Group housing of dry sows is compulsory in Europe from 2013 onwards. Many pig farmers who still have to convert to group housing fear the resulting demand on their ability to interact with individual animals. An example of such interaction is the training of gilts to use economically attractive but complicated feeding systems such as electronic sow feeding stations (ESF). Electronic Sow Feeding is a more complex husbandry system, which requires training from both animal and human. Pig farmers use a wide variety of training methods, ranging from a total free situation where the animals have the possibility to learn the feeding station without human interaction to systems in which the animal is confronted with thorough human interventions. The first method incorporates the risk that some animals do not consume any feed in several days. The second method is more time consuming and sometimes stressful for the animals. If a calm and relaxed training method proves to be an efficient way to train animals, this could also be used in other on farm situations. Wechsler and Lea (2007) concluded that there is a lack of studies focusing on the initial phase after the introduction of farm animals into a new housing system and a lack of studies on the way they learn to use new housing equipment. An assessment of training systems on Danish pig farms (Hansen and Vinther, 2004) has resulted in the advice not to interact too soon and let the animals discover the skills themselves. The way the animals experience the human intervention can be assessed by measuring heart rate variability (HRV) (Von Borell et al., 2007). They state that “HRV is a promising approach for evaluating stress and emotional states in animals”. The results of this project can be used in the knowledge transfer about human animal relationships within the Welfare Quality programme

Kiezebrink, M.C.

Spoolder, H.A.M.

Vermeer, H.M.

Werf, J.T.N., van der

English

Name not available

Training gilts to use a feeder station

Wageningen Yield 

Final Report Pig Handling Experiment, April 21, 2009 
 1 
 
Sub-task 3.1.2.3 Training gilts to use a feeder station 
Herman Vermeer, Maudia Kiezebrink, Joop van der Werf en Hans Spoolder (ASG, Lelystad, NL) 
Correspondence: herman.vermeer@wur.nl  
 
Introduction 
Group housing of dry sows is compulsory in Europe from 2013 onwards. Many pig farmers who 
still have to convert to group housing fear the resulting demand on their ability to interact with 
individual animals. An example of such interaction is the training of gilts to use economically 
attractive but complicated feeding systems such as electronic sow feeding stations (ESF). 
Electronic Sow Feeding is a more complex husbandry system, which requires training from both 
animal and human. Pig farmers use a wide variety of training methods, ranging from a total free 
situation where the animals have the possibility to learn the feeding station without human 
interaction to systems in which the animal is confronted with thorough human interventions. 
The first method incorporates the risk that some animals do not consume any feed in several 
days. The second method is more time consuming and sometimes stressful for the animals. If a 
calm and relaxed training method proves to be an efficient way to train animals, this could also 
be used in other on farm situations.  
Wechsler and Lea (2007) concluded that there is a lack of studies focusing on the initial phase 
after the introduction of farm animals into a new housing system and a lack of studies on the 
way they learn to use new housing equipment. An assessment of training systems on Danish 
pig farms (Hansen and Vinther, 2004) has resulted in the advice not to interact too soon and let 
the animals discover the skills themselves.  
The way the animals experience the human intervention can be assessed by measuring heart 
rate variability (HRV) (Von Borell et al., 2007). They state that “HRV is a promising approach for 
evaluating stress and emotional states in animals”.  
The results of this project can be used in the knowledge transfer about human animal 
relationships within the Welfare Quality programme. 
 
Objective 
The objective experiment was to test the hypothesis that calm & quiet handling will improve 
learning speed and welfare of gilts. Principles used when training gilts to use feeding stations 
can also be applied to other practical new and learning situations. 
 
 
 
Final Report Pig Handling Experiment, April 21, 2009 
 2 
 
Material and Methods 
Animals and handling 
In an experiment on the Pig Research Centre in Raalte 18 groups of 4 naïve gilts each (3 groups 
per week/batch) were trained to use an ESF station. The gilts were selected from near slaughter 
weight female finishing pigs. The average body weight was 103 kg (90-120) at the start of the 
experiment. They were selected, weighed and given an ear transponder on Monday, and 
subsequently housed separately in 3 groups of 4 animals during 7 days (the ‘preparation 
week’). The feed ration in that week was 2.5 kg pelleted feed in one meal per day in a long 
trough. Four times per week the observer entered the pen, walked around and touched the 
animals so the pigs got used to this person. On 2 occasions, 2 animals from a group of 4 
received a Polar girth transmitter during 2 hours to get used to future heart rate monitoring. On 
the next Monday morning they were not fed and brought to the ESF pen, where they were kept 
as a group. In the ESF pen each group was kept for 7 days (‘test week’). They were fed 
individually through the ESF system in a self chosen order. Each group was assigned to one of 
three treatments (see below). In every batch the order in which the treatment groups were fed 
was changed randomly.  
 
Housing 
In the preparation week the animals were kept in pens with partly slatted floors with 1.5 m² per 
animal. The animals were fed simultaneously in a long trough along the feeding alley. A 
drinking bowl was situated above the slatted floor in the back of the pen. 
Figure 1 shows the layout of the ESF pen with the Electronic Sow Feeder in the middle and a “pre 
feeding pen” at the entrance side of the feeder and a “post feeding pen” on the exit side of the 
feeder. The pigs could not go back to the “pre feeding pen” after they passed the feeder. Two 
hours after the feeding start of the first group the groups changed pens and the procedure was 
repeated for the second group. Another two hours later this was repeated again for the third 
group. The feeder was a Porcode Electronic Sow Feeder (Nedap Agri, Groenlo, NL). The feeding 
cycle started at 7.00 am, so feed was available from the moment of entrance of the “pre feeding 
pen”. The feed dispensing rate was 120 g/min with a small quantity of water (40 cc water per 
100 g feed). The daily ration was 2.4 kg pelleted feed per animal. At night a dim light above the 
feeder was on.  
 
 
Final Report Pig Handling Experiment, April 21, 2009 
 3 
ES
F 
(no
t i
n
 
u
se
)
1.0 3.5 3.0 1.5 2.0     3.5 1.0 m
3.
1 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3.
1 
m
Prefeeding 
pen
Concrete 
slats
Waiting 
pen 1
Waiting 
pen 2
Postfeeding 
pen
Solid floor + 
some bedding drinker
ES
F drinkerdrinker P
e
rfo
ra
te
d 
co
n
cr
e
te
 
 
Fig.1. Layout of the experimental pen; a group of 4 gilts started in the prefeeding pen and 
passed the ESF one by one to the postfeeding pen; meanwhile the other two groups were waiting 
in the pens on the right side of the room. 
 
Treatments 
We used the following three different training techniques, one technique per group. Treatments 
were applied on Monday, Tuesday and Wednesday: 
Minimal: minimal interaction (no farmer interference, just supervision) only after two days 
without feed intake the sow was triggered with a little bit of feed on the floor;  
Gentle: gentle vocal and soft-physical coaching; using the voice and a hand on the back if 
necessary, a board to point the right direction and always some feed on the floor in the 
feeder; if an animal refused to enter another one was tried first. 
Active: active physical encouragement; the trainer used a loud voice and slapping on the side 
walls or board, the animals were physically driven to the feeder. If an animal refuses it is 
still forced to enter the feeder, with the aid of a large board.  
 
The treatments started in a random order per batch at 8.00 h, 11.00 h and 14.00 h. After a 
habituation period of 10 min the pigs were free to go to the feeder. In the two “intervention” 
treatments the animals closest to the feeder when the intervention started were guided or 
driven to the entrance one by one. See photo on the right. The exit of the feeder was blocked in 
the first 3 minutes after entrance to prevent an animal passing the feeder without eating. The 
animals in the third group, starting at 14.00 h stayed in the post feeding pen until the next 
morning. The feed intake of some of the animals was so low that they were given a second 
chance to eat. However this was only done after the 30 min post feeding period and was not 
Final Report Pig Handling Experiment, April 21, 2009 
 4 
included in the observations. The same treatments were applied during these prefeeding 
periods. On Thursday and Friday the animals received no human intervention. 
 
    
Photo 1. Prepared for HR-observations Photo 2. Situation in the ESF-pen 
 
Observations 
From every sow we recorded the entrance and exit time on day 2 and day 4 (Tuesday and 
Thursday). On the same days we measured heart rate data from 2 of the 4 animals in every 
group. HR was recorded with Polar S810 (Polar Electro OY, Kempele, Finland), which consisted 
of a girth belt with built-in transmitter and a wristwatch receiver. The girth belts were attached 
shortly before the start of the training session and removed after finishing the training session, 
about 2 h later. The belts were protected with tape against the teeth of curious pen mates. 
 
The heart rate recordings were split into three periods: 1) prefeeding, just before entering the 
feeder, duration 10 min. 2) feeding, the time the animal stood in the feeder, 3) postfeeding, 
started when leaving the feeder, duration 30 min. In between these periods we excluded 2 
minutes to prevent the observations from being disturbed by sudden movements when entering 
and leaving the feeder and by lack of synchronicity of clocks of Polar and VCRecorder 
(behaviour study). There was at maximum 1 minute difference between the video time and the 
Polar time. Mean HR and HRV measures were  calculated after systematic removal of artefacts 
on the basis of visual inspection. Approximately 7% of the beats in individual HR recordings 
were not used because of excessive artefacts. In general, the quality of the series of heart rate 
measurements was poor for both part of the animals and part of the periods. For instance 
animals with repeated periods without signal (0) or the maximum (255) heart rate were of too 
low quality. We selected only the animals with reliable measurements in all three periods 
(prefeeding, feeding and postfeeding). Of the 72 measurements 38 (53%) could be used in the 
final analysis. (6 batches x 3 treatments x 2 days x 2 animals = 72 measurements) 
Final Report Pig Handling Experiment, April 21, 2009 
 5 
From these heart rate observations we calculated the mean heart rate in beats per minute and 
the heart rate variability (HRV) as root mean square of successive beat-to-beat differences 
(RMSSD). An example of an heart rate recording is shown in figure 2. 
 
 
Fig.2 Example of heart rate recording during 2.5 hrs, split up in three periods. 
 
Statistical analysis 
The time for a group to pass the feeder was analysed using “General Analysis of Variance” 
(Genstat, 2007) with the model  duration = µ + training method + day of the week + interaction 
+ e. The difference in duration between day 2 and 4 was analysed with only the factor “training 
method”. 
The heart rate (BPM) and the heart rate variability (RMSSD) per individual pig were analysed 
using the REML procedure of Genstat (2007). The variable RMSSD was transformed to 1/RMSSD. 
The model was BPM/RMSSD = µ + training method + day of the week + interaction + e. 
 
 
Results 
All the gilts passed the feeder at least once per day, also in the Minimal group. It took the 4 
animals of a group on average 1 h and 21 min to pass the Electronic Sow feeder. The statistical 
analysis showed no difference between treatments or day of the week on passing time. Also the 
difference between day 2 and 4 was not significantly different. Figure 3 shows the average 
passing time for a group of 4 animals per training method and day of the week. The group 
without intervention showed a “learning effect” which was 14’40” quicker, the gently treated 
Final Report Pig Handling Experiment, April 21, 2009 
 6 
animals were 12 minutes slower and the forced animals were 1’30” quicker, but these 
differences did not show statistically significancy. 
On average after 30% of the visits the total ration was not dispensed. This was on average 216 g 
per visit or 716 g per visit with not completed rations. Secondary visits to the feeder were not 
included in the final data. From Monday to Friday no differences or tendencies were present. 
 
0:00
0:15
0:30
0:45
1:00
1:15
1:30
1:45
2:00
Minimal Gentle Active
tim
e
 
fo
r 
gr
o
u
p 
to
 
pa
s
s
 
ES
F 
(h
:m
m
)
Day 2 = with intervention
Day 4 = no intervention
 
Figure 3. Average passing time for a group of 4 animals per training method and day of the week. 
 
The quality of the heart rate measurements was poor for part of the animals and part of the 
periods, possibly caused by other animals biting on the tape around the girth collar and activity 
of other thoracal muscles. We selected only the animals with reliable measurements in all three 
periods (prefeeding, feeding and postfeeding).  
 
The only significant differences for heart rate and heart rate variability were found between the 
different periods. Table 1 presents the estimates of the statistical analysis. Figure 4 presents 
the results graphically, including the treatment. The heart rate was lowest before feeding, 
highest during feeding and intermediate after feeding (P<0.001), but without differences 
between the training methods.  
 
 
 
Final Report Pig Handling Experiment, April 21, 2009 
 7 
Table 1. Estimates of heart rate and heart rate variability per period. 
 Prefeeding Feeding Postfeeding Significance 
BPM 120.9a 136.1b 124.7c P<0.001 
HRV 12.85a 9.34b 17.51c P<0.001 
abc Numbers with different superscripts differ significantly (P<0.05) 
 
105
110
115
120
125
130
135
140
Prefeed Feed Postfeed
He
a
rt
 
ra
te
 
(B
PM
) Minimal
Gentle
Active
0
5
10
15
20
25
30
Prefeed Feed Postfeed
H
RV
 
(R
M
SS
D)
Minimal
Gentle
Active
 
Figure 4. Estimated values for heart rate and heart rate variability per treatment and period. 
 
Discussion 
Learning to use the Electronic Sow Feeder was easy in a group of 4 gilts. All the animals used 
the feeder from the first day with an average visiting time of 20 minutes. Some animals left the 
station before they finished their total daily ration, and the feed intake did not improve as the 
testweek went on. Only in the treatment without human intervention the time for the group to 
pass the feeder was longer on the second day and shorter on the fourth day. On day four it was 
comparable with the duration of the other treatments. The training methods did not affect the 
time and duration the animals spend to pass the feeder on the first day without human 
intervention. 
 
The heart rate was significantly affected by the period around feeding. Prefeeding HR was the 
lowest, Feeding HR the highest and Postfeeding was intermediate. For mean HR there was no 
indication of differences between treatments. The average HR was around 120 BPM where in 
socially isolated gilts it was 104 BPM (Marchant-Forde et al., 2004). Within the periods the 
treatments did not differ significantly..  
Heart Rate Variability (RMSSD) was lowest during feeding and highest post feeding. There were 
no significant differences in HRV for the different treatment groups. So an active human 
intervention did not result in an increased or decreased HRV. In other studies a decreased heart 
rate variability is associated with an increased level of stress and hence can compromise pig 
welfare. In the present study the average heart rate variability was almost 14 where in the gilts 
of Marchant-Forde et al. (2004) this was 21. This slightly lower value in the current experiment 
Final Report Pig Handling Experiment, April 21, 2009 
 8 
is probably caused by the arousal caused by moving the animals to the prefeed pen and fixing 
the girth transmitters.  
 
We found no negative effects of any human interventions, but also no advantages for training 
time. This fits in the Danish advice (Hansen and Vinther, 2004) to optimize the pen design and 
equipment and to let the gilts “train themselves” in small groups. This also requires less labour 
from the stockman and does not make the feeding behaviour dependent on human presence.  
Surprisingly we did not find differences between minimal and active training. Hemsworth et al. 
(1993) found differences between aversive handling on one side and positive and minimal 
handling on the other side on fear responses of pigs. In the current study the authors believe 
that the impact of the short moment to force or to help the animals gently to the feeder on 
three consecutive days was not a big enough intervention to have an effect on the behavioural 
and heart rate responses.  
The hypothesis that gentle human intervention would help the animals to learn faster without 
experiencing stress could not be confirmed. One of the reasons could be that the challenge (the 
task of learning how to use an ESF) in combination with a relatively small group resulted in too 
less variation to detect any significant difference. A larger group or the presence of older and 
unfamiliar sows, resulting in aggressive interactions, would certainly make it more difficult.  
 
Conclusions 
- Positive nor negative human intervention during ESF training did adversely affect learning 
speed of gilts as measured by passage time through the feeder 
- Neither gentle nor active prefeeding human intervention affected stress as indicated by heart 
rate and heart rate variability, compared to no intervention. 
 
Practical implications 
The results indicate that at least in small groups of gilts the preferred level of human 
interference when training gilts to use an ESF is a minimal level, because it requires least 
labour. The general advise based on practical experience is that gilts should be grouped in a 
prefeeding pen, separated from the post feeding pen, with no possibility to return. This gives 
the last and probably lowest ranking animals the chance use the ESF without any intervention of 
dominant pen mates. From experience in this and other studies we recommend that the 
minimal duration of this training period is 7 days. 
 
Final Report Pig Handling Experiment, April 21, 2009 
 9 
 
References 
Borell, E. von, Langbein, J., Després, G., Hansen, S., Leterrier, C., Marchant-Forde, J., Marchant-
Forde, R., Minero, M., Mohr, E., Prunier, A., Valance, D. and Veissier, I., 2007. Heart rate 
variability as a measure of autonomic regulation of cardiac activity for assessing stress and 
welfare in farm animals — A review. Phys. Behav. 92:293-316. 
 
Hansen, L.U. and Vinther, J., 2004. Træning af polte i systemer med elektronisk sofodring (ESF) 
(Training of gilts in Electronic Sow Feeding systems). Erfaring nr. 0410, Landsudvalget for Svin, 
Den rullende Afprøvning, Denmark, 29 p. 
 
Hemsworth, P.H., J.L. Barnet and G.J. Coleman, 1993. The human-animal relationship in 
agriculture and its consequences for the animal. Animal Welfare 2:33-51. 
 
Marchant-Forde R.M., Marlin D.J., Marchant-Forde J.N., 2004. Validation of a cardiac monitor for 
measuring heart rate variability in adult female pigs. Accuracy, artefacts and editing. Physiol 
Behav 80:449–558. 
 
Wechsler, B. and Lea, S.E.G., 2007. Adaptation by learning: Its significance for farm animal 
husbandry. Appl. Anim. Behav. Sci. 108:197-214 
 
 
Acknowledgements 
 
The present study is part of the Welfare Quality® research project which has been co-financed 
by the European Commission, within the 6th Framework Programme, contract No. FOOD-CT-
2004-506508 and the Dutch Ministry of Agriculture, Nature and Food Quality. The text 
represents the authors’ views and does not necessarily represent a position of the Commission 
who will not be liable for the use made of such information. 


Adaptation by learning: Its significance for farm animal husbandry.

Heart rate variability as a measure of autonomic regulation of cardiac activity for assessing stress and welfare in farm animals — A review.

The human-animal relationship in agriculture and its consequences for the animal.

Træning af polte i systemer med elektronisk sofodring (ESF) (Training of gilts in Electronic Sow Feeding systems). Erfaring nr. 0410, Landsudvalget for Svin, Den rullende Afprøvning,

Validation of a cardiac monitor for measuring heart rate variability in adult female pigs. Accuracy, artefacts and editing. Physiol Behav 80:449–558.

Training gilts to use a feeder station

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