Evaluating the accuracy of facial expressions as emotion indicators across contexts in dogs.

Facial expressions potentially serve as indicators of animal emotions if they are consistently present across situations that (likely) elicit the same emotional state. In a previous study, we used the Dog Facial Action Coding System (DogFACS) to identify facial expressions in dogs associated with conditions presumably eliciting positive anticipation (expectation of a food reward) and frustration (prevention of access to the food). Our first aim here was to identify facial expressions of positive anticipation and frustration in dogs that are context-independent (and thus have potential as emotion indicators) and to distinguish them from expressions that are reward-specific (and thus might relate to a motivational state associated with the expected reward). Therefore, we tested a new sample of 28 dogs with a similar set-up designed to induce positive anticipation (positive condition) and frustration (negative condition) in two reward contexts: food and toys. The previous results were replicated: Ears adductor was associated with the positive condition and Ears flattener, Blink, Lips part, Jaw drop, and Nose lick with the negative condition. Four additional facial actions were also more common in the negative condition. All actions except the Upper lip raiser were independent of reward type. Our second aim was to assess basic measures of diagnostic accuracy for the potential emotion indicators. Ears flattener and Ears downward had relatively high sensitivity but low specificity, whereas the opposite was the case for the other negative correlates. Ears adductor had excellent specificity but low sensitivity. If the identified facial expressions were to be used individually as diagnostic indicators, none would allow consistent correct classifications of the associated emotion. Diagnostic accuracy measures are an essential feature for validity assessments of potential indicators of animal emotion.

Genetic selection to increase bone strength affects prevalence of keel bone damage and egg parameters in commercially housed laying hens.

The prevalence of keel bone damage as well as external egg parameters of 2 pure lines divergently selected for high (H) and low (L) bone strength were investigated in 2 aviary systems under commercial conditions. A standard LSL hybrid was used as a reference group. Birds were kept mixed per genetic line (77 hens of the H and L line and 201 or 206 hens of the LSL line, respectively, per pen) in 8 pens of 2 aviary systems differing in design. Keel bone status and body mass of 20 focal hens per line and pen were assessed at 17, 18, 23, 30, 36, 43, 52, and 63 wk of age. External egg parameters (i.e., egg mass, eggshell breaking strength, thickness, and mass) were measured using 10 eggs per line at both 38 and 57 wk of age. Body parameters (i.e. tarsus and third primary wing feather length to calculate index of wing loading) were recorded at 38 wk of age and mortality per genetic line throughout the laying cycle. Bone mineral density (BMD) of 15 keel bones per genetic line was measured after slaughter to confirm assignment of the experimental lines. We found a greater BMD in the H compared with the L and LSL lines. Fewer keel bone fractures and deviations, a poorer external egg quality, as well as a lower index of wing loading were found in the H compared with the L line. Mortality was lower and production parameters (e.g., laying performance) were higher in the LSL line compared with the 2 experimental lines. Aviary design affected prevalence of keel bone damage, body mass, and mortality. We conclude that selection of specific bone traits associated with bone strength as well as the related differences in body morphology (i.e., lower index of wing loading) have potential to reduce keel bone damage in commercial settings. Also, the housing environment (i.e., aviary design) may have additive effects.

The impact of environmental enrichment on the outcome variability and scientific validity of laboratory animal studies.

It has been widely accepted for some time that species-appropriate environmental enrichment is important for the welfare of research animals, but its impact on research data initially received little attention. This has now changed, as the use of enrichment as one element of routine husbandry has expanded. In addition to its use in the care of larger research animals, such as nonhuman primates, it is now being used to improve the environments of small research animals, such as rodents, which are used in significantly greater numbers and in a wide variety of studies. Concern has been expressed that enrichment negatively affects both experimental validity and reproducibility. However, when a concise definition of enrichment is used, with a sound understanding of the biology and behaviour of the animal as well as the research constraints, it becomes clear that the welfare of research animals can be enhanced through environmental enrichment without compromising their purpose. Indeed, it is shown that the converse is true: the provision of suitable enrichment enhances the well-being of the animal, thereby refining the animal model and improving the research data. Thus, the argument is made that both the validity and reproducibility of the research are enhanced when proper consideration is given to the research animal's living environment and the animal's opportunities to express species-typical behaviours.

Influence of strain and parity on the risk of litter loss in laboratory mice.

Pup mortality is a considerable problem in laboratory mouse breeding and the view that parity influence survival of newborn mice is widespread. Some evidence suggests that maternal behaviour is related to offspring mortality in mice. Parental experience is a factor that can improve maternal behaviour and offspring survival in some mammals. However, few papers report a relationship between parity and pup survival in mice. We investigated the influence of strain and parity on loss of entire litters of C57BL/6 and BALB/c mice using data from a breeding colony. In total, 344 C57BL/6 and 146 BALB/c litters were included. We found a considerable mortality rate for both strains: 32% of C57BL/6 litters and 20% for BALB/c litters were lost. There was a significant difference in survival of the first litter between strains, with 3.6 times higher odds of mortality in C57BL/6 mice (p = 0.0028). Parity or previous parental experience of litter loss did, however, not affect litter loss. The scientific literature does not provide a clear picture of perinatal mortality in laboratory mice. Very few studies report perinatal mortality, and only a handful of papers exist where mortality was systematically studied; this area is thus poorly understood. If perinatal mortality in mice is not recognized and investigated, but instead considered normal when breeding mice, a serious welfare problem might be overlooked.

Feather-pecking response of laying hens to feather and cellulose-based rations fed during rearing.

Recent studies in laying hens have shown that feather peckers eat more feathers than nonpeckers. We hypothesized that food pellets containing feathers would decrease the birds' appetite for feathers and thereby also decrease feather pecking. To separate the effect of feathers from that of insoluble fiber per se, additional control groups were fed pellets containing similar amounts of cellulose. Sixty (experiment 1) and 180 (experiment 2) 1-d-old Lohmann-Selected Leghorn birds were divided into 12 groups of 5 (experiment 1) and 15 (experiment 2) birds, respectively, and kept on slatted floors. During the rearing period, 4 groups each had ad libitum access to either a commercial pelleted diet, a pelleted diet containing 5% (experiment 1) or 10% (experiment 2) of chopped feathers, respectively, or a pelleted diet containing 5% (experiment 1) or 10% (experiment 2) of cellulose, respectively. In the consecutive laying period, all groups received a commercial pelleted diet. In experiment 1, feather pecking was recorded weekly from wk 5 to wk 16. In the laying period, observations were made in wk 18, 20, 22, 23, 24, 25, 26, 27, 28, and 30. In experiment 2, feather pecking was recorded weekly from wk 5 to 11, in wk 16 to wk 18, and in wk 20 and 21. At the end of the rearing period, plumage condition per individual hen was scored. Scores from 1 (denuded) to 4 (intact) were given for each of 6 body parts. The addition of 10% of feathers to the diet reduced the number of severe feather-pecking bouts (P < 0.0129) and improved plumage condition of the back area (P < 0.001) significantly compared with control diets. The relationship between feather pecking/eating and the gastrointestinal consequences thereof, which alter feather pecking-behavior, are unclear. Understanding this relationship might be crucial for understanding the causation of feather pecking in laying hens.

Perch use by broiler breeders and its implication on health and production.

Broiler breeders are commonly kept without perches, although perching has been shown to be a high-priority behavior in laying hens. We studied whether broiler breeders used elevated perches of different lengths during the night and how access to perches affected health and production. Using the Ross 308 hybrid, pens offering 4 different perch spaces per bird (5, 10, 14, and 20 cm) in a cross-over design were compared with pens without perches. The number of birds on perches at midnight were recorded 7 times during production. Prevalence of keel bone fractures, breast blisters, pododermatitis, and plumage quality of hens was assessed at 45 wk, and production was monitored daily. To determine subsequent effects on offspring, chicks from hens with and without perches were reared and their growth rate was assessed. Analysis found more broiler breeders perched at night when 14 cm perch length per bird was provided than with less available perch length (P = 0.0005), but there was no difference between 14 and 20 cm per bird. Perch use declined with age from about 50 to 20% (P < 0.0001). The number of eggs and hatchability were not affected by treatment. During a period of high temperatures, mortality was lower in pens with perches (P = 0.001). Keel bone fractures were present in 1/4 of hens and were not affected by the presence of perches. The growth of chicks was not affected by the parent treatment. In conclusion, our results suggest that perches were chosen for roosting by broiler breeders depending on their age and did not impair production.

Ideal homes? Housing effects on rodent brain and behaviour.

Rodents used in biomedical research are typically reared in small cages that lack key features of their natural habitats. These conditions impose constraints on behaviour and brain development, resulting in altered brain functions. In this article, evidence for three different ways in which barren housing conditions interfere with brain development and behaviour is reviewed. Early environmental deprivation, thwarting of behavioral response rules, and disruption of habitat-dependent adaptation processes are shown to result in aberrant or maladaptive brain functions. Current standard housing conditions could therefore compromise the utility of rodents for research, especially in behavioural neuroscience. However, a better understanding of the animals' needs and of the environmental factors involved in the control of behaviour could offer a biological basis for refinement.

Behavioral phenotyping enhanced--beyond (environmental) standardization.

It is basic biology that the phenotype of an animal is the product of a complex and dynamic interplay between nature (genotype) and nurture (environment). It is far less clear, however, how this might translate into experimental design and the interpretation of animal experiments. Animal experiments are a compromise between modelling real world phenomena with maximal validity (complexity) and designing practicable research projects (abstraction). Textbooks on laboratory animal science generally favour abstraction over complexity. Depending on the area of research, however, abstraction can seriously compromise information gain, with respect to the real world phenomena an experiment is designed to model. Behavioral phenotyping of mouse mutants often deals with particularly complex manifestations of life, such as learning, memory or anxiety, that are strongly modulated by environmental factors. A growing body of evidence indicates that current approaches to behavioral phenotyping might often produce results that are idiosyncratic to the study in which they were obtained, because the interactive nature of genotype-environment relationships underlying behavioral phenotypes was not taken into account. This paper argues that systematic variation of genetic and environmental backgrounds, instead of excessive standardization, is needed to control the robustness of the results and to detect biologically relevant interactions between the mutation and the genetic and environmental background of the animals.

Early social deprivation disrupts attentional, but not affective, shifts in rats.

This study examined the effects of early social deprivation in rats on 2 dissociable forms of inhibitory control of behavior that operate at 2 different levels of response selection: reversing the assignment of stimulus-reward associations within perceptual dimensions (affective shifts) and switching selective attention from 1 perceptual dimension to another (attentional shifts). Isolated subjects (isolates) and social controls (socials) were individually trained to spatial and nonspatial visual discrimination criteria on a radial arm maze. Whereas isolates and socials differed in neither acquisition nor reversal of both versions of the task, isolates were selectively impaired in shifting from spatial to nonspatial discrimination and vice versa. These findings demonstrate that isolation rearing selectively disrupts inhibitory control in attentional selection but leaves inhibitory control in affective processing intact.

Enrichment-dependent differences in novelty exploration in rats can be explained by habituation.

In rats, exploratory activity and emotional reactivity towards novel stimuli reflect independent biological functions that are modulated differently by rearing experiences. Environmental enrichment is known to improve performance in exploratory tasks, while having inconsistent effects on emotionality. This study examined the effect of environmental enrichment on the behaviour of rats in two exploratory tasks. Male rats were reared under one of four conditions, differing in social and non-social complexity. At 9 weeks of age, exploration of a novel open field, and exploration of novel objects in the same open field following 24 h habituation, was assessed. Differences in social and non-social complexity of the rearing environment had inconsistent effects on exploration in the novel open field. In contrast, when rats were faced with novel objects in an otherwise familiar environment, exploration habituated faster with increasing stimulus complexity of the non-social environment. The social environment had no effect on this latter test. These findings indicate that environmental enrichment affects exploratory activity primarily through its effect on habituation to novelty. This effect depends on relative stimulus complexity of the rearing environment, but is independent of social factors. The present results further suggest that aversive tasks can obscure the expression of enrichment-dependent differences in habituation to novelty.

Prevention of stereotypy in laboratory mice: effects on stress physiology and behaviour.

According to the coping hypothesis, the adaptive significance of stereotypies in barren housing conditions may lie in their potency to attenuate the deleterious consequences of chronic stress. Present evidence from experimental studies is ambiguous. When Zur:ICR mice were selectively prevented from stereotypic wire gnawing at the cage lid, the previous amount of stereotyped behaviour after a short-term decrease in activity was compensated by variable active behaviour on the cage floor. This change in behaviour was associated with a short-term elevation of serum corticosterone concentrations 24 h after stereotypy prevention. However, 3 days later corticosterone levels were back at pretreatment base levels. Both behavioural and physiological short-term effects were caused by the impact of prevention on behavioural organization. They disappeared as soon as new habits were established, even though they were not stereotyped. In contrast to the predictions of the coping hypothesis, prevention of stereotypy had no significant effects on chronic measures of both the sympathetic-adrenal-medullary system and the hypothalamus-pituitary-adrenal system. Thus, there is no evidence that stereotypic wire gnawing reduces chronic stress in Zur:ICR mice. This implies that coping with stress is not a general aspect of cage-induced stereotypic behaviour.

Repeated blood collection in the laboratory mouse by tail incision--modification of an old technique.

Twenty years ago, tail incision for collecting serial blood samples from mice was introduced as a new technique. Despite a number of advantages over established methods, it has not become a frequently used technique. This report describes modifications of blood collection from mice by tail incision that allow obtaining rapid (1-1.5 min) serial blood samples (40-150 microliters) from unanaesthetized laboratory mice. Evaluation of corticosterone concentrations in the blood plasma from repeated samples indicated that subsequent samples were unaffected by the procedure. Furthermore, histopathological examination demonstrated that repeated bleeding did not cause any lasting harm to the animals. Blood collection by tail incision may, therefore, be of particular interest for studies that attempt to relate physiological measures to behavioral responses in laboratory mice, and may contribute to the refinement of animal experimentation according to the principles of the Three Rs.

Physical condition at weaning affects exploratory behaviour and stereotypy development in laboratory mice.

Laboratory mice of the ICR strain develop two morphologically distinct forms of stereotypy in the post-weaning period when kept under standard housing conditions. Wire-gnawing develops from single bites at the cage-lid during exploratory climbing whereas jumping originates from exploratory rearing at the cage wall. In a recent study nude mutants of ICR that were physically retarded around the age of stereotypy development performed more rearing but less climbing just after weaning and subsequently developed more jumping but less wire-gnawing than ICR mice (Würbel, H., Stauffacher, M. and von Holst, D. 1996. Ethology 102: 371-385). The two source behaviour patterns, climbing and rearing, could represent alternative strategies serving the same goal (e.g. exploration of external stimuli, escape). Since the ability to climb may depend on physical strength, preference for either of these two patterns may be determined by physical condition to some extent. As a consequence, the prefered pattern may determine the later form of stereotypy. To test these two hypotheses, 48 male ICR mice were assigned to three groups of 16 each. One group was prematurely weaned at day 17 to mimic physical retardation, the others were weaned at the standard weaning age of 20 days and divided into two groups of high and low weaning weight. Premature weaning was associated with a shift in the relative proportions of climbing and rearing towards rearing. Although heavy males showed most climbing and least rearing, weaning weight did not significantly affect performance of these two patterns. Subsequently, all mice developed stereotypic wire-gnawing but none of them showed stereotypic jumping. Although weaning age affected the performance of the two source behaviour patterns in the predicted way, the differences may not have been large enough to cause different forms of stereotypy. However, both, premature weaning and low weaning weight resulted in higher stereotypy performance when adult.

Prevention of stereotypic wire-gnawing in laboratory mice: Effects on behaviour and implications for stereotypy as a coping response.

Three groups of six pairs of adult male laboratory mice of the ICR-strain kept in standard laboratory cages were selectively prevented from stereotypic wire-gnawing for 1, 5 or 10 days, respectively. Behaviour was observed throughout the 12 h dark period one day prior to prevention, on day 1, 4 or 9 (depending on the group) during the period of prevention and on post-inhibitory day 1 and 3. Prior to prevention wire-gnawing was positively correlated (P<0.05) with total activity and climbing. During prevention all three groups showed a significant reduction in total activity (non-stationary; P<0.05) and climbing (P<0.001) and significantly enhanced inactivity (lying motionless; P<0.05). However, the decrease in total activity was positively correlated with base levels of wire-gnawing only on day 1 (P<0.01) but not at later stages of prevention. Similarly, climbing during prevention was positively correlated (P<0.05) with base levels of wire-gnawing on day 1 and 4 but not on day 9 of prevention. These results indicate that the mice only gradually adapted to the new situation. On post-inhibitory day 1 all three groups resumed wire-gnawing at pre-treatment base levels with performance following the same time course throughout the dark period but with significantly reduced peak performance (P<0.05). In the light of motivational theory these results shed doubt on the general validity of the coping hypothesis. Two alternative explanations are discussed.

Local cooling test for clinical capillaroscopy in Raynaud's phenomenon, unstable angina, and vasospastic visual disorders.

A local cooling test produces a typical flow stop reaction in nailfold capillaries in 88% of patients with Raynaud's phenomenon, but only in 15% of healthy controls. A stop reaction occurred in 9 of 12 patients with Prinzmetal variant angina, exceeding significantly that in 2 of 12 matched control subjects. Also in patients with reversible visual disorders presumably due to vasospasm, the test resulted in a stop reaction in 16 of 25 cases exceeding that in control. In both of these patient groups the cooling test as well as the symptoms reacted favorably to nifedipine. Thus, the local cold exposure test appears to be useful for objective clinical examination not only of patients with Raynaud's phenomenon but also of patients with vasospastic syndromes such as variant angina and visual disorders.

Epidemiology and management of group B streptococcal colonization during pregnancy in Africa.

Group B streptococcal infections are a leading cause of neonatal morbidity and mortality. Maternal microbiological screening during pregnancy and intrapartum antimicrobial treatment of maternal group B streptococcus (GBS) colonization constitutes an effective prevention strategy to reduce early neonatal invasive disease due to GBS in the European and North American setting. Data on the prevalence of GBS colonization in pregnancy and incidence of neonatal invasive GBS disease are very limited for low-income regions. However, the first reports from sub-Saharan Africa indicate that GBS colonization rates may be comparable to industrialized countries and that related neonatal morbidity and mortality is of significance. Prior to the development of suitable prevention strategies, which are undoubtedly needed in resource poor settings, more evidence on GBS epidemiology in sub-Saharan Africa and assessment of cost effectiveness of different prevention strategies are essential.

Increased peripheral vasoconstrictor reaction upon local cold in patients with coronary heart disease.

A local cold exposure test of the nailfold capillaries produces a typical flow stop reaction in 88% of patients with Raynaud's phenomenon. We applied this test to 12 patients with variant angina and compared the results with the findings in 2 control groups of 12 patients each, matched for age and sex: One group with chronic stable angina and one without heart disease. We found a flow stop with cold exposure in 9/12 patients with variant angina (mean duration 24 s), in 6/12 patients with chronic angina (mean 11 s), and in 1/12 normal controls without heart disease (mean 1 s). The frequency and duration of the flow stop was significantly higher in patients with variant angina (p = 0.002) and in patients with chronic stable angina (p = 0.02) than in normal controls. Patients with variant angina also tended to have an increased frequency and longer duration of the flow stop than those with chronic stable angina (p = 0.09). Administration of sorbidilate preparations and nifedipine resulted in a decrease of the mean flow stop duration from 23.5 to 10.8 s in patients with variant angina (p = 0.03). The strong association of a vasoconstrictive reaction in finger microcirculation and coronaries in patients with variant angina suggests a vasospastic tendency with manifestation in different vascular regions.

Behavioral profiles of genetically selected aggressive and nonaggressive male wild house mice in two anxiety tests.

Artificially selected aggressive (SAL) and non-aggressive (LAL) male house mice were tested in a hexagonal tunnel maze and light-dark preference (LD) box to determine if the bidirectional selection for aggressive behavior leads to a coselection for different levels of trait anxiety. The tunnel maze consists of an open, brightly lit central arena surrounded by a complex system of interconnecting tunnels. As in the LD box, animals which spend less time and are less active in the brightly illuminated section of the maze are considered to have higher anxiety levels. In the tunnel maze, the LAL mice showed more exploration and spent more time in the central arena than the SAL animals, but only during the final 2 min of the 6-min test. This reduced preference for the central arena was not due to general inactivity or a failure of the SAL to find the central arena and indicates a higher level of state anxiety in the aggressive animals. In contrast, no "anxiety-like" differences were found in the LD box, either for the percentage of time spent in the light compartment or for the number of crossings. SAL males actually showed higher levels of moving and rearing, and lower levels of freezing, than did LAL males.