U.S. patent number RE32,758 [Application Number 06/744,636] was granted by the patent office on 1988-10-04 for method for remotely monitoring the long term deep body temperature in female mammals.
This patent grant is currently assigned to New Mexico State University Foundation, Inc.. Invention is credited to David L. Zartman.
United States Patent |
RE32,758 |
Zartman |
October 4, 1988 |
Method for remotely monitoring the long term deep body temperature
in female mammals
Abstract
This invention relates to a novel method for remotely detecting
and monitoring on a long term basis the deep body temperature of a
mammalian female which comprises the steps of attaching a
temperature-sensing probe capable of remote interrogation to an
expandable anchor, implanting the probe with the anchor attached
thereto in collapsed condition within the vaginal canal, expanding
the anchor to maintain the probe in place despite the animal's
muscular efforts to expel same, interrogating the probe from a
remote location on a daily basis at approximately the same time
each day for a period not less than one complete estrous cycle, and
noting any abrupt change in temperature within each cycle as an
indication of physiological stress.
Inventors: |
Zartman; David L. (Worthington,
OH) |
Assignee: |
New Mexico State University
Foundation, Inc. (Las Cruces, NM)
|
Family
ID: |
26846581 |
Appl.
No.: |
06/744,636 |
Filed: |
June 14, 1985 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
149250 |
May 12, 1980 |
04387724 |
Jun 14, 1983 |
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Current U.S.
Class: |
600/549;
600/551 |
Current CPC
Class: |
A01K
67/02 (20130101); A61B 10/0012 (20130101); A61D
17/002 (20130101); A61B 2010/0019 (20130101) |
Current International
Class: |
A01K
67/02 (20060101); A01K 67/00 (20060101); A61D
17/00 (20060101); A61B 10/00 (20060101); A61B
010/00 () |
Field of
Search: |
;128/736,738,130,131,127 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Singer, A. "An Automatic System for Measuring & Recording of
BBJ in the Human Female", Fertility & Sterility, 15:44-51
(1964). .
K. Maatje and W. Rossing, "Detecting Oestrus by Measuring Milk
Temperatures of Dairy Cows During Milking," (from Livestock
Production Science) 1975, from The Netherlands, pp. 85 to 89. .
"Calving Signs You Can Use", Hoard's Dairyman, 101:1188, 1956 by
Melvin Scholl. .
"Heat-Tolerance Studies of Fat-Tailed Sheep in the Subtropics", J.
Agr. Sci., 47:280-286, 1956 by E. S. E. Hafez et al. .
"Vaginal Temperature of Cows Before and After Calving", JAVMA
131:381-383, 1957 by I. D. Porterfield, Ph.D. et al. .
Report of the New York State Veterinary College at Cornell
University, 1962-1963, S. J. Roberts reference, p. 93. .
"The Fall in Rectal Temperature Seen Before Parturition in Sheep",
J. Reprod. Fert. (1969), 19, 569-571, by R. Ewbank. .
"Flucuations in Rectal Temperature of Swine at Parturition,"
Canadian Veterinary Journal, 13:72-74 (1972), G. J. King et al.
.
"Reproduction in the Dog and Cat", Reproduction in Domestic
Animals, 3d Ed. Acedemic Press, NY, p. 665, H. H. Cole, 1977. .
"Predicting the Time of Parturition in the Normal Cow . . . ", The
Veterinary Record, vol. 75, No. 14, by R. Ewbank. .
"An Autom. System for Meas. & Recording of BBT in the Human
Female", Fertility and Sterility, 15: 44-51, (1964), by Singer.
.
"Ireless Fever Alarm Device", Med. Biol. Engrg. & Computing,
1979, vol. 17, pp. 550-552, by Kingma et al. .
"Continuously Telemetered Vaginal Temp. in the Baboon", The Baboon
in Med. Res., IIed., Univ. of Texas Press, Austin, (1967), pp.
19-35 by Hendrikx et al. .
"Meas. of Elec. Res. & Temp. in Vaginal Mucosa of the Sows
During Estrous", Veterinary Bulletin, 48: 261, (1978) by Michael.
.
"The Association Between Basal Body Temperature, Sexual Swelling,
and Urinary Gonadal Hormone Levels in Menstral Cycle of the
Chimpanzee", Jrnl. of Reprod. Fertility, 1977, vol. 50, pp. 23-28
by Graham et al..
|
Primary Examiner: Jaworski; Francis J.
Attorney, Agent or Firm: Lane & Aitken
Claims
What is claimed is:
1. The improved method for detecting a feverish condition in
mammalian females which comprises the steps of: attaching a battery
powered radio telemetric temperature measuring device of a size
adapted for insertion into the uterine canal to an expandable
anchor of approximately the same size in collapsed condition as
said telemetry device, collapsing the anchor and inserting it while
thus collapsed along with the telemetry device attached thereto the
vagina to a depth where the assembly thus formed lies adjacent the
cervix, expanding the anchor "in situ", monitoring the temperature
daily from a remote external location at approximately the same
time each day for a period not less than approximately one complete
estrous cycle, and comparing the temperature each day with the
average temperature over the immediately preceding approximately
ten day period to detect any abrupt changes therein of a magnitude
several tenths of a .degree.C. higher than the deviation in
temperature upon which said average temperature was determined.
2. The improved method as set forth in claim 1 wherein the
temperature is monitored for approximately 50 days.
3. The improved method as set forth in claim 1 wherein the daily
temperature reading is taken between approximately 5:00 and 7:00
a.m.
4. The improved method as set forth in claim 1 which includes the
step of inseminating the subject no later than one day following
the day upon which said abrupt temperature change is detected.
5. The improved method as set forth in claim 1 which includes the
step of treating the subject for febrile illness if said abrupt
temperature change persists over one day. .Iadd.
6. A method for detecting ovulation in a female herd animal
selected from the bovine, equine and porcine species and subject to
climatic temperature variations, said method comprising the steps
of:
selecting an intravaginal anchor adapted for retention in said
animals's vagina for a period not less than one complete estrous
cycle of said animal and equipped with a telemetric temperature
measuring device for relaying temperature information from the
animal to a location of a remote monitoring station;
inserting said anchor into the vagina of said herd animal,
maintaining said anchor in said vagina for a period of not less
than one complete estrous cycle, and locating said animal in an
area such that a range of said telemetric measuring device allows
said device to relay said information to said station;
measuring an intravaginal temperature of said animal at least one
time daily at approximately the same time each day for a period not
less than one complete estrous cycle of said animal;
relaying said information to said remote monitoring station;
averaging temperature measurements taken over a plurality of days
and comparing a temperature taken on a succeeding day with an
average calculated in said averaging step;
repeating said averaging and comparing steps on each next
succeeding day, the number of days of said plurality of days
remaining constant;
identifying as a significant elevated temperature a temperature
taken on one of said succeeding days that is at least several
tenths of a degree Celsius higher than an average of temperatures
for a preceding plurality of days and that also exceeds
temperatures taken at approximately the same time on said preceding
plurality of days;
counting a number of days between said significant elevated
temperature and a previous temperature spike attributable to a
preceding onset of ovulation; and
identifying said succeeding temperature as a subsequent onset of
ovulation when said counted number of days is within about five
days of an average estrous cycle length of said animal. .Iaddend.
.Iadd.7. The method of claim 6 wherein said period of not less than
approximately one complete estrous cycle is approximately 50 days.
.Iadd.8. The method of claim 6 wherein said same time is the period
between about 5:00 and about 7:00 a.m. .Iaddend.
Description
Livestock breeders, especially cattlemen, find that one of their
major concerns is that of being able to maximize the conception
rate of their females. A conception percentage of 80% or above is
considered good. In the dairy industry where husbandry is practiced
more intensively than in ordinary beef production, .[.diarymen.].
.Iadd.dairymen .Iaddend.consider that a poor conception rate is one
of their most significant management as well as economic problems.
The root of the problem is basically the failure to reliably detect
estrus. This is especially significant in the dairy industry
because dairy cattle are, for the most part, hand bred and the herd
manager or operator must know when to introduce the cow to a bull
or else inseminate her artificially. As valuable a tool as
artificial insemination is to the dairy industry and others, it is
being used far less than it should be because of the difficulties
associated with detecting estrus, some of which at least can be
solved by a bull in conjunction with an assortment of commercially
available detection aids which provide visual evidence of when the
bull has mounted the cow.
A cow that has not become pregnant within 80 days after calving
costs the dairyman in excess of two dollars per day in lost income
and actual out of pocket expenses. The cow who exhibits abnormal
reproductivity, on the other hand, can easily go undetected for
even a much longer period of time.
Apart from using the bull, stallion or boar as a means in and of
himself or in conjunction with some artificial aid to detect
ovulation, much attention has been given to the detection of
abnormal body temperatures, even in humans. For the most part, the
detection of temperature changes in bovines and equines has, up
until recently, been reliant upon standard temperature probes such
as ordinary thermometers that were temporarily inserted by hand
into the rectum or vulva for the brief interval required to get a
reading and then removed. Obviously, such a technique requires
confinement of the animal and a great deal of time and effort on
the part of some human being. This labor-intensive effort is
completely impractical for use over the extended period of time
required to develop a temperature history for the animal adequate
to use as a basis for noting any anomalous state of affairs.
Early illness detection presents yet another problem because,
ordinarily, the animal does not have her temperature checked until
overt signs of physical illness have become apparent to the
observer. This is often hours, if not days, after the onset of the
illness thus necessitating a longer recovery, greater expense and
other undesirable consequences. In the dairy herd, rapid illness
detection becomes especially significant due to the decreased milk
output, possible drug contamination of the milk, reduction in feed
conversion efficiency, etc.
It has been recognized for quite a long time that various
significant physiological changes in female mammals, including the
human species, could be detected through change in deep body
temperature before other external manifestations provided any clue
to what was taking place. Ovulation in human females can, for
example, be detected in some women by a careful monitoring of their
body temperature and such a procedure is in rather widespread use
as a birth control system. While the so-called "basal body
temperature" (BBT) has been known for a long time to bear an
important correlation to the menstrual cycle of a human female, it
has also been found that the usual oral and rectal methods of
measuring body temperatures lack the precision necessary to detect
the rather minute incremental changes that signify the onset of
ovulation. In an effort to solve this problem and measure the BBT
in the human female with greater precision, Dr. John H. Mattox et
al. implanted accurate temperature sensing instruments
intravaginally in a number of women. These instruments telemetered
the BBT to remote data collection stations which monitored it and
compared the results over several menstrual cycles with similar
BBT's taken orally. The results of this study were published in
Volume 27, No. 9 dated September 1976 of the reports of the
American Fertility Society following presentation of a paper on the
subject in October 1975 at the Annual Meeting of the Pacific Coast
Fertility Society.
While the foregoing study clearly demonstrated the practicality of
telemetering deep body temperature data to a remote data collection
station from a site within the vaginal canal of a human female, it
also clearly showed how complex such a system is and how much
cooperation on the part of the participants was necessary in order
to provide the investigators with reliable data. Also, not one of
the women who participated in the study left the temperature probe
implanted more than a few hours out of each day and, while the
investigators felt that the "cumbersome and complex" system could
probably be simplified, they agreed that their study using an
intravaginal probe did little more than establish the worth of the
conventional oral temperature method as a means for detecting
ovulation. Clearly, a system such as that employed by Dr. Mattox
was unsuitable for livestock since the study demanded a great deal
of intelligent cooperation on the part of each participant which an
animal is totally incapable of providing.
.[.Diarymen.]. .Iadd.Dairymen .Iaddend.have known for years that a
cow's body temperature is capable of foretelling the onset of
estrus as well as conditions of poor health like, for example,
mastitis and other fever-inducing ailments. They also knew that a
cow's temperature varied greatly with ambient conditions and were
by no means the same from one animal to the next even under
identical conditions thus, while it has been recognized that a long
term temperature history of a particular cow related to the change
in ambient conditions should be very helpful in detecting the small
abnormalities in the temperature profile for a given animal that
are needed for a reliable prediction of estrus or a febrile
illness, no way was known in 1978 for obtaining such information as
reported in Hoard's Dairyman by Armstrong and Wiersma; 123(13):
823, July 10, 1978. These authors reported attempts at measuring
milk temperatures and analogous body temperatures predicated upon
the latter but the clear conclusion was reached that "It is
apparent that the use of cow body or milk temperature for early
detection of mastitis, estrus or illness has little value under
Arizona conditions." This same article alluded to a study in The
Netherlands when monitoring the milk temperature in the claw-piece
of the milker was effective in detecting estrus in 16 out of 19
cows based upon a 0.5.degree. change; however, these authors
seriously doubted whether deviations of this order of magnitude and
less would be effective under the conditions they were working
under in Arizona and their conclusion was that they would not. Even
before Armstrong and Wiersma were conducting their milk temperature
experiments on dairy herds in Arizona, others had experienced much
the same thing in connection with different types of temperature
measurements in dairy cattle.
During roughly the same period in which Dr. Mattox and his
associates were making the deep body temperature study on the human
female, others were attempting to use intracranial temperature
measurements taken in the ear canal of dairy cattle to provide
better reproductive management. M. Lira et al. reported the results
of their study at the annual meeting of the American Dairy Science
Association held at Kansas State University in Manhatten, Kans.
during June of 1975. As was the case with the Mattox study on human
females, the ear canal probes were inserted and removed on a daily
basis rather than being implanted and left in place over a
prolonged period of time, say a complete estrous cycle or longer.
The readings that were taken were confined to the day of estrus and
six days before and after. The data taken during this study
revealed that the temperature of the animal was elevated very
slightly and was significantly different (P<0.01) on the day of
estrus and that the ear canal measurement coincided closely with
that taken rectally. One is forced to conclude that whether the
body temperature is taken rectally or intracranially, it must be
taken quite accurately to detect a change in the order of a tenth
of a degree. Common sense dictates that many factors, both external
and internal, could be responsible for such a slight change and,
for this reason, little reliance can be placed upon the detection
of a change of this order of magnitude.
Various investigators at Los Alamos Scientific Laboratory operating
under a contract from the U.S. Department of Energy have conducted
extensive tests over the past several years on the telemetering of
body temperature data and other information from livestock carrying
both self-contained battery-operated transmitters and AC powered
ones. Among other publications, the Holm et al. Progress Report
LA-7642-PR entitled "Electronic Identification" of May 1979
summarizing work done between Oct. 1, 1977 and Sept. 30, 1978
provides one with a fairly comprehensive summary of these
activities which were, for the most part, focused upon what would
be required in a cost-effective system that could be implemented on
a national basis to trace the movement of livestock, their physical
condition, location, and other factors such as stress and estrus
that would be of assistance to the industry in terms of herd
management, disease control, reproduction and the like. For present
purposes, this research is significant in that it did provide long
term assessment of the body temperature of animals using so-called
"on board" telemetry equipment capable of being monitored at a
remote site. So far as is reflected from the above report, the
nearest approach to deep body temperature readings that were taken
came from transponders implanted surgically subdermally. While body
temperatures were measured intracranially within the ear canal as
had been done in the past, these readings do not qualify as deep
body temperature readings nor do those taken rectally. As such,
there is no teaching of any long term monitoring of deep body
temperatures within a natural body cavity like, for instance, the
vaginal canal of a female animal such as a cow, mare or sow.
Essentially, the foregoing publications reflect the state of the
art with respect to the detection and monitoring of deep body
temperatures in mammalian females for any purpose as well as for
the specific purposes of recognizing the onset of illness, estrus
or other similar physiological stress. Before proceeding with a
description of the novel method for detecting the onset of estrus
or febrile illness by means of the intravaginal measurement of deep
body temperatures in female mammalian livestock that constitutes
the subject matter of the instant invention it would, perhaps, be
helpful to look briefly at why such information is important to the
commercial livestock industry, the dairy industry and horse
breeders, among others.
Take, for instance, the dairy industry which can be considered
representative of similar situations existing in each of the
others. It can be shown that losses due to poor reproduction alone
accounted for losses totalling over a half billion dollars some ten
years ago and in the present state of the argicultural industry,
these losses are sure to be much greater. These losses are broken
down into three broad areas as follows:
(1) Loss of production--milk and calves,
(2) Replacement costs, and
(3) Additional breeding costs (vet services and medication).
With respect to the first of these, as of ten years ago a fair
consensus taken from recognized agricultural economists indicated
losses to the dairyman of about 70 cents per day resulted for each
day beyond the optimal yearly calving interval that a cow did not
conceive. Since the optimal yearly calving interval is recognized
to be twelve months and the yearly average back in 1970 was 13.5
months, the nationwide loss to the dairy industry in the United
States which numbers some twelve and a half million cows represents
a loss of just under $400,000 annually.
Add to the above the replacement cost factor nationally even back
in 1970 of a little less than $94,000,000. These losses were
occasioned by the fact that somewhere near 5% of the cows had to be
slaughtered because of their failure to conceive within a
reasonable time or at all coupled with the difference of around
$150.00 per animal that the dairyman had to absorb as the disparity
between the salvage value of the animal slaughtered and her
replacement.
A similar analysis will reveal that in excess of $50,000,000 more
is spent on the increased number of average services per
unproductive cow that are required in the attempt to successfully
breed her and the unusually high vet bills required for such an
animal. A significant reduction in these losses could be realized
by a reliable early detection of estrus in these animals
accompanied by promptly breeding them for calving at the
recommended twelve month time interval. Significant losses can also
be demonstrated for both beef cattle and hogs. While the horse
breeding industry has different economic problems; nevertheless, an
early and reliable detection of estrus in the mare can prove to be
of substantially financial advantage.
In addition to the significant economic losses occasioned by
inefficient breeding, infection and metabolic stress are equally
costly problems. Looking again at the dairy industry for an idea of
the magnitude of these problems, it can be shown that common dairy
herd diseases like mastitis, ketosis and milk fever accounted a
decade ago for losses well in excess of a half billion dollars;
yet, prospects are favorable for cutting these losses almost in
half by merely detecting these diseases in the sub or preclinical
stage before they progress to the clinical stage where they
manifest themselves in a way that they can be detected by the usual
methods. Early detection of febrile illness holds good promise of
prompt treatment and a favorable prognosis that shortens the
physical setback and restores the animal to full production before
her milk output is adversely affected, at least to the degree it
would be if the disease were allowed to progress further.
For the most part, cows and sows are bred artificially, therefore,
the best natural means, namely the bull or boar, for detecting when
the female is in heat are not available thus necessitating some
other method for detecting estrus. This is not to say that accurate
estrus detection is not also worthwhile in natural breeding. Take
for example, horses which are bred naturally. Stud fees are
generally based upon the stallion having to service the mare three
or four times to insure that she is pregnant. If, on the other
hand, he had to stand only once for each mare and could, therefore,
service several, the stud fees could be reduced to a considerable
degree. In the case of sows, they are known to exhibit no external
signs of being in heat on occasion and, therefore, even the boar is
no help under such circumstances.
Thus, while accurate body temperature measurements are known to
provide a reliable indication of both estrus and the onset of
febrile illnesses in mammalian females, both human and animal, no
one has yet developed a system for reliably ascertaining this
condition, especially with animals under practical herd management
conditions. It has also been discovered in accordance with the
teaching of the instant invention that animals differ in their body
temperature patterns from humans and, therefore, absolute or "spot"
readings cannot be relied upon in animals but rather only the
change in temperature from one day to the next recorded at
approximately the same time each day and over an extended period of
time, preferably one that encompasses more than one estrous cycle.
Moreover, small as the changes are, if accurately measured they are
capable of differentiating between the onset of an illness and
estrus, the former generally being of greater magnitude than the
latter while the latter is the shorter-lived of the two.
Temperature measuring instruments, even those sufficiently small to
be implanted, having the requisite accuracy present no problem as
they are commercially available in the marketplace as is the
radio-telemetry support system capable of transferring the
"onboard" temperature data to a remote receiving station. While the
cost effectiveness and longevity of such a system may prevent its
being used on a widespread basis in range cattle for sometime yet
as evidenced by the Los Alamos study, nevertheless, the potential
saving to the dairyman, hog farmer and other breeder of farm
animals as opposed to range stock can be very significant. The real
challenge is not the equipment but rather the method employed to
accurately measure and monitor the body temperature of the animal
in such a way and at such a site that it will reliably provide the
desired temperature data from which accurate predictions as to the
state of health and/or ability of the animal to conceive can be
made. The Mattox study previously mentioned apparently demonstrated
the inapplicability of the human intravaginal implantation method
to female animals since the system was so complex and cumbersome
that even the supposedly "intelligent" human species failed to
produce the expected results. Intracranial implantations in the ear
canal proved less than effective in addressing the accurate
temperature readings necessary for a reliable prediction of estrus
or state of ill health as did the notoriously old rectal method.
Even the surgical implantation of the radio telemetry equipment was
fraught with serious deficiencies, not the least of which is the
implantation itself. Nevertheless, the indications were that only
deep body temperature measurements were sufficiently free of
ambient climatic factors and other external influences to a point
where the necessary degree of accuracy was attainable under herd
management conditions. Also, as a practical matter, relatively long
term implants appeared to be necessary since the herd owner could
ill afford the labor cost of having to take the deep body
temperature of each individual animal separately at least once a
day and preferably at the same time. Another unknown factor was, of
course, the traumatic effect such a daily procedure might have on
the animal which might manifest itself in a brief rise in body
temperature thus providing a false indication of estrus or the
onset of some illness.
With these limitations in mind and knowing that neither the ear
canal or the rectum provided the answer, the best possibility
seemed to be the vaginal canal despite the indications to the
contrary experienced by Mattox with his human subjects or, perhaps,
intrauterine placement. Both of these internal sites held promise
of providing a true deep body temperature reading essentially
unaffected by external conditions. Also, following insemination,
there appeared to be no reason for removing the temperature probe
and associated radio telemetry apparatus until the time came for
the animal to give birth. Furthermore, by leaving the probe in
place from insemination to parturition, a long history of estrous
cycles would be available for each animal on an individual basis in
case the response happened to vary from one animal to another,
seasonally or for some other reason.
Accordingly, it was decided to implant the probes and associated
telemetry equipment within the vagina of cows, mares and sows to
see if sufficiently accurate deep body temperatures could be
remotely sensed to provide the investigator with a reliable
indication of just when estrus or some other physiological change
manifesting itself in a rise or lowering of body temperature took
place. Unfortunately, while the theory was sound, the early
intravaginal experiment failed for the simple reason that the
animal quickly expelled the probe through muscular action, perhaps
involuntary but nevertheless effective to rid her body of the
foreign object.
Notwithstanding the foregoing setbacks, it has now been discovered
in accordance with the teaching of the instant invention that long
term and remotely readable deep body temperature readings that are
accurate and virtually unaffected by external conditions can, in
fact, be taken intravaginally by the simple yet unobvious,
expedient of attaching the temperature probe to an expandable
anchor, inserting the probe and anchor deeply within the vaginal
canal with the anchor in collapsed condition, permitting the anchor
to expand to hold the probe in place despite the muscular actions
of the animal in an effort to expel same, interrogating the sensor
daily from a remote station at approximately the same time each day
for a period of not less than one full estrous cycle, and noting
any change in the deep body temperature of the animal during the
aforesaid cycle as a means for detecting estrus or the onset of
febrile illness.
It is, therefore, the principal object of the present invention to
provide a novel and improved method for the remote detection of
physiological changes taking place in female mammals.
A second objective is the provision of a method of the type
aorementioned wherein surgical invasion of the animal is
unnecessary.
Another object of the within described invention is to provide a
means for monitoring the body temperature of a female mammal on a
long term basis such that the data taken is virtually unaffected by
external conditions, stress or other outside factors.
Still another objective is to provide a method of the character
described which is sufficiently accurate to enable one to reliably
detect both the onset of febrile illness and estrus while, at the
same time, permitting the observer to differentiate
therebetween.
An additional object is to provide a long term remote temperature
sensing method particularly well suited to female farm animals of
the bovine, equine and porcine species which is cost-effective and
practical under herd management conditions.
Further objects are to provide a body temperature monitoring method
for mammalian females which is simple, efficient, dependable safe,
relatively inexpensive, long-lasting and one that is easily carried
out by unskilled personnel.
Other objects will be in part apparent and in part pointed out
specifically in connection with the description of the drawings
that follows, and in which:
FIG. 1 is a diagram showing placement of the probe and the anchor
therefore in the vagina of the animal; and,
FIGS. 2-7 are charts detailing the long term intravaginal
temperature response of various species of female mammals.
Referring initially to FIG. 1, the temperature sensing probe 10
used in the instant method is conventional and it consists of a
battery powered transmitter containing a temperature-sensing
thermistor which sends out a pulsed signal, the rapidity of which
corresponds to the temperature of the transmitter and also the deep
body temperature of the animal when implanted in her vaginal canal
12. The transmitter 10 has been shown without detail but
approximately its actual size in relation to a grown cow's vagina
12. The resulting signal is sensed at a remote location outside the
animal's body. The location of the receiver 14 is optional
depending upon its sensitivity and the strength of the signal
generated, some receivers being responsive to signals originating
miles away from the transmitter. The selection of signal strength
and receiver sensitivity is a matter of choice well within the
skill of the art and will depend to a considerable degree upon
several extraneous factors such as the size of the herd, the
ability of the equipment to differentiate among the several
animals, the degree of confinement of the herd, if any, and other
similar parameters.
The signal that is received is recorded and analyzed during a
preselected time period, say five minutes, at the same or
approximately the same time each day. In bovine animals, for
instance, it is a well-known fact that the lowest body temperatures
of the day occur early in the morning between approximately 5:00
and 7:00 a.m. The baseline against which the spikes are most
evident is likely to be established during such a time period;
therefore, for cattle at least, the measurements are preferably
made during this minimum baseline temperature interval.
For small confined herds, tunable receivers are unnecessary
provided the transmitted signal is relatively weak. In such a
circumstance, the receiver is placed in reasonably close proximity
to the particular transmitter whose temperature signal is to be
decoded so as to screen out other extraneous signals. On the other
hand, care should be taken to not excite the animal thus inducing a
false spike which is often the case with transponders inserted into
a body cavity and removed after such reading in the manner of
Mattox and others.
The battery powered radio transmitter 10 containing the
temperature-sensitive thermistor is implanted at the mouth of the
cervix 16 where, for purposes of making dependable and accurate
predictions, it must stay for at least one complete estrous cycle
and preferably fifty days or longer. Because of the stress-induced
fluctuations in temperature, handling of the animal should be
minimized; however, a 50 day test performed at the proper time will
allow the animal to settle down while at the same time provide good
baseline temperature data against which the spikes become easy to
detect as will appear presently. Notwithstanding the long term
implantation of the radio transmitter, it remains readily
accessible to serve, repair and change batteries, all without
having to resort to surgical invasion of the animal or require the
services of a D.V.M.
The act of implantation is a simple one using standard techniques
and instruments like, for instance, a trochar tube and pushrod or
plunger inside the latter. The problems do not arise in connection
with placement of the probe but rather with how to keep it in
place. The muscle contractions and relaxations of the vaginal walls
are such that they quickly eject any foreign object like the probe.
The answer came in the form of an expandable anchoring device which
is introduced into the vagina in collapsed form and then expanded
to provide a multi-fingered element which would yield under the
influence of the contracting vaginal muscles thus preventing them
from getting a sufficient hold to eject either the anchor or the
transmitter attached thereto back out through the vulva. One spider
like form of anchor which has been used with good results is shown
in FIG. 1 and identified by reference numeral 18. A device having
characteristics very much like the anchor shown, but for a
different purpose, forms the subject matter of one or more of the
following U.S. Pat. Nos. 3,811,423; 3,811,443; 3,811,424; and
4,091,807.
Once the probe is in place as shown, the herd manager or other
investigator can begin gathering data for the purpose of
ascertaining when the animal is in condition to conceive or,
alternatively, is not ovulating and cannot be impregnated. This
same data will be effective to indicate the onset of a febrile
illness well before any overt clinical signs become apparent. The
results of actual deep body temperature measurements in three
species of female livestock mammals form the subject matter of the
graphs appearing herein as FIGS. 2-7, inclusive, to which detailed
reference will soon be made; however, before doing so, it would
seem appropriate to digress briefly and explain a bit more about
when the probe should be implanted and why it should be kept in
place for an extended period of time.
Cows and other female animals are known to have cyclic variations
in basal body temperature which cycle bears a relationship to the
estrous cycle. This cycle was discovered to differ a great deal
from that of the human female. One major difference is the fact
that women experience a near constant temperature pattern from
period-to-period, whereas, cattle and other animals do not. The
fact of the matter is that farm animals exhibit a changing
temperature pattern which seems to depend to some degree at least
upon the climate and the season. For instance, it can be
demonstrated that the normal body temperature baseline takes on an
ascending pattern during prolonged periods of cold weather and a
descending one when it is warm. It is essential, therefore, that a
fairly long term history of not less than a complete estrous cycle
and preferably even longer, say 50 days, be kept and used as the
basis for detecting any significant changes such as those that
signal ovulation or the onset of febrile illness.
In the human female, despite the constant temperature pattern
between periods, Mattox found he could not .[.realiably.].
.Iadd.reliably.Iaddend. detect ovulation based upon deviations from
this pattern even though he was using highly motivated, intelligent
and cooperative women. Nonetheless, and contrary to what one might
expect, readily detectable temperature spikes signalling ovulation
do occur in farm animals. Even though the baseline temperature
varies seasonally and with environmental conditions, it has been
discovered in accordance with the teaching of the instant invention
that ovulation can be reliably ascertained provided a sufficient
temperature history leading up to the anomaly or spike is
available. The proof is, of course, that animals bred on such a
spike get pregnant while those bred at other times do not.
More specifically, the estrous cycle is such that a pronounced
spike in the order of 0.8.degree. C. is noted on the day of estrus
in a cow, for example, while an equally prominant dip in
temperature takes place on the preceding day and again on the
following day when ovulation occurs. This cyclic pattern happens in
cows with so-called "silent heats" as well as those with normal
heat periods. This 0.8.degree. spike lasts for one day only and it
is detected by measuring it against her average body temperature
over the preceding ten day period or thereabouts.
In a dairy herd, for example, a cow's greatest milk is produced
provided she is inseminated within 90 days after parturition; yet,
statistics show that about one-third of all dairy cows miss this
target for the reason that over 40% of these cows never have a heat
period recorded within the first sixty days after they have calved
and an additional 12% or so go over ninety days. Even after the
first heat period following parturition is recorded, about one in
every six thereafter is missed. For these reasons alone, it is of
utmost importance if cost-effective dairy herd management is to be
achieved, that each of these heat periods, and preferably the
first, is reliably detected.
Turning the attention next to the graph of FIG. 2, wherein Mare I
showed four spikes (A, B, C and D) that surpassed a threshold line
(spike indicates about 3/4.degree. C. above mean). These spikes are
spaced at regular intervals that coincide with the expected time
between ovulations. Also, spikes A, B and D were associated with
estrus. The mare was not teased during the period of spike C, so
the estrus status is not known. Each data point (dot) represents a
once-daily reading taken at approximately 7:30 a.m. between May 9
and Aug. 12, 1979. The ordinate scale is in radio counts per 5
minute period.
Mare II charted in FIG. 3 showed four substantial temperture spikes
(magnitude about 3/4.degree. C. above mean) which extend above the
threshold line. Spikes B and D occurred at the last day of the
estrous period. The mare was not teased during the period of spike
A, so her receptivity is not known. The spike C occurred during
mid-estrous and, curiously, no spike appeared during the subsequent
estrous period. Each data point (dot) represents a once-daily
reading taken at approximately 7:30 a.m. between June 1st and Aug.
10, 1979. The left side scale is in radio counts per 5 minute
period.
The intravaginal temperature graph of FIG. 4 was taken of a sow
instead of a mare. The sow exhibited two heat periods of 2 days
duration which is characteristic of sows. There were temperature
spikes (A and C) towards the end of each heat period. The sow was
accidentally bred on the second day after spike C and became
pregnant. Spikes A and C were nineteen days apart which matches
exactly the normal ovulation interval for sows. Spike B was quite
high and indicates a fever of short duration which might well have
been due to a mold infection such as a virus might cause.
Directing the attention next to FIG. 5, heifer 1474 initially
experienced three normal heat periods and there were temperature
spikes (A and B) recorded as shown. The transmitter was not
implanted in the heifer during the period marked xxx. Spike C was
not accompanied by standing heat, however, the interval was normal
from the previous spike and the heifer was bred. It is believed
that she became pregnant and then miscarried because she came in
heat 28 days later with a spike occurring the subsequent morning.
The 29 day interval was too long for normalcy. Eventually, the
heifer was bred again during a heat and spike episode and she
became pregnant.
FIG. 6 to which reference will next be made details the temperature
pattern of yet another heifer. Heifer 1494 presented spikes A, B
and C during her test period. She was just reaching puberty when
brought into the experiment. She only expressed heat once and that
was accompanied by spike B; nevertheless, she did have normal
intervals .[.beteeen.]. .Iadd.between .Iaddend.the three
significant spikes. Following spike C she did not show any mating
behavior or spikes during a period of very hot weather. Eventually,
she did come in heat and had a smaller spike. She was bred and
became pregnant.
Finally, with reference to FIG. 7, a cow 690 was selected because
of her infertility as a subject for examination of spike conditions
during known reproductive insufficiency. There were two very high
spikes without associated heat. She had a questionable heat once
and a definite standing heat towards the end of the observation
period. The cow was bred at spike B and did not become pregnant.
Apparently, the cow is physiologically out of phase and there was
no normal periodicity in her record at all. This example clearly
illustrates the value of the remotely-sensed temperature method of
the present invention in detecting acyclicity and probable
ovulation failure.
On the whole, the foregoing charts clearly reflect the day-to-day
physiological conditions of the subjects. When her temperature
reading is noticeably greater than her previous ten day average and
exceeds all previous highs during that time interval, the
probability is that she is preparing to ovulate and she should be
bred on either the day of the .[.estrus.]. .Iadd.estrous
.Iaddend.spike or early the next day. In the specific case of cows,
if the foregoing temperature spike falls on a 21.+-.5 day interval
from the preceding spike, the cow is very probably ovulating;
however, if the spike is out of phase with the normal estrous cycle
as above noted and has a magnitude somewhere around three times the
magnitude of previous spikes, the animal is very probably feverish
and such a spike signals the onset of some febrile illness rather
than estrus and at a time well in advance of when any clinically
recognizable symptoms appear. The random occurrence of such spikes
their magnitude and duration (more than one day) allow the observer
to readily differentiate between the fever spike and the estrus
spike. It is also significant to note that the failure to record a
spike is equally informative because it signals the absence of
ovulation which is every bit as important to know as when the
animal is experiencing normal ovulation (see FIG. 7).
The foregoing examples clearly demonstrate that, while the
temperature cycles of various species of female farm animals have
long been recognized as effective indicators of estrus, until now
there has never been a reliable, practical and effective method for
determining the animal's temperature, deep body or otherwise, on a
daily basis under herd management conditions. The instant method
permits the long term monitoring of the deep body temperature of a
female mammal without having to handle over and over again. The
subject is natural at all times and need not be agitated as is the
case with present deep body temperature measurement methods where
the thermometer or other types of temperature measurement probe is
repeatedly inserted and removed from her rectum or vulva every
single day. The animal is not harmed in any way or otherwise
traumatized yet she is constantly providing the observer with much
needed information on her physical condition which is otherwise
essentially unattainable under field conditions.
Summarizing, the instant method solves three heretofore unsolved
problems, namely: (1) it provides for remote interrogation and
possibly even automated monitoring of an animal's deep body
temperature by means of an indwelling probe implanted without
surgery; (2) it provides information on ovulation on all animals,
both those experiencing active estrus and those who are not; and
(3) it detects feverish conditions in advance of clinical
illness.
* * * * *