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.

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, realiably reliably 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°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° 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°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°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 between 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 estrous 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.

Claims

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 °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.

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. 7. The method of claim 6 wherein said period of not less than approximately one complete estrous cycle is approximately 50 days. 8. The method of claim 6 wherein said same time is the period between about 5:00 and about 7:00 a.m.