Bjarne O. Braastad

Effects of prenatal stress on behaviour of offspring of laboratory and farmed mammals

Abstract This article is a review of research on effects of stress experienced by pregnant females on the sex-ratio, behaviour and reproductive success of their offspring. Implications of such effects for the behaviour and welfare of farm, zoo, and pet animals are discussed. Evidence mainly from studies of rodents and primates strongly indicates that prenatal stress can impair stress-coping ability, and is able to cause a disruption of behaviour in aversive or conflict-inducing situations in juvenile and adult offspring. In non-challenging situations, however, behavioural effects of prenatal stress are frequently not seen. Prenatally stressed animals are reported to show retarded motor development, reduced exploratory and play behaviour, and impairments of learning ability, social behaviour, and sexual and maternal behaviour. Prenatal stress may affect the sex-ratio at birth, and the reproductive success of these offspring in the first, and sometimes also in the second, generation. Individual variation in the susceptibility to prenatal stress may exist. Behavioural inhibition and anxiety when exposed to novelty are typical results which may underlie the effects of prenatal stress on learning and various behavioural responses. This seems to be related to increased or prolonged activity in the hypothalamic–pituitary–adrenal (HPA) axis produced by impaired negative feedback of glucocorticoids in the hippocampus, although other neuroendocrine pathways may be involved. Effects of prenatal stress may reflect evolutionarily adaptive mechanisms, favouring production of the sex which may serve as a helper-at-the-nest (usually females) and producing an increased HPA-axis dominance in these offspring which would favour defensive behavioural reactions in competitive or stressful situations. Since behavioural and neuroendocrine effects of prenatal stress in rodents are quite similar to those found in depressed humans, and since increased fearfulness and frustration is implicated, farm animals subjected to prenatal stress may be predicted to show a reduced ability to cope with a difficult environment and also have increased propensity for developing behavioural disturbances and reduced welfare. Recent results on farmed foxes, and indications in other farm species, show that prenatal stress may affect the behavioural development of farm animals. As knowledge in this area is scarce, more research is warranted. Effects of qualitative and quantitative aspects of handling, social relations and its disruption, and environmental conditions prior to mating and during gestation could be investigated. Effects should be sought on sexual maturation, sexual behaviour, maternal behaviour, fearfulness, behavioural responses to stress and novel stimuli, and behavioural effects of frustration. The interrelation between effects on offspring of necessary stressful treatment of pregnant mothers and effects of habituation to such treatment could also be studied.

Animal-assisted therapy with farm animals for persons with psychiatric disorders: effects on self-efficacy, coping ability and quality of life, a randomized controlled trial.

BackgroundThe benefits of Animal-Assisted Therapy (AAT) for humans with mental disorders have been well-documented using cats and dogs, but there is a complete lack of controlled studies using farm animals as therapeutic agents for psychiatric patients. The study was developed in the context of Green care, a concept that involves the use of farm animals, plants, gardens, or the landscape in recreational or work-related interventions for different target groups of clients in cooperation with health authorities. The present study aimed at examining effects of a 12-week intervention with farm animals on self-efficacy, coping ability and quality of life among adult psychiatric patients with a variety of psychiatric diagnoses.MethodsThe study was a randomized controlled trial and follow-up. Ninety patients (59 women and 31 men) with schizophrenia, affective disorders, anxiety, and personality disorders completed questionnaires to assess self-efficacy (Generalized Self-Efficacy Scale; GSE), coping ability (Coping Strategies Scale), and quality of life (Quality of Life Scale; QOLS-N) before, at the end of intervention, and at six months follow-up. Two-thirds of the patients (N = 60) were given interventions; the remaining served as controls.ResultsThere was significant increase in self-efficacy in the treatment group but not in the control group from before intervention (SB) to six months follow-up (SSMA), (SSMA-SB; F1,55 = 4.20, p= 0.05) and from end of intervention (SA) to follow-up (SSMA-SA; F1,55 = 5.6, p= 0.02). There was significant increase in coping ability within the treatment group between before intervention and follow-up (SSMA-SB = 2.7, t = 2.31, p = 0.03), whereas no changes in quality of life was found. There were no significant changes in any of the variables during the intervention.ConclusionAAT with farm animals may have positive influences on self-efficacy and coping ability among psychiatric patients with long lasting psychiatric symptoms.

Melanin-based skin spots reflect stress responsiveness in salmonid fish

Within animal populations, genetic, epigenetic and environmental factors interact to shape individual neuroendocrine and behavioural profiles, conferring variable vulnerability to stress and disease. It remains debated how alternative behavioural syndromes and stress coping styles evolve and are maintained by natural selection. Here we show that individual variation in stress responsiveness is reflected in the visual appearance of two species of teleost fish; rainbow trout (Oncorhynchus mykiss) and Atlantic salmon (Salmo salar). Salmon and trout skin vary from nearly immaculate to densely spotted, with black spots formed by eumelanin-producing chromatophores. In rainbow trout, selection for divergent hypothalamus-pituitary-interrenal responsiveness has led to a change in dermal pigmentation patterns, with low cortisol-responsive fish being consistently more spotted. In an aquaculture population of Atlantic salmon individuals with more spots showed a reduced physiological and behavioural response to stress. Taken together, these data demonstrate a heritable behavioural-physiological and morphological trait correlation that may be specific to alternative coping styles. This observation may illuminate the evolution of contrasting coping styles and behavioural syndromes, as occurrence of phenotypes in different environments and their response to selective pressures can be precisely and easily recorded.

Behavioural differences between laying hen populations selected for high and low efficiency of food utilisation

1. The effects on behaviour of selecting light-hybrid laying hens for high and low efficiency of food utilisation were investigated. Efficiency of food utilisation was measured as the proportional deviation of observed food consumption from expected food consumption. 2. Videograms of the day-time behaviour of 48 to 53-week-old individually caged hens from the F3 generation were analysed by instantaneous sampling. 3. Low-efficiency hens spent more time food-pecking, walking, pacing, and showing escape and aggressive behaviour than did high-efficiency hens. High-efficiency hens spent more than twice as much time resting and sleeping, and were never observed pacing prior to laying. 4. These differences were larger during the 2 h before laying than at other times of day. 5. Low-efficiency hens had poorer plumage, especially on the neck and the breast, and the poorer the plumage the more agitation they showed. 6. Time spent food-pecking was negatively correlated with laying frequency. 7. Differences in the occurrence of specific behaviour patterns, particularly those symptomatic of pre-laying frustration, partly explained differences in efficiency of food utilisation. Selection for higher efficiency of food utilisation might eliminate hens which are most frustrated prior to laying in cages.

Variation in behavioural responses of ewes towards predator-related stimuli

Thirty-two groups of six sheep, classified into three breed categories according to their weight class (L: light, one breed (n=7); M: medium light, two breeds (n=10); H: heavy, three breeds (n=15)) were tested for antipredatory behaviour towards seven stimulus regimes. Tests were performed on 2-5-years-old ewes with lambs inside standardised and fenced home pastures. Stimulus regimes were: man in rain poncho, trolley, ball on trolley (blind stimuli), stuffed wolverine on trolley, stuffed lynx on trolley, stuffed bear on trolley, and man in rain poncho with a dog on leash (carnivore stimuli). The L breed showed the longest recovery time, the longest flight distance and the tightest flocking behaviour. Significant regressions indicate that there were negative linear relationships between sheep weight and recovery time and between sheep weight and flight distance. Carnivore stimuli caused longer recovery times (P<0.001) and longer flight distances (P<0.001) than the blind stimuli. Our results confirm the hypothesis that lighter sheep breeds display stronger antipredatory reactions than heavier breeds.

Effects of handling during temporary isolation after early weaning on goat kids' later response to humans

Abstract The effects of brief isolation from peers and handling at two early ages on the relationship between humans and goat kids were investigated. Norwegian dairy kids were weaned at 1 week, penned together, fed from a multinippled bucket, and allocated into three groups: H0 animals (n = 8) received no additional contact; H1 animals (n = 9) were isolated and individually handled for 5 min twice a day for 10 days after weaning; H6 animals (n = 9) were handled similarly at 6 weeks of age. Kids were tested at 5 months and 7.5 months with two tests which were conducted twice on each goat. The ‘encounter test’ included social isolation (1 min), presence of a seated familiar person (1.5 min), and presence of a standing familiar person trying to touch the kid (1.5 min). The ‘choice test’ included social isolation behind solid walls (1 min), behind fenced walls (30 s) and a choice between tied familiar peers or a familiar seated human. Handled kids moved less (P

Farm Animal-Assisted Intervention: Relationship between Work and Contact with Farm Animals and Change in Depression, Anxiety, and Self-Efficacy Among Persons with Clinical Depression

Fourteen adults with clinical depression participated twice a week in a 12-week farm animal-assisted intervention consisting of work and contact with dairy cattle. Each participant was video-recorded twice during the intervention, and the recordings were categorized with respect to various work tasks and animal and human contact. Levels of anxiety and depression decreased and self-efficacy increased during the intervention. Interaction with farm animals via work tasks showed a greater potential for improved mental health than via sole animal contact, but only when progress in working skills was achieved, indicating the role of coping experiences for a successful intervention.

Effects of prenatal handling stress on adrenal weight and function and behaviour in novel / situations in blue fox cubs Alopex lagopus

Abstract Prenatal stress is known to affect the morphology, physiology, and behaviour of rodent offspring. This study investigated the effects of a 1-min daily handling stress given to farmed blue fox females in the last third of gestation on adrenal weight and function in male and female offspring and on behaviour in novel situations. In 10-day-old cubs ( n =68), records were made of serum adrenocorticotropic hormone (ACTH), progesterone and cortisol, adrenal content of progesterone and cortisol, and in vitro production of progesterone and cortisol in adrenals, with or without synthetic ACTH in the incubate. At 35 days, three behavioural tests were made in succession ( n =72). In a Human test, the cub was held up by hand in a standardized way for 20 s. An Open-field test was followed by a Box test, where the cub placed in a small box and was allowed 30 s to enter the open field. The adrenals of prenatally stressed (PS) cubs weighed only 60% of those in the control group (C), while body weight was equal in PS and C cubs. The serum level of progesterone and the in vitro adrenal production of progesterone were higher in PS than C cubs. In PS females, the in vitro adrenal production of cortisol was higher than in C females. No significant effect of ACTH stimulation was found. In general, the effects on progesterone parallelled the effects on cortisol. These results indicate that prenatal stress may enhance the postnatal adrenocortical function. PS cubs remained more active during the human test, crossed more lines and entered more squares in the open field, and more frequently entered the open field in the box test. These results may indicate a higher behavioural reactivity in novel situations in prenatally stressed cubs. Whether the increased adrenocortical function and behavioural reactivity is related to reduced welfare remains to be determined. Further studies on the effects of prenatal stress in farm animals are recommended.

Pigments, Parasites and Personalitiy: Towards a Unifying Role for Steroid Hormones?

A surging interest in the evolution of consistent trait correlations has inspired research on pigment patterns as a correlate of behavioural syndromes, or “animal personalities”. Associations between pigmentation, physiology and health status are less investigated as potentially conserved trait clusters. In the current study, lice counts performed on farmed Atlantic salmon Salmo salar naturally infected with ectoparasitic sea lice Lepeophtheirus salmonis showed that individual fish with high incidence of black melanin-based skin spots harboured fewer female sea lice carrying egg sacs, compared to less pigmented fish. There was no significant association between pigmentation and lice at other developmental stages, suggesting that host factors associated with melanin-based pigmentation may modify ectoparasite development to a larger degree than settlement. In a subsequent laboratory experiment a strong negative correlation between skin spots and post-stress cortisol levels was revealed, with less pigmented individuals showing a more pronounced cortisol response to acute stress. The observation that lice prevalence was strongly increased on a fraction of sexually mature male salmon which occurred among the farmed fish further supports a role for steroid hormones as mediators of reduced parasite resistance. The data presented here propose steroid hormones as a proximate cause for the association between melanin-based pigmentation and parasites. Possible fundamental and applied implications are discussed.

Equine-assisted activities and the impact on perceived social support, self-esteem and self-efficacy among adolescents – an intervention study

In this project, we examined the effect of a 4-month intervention with horses on perceived social support, self-esteem and general self-efficacy among Norwegian adolescents aged 12–15 years. The intervention took place at farm-based stables and included work with the horses and riding. A waiting-list crossover design was used and the participants answered questionnaires at three time periods. Study I (N = 49) examined the effect of the intervention compared with the control group. Study II (N = 41) examined the relationship between the same psychological variables and change in mastering skills with horse. The intervention group reported a significant increase in perceived social support compared with the control group. There were no differences in self-esteem and general self-efficacy between the groups. The results from study II showed that a lower level of perceived social support prior to the intervention predicted an increase in mastering skills with the horse during the intervention.