In this paper, we assessed the relative importance of handling and feeding lambs in the development of affinity for their stockperson. We also tested the extent to which this affinity can be linked ...to feeding motivation and behaviour in a conditioning hypothesis. Lambs were reared in groups of three and artificially fed from a multiple-nipple bucket. From the first day of age, contacts with the stockperson were given in the home pens three times a day for 5 consecutive days, then 2 days a week until the tests. In five groups (Presence), the stockperson sat motionless; in five groups (Handling), he caught the lambs and stroked them; in six groups (Handling & Feeding), he caught and stroked the lambs while placing them at the food bucket. At 3.5 weeks of age, the lambs were individually tested in a 6
m
×
1.5
m arena. In Test 1 (Human Test), the lambs stayed 2
min alone, 2
min with the familiar stockperson, then 2
min alone again. In Test 2 (Bucket Test), a milk bucket was added to the arena and the same procedure was followed. For each test, the lambs were observed after 5
h of starvation or ad libitum feeding (cross-over design). In the Human Test, Presence lambs spent less time near the stockperson (27
±
7
s) than Handling lambs (59
±
9
s,
P
=
0.03) or Handling & Feeding lambs (59
±
6
s,
P
=
0.03). In the Bucket Test, three lambs suckled from the bucket. Only Handling & Feeding lambs increased their time spent near the bucket when the stockperson entered (treatment
x time,
P
=
0.05). No interaction between the treatments and the hunger state was observed in any test.
Handling per se contributed to the development of lambs’ affinity for their stockperson during individual tests, and could have calming and rewarding properties for the lambs. Neither feeding from a bucket during handling nor hunger state increased this affinity. Nevertheless, some association of the stockperson with the milk bucket seemed to occur, suggesting a food conditioning. The way of feeding the animals and their perception of the test as an alimentary situation are discussed.
Feeding young mammals is often used as a way to increase their affinity to their human caregiver. However, feeding is not always necessary, which raises questions as to the feeding method used ...(bottle, bucket) and to the importance of contacts surrounding feeding compared to an absence of human contact. These questions are the focus of this study.
At early age, lambs were divided into 4 treatments: no contact, holding, holding and hand-feeding with a bottle (hand bottle-fed), or feeding using a bottle attached to a stand (wall bottle-fed). The treatment sessions (5
min) were repeatedly applied every day for 1 week and then twice-a-week for 2 weeks. Contacts to the caregiver were measured during the treatments. Then, from 3 weeks of age, the lambs were tested in an unfamiliar pen to measure their attraction to the caregiver and the effects of caregiver presence and departure on distress behaviours. Exploration of objects and response to a sudden event in the presence of the caregiver were also measured.
During the treatments, hand bottle-fed lambs interacted more with their caregiver (54
±
2% of the observations) than held lambs (25
±
3%,
p
<
0.001), while both interacted more than wall bottle-fed lambs (19
±
2%,
p
<
0.001). In unfamiliar environments, affinity to the caregiver (latency to approach, time spent near the caregiver) was not increased by feeding, but all lambs from treatments involving human contact expressed a higher affinity than “no contact” lambs (
p
<
0.05). Handled lambs showed a decrease in distress behaviours in the presence of their caregiver and an increase in these responses after separation. Exploration was not affected by the treatments but held lambs returned faster to their caregiver after a sudden event (9
s (3–16)) than the other lambs (42
s (13–60) for wall bottle-fed, 61
s (61–61) for the others,
p
=
0.02).
Thus, even if food does orient animals to the place where it is provided, it does not allow the development of an affinity for a human caregiver that can be generalised out of the home environment; holding lambs is sufficient to achieve this. These soft physical contacts could be rewarding due to the gregariousness of sheep.
Devices used to measure cardiac activity (elasticized belt, electrodes, etc.) in standardised behavioural tests could be stressful for the animals, and therefore affect their responses. Preliminary ...habituation to the device is not always possible. To date, the impact of carrying such devices has been poorly evaluated. In the present experiment, we examined the impact of a device used to measure cardiac activity on the behavioural responses of handled and non-handled lambs in a standard human test. We also studied variations in heart rate in response to human presence and separation. Twenty-one lambs were separated from their dam 12
h after birth: 11 received no additional human contact (non-handled) and 10 received additional contact for 1 week and then 1 day a week until 6 weeks. They consisted of stroking and milk-feeding (handled). At 6.5 weeks of age, each lamb was submitted twice to a behavioural test. The procedure comprised three phases: the lamb stayed alone for 2
min, then for 2
min with the familiar stockperson, and then alone for 2
min again. The tested lambs were equipped or not with a cardiac device in a cross-over design. The device used to measure cardiac activity led to a decrease in vocalisations and locomotion (
P
<
0.05). It had only a limited impact on the behavioural differences between handled and non-handled lambs. It reduced slightly the time spent near the stockperson for the non-handled lambs (mean
±
S.E. 0.1
±
0.1
s with cardiac device versus 3
±
1
s without;
P
<
0.05) but had no effect on the handled lambs (35
±
15
s versus 23
±
10
s;
P
>
0.1). In handled lambs, the frequency of vocalisations and the heart rate decreased as the stockperson entered (
P
<
0.05). When he left, we observed an increase in frequency of vocalisations but no change in heart rate (
P
>
0.1). No change in heart rate was observed for the non-handled lambs.
We conclude that the device used to measure cardiac activity led to a general decrease in activity but did not affect the difference between handled and non-handled lambs. Consequently, this method seems to be appropriate for further exploring artificially reared lambs’ perception of humans, with few risks of behavioural alterations. However, the absolute values of locomotor and vocal activities should be taken with caution. Behavioural and physiological measures were not totally consistent, which questions then-respective emotional significance.
Understanding how farm animals perceive their stockperson is a major challenge, especially for artificially reared animals which are known to show strong attraction to humans. Replacing the ...stockperson by its photograph in an arena test could be a useful method for standardising human stimuli. Such an approach requires individual consistency in young lambs’ responses to their stockperson, which has not yet been demonstrated. Our objective was to test this consistency and to determine whether the responses of lambs to a photograph of a stockperson in an arena test are linked in a specific way to their responses to the real stockperson in that same test. Thirty-six female lambs were bucket-fed by two men. The individual responses of the lambs to the person feeding them were assessed when the lambs were 4, 5 and 10 weeks of age, in a test pen where the lambs were first alone for 2
min, then left with their stockperson for 2
min, and then left alone again for a further 2
min. At 11 weeks of age, a similar test was run with photographs (object and stockperson). Responses to the real stockperson were positively correlated between tests (
r
s
>
0.44,
P
<
0.01). The lambs spent more time near the photograph of their stockperson than a photograph of an object (40
±
5
s versus 29
±
4
s,
P
=
0.02). The time spent near the two photographs was statistically linked (
P
<
0.02) to the time spent near the real stockperson in the previous test. We observed an increase of the frequency of vocalisations and locomotion when the stockperson left the pen (
P
<
0.001), but not when the photographs were removed. In conclusion, individual lambs’ give consistent responses to the presence or disappearance of a stockperson in an arena test. This suggests an early individual behavioural trait in lambs, and therefore the possibility of early selection for this trait. Our results do not support the use of photographs of humans in arena tests, due to an absence of specific link.
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