a method to record the feeding behaviour of goats

A method to record the feeding behaviour of goats

J.A. AbijaoudeÂa,*, P. Morand-Fehra, G. BeÂchetb, J-P. Brunb, J. Tessiera, D. Sauvanta

aLaboratoire de Nutrition et Alimentation, INRA de l'INAPG, 16 rue Claude Bernard 75231, Paris Cedex 05, FrancebLaboratoire Adaptation des Herbivores aux Milieux, Theix 63122, St-GeneÁs-Champanelle, France

Accepted 22 March 1999

Abstract

We developed a method to record the feeding behaviour of up to four stall-housed goats simultaneously. It consists of a series

of tests to monitor intake, rumination and idling in Alpine and Saanen dairy goats. We used two complementary systems to

record simultaneously jaw movements and the weight of the ingested quantities. The recording apparatus was composed of a

portable electronic device connected by a ¯exible pipe to another softer pipe ®xed on the inside part of the lower strap of the

halter, between the halter and the mouth of the animal. The portable device was placed on the back of the animal, ®xed on a

basal plastic part which neither disturbed the animal nor changed its behaviour. The portable device transforms air pulses

generated from the compression of the halter pipe into binary signals recorded every 2.5 s. Weighing machines, ®xed under the

feeding pans of the four goats, transmit weights to an adapted electronic memorizer able to store data every 2 min. The results

showed very little discordances between the two sets of recorded data. Video recordings were performed to test the reliability

of the systems. Comparisons between ®lmed and recorded behaviours showed a non-signi®cant difference which did not

exceed 1% when the goats were clearly seen. This method seems well adapted to stall-housed goats and provides complete and

exact data on intake, rumination and idling over a continuous period (48 h in our case) and also on intake level and rate.

# Published by 1999 Elsevier Science B.V. All rights reserved.

Keywords: Goat; Recording methods; Chewing; Feeding behaviour

1. Introduction

Feeding behaviour of ruminants has been studied

thoroughly, more with cattle and sheep than with

goats. Feeding patterns have been described and

recorded owing to many methods which depend on

the objectives of the studies and on the system Ð

rangeland, pasture or indoors Ð as well as on the

characteristics of the feeding behaviour of each spe-

cies. Our purpose was to adapt an automatic system to

stall-housed goats which enables continuous and

simultaneous recording of chewing activity and level

of intake.

The methods have evolved considerably. Automatic

monitoring reduces tedious visual and manual pro-

cesses and also allows a continuous recording of

behaviour over longer periods with more frequent

data acquisition and more precision. Numerous

devices have been described to record head position

or chewing activity of ruminants. The most commonly

used can be divided into three groups: electric with a

carbon transducer (Penning, 1983; Rutter et al., 1997),

hydraulic with a submandibular balloon (Jaster and

Small Ruminant Research 33 (1999) 213±221

*Corresponding author: Tel.: +33-1-44-08-18-85; fax: +33-1-44-

08-18-53; e-mail: [email protected]

0921-4488/99/$ ± see front matter # Published by 1999 Elsevier Science B.V. All rights reserved.

PII: S 0 9 2 1 - 4 4 8 8 ( 9 9 ) 0 0 0 3 5 - 8

Murphy, 1983; Dado and Allen, 1993) or pneumatic

with a submandibular pear-shaped balloon ®lled with

foam (Brun et al., 1984; Baumont, 1989).

These electric, hydraulic or pneumatic systems with

sensors directly connected to remote computers

(Beauchemin et al., 1989; Baumont, 1989) or to light

portable recorders (BeÂchet et al., 1989; Matsui, 1994)

have been used with cattle and sheep but rarely with

goats. In fact, few studies were done on goats and little

is known about their feeding pattern. A selective

dietary behaviour of goats has been described by

direct observation both indoors (Morand-Fehr,

1981; Morand-Fehr et al., 1977, 1980) and on range-

lands (Davendra and Burns, 1970; Bourbouze and

Guessous, 1977). Hooper and Welch (1983) used

the same pneumatic system described for sheep by

Welch and Smith (1969) to determine the chewing

ef®ciency of kid goats. Lu (1987) recorded the chew-

ing activity of dairy goats every 5 min during a 24 h

period.

As the feeding behaviour of goats is characterized

by a high rate of refusals and a marked selection of

ingesta, precise measurements are required to clarify

their dietary behaviour. We have modi®ed the pneu-

matic system of Brun et al. (1984) to propose, in this

paper, a method which provides complete information

about the behavioural states of stall-housed dairy

goats by continuous recording of jaw movements

and manger weights in order to determine intake,

rumination and idling periods and to quantify the

levels of nutrient intake without modifying behaviour.

2. Materials and methods

Eight Saanen and Alpine dairy goats were housed in

individual stalls in order to study their feeding beha-

viour. They were able to move freely with minimal

physical constraints and also to see other goats

and humans. They had constant access to food, water

and trace-mineralized salt blocks. As the goats were

accustomed to stall housing, their behaviour was

believed not to be in¯uenced by the experimental

disposition. The eight goats were divided in two

groups.

We have adopted a pneumatic system and a portable

device for the detection and recording of jaw move-

ments. Mangers were weighed to determine feed

disappearance. Data were collected continuously over

4 � 2-day periods for each group of four goats.

2.1. Jaw-movement recording apparatus

The jaw-movement recorder is composed of a

portable electronic device: APEC (Appareil Portatif

pour l'Etude du Comportement: Brun et al., 1984). It

is a small rain-proof rectangular box of light weight

(350 g) and small dimensions (15.5 cm � 9 cm �4.5 cm). It works with four batteries (1.5 v ± size

AA), which provide it autonomy for approximately

6 days.

2.1.1. Adaptation to goats

The APEC is designed to be carried by the animal.

The anatomy of the goats makes attaching the APEC

very dif®cult because of their excessive mobility. We

®xed the device on a U-shaped plastic base fastened by

means of a harness to the back of the goats. With this

system on their backs, the animals can move easily

without damaging the device or being disturbed

(Fig. 1). The animals have to carry the device only

during testing, but the basal part and the harness are

carried throughout the experiment to avoid problems

of adaptation every time we put them in place. To

ensure that the system did not cause any injuries and

was well-tolerated by the goats, it was periodically

removed and the animals examined.

The goats also have to wear a halter around the head

and the muzzle throughout the experiment. On the

inside surface of the lower strap of the halter, we

Fig. 1. A stall-housed dairy goat with the jaw-movement recorder

on its back and the pipe connecting it to the halter.

214 J.A. AbijaoudeÂ et al. / Small Ruminant Research 33 (1999) 213±221

replaced the pear-shaped submandibular balloon (used

with sheep and cattle by BeÂchet, 1978; Baumont,

1989) by a 10 cm ¯exible silicone pipe (8 mm internal

and 12 mm external diameters). This pipe, ®xed

between the halter and the muzzle, was harmless to

the goats. It occupied only the lower half of the halter

and was stoppered at one end. When the jaw moves,

the compression of the halter pipe generates air pulses.

These pulses are transmitted via a second, less com-

pressible, ¯exible silicone pipe (4 mm internal and

8 mm external diameters) to the APEC where they are

transformed into electrical signals which are stored in

the memory until downloading. Perfect air-tightness

of the circuit is not required as long as the amplitude of

jaw movements is not measured. In our case, the only

information needed was the presence or absence of

jaw movements. With this system, the goat, accus-

tomed to its halter and harness, had only a ¯exible pipe

added in the periods of tests, instead of wires directly

connected to a computer.

2.1.2. Installation and connections

The APEC can be connected by a cable (RS232) to a

microcomputer which can command all functions.

Recording can be started and stopped either by means

of a microcomputer or by passing a small magnet in

front of the magnetic-sensitive switches found on both

sides of the device. The APEC is equipped with a

sensible pressure transducer, placed at the end of a

pneumatic circuit which gives a variation of tension

for every stimulation.

To allow the operator to visually con®rm the good

functioning of the ®rst part of the device (captation), a

monostable and 2 NAND gates permit, on command,

the excitation of an electroluminescent diode.

2.1.3. Signal processing and data sampling

The analogical tension issued by the transducer

is applied to the entrance of a tension comparator

which converts it into logical levels: `0' or `1' corre-

sponding, respectively, to the absence or presence of

jaw moves.

Sampling is intermittent with a 2.5 s sampling

interval. At every sampling time, the logical state is

recorded. The sampling period of 2.5 s will be written

in memory as `0' if no jaw movement is detected or `1'

if at least one jaw movement is detected. Successive

2.5 s intervals with the same state are summed and

stored in the memory. This process is repeated till the

end of recording or till the ®lling-up of memory

(Fig. 2). Data storage capacity (8096 octets) is 4±6

days depending on the conditions of sampling.

2.1.4. Data transfer

The transfer to a microcomputer can be done when

data collection is ®nished. The same connection cable

(RS232) is used to download data ®les. These ®les are

converted, when downloading, to ASCI ®les com-

posed of lines of 20 numeric values each, representing

alternatively the number of periods (of 2.5 s) of idling

and of chewing.

The total number of lines is related to behaviour and

especially to the recording duration. A recording

period of 24 h produces a mean of 100 lines.

2.1.5. Data processing

A program written in PASCAL language allows the

determination of rumination, intake and idling peri-

ods. Parameters like minimal boli number per

sequence of rumination, minimal inter-boli resting,

minimal meal duration and inter-meal resting are

required. They are determined by the operator.

2.2. Intake level determination

To complete the chewing data, intake level was

continuously determined by means of digital balances

®xed under the feed containers (Fig. 3) of the four

goats equipped with the jaw-movement recorders. No

adaptation period was required for the goats. The

weights were transmitted to an adapted electronic

memorizer. Sampling intervals (in minutes) can be

varied beginning from a minimal value of 1 min. We

have chosen to record data every 2 min for 48 h

because of the limitation of memory capacity. The

data recorded were then transferred to a microcom-

puter.

2.3. Video recording

The goats were ®lmed during 4 days (light period:

10 h), to verify the data collected and the reliability of

the methods used. Each couple of tested goats was

®lmed with a far and elevated video camera which did

not in¯uence their behaviour. The program ETHOLOG

(Ottoni, 1996) was used to manually transform video

J.A. AbijaoudeÂ et al. / Small Ruminant Research 33 (1999) 213±221 215

Fig. 2. Flow diagram of the APEC ± Running mode


observations to computer ®les. This allowed us to

compare ®lmed behaviour with recorded data.

3. Results

There were no differences in intake levels between

the periods before and after ®xing the halters and

harnesses on goats (4.40 vs. 4.55 kg/day; SEM �0.06).

We gathered a total of 192 h (4 periods � 48 h) of

feeding pattern per goat with each of the APEC and

balances, and 20 h (2 days � 10 h/day) of video tapes

per goat. Incomplete or damaged ®les due to pipe

rupture, halter or harness loss, abnormal functioning

of a device or a balance and any other cause of error,

were discarded from all calculations. They repre-

sented approximately 70 h. The system provides

intake level and nycthemeral distribution of intake

(balances), and rumination, intake and resting distri-

bution per hour (APEC). In addition, the program

gives the number of rumination boli as well as the

total and net (without intra-activity idling) rumination

and intake periods (Table 1). Activities like drinking,

licking and bleating are grouped as `other activities'.

The complete feeding pattern results obtained from

this experiment with different types of diets are pub-

lished in AbijaoudeÂ et al. (1999). Examples of the data

for chewing (APEC) and intake (balances) of one goat

over 2 consecutive days are presented in Fig. 4. They

show good agreement between the two methods of

sampling. The four distributions of meals can clearly

be seen (08:00 and 17:00 h). The intake activity shown

especially at the beginning of the meals (Fig. 4(a)) is

accompanied by an increase of the ingested quantities

(Fig. 4(b)). In the curves of Fig. 4(b), a plateau cor-

responds to rumination and/or idling in Fig. 4(a).

This example was chosen for a discordance between

the sampling methods with this goat which occurred

between noon and 13:00 h on the ®rst day where jaw

activity (Fig. 4(a)) Ð given by the APEC as an intake

activity Ð corresponds to a stable weight of the

feeding pan (Fig. 4(b)). After replaying the corre-

sponding video tape, we noted that the goat was

licking its salt block. In this case, the time spent

licking the salt block (less than 9 min) was within

Fig. 3. Balances fixed under the feed containers of stall-housed

dairy goats for continuous intake level determination.

Table 1

Example of the final output of the APEC files showing activities (in seconds) and the number of rumination boli of a stall-housed dairy goat

Time

(hours)

Total

rumination

Net

ruminationa

Total

intake

Net

intakeb

Idlingc Other

activities

Number

of boli

8 138 123 2598 2068 864 0 4

9 3360 2890 0 0 240 75 77

10 2005 1645 0 0 1595 15 42

11 1213 928 2073 1155 314 28 22

12 2435 2130 1088 510 77 10 53

13 1570 1380 1288 690 742 53 36

14 1393 1223 1618 1058 589 293 35

15 1638 1365 1478 1123 484 273 37

16 1075 915 1935 1463 590 8 32

a Net rumination � Total ruminationÿintra rumination idling.b Net intake � Total intakeÿintra intake idling.c Idling � Jaw inactivity � other activities.

Total rumination � Total intake � Idling � 3600 s.


the range noted as the average duration of this activity

in these goats did not exceed 0.1% of the day.

According to Fig. 4(a), the goat has eaten for 27%,

ruminated for 41% and rested for 32% of the 2-day

period.

All data given by the balances have been kept

(Fig. 4(b)). Indentations represent feeding bouts. If

accompanied by an increase in the weight of intake,

they indicate that the goat is eating, and if not, the goat

will be selecting food.

The comparison between the results of the main

activities obtained by the computer program and video

recordings is shown in Table 2. The 10 h recordings

have been divided into three intervals of 3, 4 and 3 h.

Fig. 4. (a) Intake, rumination and idling periods of a stall-housed dairy goat over a 2-day period obtained with the jaw-movement recorder (~feed distribution) (b) Intake of a stall-housed dairy goat over a 2-day period obtained after continuous weighing of the feed container (~ feed

distribution).


Data were analysed using the GLM procedure of SAS

(1996). There was a relatively high agreement (no

signi®cant differences) between the two sets of data in

each interval of time as long as the goats were clearly

seen on the screen. The difference did not exceed 1%

in the case of intake, but reached 14% in the cases of

rumination and resting.

4. Discussion

The electrical detection of jaw movements might be

better than the pneumatic one in the case of remote

computer terminals. Direct connection of halter sen-

sors to a computer depends on the animal species and

character. It is more or less easy with sheep and cattle

but more dif®cult with goats which have a special

temperament and behaviour. Pneumatic systems, with

stall-housed animals, transmit a signal at every acci-

dental touch of the stall walls but ®ltration of data

(needed in both systems to eliminate drinking, licking

and bleating) during processing eliminates all inter-

ferences.

As our aim was to study the behaviour of stall-

housed goats, we have preferred to adopt the portable

pneumatic system (APEC) of Brun et al. (1984)

because of its light weight, its relatively simple instal-

lation, its longevity, its resistance to shocks and the

rapid replacement of pipes in case of damage. We have

used two types of pipes. The less sensitive one, used to

connect the halter pipe to the APEC, reduced inter-

ference considerably.

Counting of jaw movements was not required

indoors as there was no need to determine prehension

bites and mastication chews as in grazing.

The light device developed by Matsui (1994)

for grazing animals has not been tried with free-

ranging goats. Indoors, its use with stall-housed goats

requires a certain degree of resistance to shocks. Even

if the neckband used to ®x the device is accepted by

the goats for a long period of time, it might have a

certain in¯uence on their behaviour more than an

apparatus carried on the back. But this needs to be

proved.

The system described by Rutter et al. (1997) may be

accepted by grazing sheep but its use would not be

easy with grazing goats because of their different

behaviour and particularly their frequent vertical posi-

tion in bushy rangelands and their ability to perform

diversi®ed movements with their body. The wire

connecting the noseband to the recorder requires

constant surveillance to prevent it from being caught

in vegetation. Even indoors, its heavy weight (2 kg for

the sheep model) is a handicap and could not be used

with goats.

We assume that our system was well borne by the

goats because there were rare tentatives to get rid of it

only during the period of adaptation. However, pipe

ruptures or unpluggings are likely to occur. The goats

may as well reach and bite the pipes. A continuous and

close watch is therefore necessary to collect a com-

plete set of data.

Video tapes appeared to be very precise and showed

a lot of details for long periods of time (when the goats

were clearly seen on the screen) and could be replayed

inde®nitely afterwards to test the reliability of the

recordings.

In general, licking the salt block is scattered all over

the day, and may even not exist on some days. In our

case, it was rarely grouped in one period, as in the

Table 2

Comparison between the observed filmed behaviour (Obs) and the recorded behaviour (Rec) results given by the APEC with stall-housed dairy

goats over 10 light hours

Time (hours) 8±10 SEMa 11±14 SEM 15±17 SEM

Obs Rec Obs Rec Obs Rec

Intake 351 348 19 385 380 28 309 306 18

Rumination 96 84 12 246 260 18 84 90 12

Resting b 85 89 17 296 288 22 129 126 16

Other activities 8 8 3 32 33 5 17 17 3

a SEM: standard error of the mean.b Resting � Jaw inactivity.


example above, but this always depends on the vari-

able behaviours of the animals.

The differences in rumination and resting periods

between the ®lmed and the recorded behaviours are

due to the dif®culty of watching the goats when they

were lying. Due to the wooden stall walls, lying goats

could not be seen on video tapes, and they might be

either ruminating or resting but undoubtedly not eat-

ing. So, in visual ®lmed observation, the confusion

between rumination and resting can occur only when

the goats are lying as long as we suppose that, when

their heads are in the trough, the goats are eating. As a

high concordance exists between the two sets of data

during the seen sequences, the recording system can

be securely reliable when the goats cannot be seen.

Most authors attribute discordances between the

observer and the automatic system to errors com-

mitted by the observer (Penning, 1983), but differ-

ences between intake and rumination may also be due

to the automatic recording because certain intake

phases can be identi®ed as rumination cycles or vice

versa if they satisfy the program parameters intro-

duced by the operator. In this case also, the video

recordings can be of great help to determine the

parameters to be used.

Keeping all the intake data collected with the

balances gives additional information on behaviour.

The indentations in the intake curves can be removed

but their presence allows differentiation between

intake bites and food selection.

Equipment malfunctions were limited; neverthe-

less, a continuous control was needed to ensure good

functioning of the entire system.

5. Conclusion

The methodology described in this paper can pro-

vide precise and complete information about the diet-

ary behaviour of dairy goats.

This pneumatic system seems to be well adapted to

stall-housed goats. The portable device is light and

easily borne by the animals. The balances can be

simply installed under the feeding pans. The whole

system is convenient to study the feeding behaviour of

stall-housed goats and allows researchers to determine

intake, rumination and idling periods and to quantify

the levels of nutrient intake in dairy goats without

modifying their behaviour. In rangelands, another

adaptation of the system will be necessary to avoid

it from being caught in the bushes.

With a continuous determination of feeding para-

meters, a more complete understanding of dietary

effects on goat behaviour will be possible.

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a method to record the feeding behaviour of goats

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