Biomedical subjects

A Boissy

Publications and source records attributed to A Boissy.

16 recordsLinked to original sources

PubMed2006

Stress and welfare: two complementary concepts that are intrinsically related to the animal's point of view.

The closely associated concepts of welfare and stress may be considered as opposites since welfare cannot be achieved under stress and vice versa. Stress was first considered as an unspecific response to any challenge taxing the organism's resources where the HPA axis plays a central role [Selye H. A syndrome produced by diverse nocuous agents. Nature 1936:32]. Along the same lines, welfare was considered as the state of an individual on a continuum between poor and good depending on the efforts required to adapt to the environment [Broom DM. Animal welfare: concepts and measurement. J Anim Sci 1991;69:4167-75]. However, these views cannot explain opposite results such as up- vs. down-regulation of the HPA axis and hypo- vs. hyper-behavioural reactivity under chronic stress. Later, it was shown that aversive situations trigger stress responses only if the individual perceives them as aversive. Mason [Mason JW. A re-evaluation of the concept of 'non-specificity' in stress theory. J Psychiatr Res 1971;8:323-33] suggested that the unspecificity of stress responses originates from a common emotion that produces them. Welfare has also been defined in terms of emotional states by Dawkins [Dawkins MS. Animal suffering, the science of animal welfare. London: Chapman and Hall Ltd.; 1980] and Duncan [Duncan IJH. Welfare is to do with what animals feel. J Agric Environ Ethics 1993;6:8-14]. Hence, both concepts are linked to mental states. Recent advances in psychology suggest that the very nature of an emotion results from a series of evaluations of the triggering situation that the individual makes based on criteria including novelty, predictability, controllability, and others [Scherer KR. Appraisal considered as a process of multi-level sequential checking. In: Scherer KR, Schorr A, Johnstone T, editors. Appraisal processes in emotion: theory, methods, research. New York: Oxford University Press; 2001. p. 92-120]. It is therefore suggested that the discrepancies found in the literature in terms of responses of the HPA axis or modification of behaviour under aversive conditions may stem from differences in the way a situation is evaluated. It is argued that stress comes from the animal's evaluation of the outcome of a situation, and that welfare is the state resulting from that evaluation.

Animal Welfare↗

PubMed2006

Emotional reactivity modulates autonomic responses to an acoustic challenge in quail.

Emotional reactivity modulates autonomic responses to an acoustic challenge in quail. Physio Behav 00(0) 000-000, 2006. This study investigated the relationship between emotional reactivity and behavioral and autonomic responses to an acoustic stimulus in quail. It was hypothesized that birds with high emotional reactivity would have higher motor inhibition combined with higher sympathetic activation than birds with low emotional reactivity. Two experiments were performed. The first looked for correlations between emotional reactivity, evaluated by a tonic immobility test, and motor and Heart Rate Variability in relation to an acoustic stimulus. The second experiment compared the motor and autonomic responses to the acoustic stimulus of quail selected on either long (LTI) or short (STI) duration of tonic immobility. The first experiment showed that the acoustic stimulation induced motor inhibition and cardiac activation. Correlations were found between tonic immobility duration and both autonomic activity before stimulation and sympathovagal balance after stimulation. In the second experiment, LTI quail showed strong sympathetic activation, whereas STI quail showed parasympathetic and sympathetic activation. The activation of the parasympathetic system induced by the noise in STI quail can be explained by the predominance of this system at rest in this line. In conclusion, both the basal autonomic activity and the autonomic responses differed according to the emotional reactivity, and changes in autonomic activity appear to be related to the genetic selection process.

Acoustic Stimulation↗

PubMed2006

Genetic selection on a behavioural fear trait is associated with changes in heart rate variability in quail.

This study investigated whether genetic selection on a divergent behavioural trait of fearfulness (tonic immobility duration) was related to changes in the nervous control of the heart. Quail selected for either long or short tonic immobility (LTI or STI, respectively) duration was compared with an unselected control line (CTI). The autonomic control of the heart was assessed by heart rate variability analysis and pharmacological blockades. Quail were surgically fitted with a telemetric device. Heart rate before injection did not differ between the three lines. The vagal-sympathetic effect (VSE) at rest differed significantly from 1 in CTI and STI quail, suggesting that parasympathetic activity was dominant. In LTI quail, VSE did not differ from 1, suggesting a balance between parasympathetic and sympathetic activities. The intrinsic heart rate reached after the successive injections of propranolol and atropine did not differ between lines and was higher than the heart rate at rest in STI, which was in line with results of VSE at rest. After atropine injection, the sympathetic activity indicated by the low-frequency power was lower in CTI than in the two selected quail. After propranolol injection, the parasympathetic activity indicated by the root of the mean squares of successive differences and the high-frequency power was higher in STI than in CTI and LTI quail. Selection on tonic immobility duration thus appears to be associated with changes in the sympathovagal control of the heart, which may influence behavioural responses to stressful situations.

Animals↗

PubMed2005

Gender-specific effects of prenatal stress on emotional reactivity and stress physiology of goat kids.

The aims of this study were to investigate the effects of maternal stress during pregnancy on the emotional reactivity, the hypothalamo-pituitary-adrenocortical (HPA) axis, and the sympatho-adrenomedullary (SAM) system of goat offspring according to their gender, and to investigate the role of maternal cortisol in prenatal stress effects. Goats were exposed to ten transports in isolation or ten ACTH injections (0.125 IU/kg body weight) during the last third of pregnancy. Control goats remained undisturbed. No effect of repeated transport during the last third of pregnancy was found on basal cortisol concentrations of the offspring. However, an increase in phenylethanolamine N-methyl transferase activity in the adrenals was observed in prenatally stressed kids compared to control kids (P = 0.031). In the presence of novelty, prenatally stressed female kids were more active (P = 0.049) than control females; they also showed more signs of arousal (P = 0.039) and tended to explore more of their environment (P = 0.053) in reaction to a startling stimulus. On the contrary, prenatally stressed male kids tended to be less active (P = 0.051) than control male kids but showed more signs of distress (P = 0.047) in the presence of novelty. Intermediate effects were found on the emotional reactivity to novelty of kids born from dams given injections of ACTH. In conclusion, transport stress in pregnant goats affects the sympatho-adrenomedullary system and the emotional reactivity of their offspring in a gender-specific manner. Moreover, the effects of prenatal transport and ACTH injections showed some similarities but differed in some critical details.

Adrenocorticotropic Hormone↗

PubMed2005

Behavior, physiology, and performance of bulls mixed at the onset of finishing to form uniform body weight groups.

In some production settings, beef bulls are mixed at the beginning of the finishing period to obtain homogeneous groups to facilitate finishing and to produce more homogeneous carcasses. Given the stress induced by mixing, we questioned whether this practice was profitable. Sixty-four young bulls were finished in groups of four over 8 mo. They were either mixed or unmixed and had either homogeneous vs. heterogeneous BW at the beginning of finishing. Behavioral traits (social behavior following mixing and general activities during the finishing period), stress measurements (cortisol concentration, adrenal weight, catecholamine-synthesizing enzyme activity, and pain sensitivity), and production traits (growth rate, homogeneity, feed efficiency, and carcass measurements) were evaluated. Bulls reacted to the mixing with increased frequency of social interactions (agonistic interactions: 17.9 in mixed vs. 1.2 in unmixed bulls, P < 0.001; sexual interactions: 9.6 vs. 1.7, P < 0.001; nonagonistic interactions: 5.25 vs. 3.1, P < 0.05). Agonistic and sexual interactions were more frequent between bulls of homogeneous BW (P < 0.05). Throughout the finishing period, the synchronization of activity tended to be lower between mixed bulls (P = 0.09). At slaughter, the activity of tyrosine hydroxylase, a catecholamine-synthesizing enzyme, was increased in mixed bulls (1.52 vs. 1.16 nmol.h(-1).mg(-1), P < 0.05), which may indicate chronic stress. No differences were noted in ADG or carcass traits among treatments. The variability of BW within groups increased in groups that were initially homogeneous, whereas it decreased in groups that were initially heterogeneous. In conclusion, mixing young beef bulls at the beginning of the finishing period did not have detrimental effects on health and production, but mixing induced stress, perhaps due to decreased cohesion within groups. Thus, we failed to confirm the proposed benefit of mixing bulls to homogenize their BW at the onset of finishing because BW homogeneity within groups was not maintained throughout the finishing period.

Adrenal Glands↗

PubMed2002

Effect of autonomic blockers on heart period variability in calves: evaluation of the sympathovagal balance.

This study was designed to validate the measures of heart period variability for assessing of autonomic nervous system control in calves. Eight calves received an injection of either 0.5 mg/kg atenolol (sympathetic tone blockade), 0.2 mg/kg atropine sulfate (parasympathetic tone blockade), 0.5 mg/kg atenolol + 0.2 mg/kg atropine sulfate (double autonomic blockade) or saline. In the time-domain, we calculated the mean instantaneous heart rate (HR), mean of RR intervals (MeanRR), standard deviation of RR intervals (SDRR) and that of the difference between adjacent intervals (RMSSD). In the frequency-domain, the power of the spectral band 0-1 Hz (TPW), the power of the 0-0.15 Hz band (LF), that of the 0.15-1 Hz band (HF), and the LF/HF ratio were considered. The net vago-sympathetic effect (VSE) was calculated as the ratio of MeanRR in a defined situation to MeanRR during the double blockade. Atenolol injection had no effect on cardiac activity, whereas atropine induced large modifications which were moderated when atenolol was administered at the same time. VSE, HR, MeanRR and RMSSD were found to be valid indicators of the parasympathetic tone of calves because of large variations due to the drug and low individual variations. No measure reflected the sympathetic tone.

Adrenergic beta-Antagonists↗

PubMed2001

Do beef cattle react consistently to different handling situations?

Beef cattle responses to handling depend partly on the genetic characteristics of the animals. However, the various methods used in order to assess these responses differ to a great extent. The purpose of this work is to study the relationship between two different situations extensively used to evaluate cattle reactions to handling. Moreover, the genetic variability of cattle responses to these two handling situations was investigated. Behavioural reactions of 245 Limousine heifers, from 10 sires, were evaluated both in a docility test and in a crush test. In the docility test, a human tried to lead and then to maintain the animal in the corner of a pen during 30 consecutive seconds, with a maximum duration of the test of 3.5min. A docility score summarised the animal's behavioural reactions to the test. The crush test procedure consisted of social isolation of the animal in a crush, with the head maintained in a head gate (5min), then exposure to a stationary human (30s), and finally stroking on the forehead (30s). An agitation index for each part of this test was computed from PCA analyses based on agitation behaviours. Sire effect was significant for every part of both tests (P<0.05). Heifers' behavioural responses to the docility test were significantly correlated with their responses to the crush test, when the animals were in isolation (r=0.29; P<0.001), when the human stood motionless in front of the animals (r=0.37; P<0.001), and when the human stroked them (r=0.28; P<0.001). Sires' behavioural reactions to the docility test (computed from their daughters' scores) were correlated with their reactions to the crush test only when the human was present, both when motionless (r=0.88; P<0.001) and when stroking the heifer (r=0.81; P<0.05). No relationship appeared between sires' behavioural reactions to the docility test and their responses to restraint in the crush when the human was absent (P=0.17). Furthermore, the crush test did not reveal the animals which presented aggressive reactions to handling in the docility test. The results exposed in this paper pointed out the existence of a general reactivity of beef cattle to handling, whether the animals are restrained or not, which appears influenced by the sire. Such reactivity is suggested to be mainly a consequence of the animals reactions to humans. The human environment needs to be precisely defined in the handling test procedures before using them as a selection criteria.

Journal Article↗

PubMed2001

Calves' responses to repeated social regrouping and relocation.

Because of welfare concerns and increased labor efficiency, calves are increasingly housed in groups. To reduce variability in live weight within groups, farmers frequently regroup calves according to growth rate. We assessed the consequences of repeated regrouping and relocation on the welfare of 32 male Holstein calves housed in pairs. Animals of half of the pairs (regrouped calves) were placed in a new pen with a new partner once a week for 14 wk. Animals of the other half of the pairs (control calves) stayed in the same pen with the same partner. Behavior was observed for the 3 h following four mixings and for 24 h after all relocations were finished. The functioning of the hypothalamic-pituitary-adrenal axis and of the sympathetic nervous system were assessed. Calves were weighed once a week, their health was assessed daily, and abomasa were inspected when the calves were slaughtered. Calves reacted to the first mixing by interacting with the new partner and increasing their general activity (sniffing the partner in regrouped calves vs controls: 5.5 vs 2.9, P < 0.01; percentage time stepping: 3.2 vs 1.3, P < 0.001). This effect disappeared by the ninth mixing. After all relocations were completed, regrouped calves were more active at the end of the day and less active at night (P < 0.05). Cortisol responses to exogenous ACTH were higher in regrouped calves (integrated response: 6,688 vs 5,508 ng x min/mL, P < 0.01). Basal cortisol levels, ACTH responses to corticotropin-releasing hormone, activities of catecholamine-synthesizing enzymes (tyrosine hydroxylase and phenylethanolamine N-methyl transferase), and the incidence of health problems and growth rates did not differ between the two groups. Regrouped calves had fewer abomasal ulcers. Apart from the increased sensitivity of the adrenal cortex of regrouped calves to ACTH and the modification in the daily rhythm of activity, there was no clear evidence that repeated regrouping and relocation stresses calves. Aggression between calves was rare, and calves seemed to habituate to repeated mixing.

Abomasum↗

PubMed2000

Grazing behaviour of sheep in a situation of conflict between feeding and social motivations.

We investigated how food preferences and social bonds interact to determine the choice of grazing location in sheep. Ewes of INRA 401 breed were grazed in plots in which taller areas, i.e. preferred feeding sites, were left to grow at 15 or 50 m from a socially attractive site, i.e. familiar ewes placed in a public pen at one end of the plot. Eight experimental ewes were tested either alone or in groups with one, three or six accompanying animals chosen amongst 20 other familiar ewes. We used a Latin square design, in which the eight treatments (two distancesxfour group sizes) were balanced in 8 measurement days. We recorded, in 20-min tests, the behaviour of the experimental ewes by focal sampling, and the location of each animal in the groups by scan sampling. Foraging location, dietary choices and vigilance behaviour of ewes were affected by both the distance between the group of public peers and the preferred feeding site, and the size of their own group. Our results suggest that a sheep will move whether alone or with a few peers to a preferred feeding site located close to the core of its social group. In a small sub-group, its frequency of vigilance behaviour increases, probably to maintain social contact with the rest of the group. Conversely, a sheep will not leave its group to reach a preferred feeding site located further away unless it is followed by several other peers.

Journal Article↗

PubMed2000

The social environment influences the behavioural responses of beef cattle to handling.

In cattle, a gregarious species, the social group influences individual stress responses to fear-eliciting situations. As handling can be stressful for farm animals, it can be hypothesised that social partners modify individual responses to handling. The present experiment investigated the effect of the presence or absence of social partners on behavioural reactions of beef calves in a handling test. At the age of 10 months, 38 calves from two breeds (Salers and Limousine) were individually subjected to the docility test, once while in visual contact with four familiar peers, and once in the absence of peers, following a crossover design. The docility test procedure included physical separation from peers (30 s; period 1), exposition to a stationary human (30 s; period 2), and handling by human (30 s-2.5 min, according to the success in handling; period 3). In absence of human (period 1), calves in visual contact with their peers spent more time motionless than when peers were totally absent (P<0.001). The social environment also influenced the duration of handling (period 3); the human required more time to successfully handle calves when peers were present (P<0.05). In conclusion, the presence of peers affects individual calves' reactions to the docility test.

Journal Article↗

PubMed1999

Pheromones and novel male-induced pregnancy disruptions in mice: exposure to conspecifics is necessary for urine alone to induce an effect.

Previous research indicates a role of pheromones in novel male-induced early pregnancy disruptions. Although some reports suggest that urine alone is sufficient to produce this effect, others raise procedural concerns and fail to replicate such effects. On Days 1 to 5 after insemination, female CF-1 mice had their nasal regions repeatedly painted with water, urine from males housed in isolation, or urine from males housed in proximity to females. Almost all (87.5%) of the control females delivered litters. There was a small nonsignificant reduction in proportion parturient (78.5%) among females exposed to urine of males housed without social contact. The proportion of females parturient (57.1%) after treatment with urine from males housed in proximity to females was significantly different from controls. The magnitude of the effect of socially stimulated male urine is substantially less than that recorded when males are housed directly above inseminated females separated by a wire-mesh grid. These data suggest that production of pregnancy-disrupting male pheromones is stimulated by contact with conspecifics.

Animals↗

PubMed1999

Opioid peptides and behavioral and physiological responses of dairy cows to social isolation in unfamiliar surroundings.

To test whether endogenous opioid peptides are involved in the behavioral and physiological responses of cattle to stress, 12 Holstein cows were either placed in social isolation in unfamiliar surroundings for 15 min or remained in their home stalls, either with or without naloxone treatment, following a Latin square design. Vocalizations (judged as high or low frequency), defecation/urination, and heart rate were recorded, latency to respond to local thermal stimulation of the leg by means of a laser was measured to detect pain sensitivity, and blood was sampled and assayed for cortisol concentrations. Naloxone in the home stall increased cortisol concentrations and tended to reduce response latencies to the laser but did not induce vocalization. Social isolation increased the incidence of high-frequency vocalization and of defecation/urination, heart rate, cortisol concentrations, and response latencies to the laser. Prior administration of naloxone increased the incidence of low-frequency vocalization in isolation, but it had no effect on heart rate or on responses to the laser and only limited effect on cortisol concentrations when the cows were isolated. Brief periods of social isolation in unfamiliar surroundings seem to be stressful to cows, as indicated by increased heart rate, hypothalamic-pituitary-adrenocortical axis activity, and vocalization. Isolation also reduces pain sensitivity, suggesting a stress-induced analgesia. However, we found no evidence that naloxone-sensitive opioid receptors were involved in these responses.

Animals↗

PubMed1998

Presence of cues from stressed conspecifics increases reactivity to aversive events in cattle: evidence for the existence of alarm substances in urine.

In gregarious species like cattle, the presence of partners often affects fear-related reactions. The first experiment investigated whether behavioral and physiological responses to stress depend on the emotional state of the partner. Aubrac heifers were presented with food in a novel environment. Compared to heifers in the presence of a companion that had been previously habituated to the environment without receiving shocks, those in the presence of a companion animal that had previously received electric shocks in that environment had a stronger increase of cortisol response (11.2+/-1.1 vs. 7.4+/-0.9 ng/mL), showed a significantly longer latency to feed (60.1+/-12.3 vs. 17.8+/-5.9 s), and fed more slowly (54.5+/-11.4 vs. 110+/-7.3 s). After repeated exposure to the test conditions, when heifers of both treatments fed rapidly after entrance, response to an unexpected air blast from the feeding bucket was measured. Heifers in the presence of a stressed companion showed an increased latency to feed again compared to those with a nonstressed companion (44.5+/-5.1 vs. 22.8+/-4.3 s). Stressed companions urinated during tests; therefore the second experiment investigated whether heifers respond differently to urine collected from stressed and nonstressed conspecifics. In a first test, heifers were presented with food on a grid in a bucket in a novel environment. They had a longer latency to feed when the bucket contained urine from stressed rather than from nonstressed conspecifics underneath the grid (128.1+/-9.6 vs. 108.2+/-4.9 s). In a second test, heifers were presented with a novel object in a familiar environment. Heifers showed a longer latency to explore the object when it had been sprayed with urine from stressed compared to urine from nonstressed conspecifics (215.2+/-45.0 vs. 25.8+/-8.6 s). The results show that heifers perceive the state of increased stress of conspecifics and become more fearful as a result. They further show that this perception is at least partly mediated by olfactory cues in the urine.

Animals↗

PubMed1997

Behavioral, cardiac and cortisol responses to brief peer separation and reunion in cattle.

Behavioral, cardiac, and adrenal responses of heifers to short-term isolation and to subsequent reunion with familiar or nonfamiliar conspecifics were measured. Two groups of heifers were studied according to their different social reactivity: Aubrac heifers (n = 12) reared under suckler conditions and Friesian heifers (n = 12) reared under dairy management. Because these two groups could also react differently to human beings, testing social isolation was realized by removing pen mates without handling the subject. Moreover, heifers were tested in confinement to avoid an alteration of the cardiac response to isolation by an excessive motor activity. Although physical restraint can influence the reactions, this effect is assumed to be weak because heifers had been exposed to the experimental procedures, including confinement for 3 days before isolation test, in addition to brief periods of physical restraint occurring regularly according to rearing practices. Results show that social separation induced struggling and large increases in vocalization, heart rate, and plasma cortisol concentrations in all heifers. Except for vocalization, these effects were more severe in Aubrac than in Friesian heifers. For all heifers, isolation-induced distress was positively correlated with the duration of social contacts they engaged with the pen mates prior to separation. Behavioral responses, i.e., struggling and vocalization, decreased when conspecifics were brought back, independently of their familiarity to the subject. In contrast, the heart rate decline induced by the entrance of conspecifics was more pronounced in response to reintroduction of pen mates. These findings indicate that social isolation is a severe psychological stress in cattle and that the mere sight of conspecifics reduces behavioral distress regardless of peer identity. The isolation-induced distress depends on the genetic and rearing backgrounds of the heifers without allowing to differentiate their respective effects.

Animals↗

PubMed1995

Fear and fearfulness in animals.

Persistence of individual differences in animal behavior in reactions to various environmental challenges could reflect basic divergences in temperament, which might be used to predict details of adaptive response. Although studies have been carried out on fear and anxiety in various species, including laboratory, domestic and wild animals, no consistent definition of fearfulness as a basic trait of temperament has emerged. After a classification of the events that may produce a state of fear, this article describes the great variability in behavior and in physiological patterns generally associated with emotional reactivity. The difficulties of proposing fearfulness--the general capacity to react to a variety of potentially threatening situations--as a valid basic internal variable are then discussed. Although there are many studies showing covariation among the psychobiological responses to different environmental challenges, other studies find no such correlations and raise doubts about the interpretation of fearfulness as a basic personality trait. After a critical assessment of methodologies used in fear and anxiety studies, it is suggested that discrepancies among results are mainly due to the modulation of emotional responses in animals, which depend on numerous genetic and epigenetic factors. It is difficult to compare results obtained by different methods from animals reared under various conditions and with different genetic origins. The concept of fearfulness as an inner trait is best supported by two kinds of investigations. First, an experimental approach combining ethology and experimental psychology produces undeniable indicators of emotional reactivity. Second, genetic lines selected for psychobiological traits prove useful in establishing relationships between behavioral and neuroendocrine aspects of emotional reactivity. It is suggested that fearfulness could be considered a basic feature of the temperament of each individual, one that predisposes it to respond similarly to a variety of potentially alarming challenges, but is nevertheless continually modulated during development by the interaction of genetic traits of reactivity with environmental factors, particularly in the juvenile period. Such interaction may explain much of the interindividual variability observed in adaptive responses.

Animals↗

PubMed1994

Effects of androgen treatment on behavioral and physiological responses of heifers to fear-eliciting situations.

Sex steroids are known to influence dominance relationships in cattle. This effect seems due to a reduction of fear in response to conspecifics. In order to determine if gonadal steroid can also modulate fear reactions in nonsocial situations, testosterone-treated heifers were exposed to various events reported to elicit fear in cattle. The experimental subjects received daily im injections of testosterone propionate (0.60 mg/kg body wt) for 100 days while controls received the same volume of the vehicle. In a first experiment, the influence of testosterone treatment on behavioral reactions of animals was studied. Treated heifers were much less fearful than controls: they were less reactive to an unfamiliar environment or to a novel object, and they were also less disturbed by a surprising event. In a second experiment, the effects of androgen treatment on cardiac and adrenal responses were evaluated in another group of subjects placed in the same situations. Whereas heart rates after the fear-eliciting events never differed between groups, the increase in cortisol levels was always lower in treated heifers than that in controls in response to human approach, to a surprising event, and to fear conditioning. Furthermore, after stimulation of the adrenal cortex by ACTH administration, the increase in cortisol levels was twice as great in controls than in treated heifers. Thus, prolonged androgen treatment reduces fearfulness in cattle, at least in some situations. Possible mechanisms by which testosterone influences fear-related behaviors are proposed.

Adrenal Cortex↗