Patent Publication Number: US-2023137167-A1

Title: Wireless terminal, livestock monitoring system, and livestock monitoring method

Description:
TECHNICAL FIELD 
     The present disclosure relates to a wireless terminal for monitoring physical conditions of livestock, a livestock monitoring system, and a livestock monitoring method. 
     BACKGROUND ART 
     A wireless terminal for this type of application, which is left inside a stomach of a livestock animal for wireless transmission of body temperature and pH measurement data, has been conventionally known (see, for example, Patent Document 1). 
     RELATED ART DOCUMENT 
     Patent Document 
     Patent Document 1: JP 2018-74992 A (paragraphs [0035] to [0039], and  FIG.  2   ) 
     SUMMARY OF THE INVENTION 
     Technical Problem to Be Solved by the Invention 
      Livestock that feed mainly on roughage such as cows are prone to bloat because of constant gas production due to the rumen fermentation of roughage for digestion and absorption. While conventional wireless terminals provide measurement data useful for finding cows with bloat, it was often too late, and therefore there is a need for the development of a technique that enables detection of early stages or prior signs of bloat. 
     Means of Solving the Problem 
     A first aspect of the present disclosure made to solve the above problem is a wireless terminal including a pressure sensor, a wireless circuit, and a case that accommodates the pressure sensor and the wireless circuit in a waterproof manner, the wireless terminal being left inside a stomach of a livestock animal to measure pressure inside the stomach and wirelessly transmit acquired pressure data, in which the case includes a cylindrical case body with a bottom at one end and an opening at an other end, and a lid member closing the opening of the case body, the lid member has a measurement hole extending between inside and outside of the lid member and a protection wall part located outside of the case body, the measurement hole having a pressure-receiving pressure measurement part inside for measurement of the pressure and being closed with the pressure-receiving pressure measurement part, the measurement hole includes a first linear part extending linearly from an inner face of the lid member to an internal portion of the protection wall part, and a second linear part extending through the protection wall part in a direction perpendicular to an axial direction of the case body, intersecting in T shape with the first linear part, and having distal ends open to an outer face of the protection wall part. 
     A second aspect of the present disclosure is a wireless terminal including a pressure sensor, a wireless circuit, and a case that accommodates the pressure sensor and the wireless circuit in a waterproof manner, the wireless terminal being left inside a stomach of a livestock animal to measure pressure inside the stomach and wirelessly transmit acquired pressure data, in which the case includes a cylindrical case body with a bottom at one end and an opening at an other end, and a lid member fitted to the case body so as to close the opening of the case body and having a measurement hole extending between inside and outside of the lid member, the pressure sensor is fixed to the case body, protruding toward the lid member, and having a pressure-receiving pressure measurement part at a distal end for measurement of the pressure, and the pressure sensor fits into the measurement hole so that the pressure-receiving pressure measurement part closes the measurement hole by fitting the lid member to the case body. 
     A third aspect of the present disclosure is a wireless terminal having a pressure sensor and a wireless circuit, and left inside a stomach of a livestock animal to measure pressure inside the stomach and wirelessly transmit acquired pressure data, the wireless terminal including: a sensor-carrying circuit board having the pressure sensor mounted thereon, and a waterproofed sensor-carrying waterproof part; a waterproof case having therein a waterproof compartment that accommodates an electrical circuit disposed in a part other than the sensor-carrying waterproof part of the wireless terminal, and supporting the sensor-carrying circuit board such that the sensor-carrying waterproof part extends out of the waterproof compartment; and a sensor protection case integrally formed in or attached to the waterproof case, accommodating the sensor-carrying waterproof part, and having a plurality of through holes extending between inside and outside of the sensor protection case, in which the wireless terminal has a center of gravity located at a lower point of the wireless terminal in a basic posture so as to be maintained in substantially the basic posture in liquid, and a surface of the sensor-carrying waterproof part on which the pressure sensor is mounted faces downward, and a pressure-receiving pressure measurement part of the pressure sensor faces downward when the wireless terminal takes the basic posture. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a schematic diagram illustrating an overall configuration of a livestock monitoring system according to a first embodiment of the present invention. 
         FIG.  2    is a cross-sectional side view of a wireless terminal. 
         FIG.  3    is a cross-sectional plan view of a front end part of the wireless terminal. 
         FIG.  4    is a conceptual diagram of a main circuit board and a sub circuit board. 
         FIG.  5    is a block diagram of the wireless terminal and a monitoring apparatus. 
         FIG.  6    is a cross-sectional side view of a front end part of the wireless terminal according to a third embodiment. 
         FIG.  7    is a cross-sectional side view of a front end part of the wireless terminal according to a fourth embodiment. 
     
    
    
     MODE FOR CARRYING OUT THE INVENTION 
     First Embodiment 
     Hereinafter, a first embodiment of the livestock monitoring system  100  of the present disclosure will be described with reference to  FIG.  1    to  FIG.  5   . The livestock monitoring system  100  of this embodiment illustrated in  FIG.  1    includes a plurality of wireless terminals  20  left in stomachs  10 S (specifically, first and second chambers of the stomach) of a plurality of cows  10  that is monitoring targets, a cloud server  50  that manages the information acquired by the wireless terminals  20 , and a user terminal  60  that receives the information acquired by the wireless terminals  20  via the cloud server  50 . The wireless terminals  20 , cloud server  50 , and user terminal  60  are connected to each other via a communication network  101  including wireless base stations  400  and  401 . The cloud server  50  corresponds to a “monitoring apparatus” in the claims. 
     As shown in  FIG.  2   , the wireless terminal  20  is equipped with a main circuit board  21 , a sub circuit board  31 , a battery  22 , etc., contained inside a case  40 . The case  40  is made up of a cylindrical case body  41  with one end open and the other end closed, and a lid member  42  that closes the opening on the one end. In the description below, the axial direction of the case  40  will be referred to as “front-back direction,” and the end closed by the lid member  42  as “front side.” 
     The case body  41  and lid member  42  in this embodiment are molded products of resin, for example. Both or either of them may be a metal product. 
     The battery  22 , main circuit board  21 , and sub circuit board  31  are supported by a support frame  28  that is snugly fit inside the case body  41  and fixed inside the case body  41 , for example. 
     The support frame  28  has a circular relay disc  29 A located substantially at the center in the front-back direction of the case body  41  and perpendicular to the center axis J 1  of the case body  41 . The battery  22  is supported by a rear part of the support frame  28  behind the relay disc  29 A and accommodated deep in the case body  41 . A pair of bus bars  28 B is provided to the support frame  28  to be connected to electrodes on a front face and a rear face of the battery  22 . The terminal ends of the pair of bus bars  28 B are disposed on a front face of the relay disc  29 A. 
     The main circuit board  21  and sub circuit board  31  are supported by a front part of the support frame  28  relative to the relay disc  29 A. The main circuit board  21  is disposed parallel to the center axis J 1  and shifted from the center axis J 1  of the case body  41 , for example. Therefore, when the wireless terminal  20  takes a basic posture to be described later, the main circuit board  21  is positioned above the center axis J 1  and substantially parallel to the center axis. A rear end portion of the main circuit board  21  is opposed to the relay disc  29 A, and the pair of bus bars  28 B mentioned above is connected to the rear end portion of the main circuit board  21 . 
     As illustrated in  FIG.  4   , a wireless circuit  11 , a signal processing circuit  13 , and so on are mounted on the main circuit board  21 , and an antenna  12  (such as loop antenna) of the wireless circuit  11  is printed on the board. The signal processing circuit  13  includes a microcomputer  13 A and a memory  13 B. The memory  13 B stores a signal processing program executed by the microcomputer  13 A, terminal identification data for distinguishing the wireless terminals  20  from one another, and so on. 
      A weight  23  is supported on the support frame  28  below the main circuit board  21 . The weight  23  is provided for maintaining the wireless terminal  20  in the basic posture to be described later, and has a semicircular cross-sectional shape that is substantially the same as the half of the circular internal cross-sectional shape of the case body  41 . The weight  23  is made of a material having a higher specific gravity than the battery  22  (e.g., iron or tungsten). 
     The sub circuit board  31  is supported by an annular plate-shaped relay disc  29 B that is provided to the support frame  28  and perpendicular to the center axis J 1  of the case body  41 . A plurality of pins protruding from the main circuit board  21  passes through a plurality of through holes in the sub circuit board  31  and are soldered so that an electrical circuit on the sub circuit board  31  is connected to an electrical circuit on the main circuit board  21 . As illustrated in  FIG.  4   , a pressure sensor  30 , a sensor circuit  30 C that operates the pressure sensor  30  for measurement of pressure and so on are mounted on the sub circuit board  31 . The signal processing circuit  13  of the main circuit board  21  takes in pressure measurement results obtained by the pressure sensor  30  via the sensor circuit  30 C. 
     The pressure sensor  30  is disposed on a front face of the sub circuit board  31  as illustrated in  FIG.  3   . The pressure sensor is columnar and extends forward from the sub circuit board  31 . The sub circuit board  31  is positioned on the support frame  28  such that the center axis of the pressure sensor  30  is coaxial with the center axis J 1  of the case body  41 . The pressure sensor  30  has a stepped surface  30 D in a midway position in the axial direction so that the pressure sensor is reduced stepwise in diameter. A front end face of a head part  33  on a front side of the stepped surface  30 D of the pressure sensor  30  servs as a pressure-receiving measurement surface  34  that receives pressure, which the pressure sensor  30  measures. One end of the support frame  28  is abutted against an inner end face of the case body  41  and thereby positioned in the axial direction of the case body  41 , which also sets the pressure sensor  30  in position in the axial direction of the case body  41 . 
     The support frame  28  may be fixed to the case body  41  with adhesive or by welding, or may be fixed by being held between the inner end face of the case body  41  and an inner face of the lid member  42  to be described next. In this embodiment, the pressure-receiving measurement surface  34   of the pressure sensor  30  corresponds to a “pressure-receiving pressure measurement part” in the claims. 
     The lid member  42  is disc-shaped and has the same outside diameter as that of the case body  41 . Provided on a rear face of the lid member are an annular rib  43  protruding from near the outer edge, and a rear-side center protrusion  47  protruding from a center part, as shown in  FIG.  2   . By fitting the annular rib  43  into the case body  41  to bring the rear-side outer edge of the lid member  42  into contact with the front face of the case body  41 , the center of the lid member  42  is aligned with that of the case body  41 , as well as the lid member  42  is axially positioned. The lid member is fixed along the entire outer edge in a waterproof manner by vibration welding or with adhesive. 
     The lid member  42  has a lid body  42 H, which corresponds to a “protection wall part” in the claims, and is positioned on a front side of the front face of the case body  41 . This lid body  42 H is formed with a second linear part  45  radially extending through the lid body  42 H. As shown in  FIG.  3   , the second linear part  45  has a laterally wide flat cross-sectional shape. The second linear part  45  gives the lid body  42 H a structure having a front plate part  42 F and a rear plate part  42 R facing each other in the front-back direction interposing the second linear part  45  therebetween. More specifically, the second linear part  45  has a larger width H1 in the axial direction of the case body  41  than the thickness in the front-back direction of wall portions of the lid body  42 H left in the front and back of the second linear part  45 . The second linear part  45  has a width H2 in a direction perpendicular to the axial direction of the case body  41  that is approximately half of the outside diameter of the case body  41 . 
     A first linear part  44  is formed in a center part of the rear-side center protrusion  47 . The first linear part  44  has a circular cross section. Positioned coaxial with the center axis J 1  of the lid member  42 , the first linear part extends from a rear face of the rear-side center protrusion  47  to the second linear part  45  and intersects in T shape with the second linear part  45 . These first linear part  44  and second linear part  45  form a measurement hole  46 . The first linear part  44  is formed with an O-ring receiving part  44 A at the rear end that is increased stepwise in diameter, where an O-ring  48  is accommodated. With the lid member  42  fitted to the case body  41 , the head part  33  of the pressure sensor  30  extends through an inside of the O-ring  48 , so that the tip of the head part  33  fits into the first linear part  44  on a front side of the O-ring receiving part  44 A, and the O-ring  48  is compressed between an inner circumferential surface of the O-ring receiving part  44 A and an outer circumferential surface of the head part  33  of the pressure sensor  30 . Namely, the first linear part  44  of the measurement hole is closed in a waterproof manner by the pressure sensor  30 . 
     The wireless terminal  20  has a specific gravity of 1.8 g/cm 3  or more, which is determined from the entire weight of the wireless terminal  20  and the entire volume of the wireless terminal  20 . Therefore, the wireless terminal  20  is submerged in the liquid inside the stomach  10 S of the cow  10  and stably stays inside the stomach  10 S. The wireless terminal  20  has the center of gravity G roughly at the center in the axial direction of the wireless terminal  20  (which is also the axial direction of the case  40 ), for example. The battery  22  and weight  23  that are heaviest are arranged on both sides of this center of gravity G. The center of gravity G of the wireless terminal  20  in a direction perpendicular to the axial direction is located on the opposite side from the main circuit board  21  across the center axis J 1  of the wireless terminal  20  (which is also the center axis of the case  40 ). Therefore, the wireless terminal  20  is maintained in its basic posture or a posture close to the basic posture in which the wireless terminal is horizontal, with its axis oriented horizontal inside the stomach  10 S of the cow  10 , the main circuit board  21  being positioned above the weight  23 . The antenna  12  of the wireless circuit  11  is directed so as to have an upward transmission direction when the wireless terminal  20  is maintained in the basic posture. 
     The wireless terminal  20  is configured as has been described above.  FIG.  5    shows a control configuration of the wireless terminal  20  in block diagram. A trigger generation unit  14  and a transmission data generation unit  15  and so on shown in  FIG.  5   , which were not mentioned in the above description of the structure of the wireless terminal  20 , are configured by the microcomputer  13 A executing a signal processing program in the memory  13 B. The wireless terminal  20  operates as follows. The trigger generation unit  14  in the wireless terminal  20  generates a transmission trigger at a certain interval (of, e.g., 10 minutes), and every time a transmission trigger is generated, the pressure sensor  30  performs pressure measurement. The transmission data generation unit  15  generates transmission data including pressure data, which is a measurement result obtained by the pressure sensor  30 , and the terminal identification data stored in the memory  13 B. This is then transmitted wirelessly by the wireless circuit  11 . Thus, in the livestock monitoring system  100  of this embodiment that uses the plurality of wireless terminals  20  left inside the stomachs  10 S of the plurality of cows  10 , the plurality of wireless terminals  20  wirelessly transmits transmission data including the most recent data of pressure inside the stomachs  10 S of the plurality of cows  10 . 
     The transmission data from the plurality of wireless terminals  20  is received by the cloud server  50  that constitutes livestock monitoring system  100  of this embodiment. Specifically, as illustrated in  FIG.  1   , the transmission data from the wireless terminals  20  is first received by a gateway  500  installed in a cowhouse or farm where the plurality of cows  10  is being raised. The gateway  500  is operable as a relay base station. The gateway  500  transmits the transmission data from the wireless terminals  20  to the cloud server  50  via a general-purpose communication line  300 . While one gateway  500  is connected to one cloud server  50  in this embodiment, a plurality of gateways  500  may be connected to one cloud server  500 , with each of cowhouses or farms, for example, being equipped with a gateway  500 . 
      The cloud server  50  includes at least one or more personal computers including a monitoring terminal  50 A and a storage device  50 B. The monitoring terminal  50 A is realized by executing a signal processing program (not shown), with the control blocks illustrated in  FIG.  5   , and operates as follows. The cloud server  50  takes in transmission data sent from the plurality of wireless terminals  20  via a communication circuit  51 , assigns the time of reception to the data, for example, and stores the data in a buffer  59 . A data analysis unit  52  compares pressure data contained in the communication data stored in the buffer  59 , and identifies the wireless terminal  20  that has sent abnormal pressure data. Terminal identification data of each wireless terminal  20  is stored in the storage device  50 B beforehand, so that it is possible to identify each wireless terminal  20  from the terminal identification data. 
     Specifically, an average computation unit  53  of the data analysis unit  52  computes an overall average value, which is for example an average value of the pressure data from all the wireless terminals  20  within a most recent predetermined period (of, e.g., one hour), and computes individual average values of the wireless terminals  20 . A data comparison unit  54  of the data analysis unit  52  then compares a difference obtained by subtracting the overall average value from the individual average value, for example, with a reference difference value stored in the storage device  50 B, and determines that there is no abnormality when the difference is smaller than the reference difference value, or determines that there is an abnormality when the difference is larger than the reference difference value. The data comparison unit then generates abnormality determination data including the terminal identification data of the wireless terminal  20  that is the source of the pressure data, alert information in accordance with the level of the difference, and the time of determination. When the data comparison unit  54  generates abnormality determination data, the user terminal  60  is notified of this abnormality determination data by a communication control unit  56 . 
     More particularly, the data comparison unit  54  determines if the difference is smaller than a first reference difference value that is the smallest one of first to third reference difference values stored in the storage device  50 B, or larger than the first reference difference value but smaller than the second reference difference value that is the second smallest, or larger than the second reference difference value and smaller than the third reference value, or larger than the third reference difference value, and switches the alert information in accordance with the level of the difference. The alert information in a case where the difference is determined to be larger than the third reference difference value contains information indicating that the cow  10  having the wireless terminal  20  that transmitted the pressure data is bloated. 
     The storage device  50 B may store, for each wireless terminal  20 , livestock animal identification information (e.g., cowhouse number or photograph of the cow  10 ) of each cow  10  in which the wireless terminal  20  is left, and the communication control unit  56  may notify the user terminal  60  of the livestock animal identification information together with the abnormality determination data, to enable emergency treatment. 
     The user terminal  60  may be owned by a livestock owner, for example, and may be any of a personal computer, tablet, or smartphone, as a common communication means capable of communication with the cloud server  50 . The user terminal  60  receives a notification of abnormality determination data from the cloud server  50  as described above. The user terminal  60  may be configured to be able to access the cloud server  50  and freely browse the cloud server  50  for the status of the stomach  10 S of each cow  10  as to whether or not there is any abnormality in pressure, for example. 
     The structure of the livestock monitoring system  100  according to this embodiment is as has been described above. The livestock monitoring system  100  provides the following advantageous effects. Namely, the livestock monitoring system  100  in which wireless terminals  20  left inside the stomachs  10 S of the plurality of cows  10  wirelessly transmit the pressure data inside the stomachs  10 S enables detection of early stages or prior signs of bloat in cows  10  based on the pressure data. 
     Cows  10  feed mainly on high fiber roughages such as hay or pasture, and it matters how well the pressure-receiving measurement surface  34  of the pressure sensor  30  in the wireless terminal  20  is protected from these feedstuffs. The pressure sensor  30  of the wireless terminal  20  of this embodiment has the pressure-receiving measurement surface  34  positioned inside the measurement hole  46  formed in the case  40  that accommodates the main circuit board  21  and sub circuit board  31 , so that contact between roughages and the pressure-receiving measurement surface  34  is suppressed, which contributes to improved durability. Moreover, the sensor is less susceptible to the dynamic pressure of the liquid inside the stomach  10 S when measuring the liquid pressure, which contributes to improved measurement accuracy. 
     The center of gravity of the wireless terminal  20  is located at a lower point of the wireless terminal  20  in its basic posture so that the wireless terminal  20  is maintained in substantially the same basic posture in the liquid. This helps keep a consistent orientation of the antenna  12  of the wireless circuit  11  and enables consistent measurement and stable wireless transmission. Since the antenna  12  is oriented so as to have an upward transmission direction in this basic posture, the radio waves propagate through a relatively thin part of the body of the cow  10 , so that radio wave attenuation is reduced. 
     The livestock monitoring system  100  of this embodiment uses the cloud server  50  to collect and analyze the pressure data measured by the wireless terminals  20 , so that the plurality of cows  10  raised in a plurality of cowhouses or farms can be collectively and remotely monitored. 
      Since the cloud server  50  acquires terminal identification data as well as pressure data from the plurality of wireless terminals  20 , it is possible to monitor the pressure inside the stomachs  10 S of the plurality of cows  10  distinguishing from one another. The data analysis unit  52  of the cloud server  50  identifies wireless terminals  20  that have sent abnormal pressure data and determines health conditions of the respective cows  10 , which reduces the burden on livestock managers. 
     Second Embodiment 
     This embodiment is not illustrated, and it differs from the first embodiment only in the configuration of the data analysis unit  52  in the cloud server  50  shown in  FIG.  5   . Namely, the cloud server  50  of the livestock monitoring system  100  of this embodiment does not include the average computation unit  53 . The storage device  50 B stores reference data to be compared with pressure data from each wireless terminal  20 . In the first embodiment, the data comparison unit  54  of the data analysis unit  52  compares an overall average value of the pressure data with individual average values. This embodiment is configured such that the data comparison unit  54  of the cloud server  50  determines a difference between reference data and individual pressure data. Other features are the same as those of the first embodiment. The configuration of this embodiment provides similar advantageous effects as those of the first embodiment. 
     Third Embodiment 
     This embodiment is illustrated in  FIG.  6    and different from the first embodiment only in the structure of a lid member  42 V of a wireless terminal  20 V. Namely, in the lid member  42 V, a waterproof sheet  18  is stretched in a midway position of the first linear part  44  in the measurement hole  46 , so that a sealed space  19  is formed between the waterproof sheet  18  and the pressure-receiving measurement surface  34  of the pressure sensor  30 . The waterproof sheet  18  undergoes elastic deformation in accordance with the pressure inside the stomach  10 S, i.e., the internal pressure of the sealed space  19  changes in accordance with the pressure of the liquid inside the stomach  10 S, so that this internal pressure of the sealed space  19  is measured by the pressure sensor  30  as the pressure inside the stomach  10 S. The configuration of this embodiment provides similar advantageous effects as those of the first embodiment, and moreover, the pressure sensor  30  is protected more securely thereby improving its durability. 
      In the first embodiment, the pressure-receiving measurement surface  34  of the pressure sensor  30  corresponds to a “pressure-receiving pressure measurement part” of the present disclosure. In this embodiment, the waterproof sheet  18  corresponds to the “pressure-receiving pressure measurement part” of the present disclosure. Instead of providing the sealed space  19 , the waterproof sheet  18  may be overlapped on the pressure-receiving measurement surface  34 , so that the pressure received on the pressure-receiving measurement surface  34  through the waterproof sheet  18  is measured as the pressure inside the stomach  10 S. 
     Fourth Embodiment 
     This embodiment is illustrated in  FIG.  7    and different from the first embodiment only in the structure of a front end part of a wireless terminal  20 W. Namely, a lid member  42 W of the wireless terminal  20 W of this embodiment is integrally formed on a front end part of the support frame  28 . The lid member  42 W is disc-shaped and has substantially the same outside diameter as that of the case body  41 . The lid member  42 W is fixed with adhesive or by welding, with the outer edge of the rear face of the lid member overlapped on the front face of the case body  41 . 
      A main circuit board  21 W is provided with a sensor-carrying waterproof part  21 T that extends through the lid member  42 W and protrudes to the front of the lid member  42 W in a cantilevered manner. The part of the lid member  42 W where the main circuit board  21 W extends through is provided with a waterproof seal so that the interior of the case body  41  is a waterproof compartment  41 B. All the electrical circuits of the wireless terminal  20 W except for the sensor-carrying waterproof part  21 T are accommodated inside the waterproof compartment  41 B. 
     The pressure sensor  30  is mounted on one side of the sensor-carrying waterproof part  21 T that faces down when the wireless terminal  20 W takes the basic posture. The sensor circuit  30 C (see  FIG.  4   ) is arranged in a portion of the main circuit board  21 W that is located inside the waterproof compartment  41 B. Printed circuit lines that connect this sensor circuit  30 C and the pressure sensor  30  extend between inside and outside of the lid member  42 W. The entire sensor-carrying waterproof part  21 T is waterproofed (for example, laminated with a waterproof film) except for the pressure-receiving measurement surface  34  at a distal end of the pressure sensor  30  (in this embodiment, a lower end of the pressure sensor  30 ). 
      A sensor protection case  38  accommodating the sensor-carrying waterproof part  21 T is fixed to a front face of the case  40 W. The sensor protection case  38  is cylindrical with a bottom at one end and an opening at the other end, and has the same outside diameter as that of the case body  41 . The sensor protection case is fitted over an annular rib  39 A protruding from a front face of the lid member  42 W near the outer edge and fixed thereto with adhesive or the like. A plurality of through holes  38 A is formed in the sensor protection case  38 . 
     The wireless terminal  20 W of this embodiment provides similar advantageous effects as those of the wireless terminals  20  and  20 V of the first and second embodiments. The wireless terminal  20 W is maintained in substantially the same basic posture in the liquid. The surface on which the pressure sensor  30  is mounted in the sensor-carrying waterproof part  21 T faces downward, and the pressure-receiving measurement surface  34  of the pressure sensor  30  faces downward, too. Thus, contact between roughages and the pressure-receiving measurement surface  34  is reliably prevented. 
     In this embodiment, the case  40 W made up of the case body  41  and the lid member  42 W corresponds to a “waterproof case”, and the main circuit board  21 W corresponds to a “sensor-carrying circuit board” in the claims. 
     Other Embodiments 
     The present invention is not limited to the embodiments described above. For example, other embodiments as will be described below are also included in the technical scope of the present invention. Also, various other changes can be made in carrying out the invention without departing from the scope of the invention. 
     (1) The respective wireless terminals  20 ,  20 V, and  20 W of the embodiments described above may include a magnet fixed thereto so as to allow easy removal of the wireless terminal  20 ,  20 V, or  20 W from the stomach  10 S of a cow  10 . Specifically, a magnet may be fixed to a rear end portion of the case body  41 . A wire with a magnet fixed to the tip may be inserted into the cow’s stomach as with endoscopy so that the magnets stick together and the wireless terminal  20 ,  20 V, or  20 W can be pulled out. 
     (2) While the measurement hole  46  in the embodiments described above has a structure bent in T shape, the shape of the measurement hole  46  is not limited to this. The hole may be bent in other shapes than the T shape, or may be linear, or curved. 
     (3) A temperature sensor or acceleration sensor may be mounted to the main circuit board  21 . 
     (4) The data analysis unit  52  may use artificial intelligence to determine abnormalities. For example, a machine learning model that has learned beforehand about the pressures inside the stomachs  10 S of healthy cows  10  and cows  10  with bloat may be given a pressure output from the wireless terminal  20  in a target stomach to determine if there is bloat or not. The artificial intelligence may be trained to learn not only the pressure inside the stomach  10 S but also any corresponding relationship between pressure and physical data such as body weight and size, or other data inside the stomach  10 S such as temperature and acceleration, and this physical data or temperature/acceleration data of the cow  10  may be given together with the pressure inside the stomach  10 S of the target cow  10  when making determination. 
     (5) The wireless terminal  20  may be left in the stomachs  10 S of other livestock animals instead of the stomachs  10 S of cows  10  as in the embodiments described above. 
     (6) The support frame  28  may be integrally formed with the case body  41  instead of being a separate component from the case body  41  as in the embodiments described above. 
     (7) The battery  22  may be connected to the main circuit board  21  with a cable instead of the pair of bus bars  28 B as in the embodiments described above. 
     (8) The antenna  12  of the wireless circuit  11  may be provided in the form of an antenna pattern on the sub circuit board  31  instead of on the main circuit board  21  as in the embodiments described above. 
     (9) In the above embodiments, the pressure sensor  30  and the sensor circuit  30 C are mounted on the sub circuit board  31 , and measurement results of the pressure sensor  30  are output to the signal processing circuit  13  via the sensor circuit  30 C. Alternatively, the measurement results of the pressure sensor  30  may be output via a serial bus such as I2C. 
      (10) In the above embodiments, the O-ring  48  is compressed between the inner circumferential surface of the O-ring receiving part  44 A and the outer circumferential surface of the head part  33  of the pressure sensor  30 . In an alternative configuration, the O-ring may be compressed between the stepped surface  44 D of the O-ring receiving part  44 A and the stepped surface  30 D of the pressure sensor  30 . 
     (11) The main circuit board  21 W in the fourth embodiment may be embedded in insulating resin by potting instead of being accommodated inside the waterproof compartment  41 B. 
     DESCRIPTION OF THE REFERENCE NUMERAL 
     
         
           10  Cow (livestock animal) 
           10 S Stomach 
           11  Wireless circuit 
           12  Antenna 
           18  Waterproof sheet (pressure-receiving pressure measurement part) 
           19  Sealed space 
           20 ,  20 V,  20 W Wireless terminal 
           21 T Sensor-carrying waterproof part 
           21 W Main circuit board (sensor-carrying circuit board) 
           30  Pressure sensor 
           34  Pressure-receiving measurement surface (pressure-receiving pressure measurement part) 
           38  Sensor protection case 
           38 A Through hole 
           40 ,  40 V,  40 W Case 
           41  Case body 
           41 B Waterproof compartment 
           42 ,  42 V,  42 W Lid member 
           42 H Lid body (protection wall part) 
           44  First linear part 
           45  Second linear part 
           46  Measurement hole 
           50  Cloud server 
           52  Data analysis unit 
           60  Portable terminal 
           100  Livestock monitoring system