with the same disastrous results.
The sheep are treated for tape worms and an apparent improvement for
about two weeks follows. By this time, fortunately for the rancher,
spring is athand, the disease disappears and the sheep are subjected to
no further handling. Unfortunately the same rancher must learn the next
year- that his evidence of beneficial results from the tape worm treatment
was erroneous and that all he had succeeded in doing the previous year
was to kill off the most severe cases of “jimmies” and thus lost many
sheep that would have survived if they had not been molested.

SUDIMARY

The so-called “jimmies” which occurs on rocky, limestone areas of the
Trans-Pecos is described. The disease occurs in sheep, goats and cattle
and was found to be due to the grazing of a fern.

The symptoms of this type of fern poisoning were induced by walking
experimental sheep and goats 48 hours after they received the first dose
of the plant.

The toxic principle appears to have a direct action on the respiratory
center. It is eliminated in the milk and was found to resist drying for
as much as eight months.

Recovery from the toxic effects of the fern is complete when feeding
on the plant stops and requires from 5 to 19 days.