The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source
site maintained by the Florida
Cooperative Extension Service.
Copyright 2005, Board of Trustees, University
Bulletin 407 February, 1945
UNIVERSITY OF FLORIDA
AGRICULTURAL EXPERIMENT STATION
HAROLD MOWRY, Director
IN RANGE CALVES
M. W. EMMEL
Fig. 1.-Range calf after recovery from "swollen joints". Note the
swelling over the right stifle joint. The animal is lame in the affected leg
but still can travel surprisingly fast.
Single copies free to Florida residents upon request to
AGRICULTURAL EXPERIMENT STATION
BOARD OF CONTROL ECONOMICS, AGRICULTURAL
C. V. Noble, Ph.D., Agr. Economist1
H. P. Adair, Chairman, Jacksonville Zach Savage, M.S.A., Associates
N. B. Jordan, Quincy A. H. Spurlock, M.S.A., Associate
T. T. Scott, Live Oak Max E. Brunk, M.S., Associate
Thos. W. Bryant, Lakeland
M. L. Mershon, Miami
J. T. Diamond, Secretary, Tallahassee ECONOMICS, HOME
Ouida D. Abbott, Ph.D., Home Econ.1
EXECUTIVE STAFF R. B. French, Ph.D., Biochemist
John J. Tigert, M.A., LL.D., President of the ENTOMOLOGY
H. Harold Hume, D.Sc., Provost for Agricul- J. R. Watson, A.M., Entomologist1
ture A. N. Tissot, Ph.D., Associates
Harold Mowry, M.S.A., Director H. E. Bratley, M.S.A., Assistant
L. 0. Gratz, Ph.D., Asst. Dir., Research
W. M. Fifleld, M.S., Asst. Dir., Admin.4 HORTICULTURE
J. Francis Cooper, M.S.A., Editors
Clyde Beale, A.B.J., Assistant Editors G. H. Blackmon, M.S.A., Horticulturist1
Jefferson Thomas, Assistant Editors A. L. Stahl, Ph.D., Asso. Horticulturist
Ida Keeling Cresap, Librarian F. S. Jamison, Ph.D., Truck Hort.
Ruby Newhall, Administrative Managers R. J. Wilmot, M.S.A., Asst. Hort.
K. H. Graham, LL.D., Business Managers R. D. Dickey, M.S.A., Asst. Hort.
Claranelle Alderman, Accountants J. Carlton Cain, B.S.A., Asst. Hart.4
Victor F. Nettles, M.S.A., Asst. Hort.4
Byron E. Janes, Ph.D., Asst. Hort.
MAIN STATION, GAINESVILLE F. S. Lagasse, Ph.D., Asso. Hort.2
W. E. Stokes, M.S., Agronomist'
Fred H. Hull, Ph.D., Agronomist W. B. Tisdale, Ph.D., Plant Pathologist' s
G. E. Ritchey, M.S., Agronomist2 Phares Decker, Ph.D., Asso. Plant Path.
G. B. Killinger, Ph.D., Agronomist Erdman West, M.S., Mycologist
W. A. Carver, Ph.D., Associate Lillian E. Arnold, M.S., Asst. Botanist
Roy E. Blaser, M.S., Associate
H. C. Harris, Ph.D., Associate diOILS
R. W. Bledsoe, Ph.D., Associate
Fred A. Clark, B.S., Assistant F. B. Smith, Ph.D., Microbiologist' 8
Gaylord M. Volk, Vr.S.. Chemist
ANIMAL INDUSTRY J. R. Henderson, M.h Soil Technologist
J. R. Neller, Ph Chemist
A. L. Shealy, D.V.M., An. Industrialist 3S C. E. Bell, Ph.L Chemist
R. B. Becker, Ph.D., Dairy Husbandmans L. H. Rogers, Ph.- .ociate Biochemist4
E. L. Fouts, Ph.D., Dairy Technologist3 R. A. Carrigan, B.S., so. Biochemists
D. A. Sanders, D.V.M., Veterinarian G. T. Sims, M.S.A., Associate Chemist
M. W. Emmel, D.V.M., Veterinarians T. C. Erwin, Assistant Chemist
L. E. Swanson, D.V.M., Parasitologist' H. W. Winsor, B.S.A., Assistant Chemist
N. R. Mehrhof, M.Agr., Poultry Husb.3 Geo. D. Thornton, M.S., Asst. Microbiologist
G. :. Davis, Ph.D., Animal Nutritionist R. E. Caldwell, M.S.A., Asst. Soil Surveyor'
T. R. Freeman, Ph.D., Asso. in Dairy Mfg. Olaf C. Olson, B.S., Asst. Soil Surveyor
R. S. Glasscock, Ph.D., An. Husbandman
D. J. Smith, B.S.A., Asst. An. Hush.4
P. T. Dix Arnold, M.S.A., Asst. Dairy Husb.8
C. L. Comar, Ph.D., Asso. Biochemist
L. E. Mull, M.S., Asst. in Dairy Tech.4 1 Head of Department.
0. K. Moore, M.S., Asst. Poultry Hush.8 2 In cooperation with U. S.
J. E. Pace, B.S., Ast. An. Husbandman Cooperative, other divisions, U. of F.
S. P. Marshall, M.S., Asst. in An. Nutrition
Ruth Faulds, A.B., Asst. Biochem. 4 In Military Service.
Katherine Boney, B.S., Asst. Chem. 5 On leave.
Fig. 2.-"Swollen joints" affecting the left hock of a 4-weeks-old calf.
Fig. 3.-"Swollen joints" affecting the right
knee. Note the over-extension of the leg at
the knee, indicating degeneration of the liga-
ments of the joint.
BRANCH STATIONS SUB-TROPICAL STA., HOMESTEAD
Geo. D. Ruehle, Ph.D., Vice-Director in
NORTH FLORIDA STATION, QUINCY Charge
P. J. Westgate, Ph.D., Asso. Horticulturist
J. D. Warner, M.S., Vice-Director in Charge H. Borders, M.S., Asso. Plant Path.
R. R. Kincaid, Ph.D., Plant Pathologist
V. E. Whitehurst, Jr., B.S.A., Asst. An. W. CENT. FLA. STA., BROOKSVILLE
Jesse Reeves, Asst. Agron., Tobacco Clement D. Gordon, Ph.D., Asso. Poultry
W. H. Chapman, M.S., Asst. Agron.4 Geneticist in Charge2
R. C. Bond, M.S.A., Asst. Agronomist .,
RANGE CATTLE STA., ONA
Mobile Unit, Monticello W. G. Kirk, Ph.D., Vice-Director in Charge
E. M. Hodges, Ph.D., Asso. Agron., Wauchula
R. W. Wallace, B.S., Associate Agronomist Gilbert A. Tucker, B.S.A, Asst. An. Husb.4
Mobile Unit, Milton FIELD STATIONS
Ralph L. Smith, M.S., Associate Agronomist Leesburg
M. N. Walker, Ph.D., Plant Path. in Charge2
Mobile Unit, Mariaunna
R. W. Lipscomb, M.S., Associate Agronomist Plant City
A. N. Brooks, Ph.D., Plant Pathologist
Mobile Unit, Wewahitchka Hastings
J. B. White, B.S.A., Asso. Agronomist A. H. Eddins, Ph.D., Plant Pathologist
E. N. McCubbin, Ph.D., Truck Horticulturist
CITRUS STATION, LAKE ALFRED
S. O. Hill, B.S., Asst. Entomologist2 4
A. F. Camp, Ph.D., Vice-Director in Charge A. M. Phillips, B.S., Asst. Entomologist2
V. C. Jamison, Ph.D., Soils Chemist
B. R. Fudge, Ph.D., Associate Chemist Bradenton
W. L. Thompson, B.S., Entomologist
W. W. Lawless, B.S., Asmt. Horticulturist* J. R. Beckenbach, Ph.D., Horticulturist in
C. R. Stearns, Jr., B.S.A., Asso. Chemist Charge
H. 0. Sterling, B.S., Asst. Horticulturist E. G. Kelsheimer, Ph.D., Entomologist
T. W. Young, Ph.D., Asso. Horticulturist I. B. Creager, Ph.D., Plant Path., Gladiolus
J. W. Sites, M.S.A., J .. Horticulturist6 A. L. Harrison, Ph.D., Plant Pathologist
David G. Kelbert, Asst. Plant Pathologist
E. L. Spencer, Ph.D., Soils Chemist
EVERGLADES STA., tELLE GLADE Sanford
R. V. Allison, Ph.D., Vice-Director in Charge R. W. Ruprecht, Ph.D., Chemist in Charge
J. W. Wilson, Sc.D., Entomologist* J. C. Russell, M.S., Asst. Entomologist5
F. D. Stevens, B.S., Sugarcane Agron.
Thomas Bregger, Ph.D., Sugarcane Lakeland
G. R. Townsend, Ph.D., Plant Pathologist E. S. Ellison, Meteorologist 2 6
R. W. Kidder, M.S., Asst. An. Hush. Warren 0. Johnson, Meteorologist2
W. T. Forsee, Jr., Ph.D., Asso. Chemist
B. S. Clayton, B.S.C.E., Drainage Eng.2
F. S. Andrews, Ph.D., Asso. Truck Hort.4 1 Head of Department.
R. A. Bair, Ph.D., Asst. Agronomist 2 In cooperation with U. S.
E. C. Minnum, M.S., Asst. Truck Hort.
N. C. Hayslip, B.S.A., Asst. Entomologist Cooperative, other divisions, U. of F.
C. L. Serrano, B.S.A., Asst. Chem. In Military Service.
E. L. Felix, B.S.A., Asst. Plant Path. 6 On leave.
"SWOLLEN JOINTS" IN RANGE CALVES
M. W. EMMEL
During the 1944 calving season, cattlemen reported a condi-
tion commonly called "swollen joints" or "lameness" as being
prevalent in young calves in many sections of the state. Al-
though occasional cases of this condition have been occurring
on Florida ranges for many years, its prevalence has increased
since the introduction of the screwworm fly, Cochliomyia ameri-
cana C. and P., into this state 10 years ago but did not reach
alarming proportions until this year.
The following investigation was conducted in an attempt to
determine the cause of "swollen joints" and its means of trans-
It was found that "swollen joints" develops in calves under
4 weeks of age. Figs. 1 to 8 illustrate this disease as it occurs
in the various joints. The knee, elbow, hock, stifle or hip joint
may become affected. It occurs most frequently in the knee
or hock joint and least frequently in the hip joint. In most
instances only a single joint is involved. When several joints
are affected, 1 usually is affected much more severely (Fig. 5).
The joint becomes enlarged and intensely inflamed. The entire
area is extremely hard and painful to pressure. The animal
becomes lame and in many instances while standing will not
touch the foot to the ground.
After the development of this initial condition, a varied course
follows. Intense swelling and inflammation may persist in some
instances. In others, the development of soft spots in areas
in which the joint capsule is closest to the skin usually is an
indication of the accumulation of pus in the joint capsule.
Occasionally a joint capsule ruptures and thick creamy pus
oozes from the opening for several weeks. Some joint capsules
may become "puffy" but do not contain pus. Many calves die
within 2 to 4 weeks after becoming affected. A few survive.
However, recovery usually is slow and the muscles of the affected
leg are atrophied or shrunken from lack of use. The affected
joint usually is enlarged permanently and is more or less stiff,
depending upon the severity of the case. In a few instances
the leg becomes distorted at the affected joint and practically
6 Florida Agricultural Experiment Station
useless for locomotion. Recovered calves often are stunted and
future growth is retarded.
A loss of 5 percent of the calf crop was not unusual on in-
dividual ranches. In isolated instances losses were much higher.
On one ranch 70 of 300 calves died from the disease; none of
the affected animals recovered. Extensive observations have
indicated that mortality from "swollen joints" during the 1944
calving season was approximately 80 percent of the animals
affected. Many of those which survived were permanently
crippled or stunted.
Fig. 4.-Enlarged hock joint due to "swollen joints".
The prevalence of "swollen joints" was attributed by cattle-
men to a number of factors-mineral deficiencies, screwworm
infestations, and materials used in the control of screwworms.
The survey indicated that screwworm infestation of the navel
"Swollen Joints" in Range Calves 7
was associated with the development of approximately 90 per-
cent of the cases; the remaining 10 percent had no history of
navel screwworm infestation.
Sixteen affected calves were observed on 8 widely separated
ranches. These animals varied from 2 to 8 weeks of age. All
except 2 had a history of screwworm infestation of the navel;
3 calves had reinfestation with screwworms. All of the navels
with the exception of 1 were healing in a satisfactory manner
at the time of observation. Each affected joint of the 16 ani-
mals and the unhealed navel of 1 animal were cultured for
Fig. 5.-A case in which the stifle joint is greatly en-
larged. The arrow indicates an enlargement on the hock
joint of the opposite leg.
8 Florida Agricultural Experiment Station
bacterial infection. The joint capsule was pierced with a sterile
16 gauge hypodermic needle, after disinfection of the skin, and
"a portion of the contents of the joint capsule was aspirated into
"a sterile syringe. The unhealed navel was swabbed with a sterile
swab. The specimens were returned to the laboratory and
smears were made on dextrose agar medium. Bacterial cultures
were obtained from specimens taken from 3 calves on different
ranches. These 3 cases will be described briefly.
Case No. 1.-The calf was 5 weeks of age and had been af-
fected for approximately 18 days. The navel had been treated
once for screwworms
with a commercial
before the calf was
The left hock was al-
most 3 times normal
size. The swelling
was generalized and
hard, except for sev-
Seral soft fluctuating
areas where the joint
capsule was closest
to the skin. The
S o joint capsule con-
tained thick creamy
"pus. An apparently
pure culture of micro-
organism was obtain-
ed from the affected
Fig. 6.-Front view of a knee joint affected Case No. 2.-The
with "swollen joints". history of this calf
was identical to that
above except that the left stifle joint was involved. The joint
capsule contained whitish pus, creamy in consistency, which
yielded an apparently pure bacterial culture. The navel of this
calf had not healed; a culture also was obtained from this loca-
tion. The navel contained 4 screwworm larvae.
Case No. 3.-The calf was 7 weeks of age and had been
affected for 10 days. The navel had been treated with Smear
62 for screwworm infestation 4 days before lameness was ob-
"Swollen Joints" in Range Calves 9
served. The right knee was enlarged to approximately twice
normal size. The swelling was hard on either side but fluctuat-
ing in front. The joint capsule contained thick creamy pus
fr o m which a micro-
organism was isolated.
isolated in all instances
was identified as Strep- L
tococcus pyogenes. At-
tempts to produce
"swollen joints" with
this microorganism in i
healthy calves will be
were isolated from the
13 remaining cases. In
1 case the affected
joint had been incised
and thick creamy pus
oozed from the open- V -'
ing. The pus in 5 cases
was inspissated (dry
and flocculent). In the
remaining 7 cases the
contents of the joint
capsule were liquid but
extremely scant. It
would appear from the
histories of these ani-
mals that pus probably
does not develop to any Fig. 7.-Calf affected with "swollen
extent in the joint cap- joints" in the right hip joint. Note the
sule of some affected shrinkage of the muscles of the thigh of
the affected leg as compared with the full-
animals but that in- ness of these muscles in the unaffected leg.
tense inflammation of
the tissues surrounding the joint produces hardness, swelling
In those animals which survive the extent of recovery appears
to be dependent upon the amount of tissue damage during the
period of acute inflammation.
Several types of available commercial remedies as well as
10 Florida Agricultural Experiment Station
Smear 62 had been used in the control of screwworms in infected
navels on the 8 ranches visited. This would indicate that the
materials themselves probably were not involved in the develop-
ment of "swollen joints".
Figs. 9 to 12 illustrate tissues of the joints of affected animals.
Fig. 8.-Range calf 10 weeks after recovery from "swollen joints". The
joint capsule had ruptured and pus had oozed from 8 openings in the skin
during the active stage of the disease. Now the right hock is stiff and
has practically no mobility. The animal is considerably undersized.
Postmortem examinations were conducted on 3 calves affected
with "swollen joints". The lungs of 1 animal contained 2 ab-
scesses the size of a hen's egg; 2 others of similar size were
found in the peritoneal cavity, 1 in the region of the kidneys
and the other adjacent to the abomasum (4th stomach). Three
abscesses were found in the second calf; 1 in the peritoneal
cavity near the navel, another in the lungs and the third in the
region of the bladder. These varied from 1 to 2.5 inches in
diameter. Abscesses could not be found in the third calf.
On a ranch on which losses from "swollen joints" were severe,
2 yearlings had a history of retarded growth and clinical symp-
toms of lung involvement. Both animals were destroyed. Two
"Swollen Joints" in Range Calves 11
abscesses 1.5 to 2.5 inches in diameter were found in the lungs
of 1, and 3 abscesses 2 to 3 inches in diameter were found in
the lungs of the other. Extensive inflammation occurred in
the surrounding tissue.
The abscesses in all 5 of these animals contained thick creamy
pus. Culture of their contents failed to yield bacterial growth.
Comment on these cases will be made later.
Fig. 9.-The bones from the stifle joint of a case of "swollen joints"
after recovery. The appearance of the joint was similar to that of the
calf in Fig. 1. The bones from the normal joint are on the left, those from
the affected joint on the right. The arrow above points to a cavity about
% inch deep eroded into the articulating surface of the bone. The arrow
below points to a groove %1 inch deep eroded into the condyle of the
"thigh" bone. The erosion was due to accumulation of pus in the joint
capsule during the active stages of the disease.
12 Florida Agricultural Experiment Station
EXPERIMENTAL CASES 1
Case No. 1.-The navel of a 2-weeks old Jersey calf was in-
fested with screwworms in a cavity about 1 inch in diameter
and 1.5 inches deep. It was contaminated with 2.0 cc. of a
48-hour dextrose broth culture of Streptococcus pyogenes which
had been isolated from natural Case No. 1. Three days later 21
larvae, most of which were practically mature, were removed
from the navel with a pair of forceps. The wound then was
treated with Smear 62 as done under range conditions.
Fig. 10.-Cross-section of the hock joints of a semi-recovered calf.
That on the left is normal, that on the right affected. The enlargement
is due entirely to the formation of scar tissue and does not involve the bone.
The screwworm larvae from this case were allowed to pupate
and the flies were used in connection with experimental Case
Five days later, or 8 days after navel infection, the right knee
was enlarged slightly. The swelling was hard on either side
and rather "puffy" in front, the latter indicating the swelling
was not due to pus accumulation in the joint capsule. The fol-
lowing day the calf was slightly lame. The swelling continued
to increase. Examination on the third day indicated pus ac-
The calves used in these experiments were secured from a farm on
which there had been no history of "swollen joints".
"Swollen Joints" in Range Calves 13
cumulation in the joint capsule. A sterile syringe and hypo-
dermic needle were used to aspirate a portion of the contents
of the capsule. Culture of the pus yielded Streptococcus pyogenes
whose characteristics were identical with those of the micro-
organism with which the navel was infected 11 days previously.
The maximum swelling reached at least twice normal size 6 days
after it had developed and the calf while standing seldom
touched the foot to the ground. The calf had difficulty in rising
to its feet 14 days after infection and was destroyed (Fig. 13).
Fig. 11.-The longitudinal section of the hock joints of the calf in
Fig. 8. The normal hock is on the right while the affected one is on the
left. The joint capsule has almost entirely disappeared except around
the circular bone in the center. The spaces between the bones have been
filled with whorls of scar tissue, making the joint practically rigid.
The front legs were removed and placed in the freezing com-
partment of the refrigerator. The following day the knee
joints were sectioned longitudinally. The joint capsule of the
affected knee was filled with pus and markedly thickened; in
some areas this thickness was 5/8 inch. The other tissues sur-
rounding the joint were thickened markedly. The joint capsule
was being eroded in several areas. The bones also showed
erosion at several points at which they were in contact with
14 Florida Agricultural Experiment Station
Fig. 12.-Longitudinal section of the stifle joints of a calf affected with
"swollen joints". An abscess in the affected leg on the right is circum-
scribed by a dotted line. Note also the swelling in the tissues surrounding
the joint of the affected leg. The section on the left is from the normal leg.
Fig. 13.-Experimental Case No. 1, in which "swollen joints" of the
right knee resulted from contaminating a screwworm-infested navel with
Streptococcus pyogenes isolated from a naturally-occurring case of the
"Swollen Joints" in Range Calves 15
pus. Several carpal bones showed slight separation between
the cartilage and bone tissue.
Case No. 2.-This animal was a Jersey calf 7 days of age,
whose navel had not completely healed but which was not in-
fested with screwworms. A curette was used to create a cavity
which was contaminated in the same manner as Case No. 1,
with the microorganism isolated from natural Case No. 3.
The left hock showed slight enlargement 10 days after infec-
tion. The calf was lame the following day. The hock continued
to enlarge until the maximum swelling occurred 14 days after
infection. At this time the hock was enlarged 2 to 3 times
over normal. The animal exhibited considerable pain when the
affected hock was handled (Fig. 14).
A sterile syringe and hypodermic needle were used to aspirate
pus from the joint capsule. Culture of this material yielded a
pure culture of Streptococcus pyogenes whose characteristics
were identical with those of the microorganism with which the
navel had been infected previously.
Fig. 14.-Experimental Case No. 2, in which the "swollen joints" trouble
was produced in the right hock by contaminating an artificially wounded
navel with Streptococcus pyogenes isolated from a naturally-occurring case
of the disease.
16 Florida Agricultural Experiment Station
Eighteen days after infection the calf became weak, had diffi-
culty rising to its feet and consequently was destroyed.
The hind legs were removed, frozen and sectioned longi-
tudinally for study (Figs. 15-16). The condition on the interior
of the joint was similar
to that found in experi-
mental Case No. 1 except
that a much greater ac-
cumulation of pus occur-
red and erosion of the
joint capsule was more
extensive. At 2 points
the pus cavity extended
iA to the skin and probably
w 3 would have ruptured
Within another 24 hours.
w Case No. 3.-The screw-
worms secured from ex-
perimental Case No. 1
were confined and allow-
ed to pupate and develop
Into mature flies. The
flies then were allowed
to lay eggs on the arti-
ficially wounded navel of
a calf the day after the
Fig. 15.--Longitudinal section of the hock wounded navel had been
joint of the normal leg of the calf shown
in Fig. 14. contaminated with Strep-
tococcus pyogenes iso-
lated from natural Case No. 2. The flies then were transferred
to the artificially wounded navel of the calf represented as Case
No. 3. This was a 4-day old calf whose navel had been curetted
to form a cavity about an inch in diameter. The flies were kept
in contact with the navel until they laid their eggs. This ex-
periment was conducted to determine whether or not the screw-
worm fly could carry the infection from the navel of 1 calf to
that of another. Five days later 41 screwworms were removed
from the navel with a pair of forceps. The wound was treated
with Smear 62. Fourteen days after screwworm flies were
allowed to lay their eggs on the artificially wounded navel, swell-
ing was observed in the left knee joint. The swelling increased
in intensity until the fifth day, when the animal was quite lame.
"Swollen Joints" in Range Calves 17
The affected knee was painful to palpation and extremely hard.
No accumulation of pus occurred in the joint capsule. At this
time, which was 19 days after infection, 10 cc. of sterile saline
solution was injected into the joint capsule under sterile condi-
tions and aspirated
into the syringe. One
cubic centimeter of
this fluid was cul-
tured on dextrose
agar in each of 5
pet ri dishes. Two
sterile while sparse .. -
colonies of Strepto-: .
coccus pyogenes de- -
veloped on the re- n a.(
mining 3 plates.
T h e characteristics .
of this microorgan-
ism appeared identi-
cal in all respects to
those of the micro-
organisms which the
screwworm flies car-
ried to the navel.
Twenty-four days Fig. 16.-Longitudinal section of the af-
after infection the fected hock joint of the calf shown in Fig. 14.
The dotted lines indicate accumulations of pus
swelling subsided in the joint capsule which has been distended
somewhat a n d the greatly and partially eroded in some areas.
Note the separation of some of the bones by
animal subsequently pus accumulation and the increased thickness
recovered. The swell- of the tissues on the back of the leg and over
the point of the hock, as compared with the
ing which remained normal hock in Fig. 15.
w a s confined prin-
cipally to the fore part of the knee joint, although the entire
area swelled slightly. Slight lameness existed and the animal
favored the affected leg at every opportunity. The animal was
destroyed 30 days after the lameness occurred. Dissection of
the affected joint showed that the bones were not affected, the
swelling which remained being due to an increase or thickening
of the tissues surrounding the joint.
18 Florida Agricultural Experiment Station
Streptococcus pyogenes, which was isolated from the joint
capsule of 3 naturally occurring cases of "swollen joints" and
from the unhealed navel of 1 of these calves, was first described
about 1884 and is widely disseminated in nature. It is known
to cause acute inflammatory conditions usually associated more
or less with development of pus. The isolation of this micro-
organism from naturally occurring cases, the development of
"swollen joints" in experimental calves after navel infection
by this microorganism with or without screwworm infestation,
and the subsequent recovery of this microorganism from affected
joints of experimentally induced cases definitely incriminates
it as a causal agent of "swollen joints" in calves. It should be
indicated, however, that possibly certain other microorganisms
may be involved in naturally occurring cases of this disease.
Infections of this type often are referred ito as "low grade"
infections. The microorganism does not have invasive powers
sufficient to cause immediate illness or death by overwhelming
the resistance of the animal. The bacteria after gaining en-
trance to the blood stream localize in the tissues of the joint
area, which is a point of low resistance in the body of the animal.
Here, the microorganism causes acute inflammation and often'
pus formation. The defenses of the body do not allow the in-
fection to become generalized unless at a later date the toxic
materials absorbed by the animal from the affected joint suffi-
ciently lower body resistance, or the body defenses become more
or less exhausted in combating the infection in the joint. This
actually occurs, as many animals affected with "swollen joints"
do not develop septicemia with subsequent death until 2 to 4
weeks after developing lameness. Those which survive retain
sufficient body resistance to overcome the infection.
"Low grade" infections of this type are not uncommon among
animals. The development of the disease, known as "navel ill"
in young colts, occurs under exactly the same principle of in-
fection as "swollen joints" in calves-as a result of navel infec-
tion. In fact, "swollen joints" in calves should be termed, more
properly, navel ill in calves. This type of infection also occurs
to some extent in young pigs.
The navel cord of the new-born calf contains blood vessels
"Swollen Joints" in Range Calves 19
which communicate directly with the circulatory system of the
animal as well as a vessel which communicates directly with
the urinary bladder. The unhealed navel furnishes a direct
route of infection into the body of the animal. Thus, infection
of this type can take place much more readily from this location
than from any other site on the exterior of the body. In some
new-born calves a "leaky navel" develops. This occurs as a
result of the failure of the vessel from the bladder to close.
Leaky navels retard healing and prolong the period during which
the animal is exposed to navel infection and screwworm in-
Streptococcus pyogenes infection of wounds at sites on the
exterior of the body other than the navel invariably results in
the formation of an abscess, sometimes of considerable size,
but very rarely does such infection result in the development
of "swollen joints". Thus, "swollen joints" in calves results
almost exclusively from infection of the unhealed navel.
THE ROLE OF THE SCREWWORM FLY
Although it has been shown in these experiments that "swol-
len joints" can develop in calves as a result of infection of the
navel by Streptococcus pyogenes without screwworm infestation,
the larva and adult of the primary screwworm fly, Cochliomyia
americana, are considered to be of great importance in the de-
velopment of this disease.
It has been shown experimentally that the adult screwworm
fly is capable of carrying Streptococcus pyogenes from an in-
fected to a non-infected navel with the subsequent development
of "swollen joints". As far as can be ascertained this is the
first time the screwworm fly has been incriminated as a mechani-
cal carrier of disease-producing bacteria. Since a screwworm
infested navel is associated with the great majority of the
naturally occurring cases of "swollen joints" it would appear
that the screwworm fly must be considered as the most important
factor in the spread of this type of infection.
The screwworms or larvae of this fly also are considered im-
portant in the development of "swollen joints". The eggs
deposited by the adult fly on the edges of the unhealed navel
hatch in 11 to 21 hours and the screwworms or larvae invade
the wound. Any bacteria which may have been carried to the
wound by the adult fly are carried to the deepest recesses of the
wound by the larvae. The activities of the larvae are such as
20 Florida Agricultural Experiment Station
to produce a constantly open raw wound which is an ideal situ-
ation for infection to occur.
Thus, adult screwworm flies play an important part in the
spread of infection while the screwworms or larvae facilitate
infection by their activities in the navel.
During the 1944 calving season screwworms have been ex-
tremely prevalent in many sections of the state. This has been
attributed to the preceding mild winter season and the lack of
sufficient manpower on many ranches to treat promptly screw-
worm-infested wounds. Cattlemen should note that during the
calving season susceptible animals are on hand at almost all
times. Consequently, it is important that screwworm-infested
wounds should be treated promptly to reduce the prevalence of
Another important factor on some ranges which contributes
materially to the prevalence of screwworm flies is the presence
of range hogs. Screwworm infestations in these animals are
untreated, with the result that the prevalence of adult screw-
worm flies is increased greatly. Infestation of wild animals may
be a minor factor but they are not nearly so important as range
hogs which roam many ranges uncontrolled and uncared for.
It has been mentioned previously that abscesses were found
upon post mortem examination in the bodies of 2 of 3 calves
affected with "swollen joints". Also, lung involvement with
abscess formation was observed in 2 calves on a ranch on which
losses from "swollen joints" had been extensive. Reports from
cattlemen indicate that abscesses are found in various locations
in the body in numerous animals which have died as a result of
While the abscesses which were cultured in the laboratory
during this investigation were sterile, every indication points
to some association between their development and "swollen
joints". The microorganism concerned is a pus-forming one.
Failure to isolate this microorganism from affected joints re-
sulted in many instances. While some calves recover from
"swollen joints" with practically no retardation of growth, in
many instances the growth of the animal is seriously retarded
and in a few instances the animal is stunted. These latter results
could be caused easily by abscess formation in the body from
"Swollen Joints" in Range Calves 21
which affected animals continuously absorb toxic substances
which retard growth.
Then also, as indicated on 1 ranch, occasional calves may de-
velop body abscesses with no evidence whatsoever of the develop-
ment of "swollen joints".
As no microorganism has been isolated from abscesses occur-
ring under these conditions, it is impossible to say definitely
that "swollen joints" is associated with their development. How-
ever, all available evidence indicates a relation.
The conditions existing on most beef cattle ranges in this
state make treatment of "swollen joints", other than navel treat-
ment, more or less impractical. Under farm conditions or those
in which an animal can be handled frequently, treatment is more
practical. In all instances, the navel should be inspected. When
it is unhealed, with or without screwworm infestation, it should
receive a liberal application of tincture of iodine and a reliable
screwworm fly repellant.
Treatment with certain of the sulfa drugs may be beneficial
in many cases. This requires dosing the animal 2 or 3 times
a day. If this treatment is to be given, most effective results
can be obtained if administered when the animal first becomes
affected. The application of liniments may be of some benefit
to affected joints but results from their use should not be ex-
pected to be very marked.
Some cattlemen have made a practice of incising the capsule
of an affected joint in those animals in which the area develops
soft spots and indications of rupture occur. In such cases thick
creamy pus may flow from the wound for several weeks and
the wound usually is obstinate in healing. However, "open
joints" always are difficult to heal under these conditions. In-
cision of the joint capsule may save the life of the animal. The
joint should not be incised unless the joint capsule contain pus.
On the other hand, incision of swollen joints filled with pus may
serve as a means of further spreading contamination about the
premises. Animals so treated should be isolated if possible.
Animals which recover from "swollen joints" may be sal-
vaged by slaughtering for food. However, if intended for human
consumption the carcass should have veterinary inspection.
Under such inspection the affected parts of the carcass are con-
demned. The percentage of the carcass which can be salvaged
22 Florida Agricultural Experiment Station
in this manner depends upon the extent to which the bacteria
invaded the tissues of the body.
The most practical approach to the solution of the problem
of "swollen joints" in range calves is in prevention, which should
1. Prompt treatment of unhealed navels of new-born calves
with tincture of iodine and a reliable screwworm fly repellant.
2. Prompt treatment of screwworm-infested navels with
tincture of iodine and a reliable screwworm fly repellant.
3. Repeated checking and treatment of unhealed navels with
or without screwworm infestation until the wound is healed
Under range conditions cattlemen have discarded the use of
benzol to kill the screwworms in a wound. They have found that
the application of a reliable screwworm fly repellant serves to
kill the larvae as well as to repel the flies. It has been shown
that Smear 62 2 applied to a screwworm-infested navel will not
destroy the bacteria causing "swollen joints". As commercial
screwworm fly repellants are similar in composition to that of
Smear 62, and were used on ranches on which "swollen joints"
was occurring, it is doubtful if any of these preparations will
serve to disinfect an infected navel. These preparations have
been intended to kill screwworms rather than to disinfect. There-
fore, it is essential that a good disinfectant should be used in
conjunction with a reliable screwworm repellant when navels
are being treated.
Tincture of iodine is the best disinfectant that can be used
for this purpose. It is an alcoholic solution which gives it con-
siderable penetrating powers. Tincture of iodine is a standard
solution and by no means should be diluted when used for this
purpose. When a cavity occurs the opening should be held so
it can be poured full of the solution. Allow it to remain for a
minute or so. Then apply a reliable screwworm repellant. The
bottle of tincture of iodine should be handled so the contents
will remain clean. Swabs should not be placed in the wound
and then in the bottle of iodine. Tincture of iodine should be
used freely and can be used on the unhealed navel repeatedly.
"Melvin, Roy, C. L. Smith, H. E. Parrish, and W. L. Barrett, Jr. A
new remedy for the prevention and treatment of screwworm infestations
in livestock. U. S. Dept. of Agri., Bur. of Ent. and Pt. Quar. Pamphlet
E 540, May 1941.
"Swollen Joints" in Range Calves 23
However, an unhealed navel treated with this solution and free
of screworms usually heals very rapidly, even. when severely
It is impossible to say at this time just how long a navel must
be infected with Streptococcus pyogenes before "swollen joints"
can develop. This no doubt varies in individual cases. However,
the sooner this type of infection is destroyed in an unhealed
navel, the better the results should be. Therefore, prompt treat-
ment of unhealed navels always is highly desirable.
Streptococcus pyogenes has been isolated from 3 of 16 natur-
ally occurring cases of "swollen joints" (navel ill) in range
The disease has been induced experimentally by navel infec-
tion with this microorganism with and without screwworm
The primary screwworm fly, Cochliomyia americana C. and P.,
is an important means of transmission of this type of infection
and the activities of the larva apparently facilitate infection in
The most practical means of control is the prompt treatment
of the unhealed navel of new-born calves with or without screw-
worm infestation with tincture of iodine and a reliable screw-
worm fly repellant and subsequent treatment until the navel is
Acknowledgments: The author wishes to thank the following for
courtesies extended during this investigation: J. R. Gunn and Henry O.
Partin, Kissimmee, Fla.; Carl E. Barber and Dr. H. L. Moorman, St. Cloud,
Fla.; P. E. Williams, Davenport, Fla.; W. P. Hayman, Bartow, Fla.; Dr.
W. G. Bruce, Savannah, Ga.; Dr. J. D. Grossman, Columbus, O.; A. L.
Jackson, W. J. Sheely, P. T. Dix Arnold, Dr. John T. Creighton and Dr.
A. L. Shealy, Gainesville, Fla.