Early human contact and housing for pigs - part 1: responses to humans, novelty and isolation.

The development of fear and stress responses in animals can be influenced by early life experiences, including interactions with humans, maternal care, and the physical surroundings. This paper is the first of three reporting on a large experiment examining the effects of the early housing environment and early positive human contact on stress resilience in pigs. This first paper reports on the responses of pigs to humans, novelty, and social isolation. Using a 2 × 2 factorial design, 48 litters of pigs were reared in either a conventional farrowing crate (FC) where the sow was confined or a loose farrowing pen (LP; PigSAFE pen) which was larger, more physically complex and allowed the sow to move freely throughout the farrowing and lactation period. Piglets were provided with either routine contact from stockpeople (C), or routine contact plus regular opportunities for positive human contact (+HC) involving 5 min of scratching, patting and stroking imposed to the litter 5 days/week from 0-4 weeks of age. The positive handling treatment was highly effective in reducing piglets' fear of humans, based on +HC piglets showing greater approach and less avoidance of an unfamiliar person at 3 weeks of age. There was evidence that this reduction in fear of humans lasted well beyond when the treatment was applied (lactation), with +HC pigs showing greater approach and less avoidance of humans in tests at 6, 9 and 14 weeks of age. The +HC treatment also reduced piglets' fear of a novel object at 3 weeks of age, and for pigs in FC, the cortisol response after social isolation at 7 weeks of age. Rearing in FC compared to LP reduced piglets' fear of novelty at 3 weeks of age, as well as their vocalisations and cortisol response to isolation at 7 weeks of age. The FC pigs showed greater approach and less avoidance of humans compared to LP pigs at 3, 4 and 6 weeks of age, but not at 9 and 14 weeks of age. These results show that positive handling early in life can reduce pigs' fear of humans, fear of novelty and physiological stress response to social isolation. The LP pigs were reared in a more isolated environment with less overall contact with stockpeople and other pigs, which may have increased their fear responses to humans and novel situations, suggesting that different housing systems can modulate these pigs' responses.

Early human contact and housing for pigs - part 3: ability to cope with the environment.

Early experiences can have long-term impacts on stress adaptability. This paper is the last of three in a series on early experiences and stress in pigs, and reports on the effects of early human contact and housing on the ability of pigs to cope with their general environment. Using a 2 × 2 factorial design, 48 litters of pigs were reared in either a farrowing crate (FC) or a loose farrowing pen (LP; PigSAFE pen) which was larger, more physically complex and allowed the sow to move freely. Piglets were provided with either routine contact from stockpeople (C), or routine contact plus regular opportunities for positive human contact (+HC) involving 5 min of scratching, patting and stroking imposed to the litter 5 days/week from 0 to 4 weeks of age. At 4 weeks of age (preweaning), C piglets that were reared in FC had considerably lower concentrations of serum brain-derived neurotrophic factor (BDNF) than piglets from the other treatment combinations. Compared to C pigs, +HC pigs had fewer injuries at 4 weeks of age. There were no clear effects of human contact on BDNF concentrations or injuries after weaning, or on basal cortisol or immunoglobulin-A concentrations, behavioural time budgets, tear staining, growth, or piglet survival. Compared to FC piglets, LP piglets showed more play behaviour and interactions with the dam and less repetitive nosing towards pen mates during lactation. There was no evidence that early housing affected pigs' behavioural time budgets or physiology after weaning. Tear staining severity was greater in LP piglets at 4 weeks of age, but this may have been associated with the higher growth rates of LP piglets preweaning. There was no effect of lactation housing on growth after weaning. Preweaning piglet mortality was higher in the loose system. The findings on BDNF concentrations, injuries and play behaviour suggest improved welfare during the treatment period in +HC and LP piglets compared to C and FC piglets, respectively. These results together with those from the other papers in this series indicate that positive human interaction early in life promotes stress adaptability in pigs. Furthermore, while the farrowing crate environment deprives piglets of opportunities for play behaviour and sow interaction, there was no evidence that rearing in crates negatively affected pig welfare or stress resilience after weaning. Whether these findings are specific to the two housing systems studied here, or can be generalised to other housing designs, warrants further research.

Early human contact and housing for pigs - part 2: resilience to routine husbandry practices.

The ability of pigs to cope with routine farming practices can affect their welfare. This paper is part of a series on early experiences and stress, and reports on the effects of early human contact and housing on the responses of pigs to routine husbandry practices. Using a 2 × 2 factorial design, 48 litters of pigs were raised in either a conventional farrowing crate (FC) or a loose farrowing pen (LP; PigSAFE pen) which was larger, more physically complex and allowed the sow to move freely. Piglets were provided with either routine contact from stockpeople (C), or routine contact plus regular opportunities for positive human contact (+HC) involving 5 min of scratching, patting and stroking imposed to the litter 5 days/week from 0 to 4 weeks of age. At 4 weeks of age, piglets were weaned and re-housed with controlled mixing of litters within treatment. At 4 days of age, after only 3 bouts of the handling treatment, +HC pigs showed less escape behaviour than C pigs after capture by a stockperson for vaccinations and tail docking, and shorter durations of vocalisations throughout the procedures. The  +HC pigs also showed less escape behaviour when captured by a stockperson at 3 weeks of age. The FC pigs showed less escape behaviour than LP pigs after capture by a stockperson at 4 days of age but not at 3 weeks of age. Serum cortisol concentrations were lower in FC pigs than LP pigs 2 h after weaning but not at 49 h after weaning, whereas serum cortisol concentrations were lower in  +HC pigs than C pigs at 49 h after weaning but not at 2 h after weaning. In the period from 0 to 1 h after weaning, C pigs from LP performed the most escape attempts, although escape attempts were rare overall. When being moved out of the home pen by a stockperson at 21 weeks of age, FC pigs showed less baulking than LP pigs, but there were no detected effects of human contact treatment. In conclusion, both housing system and human contact during lactation affected the stress responses of pigs to routine husbandry practices. The +HC and FC pigs appeared to cope better than C and LP pigs, based on lower responses indicative of stress including escape behaviour, vocalisations and cortisol concentrations. These findings are consistent with corresponding reductions in fear that were reported in Part 1 of this series of papers.

Sexual behaviour, semen quality and fertility of young Border Leicester rams administered melatonin during spring.

This study was conducted to test the hypothesis that between year variability in reproductive response to melatonin treatment of young Border Leicester (BL) rams in spring was related to sexual maturity at the time of treatment. Two variables of sexual maturity (mating behaviour and semen quality) were examined. In Experiment 1, mating activity of melatonin-treated and untreated rams was examined at two sites before a flock mating at one site. In Experiment 2, testosterone concentrations, semen quality and variables of in vitro fertilising capacity were examined. In Experiment 1, melatonin treatment did not alter sexual behaviour (latency to nose, total nosings, courtings including Flehmen expression, attempted mounts, mounts, ejaculations) with the exception of a lesser (P < 0.05) Flehmen expression at Site 1 whereas values for most variables were greater (P < 0.05) at Site 2. Treatment resulted in a greater pregnancy rate (89 % and 82 %, respectively; P < 0.05) and advanced distribution of pregnancies (P < 0.001) at Site 1. Testicular size and testosterone concentrations were also greater (P < 0.05) as a result of melatonin treatment in spring whilst the reverse occurred in autumn. In Experiment 2, sperm motility and in vitro fertilising capacity were greater (P < 0.05) and acrosome damage less (P < 0.05) as a result of melatonin treatment. In conclusion, variability in age at sexual maturity of young BL rams at spring mating can be reduced with melatonin treatment and is associated with differences in sexual behaviour, testicular growth, testosterone concentrations, and sperm quality.

Chronic elevation of plasma cortisol causes differential expression of predominating glucocorticoid in plasma, saliva, fecal, and wool matrices in sheep.

There is increasing interest in using nonblood measures of glucocorticoids to assess the physiological response to chronic stress conditions. In sheep, cortisol has been measured in various matrices including saliva, feces, and wool, but comprehensive studies of the relationship between plasma concentrations of cortisol and concentrations in these nonblood matrices are lacking. Therefore, we tested the hypothesis that administration of cortisol to sheep would result in elevated concentrations of cortisol in blood, saliva, feces, and wool. Merino ewes were administered with saline or 2 mg/kg BW/d hydrocortisone acetate (HCA) by intramuscular (i.m.) injection for 28 d. This treatment was imposed to mimic circulating cortisol concentrations experienced during periods of chronic stress. Cortisol and cortisone were directly measured in plasma, saliva, and wool before, during, and after treatment with saline or HCA. A 14-d pre-treatment and a 14-d post-treatment period were used to measure time taken for glucocorticoid concentrations in each of the matrices to return to baseline levels. Cortisol was also measured in feces before, during, and after treatment. Wool growth was also measured. Before treatment, there was no difference in the concentration of cortisol or cortisone in plasma, saliva, feces, or wool in animals treated with saline or HCA. In contrast, treatment with HCA increased (P < 0.05) concentrations of both cortisol and cortisone in plasma, saliva, and wool and of cortisol in feces. In plasma, cortisol concentrations were higher than cortisone (P < 0.05), whereas saliva cortisol and cortisone concentrations did not differ significantly. In wool, the concentration of cortisone was about 19-fold higher than that of cortisol during treatment and post-treatment periods. Treatment with HCA inhibited wool growth. These results demonstrate that an increase in glucocorticoids in the blood of sheep is reflected in increases in saliva (after 7 d of treatment), feces (21 d), and wool (14 d). Therefore, measures of glucocorticoids in these matrices may provide a measure of activation of the adrenal glands over time in sheep, thereby providing a retrospective indicator of chronic stress. With respect to wool, it appears that cortisol is predominantly metabolized to cortisone in the skin or wool follicle and is stored as cortisone. Therefore wool cortisone may also provide an important measure in quantifiying chronic stress in sheep.

Reduced protein diet and amino acid concentration alter intestinal barrier function and performance of broiler chickens with or without synthetic glucocorticoid.

Little is known about the effect of low-protein (LP) diets on intestinal barrier function and permeability. In the first part of this study, starting on day 9 of age, the growth performance of the birds fed 3 experimental diets in each phase of feeding (G/F: grower/finisher) was investigated. Three experimental diets were as follows: LP (170/150 g/kg CP) fortified with essential amino acids (EAA), standard protein (SP), (202/190 g/kg), and high protein (HP) (220/210 g/kg). LP and SP diets contained a similar level of EAA concentration, while the HP diet contained 10% above the Ross 308 specifications. Each diet was replicated 6 times (10 male birds per replicate). The second part investigated intestinal permeability (IP) and function on additional 72 birds. On days 14, 16, and 20, a total of 36 birds (12 birds per diet) were injected with dexamethasone (DEX) to induce leaky gut. Birds fed LP diets had lower body weight gain (BWG) and higher feed conversion ratio (FCR) compared with SP and HP diets in both grower and finisher phases of feeding. For the challenge part, DEX increased the FCR independent of diets. Diet and DEX interacted for BWG, whereby the effect of diets was only evident in sham-injected birds. Birds fed LP had a higher fluorescein isothiocyanate dextran (FITC-d) concentration indicating a more permeable intestine compared to HP, but similar to SP. DEX increased FITC-d concentration in all dietary treatments. Birds fed LP had less ileal zonula occludens-2 (ZO-2) expression in comparison with SP, but not HP. DEX increased the expression of Claudin3 and ZO-2 and reduced Claudin1 (P < 0.05) and junctional adhesion molecule 2 in the ileum. Expression of ileal Na+-dependent glucose transporter 1 (SGLT1) was upregulated in LP fed group. It is concluded that compared with SP, IP can be maintained in LP by supplementing EAA. However, when compared with HP, feeding birds with LP may lead to a higher IP. DEX had a profound independent effect on intestinal barrier function.

The effects of floor space and nest box access on the physiology and behavior of caged laying hens.

Confinement housing appears to be at the forefront of concern about laying hen welfare. This experiment examined the effects of floor space during rearing (315 or 945 cm2/bird) and adulthood (542 or 1648 cm2/bird) and access to a nest box on the welfare of caged laying hens. Measurements of the normality of biological functioning, such as plasma, egg albumen and yolk and fecal corticosterone concentrations, and heterophil to lymphocyte ratios, behavioral time budgets, mortality and efficiency of productivity, and measurement of hen preferences, such as choice behavior in Y maze tests, were used to assess hen welfare. There were no effects of treatment on physiological measurements. Hens given less space during adulthood spent less time mobile, inedible pecking, drinking, and preening and spent more time resting and feed pecking and sitting (P < 0.05). Hens with access to a nest box spent more time resting (P = 0.046) and less time sham dust bathing (P = 0.044) than hens without access to a nest box. There were no effects of space allowance on choice behavior for space or a nest box over food; however, hens with access to a nest box chose the nest box over food more than hens without access to a nest box (P = 0.0053). The present experiment provides no convincing evidence that either reducing space allowance in adulthood from 1648 to 542 cm2/bird or eliminating access to a nest box results in disruption of biological function. Less space and no access to a nest box did not increase the choice for more space or a nest box, respectively, over food in the preference tests. However, reduced floor space reduced behavioral freedom and denying access to a nest box eliminated the opportunity for the motivated behavior of laying their eggs in a discrete enclosed nest box, both of which presumably provide hens with the opportunity for positive affective experiences.

Response to gonadotrophins differs for gilts from female- and male-biased litters.

In several species, females masculinised by abnormal androgen exposure in utero have poor reproductive performance and gilts born into litters with a male bias are likely exposed to greater androgen concentrations prenatally than gilts born into female-biased litters. At 24h of age, piglet plasma testosterone concentrations in gilts from male-biased litters (>60% male; n=22) or female-biased litters (>60% female; n=27) were not different. At 18 wks of age, all gilts received an injection of 400IU equine chorionic gonadotrophin plus 200IU human chorionic gonadotrophin to stimulate oestrus. Two weeks after the injection gilts were slaughtered and ovaries collected for determination of numbers of corpora lutea (CL). Compared to gilts from female-biased litters, gilts from male-biased litters were more likely to ovulate (86.0% vs 59.5%, P=0.047) and had more CL (13.1±1.5 vs 7.2±1.7, P=0.015). The present data indicate an effect of birth litter sex-bias on pre-pubertal physiological development, possibly involving organisational effects at the ovarian cellular level impacting on future ovarian function. Potential impacts on subsequent fertility remain to be determined.

Effects of varying floor space on aggressive behavior and cortisol concentrations in group-housed sows.

Floor space is an important determinant of aggression and stress in group-housed sows, and the aim of the present experiment was to comprehensively examine the effects of floor space in the range of 1.45 to 2.90 m/sow from mixing until 27 d after insemination on aggression, stress, and reproduction of group-housed sows. A previous experiment on the effects of floor space indicated spatial variability across and along the research facility in both sow aggression and stress. To minimize this spatial variability within the research facility, similar-sized pens but with varying groups sizes (10-20) in 4 separate blocks of 3 contiguous pens within each of 9 time replicates (180 sows/replicate) were used to examine 6 space allowances (1.45-2.9 m/sow). Space treatments were appropriately randomized to pens. Although it may be argued that space allowance is confounded with group size in this design, there was no evidence in our previous experiment of group size effects, for pens of 10 to 80 sows, or appreciable interactions between space and group size on aggression, stress, and reproduction. In the present experiment, sows were introduced to treatments within 4 d of insemination and were floor fed 4 times per day (2.5 kg/sow per d). On both Days 2 and 26 after mixing, aggressive behavior (bites and knocks) at feeding and plasma cortisol concentrations were measured. Restricted maximum likelihood mixed model analyses were used to examine the treatment effect after accounting for replicate and random spatial location effects within replicate. There was a consistent linear effect of floor space allowance on aggression at feeding at Day 2 ( < 0.0001) and plasma cortisol concentrations at Day 2 ( = 0.0003), with aggression and stress declining with increasing space. However, there were no effects of space allowance on aggression and stress at Day 26 ( = 0.14 and = 0.79, respectively). These results show that increased floor space in the immediate post-mixing period reduces aggression and stress and that sows may adapt to reduced floor space over time. A strategy of staged-gestation penning, with more space immediately after mixing and less space later in gestation, may address both animal welfare and economic considerations, but this clearly requires further examination.

Reducing sow confinement during farrowing and in early lactation increases piglet mortality.

The aim of this study was to investigate the effect of sow confinement and nonconfinement during parturition and early lactation on the performance of sows and piglets prior to weaning. Sows and their litters were housed in either a conventional farrowing crate (control; 1.7 × 2.4 m) or a swing-sided pen (2.8 × 2.15 m). Sows housed in the swing-sided pen had the crate open (open) or closed (closed) during farrowing and opened on d 3 (LAC3) or 7 (LAC7) of lactation. Data are means ± SEM. The numbers of total and live-born piglets were not different between treatments and averaged 13.1 ± 0.4 and 12.3 ± 0.2 piglets/litter, respectively. Sows housed in a farrowing crate had a greater ( = 0.03) number of stillborn piglets compared with open sows from pens (1.1 ± 0.2 vs. 0.6 ± 0.1 piglets/litter, respectively). Live-born piglet mortality before litter equalization on d 1 was greater ( < 0.01) for open sows compared with closed and control sows (1.6 ± 0.2 vs. 0.9 ± 0.2 vs. 1.1 ± 0.1 piglets/litter, respectively) and was largely explained by an increase in the incidence of piglets overlain ( < 0.01) in the open compared to closed and control sows (1.3 ± 0.1 vs. 0.5 ± 0.1 vs. 0.8 ± 0.1 piglets/litter, respectively). Overlay mortality between d 3 and 7 of lactation was greater ( = 0.03) in LAC3 sows compared to LAC7 and control sows (0.4 ± 0.1 vs. 0.2 ± 0.1 vs. 0.2 ± 0.1 piglets/litter, respectively). Treatment did not affect either the incidence or cause of piglet mortality after d 7 of lactation ( > 0.05). Total live-born piglet mortality from birth until weaning for the control, closedLAC7, closedLAC3, openLAC7, and openLAC3 was 1.86 ± 0.19, 1.95 ± 0.23, 2.10 ± 0.39, 2.45 ± 0.27, and 3.74 ± 0.48, piglets/litter, respectively. Total live-born piglet mortality from birth until weaning was greater in the openLAC3 and openLAC7 treatments compared to control ( < 0.01), and openLAC3 was also greater than openLAC7, closedLAC3, and closedLAC7 ( < 0.01). The current data indicated that reducing sow confinement during parturition decreased stillborn number but increased live-born piglet mortality compared to a farrowing crate, and removing confinement on d 3 of lactation further increased total piglet mortality compared to removing sow confinement on d 7 of lactation in sows that farrowed open. Sows that were confined during farrowing and until d 3 or 7 of lactation in a swing-sided pen had a similar piglet mortality compared to those in a farrowing crate.

INVITED REVIEW: The usefulness of measuring glucocorticoids for assessing animal welfare.

Glucocorticoids (corticosterone in birds and rodents and cortisol in all other mammals) are glucoregulatory hormones that are synthesized in response to a range of stimuli including stress and are regularly measured in the assessment of animal welfare. Glucocorticoids have many normal or non-stress-related functions, and glucocorticoid synthesis can increase in response to pleasure, excitement, and arousal as well as fear, anxiety, and pain. Often, when assessing animal welfare, little consideration is given to normal non-stress-related glucocorticoid functions or the complex mechanisms that regulate the effects of glucocorticoids on physiology. In addition, it is rarely acknowledged that increased glucocorticoid synthesis can indicate positive welfare states or that a stress response can increase fitness and improve the welfare of an animal. In this paper, we review how and when glucocorticoid synthesis increases, the actions mediated through type I and type II glucocorticoid receptors, the importance of corticosteroid-binding globulin, the role of 11 ß-hydroxysteroid dehydrogenase, and the key aspects of neurophysiology relevant to activating the hypothalamo-pituitary-adrenal axis. This is discussed in the context of animal welfare assessment, particularly under the biological functioning and affective states frameworks. We contend that extending the assessment of animal welfare to key brain regions afferent to the hypothalamus and incorporating the aspects of glucocorticoid physiology that affect change in target tissue will advance animal welfare science and inspire more comprehensive assessment of the welfare of animals.

Impact of psychosocial stress on gonadotrophins and sexual behaviour in females: role for cortisol?

This review focuses on the importance of cortisol in mediating the inhibitory effects of psychosocial stress on reproduction in females. In particular, we have summarized our research in sheep where we have systematically established whether cortisol is both sufficient and necessary to suppress reproductive hormone secretion and inhibit sexual behaviour. Our findings are put into context with previous work and are used to develop important concepts as well as to identify productive further lines of investigation. It is clear that cortisol is necessary to inhibit some, but not all, aspects of reproduction in female sheep. These actions vary with reproductive state, and there are important interactions with gonadal steroids. The impact of cortisol on the tonic secretion of gonadotrophin-releasing hormone and luteinizing hormone has been investigated extensively, but less is known about the surge secretion of these hormones and their effects on sexual behaviour. Furthermore, there are separate effects of cortisol in the brain (hypothalamus) and at the anterior pituitary, illustrating that there are different mechanisms of action. Thus, although cortisol is important in mediating some of the effects of stress on reproduction, we need to look beyond cortisol and investigate some of the other mechanisms and mediators that relay the effects of stress on reproduction. In this regard, we propose that a group of neurons in the hypothalamus that co-synthesize kisspeptin, neurokinin B and dynorphin, termed KNDy cells, play important roles in mediating the effects of cortisol on reproduction. This hypothesis needs to be rigorously tested.

The hypothalamo-pituitary-adrenal (HPA) axis in sheep is attenuated during lactation in response to psychosocial and predator stress.

Activation of the hypothalamo-pituitary-adrenal (HPA) axis by psychosocial stress is attenuated during lactation. We tested the hypothesis that lactating ewes will have attenuated HPA axis responses to isolation and restraint but will have greater responses to predator stress in the form of barking dogs. We imposed two 4 h stressors: psychosocial stress (isolation and restraint of ewes) and predator stress (barking dogs). Blood was collected intravenous every 10 min from nonlactating ewes (n = 6), lactating ewes with lambs present but not able to be suckled (n = 6), and lactating ewes with lambs present and able to be suckled (n = 6). Plasma cortisol and oxytocin were measured. For nonlactating ewes, cortisol increased (P < 0.01) in response to both stressors, and these increases were greater (P < 0.01) than that in the lactating animals. For lactating ewes with lambs present but unable to be suckled, cortisol increased (P < 0.05) in response to both stressors with a greater response to barking dogs (P < 0.05). For lactating ewes with lambs present and able to be suckled, cortisol increased (P < 0.01) in response to barking dogs only. Plasma oxytocin was greater (P < 0.01) in lactating ewes than in nonlactating ewes and did not change in response to the stressors. In conclusion, lactating ewes are likely to have a greater HPA axis response to a stressor that may be perceived to threaten the welfare of themselves and/or their offspring. The role of oxytocin in attenuation of the HPA axis to stress in sheep is unclear from the current research and requires further investigation.

Relationship between plasma and tissue corticosterone in laying hens (Gallus gallus domesticus): implications for stress physiology and animal welfare.

This study directly compared the dynamics of change in plasma corticosterone concentration with the dynamics of change in tissue corticosterone concentration in laying hens. In concert, we measured the rate of gluconeogenesis, glycogenesis, and glycolysis in the liver, kidney, skeletal muscle, and heart. We evaluated these changes acutely, over 3 h in response to an adrenocorticotropic hormone (ACTH) injection, and chronically, over 24 h in response to food and water deprivation. In response to ACTH injection, there was a significant (P < 0.05) increase in plasma corticosterone concentration and a parallel significant increase in corticosterone concentration in the skeletal muscle, kidney, and heart. However, the change in corticosterone concentration in the liver did not parallel the plasma, at times it was greater than the plasma, and there was a second significant increase (P < 0.05) in corticosterone concentration in the liver after 180 min. Under these conditions, the rate of gluconeogenesis in the liver decreased and the rate of glycogenesis increased. In contrast, after 12 h and 24 h of food and water deprivation plasma corticosterone concentration was increased, and this was paralleled by increased corticosterone concentration in the liver, an increase in the rate of gluconeogenesis and a decrease in the rate of glycogenesis. After ACTH injection, glucose concentration in the liver was not significantly depleted but after 12 h or 24 h of food and water deprivation it was significantly depleted (P < 0.05). Plasma corticosterone concentration provided different insight into the effect of the stressor on hen physiology under acute and chronic conditions. Our data suggest that extending our evaluation of stress to the site of corticosterone action, that is, the target tissue, may enhance our ability to evaluate stress and the welfare of laying hens.

Scientific assessment of animal welfare.

Animal welfare is a state within the animal and a scientific perspective provides methodologies for evidence-based assessment of an animal's welfare. A simplistic definition of animal welfare might be how the animal feels now. Affective experiences including emotions, are subjective states so cannot be measured directly in animals, but there are informative indirect physiological and behavioural indices that can be cautiously used to interpret such experiences. This review enunciates several key science-based frameworks for understanding animal welfare. The biological functioning and affective state frameworks were initially seen as competing, but a recent more unified approach is that biological functioning is taken to include affective experiences and affective experiences are recognised as products of biological functioning, and knowledge of the dynamic interactions between the two is considered to be fundamental to managing and improving animal welfare. The value of these two frameworks in understanding the welfare of group-housed sows is reviewed. The majority of studies of the welfare of group-housed sows have employed the biological functioning framework to infer compromised sow welfare, on the basis that suboptimal biological functioning accompanies negative affective states such as sow hunger, pain, fear, helplessness, frustration and anger. Group housing facilitates social living, but group housing of gestating sows raises different welfare considerations to stall housing, such as high levels of aggression, injuries and stress, at least for several days after mixing, as well as subordinate sows being underfed due to competition at feeding. This paper highlights the challenges and potential opportunities for the continued improvement in sow management through well-focused research and multidisciplinary assessment of animal welfare. In future the management of sentient animals will require the promotion of positive affective experiences in animals and this is likely to be a major focus for animal welfare science activity in the early twenty-first century.

Positive effects of melatonin treatment on the reproductive performance of young border leicester rams mated to merino ewes in spring: preliminary observations.

Poor reproductive performance of Merino ewe flocks when mated to Border Leicester rams during spring may be due to seasonality of the Border Leicester breed. Two approaches were taken to test this assumption. Six young (12 months old) or six mixed-age (12, 24 and ≥36 months old) Border Leicester rams were either treated or not treated with melatonin implants (2 × 2 design) 6 weeks before the four groups of rams were each put with approximately 300 Merino ewes for an 8-week mating period. Implants were inserted in early September (experiment 1). The second approach was to yard or not yard ewes and mixed-age rams on several occasions during the first 3 weeks of the mating period (experiment 2). Pregnancy rate and twinning percentage were assessed by ultrasonography. In experiment 1, melatonin treatment in young rams increased (p < 0.001) pregnancy rate from 5.0% to 92.6%, but mixed-age rams did not respond (90.7% vs 89.5% for melatonin and non-melatonin treatments, respectively). Twinning rate was similar (p > 0.05) for ewes mated to either melatonin or non-melatonin-treated young rams (36.8% vs 40.0%, respectively), whereas melatonin significantly improved (p < 0.05) twinning rate in those ewes mated to mixed-age rams (49.1% vs 36.1%). After 6 weeks of melatonin treatment, scrotal circumference was greater (p < 0.05) in both young and mixed-aged rams than in untreated counterparts. In experiment 2, yarding of ewes and rams overnight on several occasions early in the mating period reduced (p < 0.001) pregnancy rate compared with non-yarded counterparts (89.5% vs 65.5%). Twinning rate was not affected (37.7% vs 36.1%, respectively). In summary, melatonin treatment of Border Leicester rams significantly improved flock reproductive performance in spring due to improved pregnancy rates with young rams and improved litter size with mixed-age rams.

Physiological responses to psychological stress: importance of adiposity in men aged 50-70 years.

We tested the hypothesis that overweight/obese men aged 50-70 years will have a greater salivary cortisol, salivary alpha amylase and heart rate (HR) responses to psychological stress compared with age matched lean men. Lean (BMI=20-25 kg/m(2); n=19) and overweight/obese (BMI=27-35 kg/m(2); n=17) men (50-70 years) were subjected to a well-characterised psychological stress (Trier Social Stress Test, TSST) at 1500 h. Concentrations of cortisol and alpha amylase were measured in saliva samples collected every 7-15 min from 1400 to 1700 h. HR was recorded using electrocardiogram. Body weight, BMI, percentage body fat, resting systolic and diastolic blood pressure and mean arterial pressure were significantly higher (P<0.05) in overweight/obese men compared with lean men. Both groups responded to the TSST with a substantial elevation in salivary cortisol (372%), salivary alpha amylase (123%) and HR (22%). These responses did not differ significantly between the groups (time×treatment interaction for salivary cortisol, salivary alpha amylase and HR; P=0.187, P=0.288, P=0.550, respectively). There were no significant differences between the groups for pretreatment values, peak height, difference between pretreatment values and peak height (reactivity) or area under the curve for salivary cortisol, salivary alpha amylase or HR (P>0.05 for all). The results showed that, for men with a moderate level of overweight/obesity who were otherwise healthy, the response of salivary cortisol, salivary alpha amylase and HR to acute psychological stress was not impaired.

Effects of group size and floor space allowance on grouped sows: aggression, stress, skin injuries, and reproductive performance.

A total of 3,120 sows, in 4 time replicates, were used to determine the effects of group size and floor space on sow welfare using behavioral, physiological, health, and fitness variables. Within 1 to 7 d postinsemination, sows were assigned randomly to treatments of a 3 by 6 factorial arrangement, with 3 group sizes (10, 30, or 80 sows/pen) and 6 floor space allowances (1.4, 1.8, 2.0, 2.2, 2.4, or 3.0 m(2)/sow). Sows were housed on partially slatted concrete floors, and overhead feeders delivered 4 times/day to provide a total of 2.5 kg of feed/sow. As pen space increased from 1.4 to 3.0 m(2)/sow, aggression at feeding decreased from about 9 to 7 bouts/sow (linear, P = 0.029) and plasma cortisol concentrations decreased from about 28 to 21 ng/mL (linear, P = 0.0089) at 2 d. Although the results are in accord with a linear decline from 1.4 to 3 m(2)/sow, the results are also in accord with a decline in these measurements from 1.4 to 1.8 m(2)/sow and no further decline greater than 1.8 m(2)/sow. Farrowing rate (percentage of inseminated sows that farrowed) also increased from about 60 to 75% as space increased from 1.4 to 3.0 m(2)/sow (linear, P = 0.012). Group size was related to skin injuries on d 9 (P = 0.0017), 23 (P = 0.0046), and 51 (P = 0.0006), with groups of 10 consistently having the lowest number of total injuries over this period. Based on the aggression and cortisol results, it is credible to judge that, within the range of floor space allowances studied, sow welfare improves with increased space. However, from a sow welfare perspective, the experiment had insufficient precision to determine what is an adequate space allowance for sows. Thus, although the results definitely support a space allowance of 1.4 m(2)/sow being too small, it is not possible to give guidance on an actual space allowance at mixing that is adequate.

The effects of dietary weight loss with or without exercise training on liver enzymes in obese metabolic syndrome subjects.

AIM: Insulin resistance and visceral adiposity are predisposing factors for fatty liver disease. The main objectives of this study were (i) to compare the effects of caloric restriction (CR) alone or together with moderate-intensity aerobic exercise training (CR+EX) on liver enzymes, a surrogate marker of liver injury, in obese metabolic syndrome (MetS) subjects and (ii) to identify anthropometric, metabolic, cardiovascular and dietary predictors of changes in liver enzymes. METHODS: Sedentary men and women (n = 63), aged 55 ± 6 (s.d.) years with body mass index 32.7 ± 4.1 kg/m(2) and confirmed MetS, were randomized to 12-week CR, CR+EX or no treatment (Control). RESULTS: Weight loss averaged 7.6% in the CR and 9.1% in the CR+EX group (time effect, p < 0.001; group effect, p = 0.11); insulin sensitivity improved by 49 and 45%, respectively (both p < 0.001). Fitness (maximal oxygen consumption) increased by 19% in the CR+EX group only (p < 0.001). Alanine aminotransferase (ALT) levels decreased by 20% in the CR and 24% in the CR+EX group (time effect, both p < 0.001; group effect, p = 0.68); corresponding values for γ-glutamyltransferase (GGT) were -28 and -33%, respectively (time effect, both p < 0.001; group effect, p = 0.28). Reduction in abdominal fat mass (measured by DXA from L1 to L4) independently predicted ΔALT (r = 0.42, p = 0.005) and ΔGGT (r = 0.55, p < 0.001), whereas change in dietary saturated fat intake was independently associated with ΔALT (r = 0.35, p = 0.03). CONCLUSIONS: Reductions in central adiposity and saturated fat intake are key drivers of improvement in liver enzymes during lifestyle interventions. Exercise training did not confer significant incremental benefits in this study.

Acute and chronic stress-like levels of cortisol inhibit the oestradiol stimulus to induce sexual receptivity but have no effect on sexual attractivity or proceptivity in female sheep.

Stress-like levels of cortisol inhibit sexual receptivity in ewes but the mechanism of this action is not understood. One possibility is that cortisol interferes with the actions of oestradiol to induce sexual receptivity. We tested this hypothesis in 2 experiments with ovariectomised ewes that were artificially induced into oestrus by 12 days of i.m. injections of progesterone followed by an i.m. injection of oestradiol benzoate (ODB) 48 h later. In Experiment 1, ewes were randomly allocated to the following groups: saline infusion+25 µg ODB, saline infusion+50 µg ODB, cortisol infusion+25 µg ODB or cortisol infusion+50 µg ODB (n=5 per group). Saline or cortisol was infused i.v. for 40 h beginning at the ODB injection. In Experiment 2, ewes were infused with saline or cortisol (n=5 per group) for 5h beginning 1h before ODB injection. In both experiments, ewe sexual behaviour (attractivity, proceptivity and receptivity) was quantified every 6h. Blood samples were also collected. The cortisol infusion yielded plasma concentrations of cortisol similar to those seen during psychosocial stress. In both experiments, cortisol suppressed receptivity index (number of immobilisations by ewe/courtship displays by ram) and the number of times ewes were mounted but had no effect on attractivity or proceptivity, irrespective of the dose of ODB (Experiment 1). Cortisol also suppressed LH pulse amplitude. These results suggest that both an acute (5h) and chronic (40 h) infusion of cortisol inhibit oestradiol-induced sexual receptivity in ewes and that increasing the dose of ODB does not overcome the inhibitory effects of cortisol.