Shelter dogs may experience long-term environmental and social stressors that can affect their behaviour and welfare. Some individuals show reduced activity, low responsiveness to environmental stimuli, and limited interaction with their surroundings. This pilot study investigated behavioural patterns and allopregnanolone concentrations in shelter dogs exhibiting these behavioural characteristics. Ten shelter dogs were enrolled and divided into two groups: five dogs showing depression-like patterns and five matched control dogs. Each dog wore a three-axis accelerometer for 30 days to quantify activity levels. Behavioural observations were conducted using video recordings, and hair samples were collected at baseline and after 30 days to assess allopregnanolone concentrations as a potential stress marker. Dogs in the case group showed significantly longer resting time than controls (p ≤ 0.05), indicating reduced activity levels. Trends toward lower levels of exploratory and social behaviours were also observed, although the differences were not statistically significant. Allopregnanolone concentrations ranged from 0.6 to 4.6 pg/mg and showed considerable inter-individual variability, with no significant differences detected between groups. These findings provide preliminary evidence of behavioural and physiological alterations in shelter dogs displaying depression-like patterns. However, further studies with larger populations are needed to validate these findings and improve welfare assessment in shelter environments.

Understanding how husbandry practices affect chronic stress in growing-finishing pigs is essential to improve their welfare. The objective of this study was therefore to investigate the effect of two important practices, i.e., stocking density and enrichment, within different husbandry systems by studying concentrations of hair cortisol and hair dehydroepiandrosterone (sulphate) (DHEA(S)) and their ratio, as markers for chronic stress. Hereto, in six experiments, various organic and conventional systems were studied in which the stocking density and the level of enrichment varied. We found that a lower stocking density generally resulted in lower hair cortisol and DHEA(S) concentrations, but the effect of stocking density on the hair cortisol/DHEA(S) ratio was less clear. Access to enrichment only tended to result in higher DHEA(S) concentrations in one of the experiments. Furthermore, sex tended to affect or affected hair cortisol, DHEA(S) and/or the ratio only in some of the experiments. These results suggest that a lower stocking density is beneficial for growing-finishing pigs as they seemed to be less chronically stressed. That the enrichment items did not beneficially affect hair cortisol and DHEA(S) was likely due to the relatively small contrast between the control and enriched condition, as the pigs in the control condition already had access to straw. As not much studies have investigated hair DHEA(S) concentrations in pigs, more research is needed to get more insight of this hormone in relation to chronic stress and the effect of sex in pigs.

This paper presents the preliminary development and experimental validation of an artificial intelligence–based measurement system for automated feed monitoring and direct feed weight estimation in the context of Precision Livestock Farming. The proposed approach relies exclusively on RGB imaging and supervised deep learning techniques to estimate feed mass, deliberately avoiding explicit three-dimensional geometric reconstruction or density-based calibration procedures typically adopted in existing solutions. A single-stage object detection and classification framework is employed to jointly localize the feed heap and infer its weight class in a single forward pass. The model is trained on a large, carefully annotated dataset covering a wide range of feed weights, with controlled quantization and extensive variability in illumination conditions and feed arrangement, in order to enhance robustness and generalization capability.Experimental results show excellent detection performance and a strong correlation between predicted and reference weights, with most estimation errors confined to adjacent quantized classes. Beyond conventional computer vision metrics, the proposed system is explicitly treated as a measurement instrument. A metrological characterization is therefore performed, including calibration for gain and offset correction and a quantitative evaluation of measurement uncertainty following ISO GUM principles [1]. The results demonstrate a near-unitary calibrated response and an expanded uncertainty compatible with the requirements of feed intake monitoring applications.Compared to camera-based 3D systems, the proposed RGB-only solution significantly reduces hardware complexity, computational burden, and deployment constraints, while maintaining high accuracy and repeatability. These features make the system particularly suitable for large-scale farm deployment and for integration within multimodal sensing platforms aimed at improving feed efficiency assessment and sustainability in livestock production systems.

Besides metabolic and cardiovascular parameters, fluctuations in endocrine and inflammatory biomarkers might be regarded as reliable indicators of allostatic load. Among them, glucocorticoids have been shown to correlate with social stress in animals, regardless of whether they are dominant or subordinate, thus highlighting the crucial role of physiological energetic costs, together with social challenges, in the onset and severity of allostasis. Therefore, in the present work, we evaluated and monitored monthly the concentration of cortisol in bristles (pg/mg) over six months in young (n = 8), sub-adult (n = 5) and adult female wild boars (n = 5), which were kept in a controlled State Forest in Southern Italy. Our data revealed higher concentrations of cortisol in young animals when compared to sub-adult (p < 0.01) and adult (p < 0.05) groups. Moreover, such an increase faded away over time, and cortisol concentrations were found to be overlapping those of sub-adult and adult groups, which did not display any significant variation throughout monitoring. Collectively, our findings suggest that the wild boars adapted to the controlled environment, thus preserving both a physiological state and animal welfare.

Assay of steroid hormones in hair has become an attractive alternative for studies focusing on the perinatal period in equine medicine. The aim of the present study was to evaluate mares’ and foals’ hair ALLO concentrations and their ratio in relation to clinical conditions and selected clinical parameters. The 37 mare–foal pairs were categorized into healthy (group H; n = 15) and sick (group S; n = 22) groups. ALLO from hair was measured using a commercial ELISA kit. Foal ALLO and foal/mare ALLO ratio were lower in group S compared to group H (p < 0.001). Moderate positive correlations were found between both the foal ALLO and foal/mare ALLO ratio and the mare’s gestation length (p = 0.003; r = 0.476 and p = 0.002; r = 0.487), between the foal ALLO and foal’s weight (p = 0.042; r = 0.336), and between the foal/mare ALLO ratio and foal’s Apgar score (p = 0.047; r = 0.410). Based on a logistic regression model, a strong relationship (R2 = 0.75) emerged between ALLO concentrations and foals’ clinical outcome, with concentrations of the hormone predicting foals’ clinical outcome with high accuracy (86.8%). Decreased foal ALLO and foal/mare ALLO ratio in sick foals appear to be potential biomarkers of prenatal disease toward the end of pregnancy.

Poor health and increased susceptibility to infectious diseases are among the main sources of economic losses in the pig industry worldwide, and they also serve as indicators of compromised animal welfare. However, there is limited information on long-lasting biomarkers of poor health and common infections experienced by piglets early in life. Hair cortisol, dehydroepiandrosterone sulfate (DHEA(S)), and their ratio have been proposed as components of the mammalian stress response due to the activation of the hypothalamus-pituitary-adrenal axis and were investigated in this study using 30 batches of pigs from 16 farms. The research hypothesis was that batches of piglets experiencing clinical syndromes (as indicated by enteric, neurological, cutaneous, and locomotor scores) during suckling would exhibit a different pattern of resilience and allostatic load later in life compared to healthy ones. Hair from 25 gilts per batch were collected at either 3.5 or 9 months of age, and hormone extraction was subsequently performed. The farm of origin and the age of the animals significantly influenced hormone concentrations. Moreover, batches affected by enteric disease showed lower DHEA(S) levels (p < 0.0001; 15.89 vs. 23.51 pg/mg) and higher cortisol/DHEA(S) ratio (p < 0.0001; 82.83 vs. 55.02) than healthy batches. Similar results were observed in batches with a neurological syndrome (DHEA(S): p < 0.0001; 12.91 vs. 19.43; cortisol/DHEA(S) ratio: p < 0.0001; 97.15 vs. 70.26 pg/mg). These results suggest that pig hair biomarkers carry an intrinsic and temporally stable signal related to early life health status.

An unhealthy prepubertal diet can have long-lasting effects throughout life. This study investigated hair concentrations of adrenal and sex steroids, in an in vivo mouse model of juvenile obesity subjected to control (CTRL), obesogenic (HFHC) diet, or nutraceutical supplementation (silymarin or coconut oil) diets. 87 3-week-old C57BL/6 mice (42 females, 45 males) were fed CTRL or HFHC diets for 8 weeks. Afterward, the CTRL group continued on CTRL diet while the HFHC diet group was divided into five groups: HFHC, HFHC→CTRL, HFHC→CTRL + silymarin (SIL), HFHC→HFHC + SIL and HFHC→HFHC + Coconut oil. At 4 weeks, the HFHC group showed increased cortisol/dehydroepiandrosterone (DHEA) ratio compared to CTRL group. At 20 weeks, the HFHC→HFHC group showed higher levels of progesterone (P4) and dehydroepiandrosterone sulfate (DHEA-S) and lower levels of estradiol (E2) compared to the CTRL→CTRL group. The switch from HFHC→CTRL was the optimal therapy because the body weight and almost all the hormones were close to those observed for the CTRL diet group. Supplement with SIL or Coconut oil reduced DHEA-S and increased in E2 compared with the endocrine setting seen with the HFHC diet. These interventions should be considered as supportive measures rather than substitutes for dietary correction.

IntroductionBuilding on the motivational process of the job demands-resources (JD-R) theory, in the current research we investigated the longitudinal association between supervisor support/resilience as job/personal resources, work engagement (WE) and hair dehydroepiandrosterone sulfate, or DHEA(S), as a possible biomarker of employees’ well-being.MethodsIn the context of the COVID-19 pandemic, 122 workers completed two self-report questionnaires (i.e., psychological data): the former at Time 1 (T1) and the latter three months afterwards, at Time 2 (T2). Participants also collected a strand of hair (i.e., biological data) at T2.ResultsResults from path analysis showed that both SS and resilience at T1 were positively related to WE at T2, which, in its turn, was positively related to hair DHEA(S) at T2. Both SS and resilience at T1 had a positive indirect effect on hair DHEA(S) at T2 through WE at T2, which fully mediated the association between job/personal resources and hair DHEA(S).DiscussionOverall, results are consistent with the motivational process of the JD-R. Furthermore, this study provides preliminary evidence for the role of hair DHEA(S) as a biomarker of WE, a type of work-related subjective well-being that plays a central role in the motivational process of the JD-R, leading to favorable personal and organizational outcomes. Finally, the article outlines practical implications for organizations and professionals to foster WE within the workplace.

Background: Unlike psychological distress, which has been extensively studied during the COVID-19 pandemic, the impact of the pandemic on stress hormones has been overlooked. The aim of this study is to examine the hair cortisol/dehydroepiandrosterone sulfate (DHEA-S) ratios as markers of HPA axis dysregulation in healthcare workers and their patients. Methods: A total of 200 healthcare workers and 161 “patients” patients with special healthcare needs due to chronic illness or motor disabilities were included in this study. The hormone concentrations were measured using a radioimmunoassay. Results: Our results show that the patients had significantly higher cortisol/DHEA-S ratios than the workers. A high cortisol/DHEA-S ratio in the patients reflects higher cortisol concentrations (p < 0.001) and lower DHEA-S (p < 0.05) concentrations compared to those of the healthcare workers, suggesting that they may be exposed to a greater degree of stress and a decrease in their ability to cope with their disease. The cut-off value of the hair cortisol/DHEA-S ratio in our study for detecting people with needs that require special consideration and attention was 1.46 (p ≤ 0.01). Conclusions: Assessing the hair cortisol/DHEA-S ratios in both healthcare workers and the patients allowed us to identify a non-homeostatic condition that could lead to disease and to understand psychophysical well-being during the COVID-19 pandemic. They also play a crucial role in preventive and personalized medicine.

Hair steroid measurement has received increasing attention for monitoring hypothalamic-pituitary-adrenal axis function, as it offers the advantages of being noninvasive, fast, and able to indicate steroid concentrations over long periods. The objects of the study were to evaluate cortisol (C) and dehydroepiandrosterone sulfate (DHEA-S) hair concentrations and their ratio (C/DHEA-S) in beef cows from calving to 100 days (d) postpartum (pp) and to assess possible differences related to parity (primiparous vs multiparous) and conception outcome (pregnant vs not pregnant). Hair samples were collected from 6 primiparous and 5 multiparous pregnant beef cows by clipping the coat at calving (T0) and every 20 d for 5 times (T1-T5), collecting only the regrown hair. Starting from the 6th-week pp, cows were submitted to artificial insemination at spontaneous estrus; by 100 d pp, 7 cows were pregnant and 4 were not pregnant. Statistical analysis showed higher hair C concentrations in the 11 cows at calving (T0) compared to all the subsequent samplings except for T1, and higher C concentrations at T1 compared to T3, T4, and T5. These results indicate that hair C concentrations in beef cows are affected by sampling time, with a decrease from calving, as reported in other matrices. When exploring changes within parity groups, no differences were found in the multiparous among sampling times, while hair C concentrations at T0 and T1 tended to be higher than at T2 (0.01 ≤ p < 0.05) and were higher (p < 0.01) than in all the subsequent samplings (T3, T4 and T5) within the primiparous group. Higher hair C concentrations were found at T0 and T1 in the primiparous compared to multiparous (p < 0.01), suggesting that primiparous cows undergo a greater stress level before and around parturition compared to multiparous, probably due to the novelty of the calving experience. No differences were detected in C hair concentrations according to conception outcome (pregnant versus not pregnant) in each sampling time. Hair DHEA-S concentrations were neither affected by time nor by parity or conception outcome. Differences in the C/DHEA-S ratio were found at T1, with higher C/DHEA-S in the multiparous compared to primiparous cows (p < 0.001), and a tendency for higher ratio in the not pregnant compared to the pregnant (0.01 ≤ p < 0.05). These results support the choice of hair as a valuable biological matrix when investigating long-time periods such as postpartum in cows and suggest an enhanced immunoprotective effect of DHEA-S in the postpartum of primiparous cows, and in cows that get pregnant within 100 d postpartum.

Feces are a noninvasive and easily collectible matrix that may help determine cumulative hormone metabolite concentrations over medium-to-long times. To date, 11-oxoetiocholanolone, an important metabolite of cortisol, has been measured in equine and bovine feces solely by an in-house enzyme immunoassay (EIA). Therefore, we validated the use of a commercial ELISA kit (11-oxoetiocholanolone ELISA kit; Cayman Chemical), which had been validated on sheep feces and human urine, to measure 11-oxoetiocholanolone in feces from 42 horses and 32 bulls. The ELISA kit had good precision (intra- and inter-assay CVs: 5.8% and 11.2% for equine feces; 9.9% and 11.2% for bovine feces, respectively), analytical sensitivity (0.186 ng/mL for both equine and bovine feces), and accuracy (parallelism and recovery tests) in determining 11-oxoetiocholanolone concentrations in feces from both species. We found ranges of 11-oxoetiocholanolone concentrations of 1-109 ng/g in equine feces and 40-302 ng/g in feces of bulls. The Cayman Chemical ELISA kit offers a simple and accessible means of analysis of 11-oxoetiocholanolone in equine and bovine fecal samples.

Cortisol and DHEA(S) are markers of allostatic load and resilience; as such, they may be added to the definition of performance measures alongside immunocompetence. We aimed at studying the potential carryover effects of management practices on growth performances and the interrelationship between the hypothalamic–pituitary–adrenal (HPA) axis, immunocompetence and performances during the preweaning period in dairy calves. This study consisted of first a retrospective cohort study and second a prospective study. Calves had their growth performances and disease occurrence recorded, and their hair steroids (T1 at 20.03 ± 0.39 and T2 at 50.83 ± 0.41 days from birth) and plasmatic and colostral immunoglobulin G (IgG) was measured by immunoassays. The occurrence of preweaning diseases and the duration of individual housing negatively correlated to body weight (BW) at 60 days and the hair cortisol-to-DHEA(S) ratio (HC/HDHEA(S)) (T2) was negatively correlated to the daily weight gain (DWG) (−0.36; p < 0.05), plasmatic IgG (plaIgG) and the apparent efficiency of absorption (AEA) (−0.41; p < 0.01). Our results confirmed that the occurrence of diseases during the preweaning period and individual housing duration are pivotal for calves’ growth. This prospective study highlighted a detrimental effect of allostatic load on immunocompetence and described a link between resilience and growth performances.

Cortisol is the primary biomarker associated with the hypothalamic–pituitary–adrenal (HPA) axis. This research aimed at assessing the predictive potential and the relationship of cortisol concentrations in four media (blood, milk, whey and hair) with parity, lactation stage and productive classes. Multiparous (n = 30) and primiparous (n = 38) Italian Mediterranean buffaloes were used and assigned to four productive classes (based on percentiles of mature equivalent milk yield (EMY) and mature equivalent energy corrected milk (eECM)), and cortisol concentrations were measured using a in house radioimmunoassay (RIA) method. Parity did not show a significant effect on cortisol concentrations of the four media. The catabolic stage of lactation (up to 90 d in milk (DIM)) was characterised by higher cortisol concentrations compared to the second anabolic stage (beyond 150 DIM) in milk formulations. The plasmatic concentrations of cortisol were higher at the catabolic and the first anabolic stage (91–150 DIM) compared to the second anabolic (p = 0.022 and p = 0.009, respectively). Buffaloes beyond 150 DIM differed from those below 90 DIM (p < 0.001) and between 91 and 150 DIM (p < 0.05) in hair. Finally, hair cortisol concentrations were negatively correlated to EMY, mature equivalent protein content (EPC) (p < 0.01) and eECM (p < 0.05). The whey showed a potential to predict the concentrations of cortisol in whole extracted milk (R2 = 0.31). Hence the development of a real-time automated cortisol measurement in milk could be a valuable tool in Italian Mediterranean Buffalo farming.

Several matrices are available to detect the concentrations of cortisol and dehydroepiandrosterone (DHEA) as markers of allostatic load and resilience but most of them provide a measurement of the concentration at a single -time point or within a 12- 24 h period and are subjected to daily fluctuations; conversely, keratinized de-rivatives, as hair is, provide a measure of the hormonal concentrations over medium-and long-term periods, appearing unaffected by circadian changes or by factors inducing short-term variations. Aim of this study was to evaluate hair cortisol (HC), hair DHEA (HDHEA) and their ratio (HC/HDHEA ratio) as biomarkers of allostatic load and resilience in sows around farrowing, in relation to four different models of farrowing crates, and in relation to different batches by a non-invasive sampling. The study has been conducted on 296 pregnant sows managed in a batch farrowing system from February to June. Sows were kept in multiple pens of 10-15 sows until 5 days before farrowing, then were randomly divided in 4 different models of farrowing crates. The hair samples were taken by shaving for the first time (ST1) 2.6 +/- 1.6 days before the expected delivery date and for the second time (ST2) 88.9 +/- 3.3 days after parturition. The environmental temperature and the relative hu-midity data were recorded and used to calculate the Temperature Humidity Index (THI). HC and HDHEA were determined using a solid-phase microtiter radioimmunoassay (RIA) while HC/HDHEA ratio has been calculated. No differences in terms of hair steroids concentration were found between the four models of farrowing crates and the sampling times (P > 0.05). The interaction between batch and sampling time has been significant for all the biomarkers considered (HC (P < 0.01), HDHEA (P < 0.05) and their ratio (P < 0.01)). During the pregnancy period in collective pens (ST1) HC/HDHEA ratios were never lower (with an exclusion of February) than those in the following characterized by the early postpartum and lactation in individual crates (ST2). It seems that an aggregate effect of different stressors acts on the sows exhausting their ability to cope with adverse events; it should be further investigated the influence of the social interaction in collective pens that cyclically re-occurs in the standard swine production system.

Cortisol is the main glucocorticoid hormone commonly measured to assess adrenocortical activity in vertebrates in response to potential stressors. Competition and habitat quality may act as chronic stressors leading to an increase in cortisol accumulation. Moreover, chronic cortisol concentrations may seriously hamper the reproductive potential, health status and body condition of a species. Using hair collected from the rump of 88 adult roadkill roe deer Capreolus capreolus in the north-eastern Italy, we aimed to assess the effect of both ungulate competitor population densities and habitat suitability on the long-term physiological stress response of roe deer, using hair cortisol as a reference parameter. Our findings revealed that roe deer showed higher cortisol concentrations in response to higher red deer Cervus elaphus population density, most likely as a consequence of direct interspecific competition. No significant cortisol changes were however recorded in response to both wild boar Sus scrofa and roe deer population densities, probably as a result of reduced competition because of abundant feeding resources, different species population densities and spatial/temporal avoidance among species. Moreover, the absence of a significant effect as far as habitat suitability is concerned, suggest that roe deer are well adapted to live even in poor quality habitats most likely as long as they are close to better quality habitats which provide access to food resources and refuge sites. Our results highlight the importance of hair cortisol as a suitable parameter to assess physiological chronic stress response towards different environmental/ecological conditions.

The paper discusses the challenges facing the dairy industry due to increased farm sizes and reduced staff-to-animal ratios, which are impacting animal welfare. The development of precision livestock farming (PLF) technologies has gained momentum to address these challenges. PLF technologies can assess animal welfare and health status by monitoring animal behavior and biological changes, and alerting farmers of any issues. However, the applicability of PLF tools in other productive phases of the dairy cattle is still limited. The article focuses on the challenges of managing unweaned dairy calves, particularly the variability in relation to when calves start consuming solid feed, and how PLF technologies can be used to monitor individual calf intake and manage weaning at the individual level. The attention is mainly focused on the advantages of using automated feeders for unweaned dairy calves, including labor savings, greater precision in measurement and control of individual intake of liquid and solid feed, and higher preweaning growth rates. In particular, a method is proposed, involving a 3D depth camera and a proper algorithm to measure the volume and weight of eaten feed. The method is preliminarily assessed in tests conducted in laboratory, which highlight a remarkable concurrence (differences as low as 2 %) with respect to nominal values.

In humans, allopregnanolone plays important roles in a number of different neurodegenerative disorders, and it has been proposed for use in some therapies. Horses are commonly used as animal models for human neurodegenerative diseases, mental and behavioral disorders, and neuropsychiatric disorders, and there is interest in using hair as a biological sample to study hormones in these conditions. We validated the use of a commercial ELISA kit (DetectX allopregnanolone kit; Arbor Assays), which was designed for serum, plasma, feces, urine, and tissue samples, to assess allopregnanolone in hair samples from 30 humans and 63 horses. The ELISA kit had good precision (intra- and inter-assay CVs: 6.4% and 11.0% for equine hair; 7.3% and 11.0% for human hair, respectively), sensitivity (50.4 pg/mL for both equine and human hair), and accuracy (parallelism and recovery tests) in determining allopregnanolone concentrations in hair from both species. The allopregnanolone concentrations in human hair were 7.3–79.1 pg/mg; the concentrations were 286 ± 141 pg/mg (x̄ ± SD) in mares on the day of parturition and 16.9 ± 5.5 pg/mg in nonpregnant mares. The DetectX ELISA kit offered a simple and accessible analysis of allopregnanolone in human and equine hair samples.

Studies about puberty in dogs are few, probably because many factors are involved in the delicate process of puberty onset, leading to difficulties in the proper enrollment of subjects. Moreover, the use of blood for monitoring hormonal changes can be problematic, and not feasible for long-term studies. Hair and nails proved to be suitable matrices for the retrospective evaluation of hormones' long-term accumulation. This study was performed using hair and nails for the evaluation of testosterone (T), 17β-estradiol (E2) and progesterone (P4) concentrations to assess possible sexual steroid changes during the peripubertal period in dogs. The results, obtained on five males and five females, showed a significant increase in T in hair and nails of males immediately before puberty. In females, a significant increase in E2 at puberty and a marked increase in P4 after puberty was found in both biological specimens. Sex-related differences were detected only for T hair concentrations, but when the sex and sampling time were considered together, hair and nails T and nails P4 concentrations allowed us to discern between male and female dogs at specific sampling times. The results from this study showed that hair and nails are useful biological specimens for the retrospective evaluation of changes in T, E2 and P4 concentrations in peripubertal dogs.

Testicular ultrasonography and steroid concentrations (cortisol, dehydroepiandrosterone sulfate (DHEA-S), cortisol/DHEA-S ratio, testosterone) in hair were examined for their utility in the bull breeding soundness evaluation (BBSE). Beef and dairy bulls (n = 16; 2.7 ± 0.4 years old; body condition score 3.2 ± 0.1) of five breeds were maintained under the same conditions at an accredited semen collection center. Bulls underwent routine semen collection twice weekly for 12 weeks and semen was processed and cryopreserved. Ultrasonography and hair sampling were undertaken at the last semen collection. Bulls with homogeneous testicular parenchyma (n = 8) had a higher (p < 0.05) percentage of motile sperm post-thawing compared with bulls with heterogeneous parenchyma (n = 8). There were no differences (p > 0.05) in the hair concentrations of cortisol, DHEA-S, and testosterone between bulls with homogeneous and heterogeneous parenchyma. In bulls with homogeneous parenchyma, hair DHEA-S concentration was positively correlated with percentage motile sperm (R2 = 0.76), progressively motile sperm (R2 = 0.70), and motility yield (R2 = 0.71). The findings indicate that the integration of testicular ultrasonography and hair DHEA-S status in the BBSE could provide a more comprehensive assessment of indicative fertility in bulls. Additionally, ultrasonography can be used in the BBSE when the evaluation of semen parameters is not available.

Over time, cortisol has drawn more and more attention in the research on how the body reacts to stress. Furthermore, it has a catabolic role, in energy mobilisation, and in the immune response, in the activation of processes to defend the organism. This hormone is present in wool, which, differently from other biological samples, allows for an easily sampling procedure and provides a reliable retrospective matrix unaffected by acute stress. The two major goals of this study were to assess cortisol as an index of the activity of the hypothalamic-pituitary-adrenal axis in lambs prior birth to the time of slaughtering by wool in four European sheep breeds and to investigate if an increased HPA axis activity may impact the average daily weight gain in lambs. A total of 97 lambs were involved in the study. Wool samples were collected from the left shoulder of the lambs included in the study in different sampling times (ST): at birth (ST1) and then at 30-day intervals from the same area of skin for a period of up to 120 days of age as re-shaved wool (ST2, ST3, ST4 and ST5). All animals were weighed at birth and the day before slaughter. The wool cortisol was evaluated by the AlphaLISA immunoassay method after having extracted steroids from the samples. The wool cortisol concentrations were affected both by breed (P < 0.01) and ST (P < 0.01). All the breeds considered showed a reduction of the wool cortisol during the experi-mental period, but with different trends. The wool cortisol at the ST1 and the live weight at birth was negatively correlated (r =-0.574; P < 0.01) as well as the average wool cortisol concentrations without the values recorded at ST1 and the average daily gain (r =-0.542; P < 0.01). The higher concentrations recorded in the sample collected at birth could origin from the progressive rise in foetal plasma cortisol concentrations that have an important role in structural maturation and in the neonatal adaptation to the extrauterine life. The trends of wool cortisol decreasing after birth till four months of age suggest that each breed could have an its own HPA axis setting. Our findings may be related to the idea of animal robustness and the various metabolic tactics used by various breeds to adapt to their environments during evolution. In conclusion, this study underlined a time-specific and a breed-characteristic wool cortisol concentration. Moreover, from the analyses emerged that the wool cortisol at birth and the live weight at birth was negatively correlated as well as the average of the wool cortisol concentrations recorded postnatally and the average daily gain.