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ABSTRACT

Mobile, wireless sensor networks are able to bring a new

level of monitoring into many industries. In this paper, we

describe how wireless technologies can be used to create aplatform for animal health and behaviour monitoring. A

steer is used as a case study, and is instrumented with both

internal and external sensors with a minimum amount of

interference with the animal. Using matchbox sized motes

placed inside standard drug release capsules, we have been

able to monitor the intra-rumenal activity of the steer. The

sensors communicate wirelessly with each other, and are

continuously connected over the mobile telephone

network to provide a real time view of the data, using

standard web services, from anywhere on the Internet.

KEY WORDS

Sensor network, wireless, GSM, GPRS.

1. Introduction

The need for individual and herd-wide monitoring of

livestock from a physical and physiological perspective

arises from the nature of the difficulties involved with

managing farms with large grazing areas. There has

always been a need for livestock producers to be able to

“observe” their animals as often as possible. Inattention to

the wellbeing of the animals, whether it be a health or

welfare issue can lead to reduced productivity and the

death of valuable stock. Management concerns such asinteractions between cows and bulls, or dams and their

offspring are also of great concern to farmers. In addition,

the farmer needs to always be aware of matters such as

water in dams or rivers, the amount, nature and nutritive

value of the pasture (i.e. the feed for the animals), the state

of fences and potential stock rustling. Although this calls

for complete farm-wide knowledge at all times, there is

much useful information in the animals themselves.

Unfortunately, it is often the case that the farmer has

neither the time or resources at hand to “see” the animals

regularly, and even when he does, he may not be in a

position to identify some of the more deep-rooted

problems associated with the metabolic or reproductive

state of the individuals. Unlike humans who can describe

their situation to a doctor, the animal is usually unable tocommunicate symptoms to an observer.

The development of a platform technology being

described here-in, is integral to the future management of

livestock in the more remote areas of the world, but will

also find a place in intensive livestock enterprises such as

dairies and feedlots. The ability to be informed of changes

to the animals’ metabolic, behavioural or welfare status in

real time, together with input from “fixed” sensors such as

those describing food and water availability, will both

reduce the current reliance on manpower, and improve the

decision-making processes.

A problem specific to livestock monitoring (compared to

other forms of sensing currently used on farms or inintensive situations) is that animals are mobile.

Communication links need to deal with mobility and be

able to cover long distances. In addition, intra-rumenal

sensors are subject to significant translation and rotation

within the animal resulting in antenna design, power, and

data interpretation issues.

To investigate these issues we have chosen to instrument a

steer using three MICA2 Berkeley Motes[1], a variety of

sensors, and an Ultralite GPRS unit[2]. By creating a

small wireless network, we are able to investigate the

internal workings of the animal without significantly

interfering with it. The purpose of this experiment was

two-fold, to test the capabilities of motes and wirelesssensor networks for animal health monitoring, as well as to

provide a preliminary investigation into movement in a

cow’s rumen. The rumen is considered to be the animal’s

‘engine-room’, and is able to tell us much about the

animal’s health. One of the most important variables is

internal temperature, and in this experiment we chose to

measure temperature, a meaningful variable on the one

hand, but also as a proof of concept on the other. Other

health variables that are of interest to farmers and

veterinarians include pressure, pH level, conductivity and

other bio-measurements.

This experiment allows us to gain a broad understanding

of what is possible with current sensor network and mobile

Kevin Mayer

Faculty of Engineering & IT

Australian National University

[email protected]

Keith Ellis

Livestock Industries

CSIRO

[email protected]

Ken Taylor

ICT Centre

CSIRO

[email protected]

CATTLE HEALTH MONITORING USING WIRELESS SENSOR

NETWORKS



telephone technology, and what complications we may

encounter when dealing with live animals.

The next section briefly discusses other work in the area of

animal monitoring with a particular emphasis on remote

monitoring, and the use of wireless sensor networks. This

is followed by the body of the paper where we discuss theexperiments we conducted involving the instrumentation

of a steer with a wireless sensor network. We conclude

with a summary of our results and discussion of future

work.

2. Related Work

The most common methods of monitoring animal

behaviour over long periods of time are collaring a subset

of the animals with VHF beacons[3, 4], and visual

investigation by humans from fly-overs or drive-pasts.

The former method is severely limited due to not beingvery accurate and only providing location and herding

information. The latter method is more comprehensive in

that various parameters on the animal can be monitored

and transmitted back to a base station. It is still very

limited in that very little sophistication can be built into

the collars or the network on a protocol level, and it

requires either many base-stations to cover a large area, or

regular ‘drive throughs’ to collect the data. Analysis of

large areas of land using satellite techniques is another

common, yet expensive, monitoring method.

The goal of our work is to develop a low cost technology

that can be used to monitor a group of animals.

Zebranet[5] is an attempt to do this on a herd of Zebra atthe Mpala Research Centre in Kenya. Although concerned

with monitoring a large number of animals in a huge area,

Zebranet concentrates on the position and movement of

the animals rather than internal health statistics. It is this

feature in particular that we believe is most useful to

farmers, as opposed to animal behaviourists.

There is very little other research into novel platforms for

animal monitoring, in particular from a health perspective

that is beneficial to farmers.

3. Experiments

These experiments relied heavily on the remote

monitoring infrastructure[6, 7] developed at the CSIRO

ICT Centre in Canberra. The Ultralite[2], the remote

station, is a single-board computer consisting of an Atmel

128 processor, external EEPROM, and a Sony Ericsson

GM47 GSM module. The actual experiments took place at

CSIRO Livestock Industries McMaster Research

Laboratory in Chiswick, near Armidale, New South

Wales. The development of the system and its server and

database was based in Canberra.

Three experiments were conducted. Experiment 1

acquired some rumen temperature data, to test methods for

mounting instrumentation on the animal, transmitting data

and assessing its usefulness, Experiment 2 tested methods

of transmitting rumen data from inside cattle without acannula. Experiment 3 involved remote rumenal

monitoring using a technique applicable to cattle without a

cannula.

3.1. Experiment #1 - Internal Health Monitoring

In the long term, farmers need to be able to monitor the

health of their livestock in an autonomous fashion, without

significantly disturbing the animals. One of the goals of

this experiment was to remotely monitor the intra-rumenal

temperature of a steer over a long period of time and see

whether any particular patterns emerge. The experiment

was conducted on a steer fitted with a cannula that

provided access to his rumen. We configured an

Ultralite[2] with an attached temperature probe to monitor

the internal temperature and report it back to the database

in Canberra every 10 minutes, or whenever it changed by

0.2°C1. This program was written on top of the base

mobile infrastructure libraries[8] on the Ultralite. The

hardware was encased in a small package attached to a

“saddle” on the animal’s rump, with the temperature probe

wire leading through the cannula into the rumen digesta.

The steer’s paddock was located on the outskirts of a

country town, and on the border of a GSM black spot, so

continuous coverage was not guaranteed, even with an

external antenna connected to the mobile phone module.

This led to frequent connections and disconnections from

the network and consequent intermittent data availability.

In future, buffering code will be introduced to prevent

such data loss. Despite this, much data was obtained,

giving an indication of the expected rumen functions such

as fermentation of feedstuffs and the mixing of ingested

water. As illustrated in Fig. 1, we witnessed a significant

drop in temperature as the animal drank from the water

trough. The local maximum shortly after the drop in

temperature is thought to be a result of movement within

the rumen mixing the colder water with the rest of the

1 Live information was presented by a web interface (and continues to

be) available athttp://mobile.act.cmis.csiro.au/database/template/cow.xml?xsl=cowpage.xsl

Fig. 1. Intra-rumenal temperature of a steer over a 5 hour

period.



rumen’s contents. We also noted that it takes upwards of 3

hours for the rumen to heat up to its equilibriumtemperature.

Although only a single variable, internal temperature is

considered to be valuable information as it can be used as

a basic health indicator and an aid in investigating:

• When drinking occurs.

• How much water is ingested at a particular drinking

event.

• When the animal is ruminating, which acts as a proxy

to measure food intake.

• What sort of mixing occurs in the rumen.

• How much heat is generated during fermentation of

ingested feed.

• How cold water affects the animal on a warm day, and

how warm water affects the animal on a cold day.

• The optimum distribution of water within a paddock

to prevent overheating whilst still encouraging the

animal to graze throughout the paddock.

• The effect different temperature and volumes of water

have on the living organisms inside the rumen (when

combined with measurements of micro-biota).This experiment demonstrates the possibility of remote

health monitoring. It does not however provide a solution

for large scale deployment due to its configuration relying

on an animal with a cannula.

3.2. Experiment #2 – Radio transmission through a cow

The purpose of this experiment was to determine whether

it would be feasible to use Berkeley Motes[1] as internal

sensing devices, wirelessly relaying data to the outside of

the animal.

Although the approximate radio range of the motes in free

air is known[1], it is difficult to model the radio behaviour

in a non-standard environment, such as the rumen of asteer which contains a significant amount of water and

masticated and fermenting grass and micro-biota in the

digesta. The radio signal must also be able to penetrate the

animal tissue and leather between the rumen and an

external mote. An additional complexity is that the

orientation and location of the antenna on the mote inside

the rumen is unpredictable due to the churning activity of

the stomach.

This experiment was conducted in an ad-hoc manner using

qualitative analysis. Two motes were used to test the radio

signal; the mote to go inside the animal was programmed

with the TinyOS[9] demonstration application

‘CntToRfm’. This application periodically broadcasts amessage containing a uniformly incrementing integer. The

second mote was programmed with the ‘RfmToLeds’

application which lights up the LEDs on the mote to

display a binary counter showing the value of the number

in the last radio message received. No modifications were

made to these programs, meaning the standard active

messaging[10] and default MAC level protocols were

used.

The ‘CntToRfm’ mote was placed inside a standard plastic

barrel of a controlled release device[11] (CRD) shown inFig. 2. The CRD pictured here with a MICA Mote partially

inserted is a standard type of capsule that is usually dosed

orally. It has built in ‘wings’ which prevent it from being

regurgitated. We attached fishing line in order to retrieve the

ca sule from the stomach after testin .

Table 1. Empirical results of MICA radio transmission through a steer.

Type of

Mote Used

Documented

RF Range[1]

(no

obstructions)

Experimental Results

MICA

Motes

35m None of the messages sent from the internal mote were received by the external mote.

MICA2

Motes –

916MHz

150m Some of the messages from the internal mote were received by the external mote. Messages

appeared to be transmitted successfully for periods at a time, then no reception for a short period.

Rather than random noise, this was likely due to movement of the capsule inside the rumen. When

the capsule was at the top of the rumen, and physically closer to the second mote, most of the

messages were received, but when the capsule moved further away, the messages stopped being

received. Reorientation of the external antenna also improved the reception at some times,

indicating that the CRD was indeed changing its orientation.

MICA2

Motes –

433MHz

300m Most of the messages from the internal motes were received. Again, there were periods when nearly

all of the messages were received, and then periods when only a few odd messages were received –

probably as a result of movement of the capsule within the rumen.



Fig. 2, which is used routinely for medicating animals, and

then inserted into the rumen via the cannula2.

The second mote was held in a variety of positions on the

outside of the animal, and visual observation was used to

determine whether the LEDs were flashing in accordance

with the counting application.

The experiment was conducted with first generation

MICA Motes, as well as with MICA2 Motes. Both the

916MHz and 433MHz radios were tested on the MICA2s.

In each case, estimates of radio transmissibility were made

from observations of the continuity of the LED sequence

on the external mote. These results are presented in Table

1.

The experiment indicated that radio transmission is

significantly hindered by the transmission medium.

Rotation of the capsule, and thus varying antenna

orientation, was another likely source of non-reception of

messages.

This experiment suggested MICA2s with 433MHz radios

would be satisfactory for communications from within the

stomach of a steer to an external Mote. Additionally, there

was the possibility of increasing the probability of

successful data transmission by both MAC layer and

antenna design improvements.

3.3. Experiment #3 – Animal Health Monitoring

This experiment used three MICA2 Motes with 433MHz

radios, an MTS400 and an MTS420 sensor boards, and an

Ultralite for long distance communication. The three

motes were configured as follows:

Mote 1 - Attached to an MTS400 Environmental

Monitoring Board: Used to measures 2-axis

acceleration and temperature. This mote is

2

The capsule was inserted through the cannula to facilitate easyinsertion and retrieval of the device.

placed inside a CRD and inserted into the

steer’s rumen via a cannula. The sensors were

sampled every 8 seconds and the readings

transmitted to the base station mote.

Mote 2 - Attached to an MTS420 Environmental

Monitoring Board: Used to monitor GPS

location, temperature, pressure, humidity and 2-

axis acceleration. This mote captured data every

2 minutes and forwarded it to the base station.

Mote 3 - The base-station mote, whose task it was to

receive transmitted data from the other two

motes and forward it on to the Ultralite via an

MIB510 programming board and a serial cable.

The Ultralite maintained a connection to the server in

Canberra using GPRS[8] and transmit the sensor

information in real time. Fig. 4 provides a graphical

depiction of how the various pieces of hardware fit

together on the animal.

This proof of concept experiment ran over 36 hours and

gave us the animal’s position during two

afternoon/evening periods, a measure of external

environmental conditions, and intermittent data from the

internal sensors.

The plot in Fig. 3 shows the GPS information transmitted

from the external mote. Due to the high power

consumption of GPS, the batteries on this mote lasted

approximately 6 hours before they needed to be replaced.

While larger batteries can be used it seems a GPS sensor is

unsuitable for continuous monitoring of animal location in

a production environment where the sensor needs to last

years without servicing. Either relative position

monitoring, or other methods of localisation[12, 13] using

a small number of fixed beacons may be more suitable.

The GPS data shows us where the steer prefers to roam.

This data is useful for farmers in order to utilise their

grazing land with maximum efficiency by distributing

Smarty's Position

-36.64

-36.62

-36.6

-36.58

-36.56

-36.54

-36.52

32.52 32.54 32.56 32.58 32.6 32.62 32.64 32.66 32.68 32.7 32.72 32.74

Longitude in Minutes (151' E)

L a t i t u d e i n M i n u t e s ( 3 0 ' S )

Water trough

Yard

Fig. 3. GPS Data over ~36 hours.



water troughs, trees and fodder appropriately.

Alternatively, the farmer may want to utilise land that the

animals never roam around in for other purposes.

The intra-rumenal movement plot, together with the

temperature plots in Fig. 5 shows that there was not a

continuous connection between the internal mote and the

database. The two critical communication links are

between the internal mote and the base mote, and the

GPRS connection between the Ultralite and the Internet.

The mobile infrastructure[8] logs all Ultralite connections

and disconnections. By correlating this data with the timesof data availability, we determined that for much of the

time the breakdown in communication occurred between

the internal mote and the base mote. Although there were a

significant number of connects and disconnects between

the Ultralite to the backend system, connections tended to

last for at least a few minutes each time – longer than the

sampling period of the internal mote. As one can see in

Fig. 5, there are periods where data is received from the

external mote and not the internal mote, again indicating a

loss of communication between the internal mote and the

base-station. An internal logging facility is being planned

to buffer data during these periods of poor connectivity.

The plots in Fig. 5 indicate that the internal temperature(two independent sensors were used for verification and

redundancy) rises upon inserting the capsule into the

animal as expected. It stabilises at the expected

temperature of ~38°C as is seen by ~1:00pm and there is

an indication of a drinking even at around 4:30pm (which

is correlated with the GPS location at that time together

with the known location of the water trough). In the first

experiment we demonstrated a relationship between the

volume of water ingested and the change in rumen

temperature. The drop in temperature shown in Fig. 5

being less than that shown in Fig. 1 is an indication that

the animal drank less water.

External temperature is also plotted in Fig. 5.

Unfortunately, the plastic box housing the external

temperature probe acted like a greenhouse on the animal’s

back, causing this measurement to be higher than the

actual outside temperature on the day. It is still interesting

to note that the temperature did fall sharply very soon after

the sun dropped over the horizon late in the afternoon. For

similar reasons, the humidity and pressure readings from

the external sensor were not particularly meaningful.

Fig. 6 shows intra-rumenal movement using a dual-axis

accelerometer and a sampling period of 8 seconds.Although there is an indication of very slow movement,

we suspect that the sampling frequency is considerably

slower than some of the frequency components of the

digestive movement, so the data does not necessarily fully

characterise rumenal movement. Physical observation also

shows that even within the rumen digesta, one of the three

stomachs, there is considerable difference in the rate of

movement in different places, at different times in the

animals feeding cycle, and with differing amounts of water

in the rumen. Therefore further experimentation will be

required to fully characterise rumen movement.

Although not plotted, since no meaningful data was

gathered, the accelerometers on the external mote could beused to provide a variety of valuable data. Firstly, by

placing one axis of the accelerometer along the length of

the animal’s neck, a grazing clock could be developed to

monitor feeding behaviour, and similarly if strapped to a

leg or on the rump, it could act as a pedometer to measure

distance travelled. Alternatively, placed anywhere

horizontally on a bull it could be used to identify a mating

activity, which, when used in conjunction wit the

positional identity of cow, could be used to subsequently

indicate parentage. In this way, a farmer would have

instant knowledge of mating and would bring him a step

closer to being able to control breeding.

Fig. 4. Instrumentation of Smarty the steer.



4. Future WorkThere are a few avenues we consider are worth pursuing in

this area, and each of them is discussed below.

4.1. Technical Improvements

As witnessed in the third experiment, the radio

transmission between the internal mote and the base node

is not particularly reliable. The antennae used were

standard ¼ wave dipole without any modification. We

believe the transmission radius can be improved by using a

½ dipole antenna. Different antenna shapes and

configurations may also boost antenna output – although

there is limited possibility here due to the small size of the

drug release capsule.A second area of potential technical improvement is the

MAC layer protocol. An enhanced MAC layer with a

suitable retry system would increase the probability of

messages getting transmitted successfully. Additionally,

we would like to implement internal logging on the motes

so that when the mote is out of range of the base node, the

measurements are buffered.

There are also plans to implement buffering on the

Ultralite in order to prevent loss of data when the animal

wanders into a GSM black-spot.

4.2. Renewable Energy

Physical observation shows movement within the rumen

digesta to be similar to that of a washing machine. This

movement could be used as a source of energy to power

the internal Mote for the life of the animal. Further work is

required to characterise this movement and assess methods

of harvesting power from it. This work needs to include

sampling at much higher frequencies than the acceleration

sampling period of 8 seconds used in this experiment as

higher frequency movements could be used as a source of

energy[14].

Particularly when utilising GPS, power requirements of

the electronics external to the animal are also a concern.

Perhaps, a renewable energy source, such as solar, would

be of most benefit as this allows for longer term

autonomous operation.

4.3. Larger Scaled, Multi-homed Deployment

The ultimate goal of creating an animal health monitoring

system is to monitor a representative sample and ideally

all the cattle on a farm, not just a single steer. We have a

number of ideas of how to extend this experiment to

monitor many cows without duplicating all the equipment

on each steer.

One idea is to have one animal with the equipment as per

this experiment, and the rest of the animals with only an

internal sensor. This would be suitable for animal

instrumentation where we are concerned with internal

health and biological parameters, and not their position or

Internal Temperature

26

28

30

32

34

36

38

40

9/06/2004 11:20 9/06/2004 12:40 9/06/2004 14:00 9/06/2004 15:20 9/06/2004 16:40 9/06/2004 18:00

Time

T e m p e r a t u r e ( d e g r e e

s C e l s i u s )

Intersema Temperature Probe Sensiron Temperature Probe External Mote Temperature

Fig. 5. Intra-rumenal temperature over an afternoon.

Intra-Rumenal Acceleration & Movement

-1000

-500

0

500

1000

1500

2000

9/06/2004 11:16 9/06/200 4 11:31 9/06/2004 11:45 9/06/2004 12:00 9/06/2004 12:14 9/06/2004 12:28 9/06/2004 12:43 9/06/2004 12:57 9/06/2004 13:12 9/06/2004 13:26

Time

m i l l i - g

X Axis Acceleration Y Axis Acceleration

Fig. 6. Intra-rumenal movement over two ~30 minute periods.



other external measurements. For this to work though, one

would require an improvement in radio transmission range

to ensure the internal mote from one animal, can

successfully transmit data to the external mote on another

animal, potentially many metres away. Alternatively, each

head of cattle have both an internal and an external mote.The internal mote would transmit measurements to the

external mote, and the external mote would transmit the

data on to the gateway animal, the one fitted with an

Ultralite. Alternatively, rather than having a single animal

with an Ultralite, acting as a gateway, one could

instrument a small proportion of the animals as gateway

nodes, and the rest as sensing only nodes.

On another project we are developing soil moisture

sensors with mote technology for communications and it is

envisaged that in an instrumented farm there will also be

many other networked sensors. The cattle operating within

this network can be mobile nodes in that network. We

could locate a number of fixed gateway nodes within thisnetwork and each animal in the herd would transmit its

data, potentially using multi-hop, to the nearest gateway.

5. Conclusion

In this paper we have described our ongoing work in

animal monitoring using wireless technologies. There is a

recognised need to provide farmers with relatively

autonomous methods of monitoring the health of their

herd, and learning about the behaviour of their animals in

order to create a productive environment. Animals,

unfortunately, are not always able to communicate healthissues such as rumenal fermentation problems or varying

micro-biota levels. Nor are farmers always able to

discover (and possibly control) breeding patterns within

herds. Visual monitoring of animals provides a very

limited view of what is happening, and is rather inefficient

as it cannot always be done 24/7. Autonomous monitoring

is required to learn the things about the animals that visual

inspection does not always tell us. This will enable new

stock management techniques like varying stocking ratios

based on animal behaviour rather than a visual assessment

of pasture quality.

By using the mobile telephone network for long distance

communication, and a wireless sensor network for shortdistance communication, we have begun to create a

platform which can be used for both external and internal

monitoring of animals. Monitoring of vital health signs,

eating and drinking habits, and location and movement in

real time brings farmers and scientists a step closer to

understanding animals better, and making farms more

productive.

Our initial experiments have shown that intra-rumenal

monitoring can be done by enclosing probes – a Berkeley

MICA2 Mote with attached sensors – in a drug control

release capsule which can be dosed to the animal orally.

This device can communicate wirelessly with a module on

the animals back and together with external probes, can

provide a comprehensive picture of the animal’s health

and activities.

References

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[12] K. Langendoen and N. Reijers, "Distributed

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[14] S. Roundy, "Energy Scavenging for Wireless

Sensor Nodes with a Focus on Vibration to

Electricity Conversion," University of California

at Berkeley, 2003.

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