Stress during first gestation of ewes impairs memory and learning of male offspring.

This study aimed to investigate the influence of gestational stress induced by lipopolysaccharide (LPS, Escherichia coli) on the physiological changes of ewes, as well as on the subsequent behavioral interaction between ewes and lambs and on the memory and learning of 30-day-old offspring in a T-maze. Thirty-six nulliparous pregnant crossbred Santa Ines ewes with an initial live weight of 45 ± 6 kg, age of 12 ± 2 months, and body condition score between 3 and 3.5 (on a scale of 1 to 5) were divided into two treatments: LPS treatment (E. coli; 0.8 µg.kg-1) and Control (placebo/saline) administered in late pregnancy (day 120). Blood samples were collected before (0 h at 5:00 h) and 1 h, 2 h, 4 h, 8 h, 12 h, 24 h after the administration of LPS or placebo to determine the cortisol release curve. Rectal temperature was measured at the same time points. After birth, male lambs (N = 19) were used to evaluate the maternal-offspring behavioral interaction, weight, and cognitive ability in a T-maze. Blood cortisol and rectal temperature of ewes increased after LPS administration and returned to baseline levels after 24 h. The activities facilitating and stimulating suckling were higher on LPS group (P < 0.05). Lambs whose mothers were challenged with LPS during late pregnancy showed greater learning and memory disabilities including fear behavior and the inability to make decisions at 30 days of age in the T-maze. In sheep, the immunological stress induced by LPS in late pregnancy promotes an inflammatory response characterized by specific rectal temperature and cortisol release profiles, improving maternal care that can increase offspring survival; however, the exposure of sheep fetuses to maternal inflammation causes cognitive impairment in lambs at 30 days of age, which could not be reduced by the behavioral interaction between the mother and offspring.

Development and validation of a multiplex fluorescent microsphere immunoassay assay for detection of porcine cytokines.

Cytokines are cell signalling proteins that mediate a number of different physiological responses. The accurate measurement of cytokine profiles is important for a variety of diagnostic and prognostic scenarios in relation to animal health and welfare. Simultaneous quantification of cytokine profiles in a single sample is now possible using fluorescent microsphere immunoassays (FMIA). We describe the development and validation of a novel multiplex assay using the Bio-Plex® 200 system to quantify cytokines in five different porcine tissues (brain, placenta, synovial tissue and fluid, plasma). The cytokine profiles are both tissue, and research hypothesis, -dependent but include Interleukin-1beta (IL-1ß), Interleukin-4 (IL-4), Interleukin-6 (IL-6), Interleukin-8 (IL-8), Interleukin-10 (IL-10) and Tumor necrosis factor (TNF-α). This methods paper is reported in two parts: the development of a FMIA for porcine tissues and validation of pre-treatment for optimal cytokine recovery in porcine brain, placenta, synovial tissue and plasma. Validation steps are critical in ensuring an assay is suitable for novel sample types. This technique advances traditional ELISAs by: •FMIA provides insight into the profiles of multiple porcine cytokines in certain situations (e.g. disease, parturition).•Use of the Bio-Plex® 200 system to investigate novel sample types, including brain, placenta and synovial tissue.•Multiplexing utilises a fraction of the sample volume compared with multiple ELISAs.

Gentle vs. aversive handling of pregnant ewes: I. Maternal cortisol and behavior.

The aim of the experiment was to study the effects of aversive vs. gentle handling in late pregnancy on maternal behavior of ewes. Sixteen Norwegian Dala ewes bearing twins were subjected to 10 min of either gentle (GEN--soft talking and calm behavior) or aversive (AVS--swift movements and shouting) handling twice a day during the last 5 weeks of pregnancy. Salivary cortisol was recorded before and after treatments. The following behaviors were recorded post-partum in the ewes: grooming duration, number of vocalizations and in the lambs: number of vocalizations, latency and duration of standing, latency and duration in udder-directed position. The ability of the ewe to follow her lamb carried away by a human was scored on day 1 and 7. After the treatment sessions, cortisol levels tended to increase in AVS ewes but not GEN ewes. At parturition, AVS ewes groomed their offspring for a longer duration than GEN ewes. AVS lambs tended to be heavier than GEN lambs at 24 h of age. Follow Scores from GEN ewes were higher than for the AVS ewes at day one, but no difference between treatment groups was detected after one week. These results show that aversively treated ewes increased their grooming behavior towards their offspring, but that fear of humans disrupted their ability to follow their lambs closely when carried away by a human. We conclude that the type of handling of ewes during pregnancy may have some impact on important maternal behaviors.

Gentle vs. aversive handling of pregnant ewes: II. Physiology and behavior of the lambs.

We compared the effects of aversive and gentle handling in late pregnant ewes on fearfulness, heart rate variability and spatial learning in lambs. Twenty-four Norwegian-Dala ewes were studied. Ewes were subjected to gentle (i.e. soft talking and calm behavior) or aversive handling (i.e. swift movements and shouting) for 10 min twice a day during the last five weeks of pregnancy. Lambs from aversively (AVS) or gently (GEN) treated ewes were tested at 4 weeks of age. Lamb behavior was recorded during a) a human approach test, composed of 4 min of isolation and 4 min of exposure to an unfamiliar human, b) an umbrella startle test followed by 5-min recording, and c) two repetitions of a maze test. In addition, heart rate variability was recorded telemetrically before and after the human and startle tests. The baseline heart rate variability measures suggested a lower influence of vagal stimulation in AVS lambs. In the human approach test, AVS lambs vocalized and explored the environment less, and were slower to approach the human. They also tended to have higher flight distances during the startle test than the GEN lambs. The prenatal treatment had no significant effect in the maze test. In conclusion, we showed that aversive handling of pregnant ewes increased fearfulness and reduced vagal tone in their progeny compared to GEN lambs. These effects can have consequences for how lambs cope with rearing conditions.

Risk factors for skin lesions on the necks of Norwegian dairy cows.

Physical restrictions at the feed barrier may cause skin lesions, especially on the necks of cows. Thus, some aspects of the functionality of feed barrier design can be assessed by observing skin lesions on the necks of dairy cattle. In this study, 232 herds, mainly of the breed Norwegian Red (94%), were investigated between September 2006 and June 2007. The herds were categorized into 2 groups. One data set, based on 1,148 cows (115 herds), was from farms using feed barriers with post-and-rail designs (86 herds) and combinations of barriers (29 herds). The second data set, which included 1,168 cows (117 herds), was from farms using only vertical feed barriers such as tombstone, diagonal, and headlock. Skin lesions were observed on the necks of 21% of the 2,335 cows observed. Forty-two percent of cows had neck lesions in herds with post-and-rail barriers, whereas 4% of cows had neck lesions in herds with vertical barriers and 30% of cows had neck lesions in herds with a combination of both horizontal and vertical barriers. Alternating logistic regression was used to identify factors associated with skin lesions on the necks of cows. The estimates were transformed into odds ratios (OR). In herds in which post-and-rail design barriers were used, the following risk factors were associated with skin lesions: manger front lower than 63 cm versus higher (OR=3.6), no feed stalls versus feed stalls (OR=10.9), mixed rations versus no mixed ration (OR=3.8), cows later than 30 DIM versus earlier (OR=1.9), cows with low milk production versus those producing 1,000 kg higher (OR=1.4), feeding frequency of less than 3 times daily versus 3 and more times daily (OR=1.9), using only post-and-rail feed barriers (OR=1.8) versus using combinations, and farmer disagreement with the statement "animals experience physical pain as humans do" (OR=1.9) versus agreement. Diagonal barriers, categorized as vertical barriers, increased the association of skin lesions with increasing manger front heights. Feed barrier design was associated with skin lesions on the necks of cows, particularly for barriers of a post-and-rail design. To minimize the risk of neck lesions, the top rail height of post-and-rail barriers should be above 109 cm, especially for cows taller than 126 cm, and the manger front should not be lower than 63 cm. Feed stalls, feeding frequency of 3 or more times daily, and the feeding of unmixed rations were also identified as preventive factors.

Dairy farmer attitudes and empathy toward animals are associated with animal welfare indicators.

Attitudes and empathy of farmers influence human-animal interaction, thereby affecting their behavior toward animals. The goal was to investigate how measures of attitude and empathy toward animals were associated with animal welfare indicators such as milk yield, mastitis incidence, fertility index, and the prevalence of skin lesions on cows. To assess empathy toward animals, a photo-based pain assessment instrument was developed depicting various conditions that could be associated with some degree of pain in cattle and included questions aimed at assessing attitudes toward animals. Photos of painful conditions are useful in eliciting measurable empathic responses to pain in humans. A total of 221 farmers were sampled via e-mail and 154 responses were obtained. In the first analysis, farmers were categorized into 2 groups according to their agreement or disagreement with the attitude statement "animals experience physical pain as humans do." In the second analysis, farmers were assigned a median pain assessment score obtained from their estimates on the visual analog scale of 21 conditions assumed painful for cattle. In the third analysis, farmers were clustered in 3 groups according to their visual analog scale responses. Three conditions were ranked as the most painful: fracture of tuber coxae, dystocia, and serious mastitis. Farmers with positive attitudes toward animals scored 2 points higher on their empathy score compared with farmers with negative attitudes. Personal experience with each additional condition resulted in a 0.09 higher score. Cluster analysis revealed 3 groups. Farmers in group 3 had the highest median pain assessment score (6.7+/-0.2), indicating a high level of empathy and a positive attitude toward animals. They had the lowest prevalence of skin lesions over the carpus (24+/-6%) and the lowest milk production (6,705+/-202 kg). The complex associations between indicators of empathy and attitudes with relevant welfare outcomes suggest that competence building to safeguard animal welfare could benefit from including both attitudes and empathy in human-animal interactions studies.

Prevalence and risk factors for skin lesions on legs of dairy cattle housed in freestalls in Norway.

Appropriate indoor housing facilities for dairy cattle promote improved animal welfare. Skin alterations are an indicator of dysfunctional housing. The purpose was to determine the relationship between different housing design and skin lesions, hence providing farmers more insight into how to reduce the occurrence of lesions. A cross-sectional study was conducted on 2,335 animals in 232 Norwegian freestall-housed dairy cattle from September 2006 to June 2007. A model was established to investigate risk factors related to the presence of lesions including hair loss, swelling, and wounds on the legs of dairy cattle. Separate models were developed to investigate risk factors related to the presence of knee and hock lesions. Previously described risk factors were included in the models, together with a questionnaire addressing the attitude of the farmer toward the animals. Mean (+/- SD) prevalence for hock lesions was 60.5 +/- 21.2% with a median value of 64%. The prevalence for knee lesions was 35.3 +/- 25.7% with a median of 30%. Cows in herds with a soft freestall base had an odds ratio (OR) for knee and hock lesions of 0.22 (0.06 to 0.73) and 0.62 (0.48 to 0.80), respectively, compared with those in herds with a harder freestall base, such as concrete and compact rubber mats. There was an increased risk of hock lesions when the length in the lying area in a double-row freestall was >250 cm (OR = 2.96; 1.02 to 8.60) compared with 260 cm (OR = 2.11; 1.53 to 2.90) compared with < or =260 cm. The risk for knee lesions increased if a row against a wall was >270 cm (OR = 1.72; 1.09 to 2.72) compared with < or =270 cm. Hock lesions were associated with lame cows (OR = 5.76; 1.14 to 29.18) versus nonlame cows, and with cows in their second or higher parity (OR = 1.27; 1.06 to 1.52) versus cows in their first parity. Knee lesions were associated with farmers' negative attitudes toward animals in pain (OR = 3.28; 1.79 to 6.03) versus those with positive attitudes; cows in the beginning of their lactation (OR = 1.84; 1.24 to 2.74) versus those at the end of their lactation; and tall animals (OR = 1.27; 1.00 to 1.61) versus shorter animals. These results show that freestall design is important with respect to skin lesions as are the characteristics of individual animals and the farmer.

Attitudes of veterinary students to pain in cattle.

Three hundred veterinary students were divided randomly into two groups to answer a questionnaire inquiring how painful they considered 23 conditions affecting cattle (seven of which were illustrated) to be, on either a numerical rating scale (NRS) or a visual analogue scale (VAS). The individual responses were used to assess whether cluster analysis could be used to divide the population into distinct groups. The ratios of men to women in the two groups were similar. The NRS scores ranged from 1 to 10 and the VAS scores ranged from 0 to 10. The conditions that were illustrated with a picture had a wider range of scores (2.65 to 9.0 v 2.67 to 7.93) and a slightly higher mean score (5.71 v 5.34) than those without pictures. Fracture of the tuber coxae, dystocia requiring the help of two people, and serious mastitis, were scored as the most painful conditions in adult cattle. Using the median score of each student as an outcome, their sex and year of enrollment and the scoring scale were significant. Women scored 0.9 points higher than men. Cluster analysis revealed two distinct groups in both the VAS and NRS, but the distribution was more even among the students using the VAS. This group was used in further analysis, and one cluster had the most men and more students with several siblings.

Depressed DHEA and increased sickness response behaviors in lame dairy cows with inflammatory foot lesions.

Lameness is a multifactorial condition influenced by the environment, genetics, management and nutrition. Detection of lameness is subjective and currently limited to visual locomotion observations which lack reliability and sensitivity. The objective of this study was to search for potential biomarkers of inflammatory foot lesions that underlie most cases of lameness in dairy cows, with a focus on the sickness response and relevant endocrine, immune and behavioral changes. Serum and peripheral blood mononuclear cells (PBMC) were collected from eight sound and eight lame high-producing Holstein cows. Immune cell activation was investigated in PBMCs using a candidate gene approach in which the expression of pro-opiomelanocortin, interleukin-1beta, l-selectin, matrix metalloproteinase-9 and glucocorticoid receptor-alpha was measured via quantitative real time-RT-PCR. Endocrine changes were investigated by monitoring serum concentrations of cortisol and dehydroepiandrosterone (DHEA). Additionally, systematic behavioral observations were carried out to characterize a behavioral profile associated with a sickness response typical of this condition. Lame cows showed significantly lower eating (P=0.01) and ruminating (P=0.01) behaviors and higher incidence of self-grooming (P=0.04) compared to sound cows. Lame cows also showed a 23% decrease in serum DHEA (P=0.01) and 65% higher cortisol:DHEA ratio (P=0.06) compared to sound cows. However, no significant differences were found in candidate gene expression between lame and sound cows. In association with sickness behaviors, serum DHEA concentration and cortisol:DHEA ratio are promising objective indicators of inflammatory foot lesions in dairy cattle and may be useful as diagnostic targets for animals in need of treatment.

Effects of boar presence on agonistic behavior, shoulder scratches, and stress response of bred sows at mixing.

The objective of this study was to determine the effects of boar presence on aggression, shoulder scratches, and salivary cortisol in group-housed sows during the period after mixing, which is when dominance hierarchies are formed. A total of 225 York-shire sows were used. Five groups of 15 sows were each exposed to 1 of 3 levels of boar presence (n = 15): physical (boar in pen with sows; 2.15 m2 per sow), fenceline (boar housed adjacent to sows; 2.3 m2 per sow), or control (no boar in the room; 2.3 m2 per sow). The experiment was divided into 2 phases. In phase 1, behavioral measurements were taken for 48 h after mixing and boar introduction. In phase 2, behavioral measurements were taken beginning on d 6 after mixing and included 24 h before and 48 h after boar removal. In phases 1 and 2, shoulder scratches were scored 24 h before and 24 h after mixing and boar removal, respectively. Saliva samples were collected each morning (0600 to 0700) and afternoon (1600 to 1700) during both phases. Frequencies of intersow aggressive contact (bite, body knock, and head knock) and threats as well as frequencies and durations of fighting bouts were determined from video recordings during daily feeding (49.6 +/- 1.4 min) and nonfeeding (21 +/- 0.2 h) periods. During phase 1, boar presence did not affect the frequency of threats during either the feeding or nonfeeding periods. Control groups had fewer aggressive contacts at feeding during the 25- to 48-h period compared with the fenceline groups (P = 0.01). Total duration of fighting and average fighting bout duration were unaffected by treatment. However, the number of fights occurring during feeding 25 to 48 h postmixing was lower in the physical groups than in the fenceline groups (P = 0.023); measures for the control groups were intermediate. Physical sows also received fewer shoulder scratches postmixing than did control sows (P = 0.048). After mixing, physical sows showed greater morning (P = 0.08) and afternoon (6 h postmixing, P = 0.01; 32 h postmixing, P = 0.08) salivary cortisol concentrations compared with fenceline sows, although they were only numerically greater than those for control sows. During phase 2, removing the boar did not increase fighting among sows or affect shoulder scratches or salivary cortisol concentrations. The presence of a boar was minimally effective at reducing fighting and scratches during the postmixing period, and sows showed a greater stress response in the presence of a boar.

Investigation of changes in global gene expression in the frontal cortex of early-weaned and socially isolated piglets using microarray and quantitative real-time RT-PCR.

We hypothesize that early-weaned piglets experience aberrant expression of stress-responsive genes in the frontal cortex, a key brain area involved in cognitive function and behavior organization. To test this hypothesis, female early-weaned piglets (EW; n = 6) were weaned 10 days after birth, while non-weaned piglets (NW; n = 6) were left with their dams. Half of EW (n = 3) and NW (n = 3) animals were socially isolated (SI) for 15 min at 12 days of age, when all animals (n = 12) were euthanized and tissue collected. The effects of EW and SI were examined by gene expression profiling using cDNA microarray hybridizations, generated from a porcine brain cDNA library. A total of 103 genes were differentially expressed (P < 0.05, fold change >1.25) among four direct comparisons. Forty-two genes had known functions, from which 24 showed relevant brain-related functions. Quantitative real-time polymerase chain reaction (Q-RT-PCR) was used to confirm regulation of expression of a subset of 6 genes with important brain functions, selected from the microarray outcomes. In non-weaned animals, a significant suppression of mRNA abundance for carboxypeptidase E, 14-3-3 protein and phosphoprotein enriched in astrocytes 15 kDa was observed in response to SI. Also, in early-weaned animals, diazepam binding inhibitor and actin-related protein 2/3 complex mRNA levels were suppressed in response to SI. Results suggest that social isolation of non- and early-weaned piglets may impact expression of genes involved in regulation of neuronal function, development, and protection in the frontal cortex of young pigs.

Effects of early weaning and social isolation on the expression of glucocorticoid and mineralocorticoid receptor and 11beta-hydroxysteroid dehydrogenase 1 and 2 mRNAs in the frontal cortex and hippocampus of piglets.

Pigs weaned at young ages show more abnormal and aggressive behaviors and cognitive deficits compared to later weaned pigs. We investigated the effects of age, weaning and/or social isolation on the expression of genes regulating glucocorticoid response [glucocorticoid receptor (GR), mineralocorticoid receptor (MR), 11beta-hydroxysteroid dehydrogenases 1 and 2 (11beta-HSD1 and 11beta-HSD2)] in the frontal cortex and hippocampus. Early- (EW; n = 6) and conventionally-weaned (CW; n = 6) piglets were weaned at 10 and 21 days after birth, respectively. Non-weaned (NW) piglets of both ages (NW; n = 6/group) remained with their dams. Immediately before euthanasia, half of CW, EW and NW animals were socially isolated for 15 min at 12 (EW, NW) and 23 (CW, NW) days of age. Differences in amounts of 11beta-HSD1, 11beta-HSD2, GR and MR mRNA were determined by quantitative real-time RT-PCR and data subjected to multivariate linear mixed model analysis. When compared with NW piglets at 12 days of age, the hippocampi of EW piglets showed decreased gene expression (P < 0.01). Social isolation decreased gene expression (P < 0.05) in the frontal cortex of all piglets. Twelve-day-old piglets showed higher MR mRNA in the frontal cortex (P < 0.01) and lower 11beta-HSD2 and GR mRNA (P < 0.05) in the hippocampus compared to 23-day-old animals. Results indicate that EW affected the hippocampus of piglets at 12 days of age, while social isolation affected frontal cortex regardless of age. These results may be correlated with behavioral and cognitive changes reported in EW piglets.

Assessing attitudes toward farm animal welfare: a national survey of animal science faculty members.

A survey to measure attitudes toward farm animal welfare was developed. We targeted animal science faculty because of their influence on animal production in the United States. We initially interviewed 34 faculty members from a large Midwestern public university to assist with questionnaire development. After our written survey was developed, we pilot-tested our questionnaire at this same university. Thereafter, we sent an e-mail advance notice, first survey, and follow-up survey/thank-you to the national population of animal science faculty members. With an n = 446 (response rate = 45%), we observed the following: 51% (for layer birds), 58% (for meat birds), 66% (for swine), 84% (for dairy), 86% (for sheep), and 87% (for beef) of our respondents agreed that the predominant methods used to produce various types of animal products provided appropriate levels of animal welfare. Our findings showed that greater than 90% of respondents support general principles of animal welfare, such as keeping animals free from unnecessary fear and distress. However, specific practices that have been shown to elicit distress (e.g., castration without anesthetic) were deemed a concern by only 32% of the respondents. Various industry practices/outcomes were assessed for level of concern and varied from a high of 83% of respondents agreeing that flooring effects on lameness in intensively farmed animals are a concern, to a low of 16% agreeing that early weaning in pigs is a concern. Summed attitude scores showed significant relationships with the demographic variables of gender (P < 0.01) and political ideology (P < 0.01), with women and those holding more liberal political views being more concerned about farm animal welfare issues. Gaining an awareness of various stakeholders' attitudes (e.g., animal scientists, veterinarians, producers, and consumers) toward farm animal welfare will assist animal welfare scientists in knowing which research topics to emphasize and, perhaps, where critical gaps in accessibility of knowledge exist.

Large round bale feeder design affects hay utilization and beef cow behavior.

One hundred sixty beef cows (631 +/- 78 kg) were used to evaluate the quantity of hay loss and feeding behaviors from different round bale feeders. Twenty cows were allotted by weight and body condition score to one of eight pens with four feeder designs: cone, ring, trailer, or cradle. All feeder types provided approximately 37 cm of linear feeder space per animal. Alfalfa and orchardgrass round bales were weighed and sampled before feeding. Hay that fell onto the concrete surrounding the feeder was considered waste and was collected and sampled daily. At the end of a 7-d period, each feeder type was assigned to a different pen for a second 7-d period. On four consecutive days in each period, animal behavior was recorded using a time-lapse video system. Data were collected from 5-min observational intervals from the video tapes every 0.5 h each day. Feeder access, occupancy rate, and occurrence of agonistic interactions were recorded. Dry matter hay waste was 3.5, 6.1, 11.4, and 14.6% for the cone, ring, trailer, and cradle feeders, respectively. Calculated dry matter intake of hay ranged from 1.8 to 2.0% of body weight and was not different among feeder type (P < 0.05). Percentage of organic matter, neutral detergent fiber, acid detergent fiber, and crude protein were all lower and acid detergent lignin was higher in the recovered waste compared to the hay fed (P < 0.05). Cows feeding from the cradle feeder had nearly three times the agonistic interactions and four times the frequency of entrances compared to cows feeding from the other feeder types (P < 0.05). Feed losses were positively correlated with agonistic interactions, frequency of regular and irregular entrances, and feeder occupancy rate (P < 0.05). Agonistic interactions by cows and frequency of feeder entrances differed among feeders and were correlated to feeder design induced feed losses.

[Salivary cortisol as a stress parameter in piglets]. / Speichelkortisol als Stressparameter bei Saugferkeln.

The relationship between salivary and plasma levels of total and free cortisol was monitored in 97 male piglets, aged two to four weeks, subjected to castration. Samples were taken 10 minutes before (basal value) as well as one, two, three, four and 24 hours post castration and at the same time intervals from a control group of 17 animals which did not undergo surgery. Simultaneously to blood (indwelling catheter) withdrawing saliva was collected by two cotton swabs. Cortisol levels were measured by radioimmunoassay (RIA). A highly significant increase in total, free and salivary cortisol was found within the first four hours after castration compared to the control group. The percentage increase one hour after castration above basal values was highest in free plasma cortisol (21.08 +/- 2.03 nmol/l vs. 61.26 +/- 4.16 nmol/l; 290.6%), and lowest in total plasma cortisol (177.33 +/- 9.69 nmol/l vs. 374.09 +/- 18.21 nmol/l; 211.0%), whereas salivary cortisol showed an 255.7% increase (10.46 +/- 1.03 nmol/l vs. 26.75 +/- 1.93 nmol/l). Total cortisol included 11.9-16.4% free cortisol. Salivary cortisol concentration was between 5.9% and 7.5% of the total plasma cortisol concentration. The highest correlation between total plasma cortisol and salivary cortisol occurred one hour after castration (r = 0.57; p < 0.01). The correlation between free and salivary cortisol was lowest for basal values (r = 0.27; p < 0.05), whereas correlations for the remaining time points were highly significant (0.41 < or = r < or = 0.61; p < 0.01). For the control group significant correlations were found between salivary and total plasma cortisol (0.58 < or = r < or = 0.89; p < 0.05) and between free and salivary cortisol (0.63 < or = r < or = 0.92; p < 0.05). The present work indicates that the measurement of salivary levels of cortisol reflects the concentration of this hormone in plasma samples of piglets.

Physiological correlates associated with cribbing behaviour in horses: changes in thermal threshold, heart rate, plasma beta-endorphin and serotonin.

The aim of the present study was to obtain information on the possible mechanisms underlying cribbing behaviour in horses. To investigate the horse's responsiveness to an external stimulus, a device for telemetric measurement of thermal threshold, using the forelimb withdrawal reflex, was developed and validated. Measurements of thermal threshold took place in cribbing horses (n = 11) before and during cribbing periods. Heart rate was monitored continuously in the same horses. Blood samples were collected before and during cribbing periods as well and in age- and sex-matched control horses (n = 11). beta-endorphin and cortisol were determined in plasma using radioimmunoassay techniques, serotonin was analysed by high performance liquid chromatography. Compared with basal values, thermal threshold was significantly (P = 0.003) lower during cribbing periods. The mean difference was 4.9 degrees C. Heart rate decreased significantly (P = 0.026) and showed a mean reduction of 2.4 beats/min during cribbing. Given the fact that arousal usually is associated with an increase in nociceptive threshold and in heart rate, the decrease in both during cribbing provide evidence that cribbing may reduce stress. Cribbers showed 3 times higher basal beta-endorphin levels than controls (mean 49.5 vs. 16.2 pmol/l, P = 0.006) and there was a trend for lower basal serotonin levels (mean 201.5 vs. 414.3 nmol/l, P = 0.07). These data indicate differences in cribber's endogenous opioid and serotonergic systems.

Brain opioid receptors in relation to stereotypies, inactivity, and housing in sows.

When animals encounter difficult conditions, endogenous opioids are often released and may help in coping with the difficulties. In sows, prolonged confinement results in behavior abnormalities: high levels of stereotypies or excessive inactivity and unresponsiveness. The possibilities of causal links between endogenous opioids and these behavioral indicators of poor welfare have been raised. Mu receptor density was found to be greater in tethered sows than in group-housed sows and to be positively correlated with time spent inactive. There were negative correlations between both mu and kappa receptor densities and stereotypy duration. Kappa agonists are associated with aversion, and there are complex links between endorphin levels, dynorphin levels, and dopamine action. These results provide the first demonstration of a relationship between abnormal behavior in pigs and opioid receptor density, and help to clarify the links between behavioral responses and opioid action.

A fast and simple technique for jugular catheterization in adult sows.

Obtaining measures of an animal's physiological state with minimum disturbance to the animal is essential in animal welfare studies and it is also ethically desirable. A simple technique for implanting a temporary jugular catheter in adult sows is described. The technique involves implantation via an ear vein and can be performed in 5-7 min. Local but not general anaesthetic is required. The technique has no effect on basal levels of salivary cortisol 1-2 h later, suggesting that it has no long term stress consequences. Catheters continue to function perfectly well after 4 h.