Alain Boissy

Maternal presence limits the effects of early bottle feeding and petting on lambs' socialisation to the stockperson

Mothered herbivores are more fearful towards humans than those reared artificially. However, in previous studies, both human contact and maternal environment factors have been confounded. This paper investigates the influence of early human contact (petting, bottle feeding) given to lambs reared artificially in the presence or absence of the dam, on their socialisation to the stockperson. Forty-eight lambs were studied. From day 1 of age until 7 weeks of age (weaning), half the lambs (M1) were individually reared in the presence of their dam and one twin lamb behind a grid. At weaning the dams were removed. The rest of the lambs (M0) were reared only in the presence of their twin lamb behind the grid. In each M0 or M1 group, half the animals received human contact until 6 days of age (H1), and the other half were not handled (H0). Later, they had no visual contact with humans during husbandry. Response to the stockperson was measured during the initial sessions of human contact, during tests in the rearing pen (at 4 and 9 weeks of age) and in a test pen at 5 and 10 weeks of age. In addition, responses to a novel object in the rearing pen at 3 and 8 weeks of age, and preference for the stockperson or their familiar conspecific(s) (no dam after weaning) at 6 and 11 weeks of age were also measured. During the sessions of human contact, lambs stayed in contact to the stockperson whatever their maternal environment. Later, whatever the age, H1 lambs approached the stockperson more quickly (P<0.01) and interacted for longer (P<0.05) in the different tests than H0. However, M0H1 lambs approached the stockperson (P<0.05) more than the other lambs, even in the choice test (P<0.01). In addition, M0 animals approached the novel object more than M1 lambs at 3 weeks of age (P<0.05), but not after weaning, and tried less to rush out into the conspecific(s)’s pen at any age (P<0.01). The results clearly show the effect of the maternal environment on lambs’ socialisation with humans. ‘Proximity seeking’ of lambs for their dam probably affects the development of other durable relationships at a young age. The results then raise the question of the contact/separation between the young and its dam in early husbandry management when socialisation of the young to humans is needed as a way to durably improve animal docility.

Effects of feed deprivation on behavioral reactivity and physiological status in Holstein cattle.

The present study evaluated whether feed deprivation can increase reactivity to stressful events, such as those that can occur at slaughter. Therefore, effects of 30 h of feed deprivation on behavior, including reactions to psychological stressors, and physiological status in cattle were determined. Sixteen Holstein cows (Exp. 1) and 32 Holstein heifers (Exp. 2) were either fed (FE) or 30-h feed deprived (FD). Throughout the first day of feed deprivation and during evening feed distribution to control animals, FD heifers and cows were more active than controls (P < 0.05). In Exp. 1, during a feeding test, in response to a sudden air blast arising from the bucket from which the cow was feeding, FD cows showed a longer latency to return to feed (P = 0.0002), spent less time in the bucket air blast zone (P = 0.008) and less time motionless (P = 0.03), and tended to withdraw over a longer distance (P = 0.07) than FE cows. In Exp. 2, during a reactivity test, FD heifers spent more (P = 0.0001) time motionless in response to social isolation than FE heifers. In Exp. 2, one-half of the FE and FD heifers were subjected to an additional physical and psychological stressor just before the reactivity test by driving them for 5 min through a labyrinth. Within heifers subjected to the additional stressor, FD heifers were less accepting of being detained (P = 0.05) and stroked (P = 0.003) by a familiar stockperson in a corner of the test arena. Compared with FE animals, FD heifers and FD cows had greater plasma cortisol concentrations (P < 0.05). Feed-deprived cows also had reduced β-hydroxybutyrate concentrations (P = 0.02) compared with FE cows. Thus, in cattle, FD influenced some of the classical indicators of energy metabolism and exacerbated reactivity to sudden events. In addition, when additional stressors were applied, FD cattle were more reluctant to accept handling. Results indicate that a multifactorial origin of stressors during the slaughter period may synergistically increase psychological stress of cattle.

Identification of QTLs for behavioral reactivity to social separation and humans in sheep using the OvineSNP50 BeadChip

BackgroundCurrent trends in sheep farming practices rely on animals with a greater level of behavioral autonomy than before, a phenotype that actively contributes to the sustainability of animal production. Social reactivity and reactivity to humans are relevant behavioral traits in sheep, known for their strong gregariousness and weak tolerance to handling, which have previously been reported with moderate to high heritabilities. To identify loci underlying such behaviors, we performed a genome study in Romane lambs.ResultsThe experiment was carried out on 934 male and female lambs allocated into 9 half-sib families (average of 103 lambs per family) and reared outside. After weaning, all the lambs were individually exposed to 4 standardized behavioral tests combining social isolation, exposure to humans or handling, confinement and novelty (i.e. arena test, corridor test, isolation box test, shearing test). A broad range of behaviors including vocalizations, locomotion, vigilance and flight distance, as well as the cortisol response to handling, were collected. All lambs were genotyped using the Illumina OvineSNP50 BeadChip. QTL detection was performed by linkage, association and joint linkage and association analyses using the QTLmap software. Five main QTL regions were identified on sheep chromosomes (Ovis Aries Region, OAR) 12, 16, 19, 21 and 23 among many other QTLs with small to moderate effects. The QTLs on OAR12, 16 and 21 showed significant associations with social reactivity. The QTLs on OAR19 and 23 were found to be associated with reactivity to humans. No overlapping QTLs were identified for the different traits measured in the behavioral tests, supporting the hypothesis that different genetic factors influence social reactivity and tolerance to humans.ConclusionThe results of this study using ovine SNP data suggest that in domestic sheep the behavioral responses to social separation and exposure to humans are under polygenic influence. The most relevant QTLs reported in the present study contain interesting candidate genes previously described to be associated with various emotional and social behaviors in mammals.

Mild effects of gestational stress and social reactivity on the onset of mother-young interactions and bonding in sheep

Abstract Consequences of prenatal stress on mother–young relationships are well-documented in altricial mammals but less so in precocial mammals. In this study, we investigated the effects of unpredictable aversive events on maternal behavior and mutual mother–young recognition in pregnant ewes while accounting for modulatory effects of ewe reactivity. From a population of 120 Romane-breed ewes, we selected 20 high-responsive (HR) and 20 low-responsive (LR) ewes according to pre-mating reactivity assessed in isolation tests. Over the final third of pregnancy, 10 HR ewes and 10 LR ewes were exposed daily to various aversive events such as social isolation, mixing and transport (stressed ewes), while the other 20 ewes were not exposed to aversive events (control ewes). Although the treatment induced chronic stress, physiologically confirmed by an increase in salivary cortisol following transport and sham shearing, maternal behavior of stressed ewes observed during the first 30 min postpartum and in the selectivity test 1 h 30 min later did not differ from controls. However, in a maternal motivation test performed 48 h postpartum, stressed ewes vocalized less than controls when separated from their lambs, and walked less readily past an unknown object to reach their lambs. Lambs of stressed ewes spent more time near their dam in a preference test performed 15 h after birth compared to control-ewe lambs. HR ewes spent more time grooming their lambs than LR ewes. We posit that domestication could have selected animals displaying robust expression of maternal behavior related to social reactivity and producing offspring that are better adapted to challenging situations.

Bird's emotionality modulates the impact of chronic stress on feeding behaviour

Chronic stress is a long-lasting negative emotional state which induces negative consequences on animals’ behavior. This study aimed at assessing whether unpredictable and repeated negative stimuli (URNS) influence feeding behavior in quail, and whether this can be modulated by their emotionality. Two lines of quail divergently selected on their inherent emotionality (low emotionality, STI; high emotionality, LTI) were either daily exposed to URNS or undisturbed from 17 to 40 days of age (n=32 for each line, in each group). During this time, quail were submitted twice to a sequential feeding procedure: they were offered a hypocaloric diet (7% less caloric than the normocaloric diet) on odd days and a hypercaloric diet (7% more caloric) on even days, for 8 days; then, they received a normocaloric diet (metabolizable energy=12.56 MJ) for 3 days. This sequential feeding procedure was used to assess anhedonia and diet preferences thanks to choice tests (hypo vs. hypercaloric diets) performed at the end of each period. Short-term (30 min) and daily intake were also measured each day. Behavioral tests were performed to assess quail’s emotional reactivity. Results showed that URNS enhanced quails’ emotional reactivity, e.g. in the reactivity to human test, disturbed quail came later (P=0.011) and spent less time (P 0.1), but URNS reduced their daily intake during the 2nd period (P<0.05). Motivation for each diet (assessed by their short-term intake) was differently affected by URNS during the 2nd period: STI quail decreased their motivation to eat the hypercaloric diet (P<0.01) whereas LTI increased their motivation to eat the hypocaloric diet (P<0.01). In conclusion, both lines of quail experienced a chronic stress as URNS induced an increase of their emotional reactivity. Interestingly, URNS induced opposite changes in quail’s feeding behavior: LTI disturbed quail seemed to express a short-term compensatory behavior because of their high motivation to eat, whereas STI disturbed quail seemed to be in a devaluation process as shown by their anhedonia and their decrease of daily intake.Farm animals have to adapt to human presence from birth and being handled may lead to fear and stress reactions. It is known that the mother can be used as a postnatal model in the development of young-human relationship. Through her, some information like auditory ones may even be learnt prenatally. We tested this idea in pigs because they communicate a lot by acoustic signals. The hypotheses were that prenatal experience with human voice could modify behavioural reactions to the experienced voice and to an unfamiliar voice expressing different emotions. We worked with 30 pregnant sows from the last month of gestation. Ten sows (treatment A) were submitted to recordings of human voices during handling: vA during positive interactions and vB during negative interactions, twice a day, 5 days a week, for 10 minutes. Ten other sows (treatment B) received the contrary, i.e. vB during positive interactions and vA during negative interactions. Ten last sows (treatment C) received no vocal stimulations during handling sessions. Two days old piglets (36 A, 39 B, 35 C) were submitted to a 5 min choice test between voices vA and vB in a testing pen (2×1 m). Each voice was played back through loudspeakers positioned at each end of the pen. At 15-18 days of age, 20 other piglets from each treatment were tested in the same conditions except that we played back the voice of an unknown person, reading the same text with a joyful or angry intention. In both tests we recorded vocalisations and locomotion. Data were analysed using non parametric statistics (Statview). In both tests, A and B piglets started to move sooner (P 0.05) to be and the time spent (178 s (46s)) close to the loudspeakers did not depend on the treatment (P>0.05). We also found no difference between the time spent close to one loudspeaker or the other, neither for vA versus vB, nor for joyful versus angry intention (P>0.05). The results show that the prenatal experience of human voice reduces postnatal behavioural reactions of stress (vocalisations, latency to move) during the playback human voices. However, it does not seem to induce specific attraction toward human voice, or human emotional intention. Therefore prenatal experience with human voice may be a good way of reducing fear reactions to human voice after birth.