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In this study, circulating β-endorphin, ACTH and cortisol concentrations were chosen as physiological markers of the hypothalamic-pituitary-adrenal (HPA) stress-related response in Therapeutic Riding Horses (TRHs). The aim of this research was to investigate HPA axis hormonal response in TRHs and check the effects of different kind of riders (mentally-impaired and able-minded riders). The main hypothesis was that, in TRHs, the HPA axis reaction would be less responsive to mentally-impaired than to able-minded riders, due to increasing levels of horse control by the able-minded riders. 6 TRHs were randomly ridden in the same setting by 2 groups of riders, adult mentally-impaired riders (Treatment Group A) and able-minded adult riders (Treatment Group B). Both groups consisted of inexperienced riders. Each rider rode 2 times a week for 6 consecutive weeks. The horses performed the same gaits and exercises at all sessions, with both Treatment Group A and Treatment Group B riders. All hormones’ concentrations were determined on a resting day (baseline, T0), before the session (T1), and at 5 min (T2) and 30 min (T3) after each session. Statistical analysis showed significant effects of the different Treatment Groups on the cortisol concentrations only, with lower cortisol concentrations both at T2 and at T3 in Treatment Group A than in Treatment Group B. Related to changes over the sampling time, ccortisol concentrations in horses were significantly higher at T1 than at T0 in Treatment Group A, and at T1, T2 and T3 than at T0, in Treatment Group B. ACTH concentrations were significantly higher at T1, T2 and T3 than at T0, only in Treatment Group B. β-endorphin concentrations at T3 were significantly higher than at T0, only in Treatment Group B. Results showed differences in the TRHs' stress levels between rider groups, with significantly lower cortisol concentrations in Treatment Group A than in Treatment Group B. Thus, although sessions’ workload stress was equivalent, the minor response of HPA axis could be related to different effects of horse-human interaction.

We compared the effects of different feeding strategies on hormonal and oxidative stress biomarkers in guide dogs during specialized training programs. Eight neutered adult dogs belonging to the Labrador retriever breed were divided during the training work into two homogeneous groups for sex (2 males, 2 females), age (17 months ± 1), initial body weight (26.3 kg ± 1), and BCS (4.5 of 9 ± 0.11) and fed two commercial diets with different concentration of energetic nutrients. One diet was a performance diet (HPF) characterized by low-carbohydrate/high-protein and fat content (29:39:19% as-fed) and the other a normal maintenance diet (LPF), characterized by high-carbohydrate/low-protein and fat content (50:24:12% as-fed). The trial lasted 84 days. At days 0, 28, 56, and 84, 180 min before the training work (T0) and immediately after (T1) and after 120 min (T2), blood adrenocorticotrophic hormone (ACTH), cortisol, d-ROMS (reactive oxygen metabolites–derived compounds), and BAP (biological antioxidant potential) were evaluated. Lactate was measured at T0 and T1. The statistical model included the effects of diet (HPF vs. LPF), time (from day 0 to day 84, end of the trial), and exercise (T0, T1, and T2) and their interaction. ACTH (P = 0.002) and cortisol (P = 0.013) showed higher values in the HPF than in the LPF group; there were no significant differences observed for lactate. Time showed no significant difference for any hormones or blood lactate. Exercise significantly (P < 0.001) influenced ACTH and cortisol concentrations, showing higher values at T1 than T0 and T2, and with lactate higher (P < 0.0001) at T1 than T0. Diet did not influence biomarkers of oxidative stress. Time did significantly (P < 0.05) influence BAP results but not d-ROMs. Exercise had no effect on BAP results, but d-ROMs were higher at T0 than T2 (P = 0.001). There was no interaction effect. The pituitary-adrenal (HPA) axis response and the oxidative stress indices could represent an objective method to identify optimal dietary protocols for creating a successful guide dog during the early training period.

The review discusses the hormonal changes during exercise stress. The exercise generally produces a rise of adrenaline (A), noradrenaline (NA), adrenocorticotropic hormone (ACTH), cortisol, glucagon, growth hormone, arginine vasopressine, etc., and a drop of insulin. The hormonal events during reestablishment of homeostasis due to exercise stress can be divided into a catabolic phase, with decreased tolerance of effort, and reversible biochemical, hormonal and immunological changes, and an anabolic phase, with a higher adaptive capacity, and enhanced performance. The two main hormonal axes activated in the catabolic phase are sympathetic–adrenal–medullary system and hypothalamic-pituitary-adrenal (HPA) axis, while in the anabolic phase, growth hormone-insulin-like factor I axis, and gonadal axes. The hormonal responses during exercise and recovery can be regarded as regulatory and integrated endocrine responses. The increase of catecholamines and ACTH is dependent on the intensity of exercise; a marked increase in plasma A occurs during exercises with high emotional content. The response of cortisol is correlated with the duration of exercise, while the effect of exercise duration on β-endorphin changes is highly dependent on the type of exercise performed. Cortisol and β-endorphin changes usually occur in phase, but not during exercises with high emotional content. Glucocorticoids and iodothyronines are involved in meeting immediate energy demands, and a model of functional interactions between HPA axis and hypothalamic-pituitary-thyroid axis during exercise stress is proposed. A modulation of coping responses to different energy demanding physical activities required for sport activities could be hypothesized. This review supports the proposed regulation of hypophysiotropic TRHergic neurons as metabolic integrators during exercise stress. Many hormonal systems (ghrelin, leptin, glucose, insulin, and cortisol) are activated to control substrate mobilizations and utilization. The cardiovascular homeostasis, the fluid and electrolyte balance during exercise are highly dependent on vasoactive hormones (antidiuretic hormone, atrial natriuretic peptide, renin–angiotensin–aldosterone, and prostaglandins) control.

The aim was to compare temporarily together the changes occurred along the early pregnant and nonpregnant mares on the ovarian, adrenocortical, thyroid, and hematochemical profiles (total protein, glucose, albumin, complete blood count). Sixteen mares were randomly divided into two groups: the experimental group of 10 mares submitted to artificial insemination, and the control group of six mares no submitted to insemination. The experimental group was analyzed after the human chorionic gonadotropin treatment (baseline = day 0), after the artificial insemination (T1), 24 hours after (T2), 15 days after (T3), and 30 days after (T4) the insemination; the control group was analyzed after placebo treatment (day 0), considering T1 the day after the placebo treatment and T2-T4 the time points after. An interaction between treatments and sampling time on estrogen (E2) (P

The purpose of this study was to evaluate the contribution of the total content of glycosaminoglycans (GAGs), cortisol, iron, and hemoglobin (Hb) in term and nursing mares. Twenty-four healthy mares, aged 7 ± 1.5 years, were examined. Eighteen pregnant mares were considered the observational group, and six nonpregnant mares were considered the control group, by random selection. Blood samples were taken at the 10 and 11 months of gestation and at 15 and 30 postpartum days for the observational group and in baseline condition for the control group. Two-way analysis of variance showed a significant interaction between peripartum, postpartum, and time points for GAGs (F = 34.75; P

To evaluate whether β-endorphin (β-END) is a reliable marker of stress in equines, the reference values and changes in different models of stress (exercise, transportation) have been considered. Baseline circulating β-END concentrations of horses showed seasonal and circadian fluctuations. Increased β-END concentrations were associated with the severity and type of exercise stress and were positively correlated with both exercise speed and intensity. Positive correlations between β-END or adrenocorticotropic hormone (ACTH) and cortisol were recorded after competitive and experimental jumping over different fence height, related to the emotional content of trials. In Standardbreds, an exercise effect on β-END changes during both training and competition emerged. In trained horses, after exercise with psychomotor disables, no β-END and ACTH changes were detected. After short road transport (100 km), concomitant variations in β-END and ACTH concentrations suggested the effect of loading and confinement. In experienced stallions, after simulated transport, higher β-END concentrations than basal, while lower concentrations than after conventional transport, were recorded. Positive correlations among β-END, ACTH, and cortisol changes in both conventional and simulated transport were observed. After a very short road transportation (50 km), no significant differences in β-END concentrations were recorded in experienced equines. Horses facing forward had significantly higher β-END concentrations than horses facing backward. It can be supposed that, in equines, β-END is released during the early stages of stress, so improving the hormonal cascade of hypothalamic–pituitary–adrenal axis and β-END could facilitate the active coping strategies under stressful conditions and can be regarded as a precocious marker of stress.

This review highlights the response of equine circulating total and free iodothyronines to exercise, as a peculiar stress model, during different competitive and noncompetitive sport activities. The interplay with the hypothalamus-pituitary-adrenal (HPA) axis, using cortisol as modulator of physical and/or mental exercise demands, is regarded in terms of coping with energy homeostasis and interfering effects of stress on performance. Triiodothyronine (T 3 ) and free iodothyronines (fT 3 and fT 4 ) respond to exercise stress, showing specific patterns according to type and workload of exercise, as well as to environmental conditions. A dependence of T 3 and fT 3 changes on exercise-related variables (fence height and performance success) can be shown. General increases of T 3 and significant positive correlations between cortisol and T 3 changes have been recorded in sport activities requiring frequent transitions from anaerobic to aerobic metabolism for energy recruitment and specific motor abilities (show jumping, western riding events, gymkhana, trekking). During competition, significant decreases have been observed concerning T 3 , fT 3 , and fT 4, in jumpers, Standardbreds, and Thoroughbreds. In jumpers, negative correlations between β-endorphin and T 3 or fT 3 changes were found, while during noncompetitive show jumping, negative correlations were recorded between T 4 and adrenocorticotropin or β-endorphin changes. The influence of mental and emotional components of exercise stress could be supposed by considering repetitive physical activities (training programs or hippotherapy). Thus, a contribution of iodothyronines to exercise-stress coping can be proposed, with a differentiated pattern according to different sport activities. An interplay of iodothyronines with HPA axis hormones could be also suggested.

We tested the hypothesis that diet affects equine feeding behavior and that diet composition affects a shift in energy metabolism characterized by a wide range of neuroendocrine changes. We investigated the effects of training sessions on circulating serotonin (5-HT), tryptophan, and β-endorphin (β-EN) concentrations in horses to ascertain whether two different isoenergetic diets would affect this response. Thirty-six Dutch Warmblood horses were randomly distinguished in 18 horses fed with a low-fiber diet (LF) and 18 horses fed with a high-fiber diet (HF). The training session was represented by a medium-heavy exercise and consisted of 21 minutes/day of walk, 36 minutes/day of trot, 15 minutes/day of canter, for a total of 72 minutes/day. At the end of this session, a set exercise test was performed. There was a significant increase in plasma 5-HT ( P P

Nutrition plays a leading role that most influences thyroid response and energetic metabolism. Aim was to compare the effect of diet on thyroid and lipid status in guide dogs during a 12-weeks training period. Eight Labrador Retrievers were divided into two groups homogeneous for sex, age, body weight, and Body Condition Score (BCS) and fed two commercial diets one, HPF, characterized by low-carbohydrate/high-protein/high-fat (29%:39%:19% as-fed) and the other, LPF, by high-carbohydrate/low-protein/low-fat (50%:24%:12% as-fed) content. The serum thriiodothyronine (T3), thyroxine (T4), cholesterol (CHOL), triglycerides (TAGs) and non-esterified fatty acids (NEFA) were determined at Day 0, 28, 56, and 84, before the daily training. Statistical model included the effects of Diet (HPF vs. LPF) and Time (Day 0 to Day 84), and their interaction. In the HPF group, Diet significantly (p &lt, 0.01) increased T4, CHOL, and TAGs and decreased NEFA. In both groups, Time significantly (p &lt, 0.05) increased T4 and TAGs, CHOL at Day 28, and NEFA at Day 56. The interaction did not influence serum hormones and lipid pattern. The adjustments in thyroid and lipid responses to moderate exercise in HPF group were driven mainly by the nutrient composition of the diet in relation to the involvement of metabolic homeostasis.

Aim: The changes of the hypothalamic pituitary adrenal (HPA) axis response to a long distance transportation results in increase of adrenocorticotropic hormone (ACTH) and cortisol levels. The purpose of the study was to quantify the level of short-term road transport stress on circulating ACTH and cortisol concentrations, related to the effect of previous handling and transport experience of horses. Materials and Methods: The study was performed on 56 healthy horses after short-term road transport of 30 km. The horses were divided into four groups, Groups A, B, C, and D, with respect to the handling quality: Good (Groups A and B), bad (Group D), and minimal handling (Group C) conditions. According to the previous transport, experience horses were divided as follows: Horses of Groups A and D had been experienced long-distance transportation before; horses of Groups B and C had been limited experience of transportation. Results: One-way RM-ANOVA showed significant effects of transport on ACTH changes in Groups B and C and on cortisol changes in both Groups A and B. Groups A and B showed lower baseline ACTH and cortisol values than Groups C and D; Groups A and B showed lower post-transport ACTH values than Groups C and D. Groups A, B, and C showed lower post-transport cortisol values than Group D. Only Groups A and B horses have shown an adequate capacity of stress response to transportation. Conclusion: The previous transport experience and quality of handling could influence the HPA axis physiological responses of horses after short-term road transport.

The purpose of this study was to determine which physiological seasonal thyroid and lipid panel (triglyceride, [TG], total cholesterol, [tCho], high-density lipoprotein cholesterol, [HDL Cho], LDL cholesterol, phospholipids, [PDs]) changes occur in 12 Thoroughbred pregnant and six nonpregnant mares over a period of 12 months, from April to March, by into account the lactation stage. Serum total triiodothyronine (T3) and thyroxine (T4) levels were measured using immunoenzymatic assay kits; the serum lipid panel was analyzed using the enzymatic colorimetric method. One-way ANOVA reported a significant effect of time over 12 months for T3 (F = 5.46; P < 0.001) and T4 (F = 3.98; P < 0.001), in both pregnant and nonpregnant mares, and for triglyceride (F = 2.57; P < 0.01), tCho (F = 2.32; P < 0.01), HDL Cho (F = 5.60; P < 0.0001), and PDs (F = 7.01; P < 0.0001) in pregnant mares. Two-way ANOVA repoted a significant lactating effect compared with nonlactating stage for T3 (F = 8.33; P = 0.006), T4 (F = 6.43; P = 0.003), tCho (F = 10.38; P = 0.0078), HDL Cho (F = 7.64; P = 0.020), and PDs (F = 5.07; P = 0.048). Thus, it appears that under similar environmental condition, nutrition regime, and management system, lactation stage plays a significant role in the seasonal thyroid and lipid profiles in Thoroughbred pregnant mares, with higher T3, T4, and PDs values, and lower tCho and HDL Cho in lactating than nonlactating mares. The physiological values obtained in this study may be used as additional resources to evaluate thyroid and lipid profiles in Thoroughbred pregnant and nonpregnant mares, generating a wished numbers of observation, especially when the additional breed and physiological conditions are considered.

Background: The hypothalamic-pituitary-adrenal (HPA) axis undergoes adaptations throughout housing system that might contribute to the avoidance of adverse effects of welfare status in dogs housed in a shelter. Nevertheless, the influence of housing systems and stabling time on glucose and PCV changes is little known. The purpose of the present study was to evaluate the patterns of cortisol, glucose and PCV in dogs housed in a kennel and normal environments, evaluating the differences between housing systems, by taking account the different stabling time and sex. Materials, Methods & Results: The study comprised 98 cross-breed dogs, aged 4 ± 1.5 years, lodged in a kennel (observational group I: N= 61, 29 females and 27 males), in paired household dogs (control group II: N= 25, 13 females and 12 males) and in unpaired household dogs (control group III: N= 12, 6 females and 6 males). Females of both groups were spayed. The subjects were studied on the basis of different stabling times, ranged among

The objective of current study was to evaluate the effect of transportation stress on the circulating adrenaline (A), noradrenaline (NA) and dopamine (DA) responses of stallions, according to the different distances. Forty-two stallions were studied before and after road transportation of 100, 200 and 300km, for a period of 1-3h. An increase in plasma A after 100km (P0.001) was observed. A similar result was seen in plasma NA after 100km (P0.001), and 300km (P0.001). Increases in plasma DA after 100 and 200km (P0.0001) were observed, with a decrease after 300km (P0.0001). Significant interactions among groups and times for A (P0.0001), NA (P0.0006) and DA (P0.0001) changes were observed. These results indicate that the sympatho-adrenal system response of horses was greater after short (100km), than medium-longer period of transportation (200 and 300km). This may indicate an adaptation process during transport, considering A and NA as the primary candidate neurotransmitters for the maintenance of homeostatic process to alleviate the effects of the perceived transportation stress.

This study compares the circulating total (T 3 and T 4 ) and free (fT 3 and fT 4 ) iodothyronine levels in horses subjected to simulated and conventional road transportations. Eighteen healthy Sanfratellano stallions were used. Three different durations were compared (1, 2, and 3 hours) in both situations. Blood samples were collected 1 week before the experimental treatment, at rest in baseline conditions, at 09:00, 10:00, 11:00, and 12:00 AM; before loading and after 1, 2, and 3 hours of simulated transport, immediately after unloading; and 3 weeks later before loading and after transport of 50, 150, and 250 km, after unloading. Results showed higher T 3 values after 150 km ( P = .0314) and 250 km ( P = .0497) and higher T 4 values after 50 ( P = .0138), 150 ( P = .0169), and 250 km ( P = .0013) after conventional than simulated road transportation. From the obtained data, it is seems that total and free iodothyronines may be useful in assessing short-term transportation stress in horses.

Foaling is a crucial period in mares' life and their newborns, resulting in a number of physiological and behavioral challenges, which may have predictable effects on foal's welfare and well-being. The aim of this study was to assess the patterns of circulating adrenocorticotropic hormone (ACTH), cortisol, and glucose concentrations in newborn foals born by full-term delivery, by taking into account the potential correlations with Appearance, Pulse, Grimace, Activity, Respiration (APGAR) scores. Newborn respiratory rate, rectal temperature, birth weight, time to stand up, time to suck, and allantochorion weight were also considered. Eight thoroughbred foals, 5 colts and 3 fillies, were assessed 20 minutes (T0) and 30 days (T1) after birth. One-way analysis of variance showed a significant effect of time on ACTH ( P = 0.0024) and cortisol ( P = 0.003) concentrations, with the highest concentrations at T0. Significant positive correlations between ACTH and cortisol values at T0 (r = 0.67; P P P P

Growth hormone (GH) and insulin-like growth factor (IGF-I) exert essential functions to maintain an adequate metabolic activity for correct placental and fetal development. Although fructosamine (FRUCT) is used in clinical evaluation to assess the glycaemic state, the relationships between GH, IGF-I and FRUCT remain unknown in the mare. Therefore, the objectives of this study were to evaluate the relationships among these parameters in pregnant mares. A total of 30 healthy Spanish Purebred mares, with an age range of 9.33 ± 3.31 years, were studied during the 11 months of gestation. Serum concentrations of GH, IGF-I and FRUCT were analyzed by EIA, competition ELISA and spectrophotometry, respectively. GH showed a biphasic pattern, the first occurred during 4th and 5th month and the second which was higher than the 1st one during the 7th, 8th and 9th month (P 0.05). Compared to the 1st month, the IGF-I concentrations increased in the 2nd month (P 0.05), decreased in the 3rd and 4th month and increased to reach the maximum average value in the 5th month (P 0.05); after slight oscillations between the 6th and 8th month, IGF-I concentrations increased in the 9th month (P 0.05), decreasing until the end of gestation. FRUCT increased progressively and significantly from the 6th month of gestation, reaching the maximum values in the last month of gestation (P 0.05). These results suggest that alternative mechanisms other than GH and IGF-I could be involved in the regulation of glycaemic metabolism in pregnant mare.

Aim: To investigate the effects of training sessions on circulating β-endorphin changes in sport horses before and after competition and to ascertain whether competition would affect this response. Materials and Methods: A total of 24 trained jumping horses were randomly assigned to one of two training groups: Group A (competing) and Group B (not competing). To determined plasma β-endorphin concentrations, two pre- and post-competition training weeks at aerobic workout and two competitive show jumping event days at anaerobic workout were measured before, 5 and 30 min after exercise. Exercise intensity is described using lactate concentrations and heart rate. The circuit design, intensity, and duration of training sessions were the same for both groups. Results: In Group A, one-way analysis of variance for repeated measures (RM-ANOVA) showed significant effects of exercise on β-endorphin changes (F=14.41; p

The aim of the research was to evaluate whether a 6-week conventional training programme for Western riding and each exercise training session can induce any different effect on changes of cortisol, total and free iodothyronine and oestradiol-17β levels of mature Quarter Horses. Eighteen Quarter Horses aged 16–20 years (six stallions, six geldings and six mares; mean body weight: 510 ± 70 kg) were recruited according to the level of competition experience, age and pre-training status and were divided into two groups paired by gender: group A, control horses ( n = 9), and group B, trained horses ( n = 9). For 6 weeks, group B horses performed a 5 days per week conventional training programme for Western riding, including 1 day of specific exercise session to simulate the different competitive events. Over the 6-week training period, blood samples from horses were collected once a week immediately before, under resting conditions and 24 h post exercise session. Two-way repeated measures analysis of variance (RM-ANOVA) showed a significant interaction between training and time for changes in triiodothyronine (T 3 ) ( P P 4 ) and free T 4 (fT 4 ) ( P 4 ( P A significant interaction between exercise session and time for T 4 ( P 4 ( P The results of this study might suggest the benefits of taking into account cortisol and iodothyronine changes to effectively monitor training in Quarter Horses.

The aim of this research was to evaluate the changes in β-endorphin, cortisol, total and free iodothyronines, and estradiol-17β levels of 10 unfit Quarter horses undergoing training under resting conditions during a 24-hour period. All animals that were sedentary since 3 months were divided into two groups comprising five animals each: group I, pre-trained for western riding (age: 8.8 ± 6.7 years; two stallions, one gelding, and two mares) and group II, not pre-trained for western riding (age: 9.4 ± 6.8 years; one stallion, three geldings, and one mare). Blood samples were collected from horses under resting conditions every 4 hours, from 5.30 am to 5.30 am of the next day. A two-way analysis of variance with repeated measures showed that the interaction between pre-training status and sampling time was not significant for hormone changes, but tended to be significant for fT 3 changes ( P 3 ( P P P 3 ( P P

REASONS FOR PERFORMING STUDY Involvement of thyroid function on performance warrants further investigation as limited data exists on the effects of showjumping on the dynamics of total and free iodothyronines. OBJECTIVES To investigate the response of circulating total and free iodothyronines in horses to experimental showjumping sessions and compare with the effects normally induced by competition and determine if fence height has any effect. MATERIALS AND METHODS Using a randomised crossover study design 6 trained horses were studied during experimental showjumping sessions over 10 fences of different height: 1.00 m (Session 1), 1.10 m (Session 2), 1.20 m (Session 3). Hormone levels were recorded before, after warm-up, 5 and 30 min post exercise. T(3), T(4), fT(3), fT(4) concentrations were analysed by ELISA/competition using streptavidin technology. RM-ANOVA was applied to test for any differences in basal and warm-up values of different sessions. Two way RM-ANOVA was applied to test for any effects of interaction between fence height and time. The differences between individual means over time were assessed using a post hoc multiple comparison test (Bonferroni). RESULTS Basal T(4) changes over the sessions (P < 0.05) were recorded. After warm-up, T(4) concentration results were lower than basal in Session 1 (P < 0.05). Higher than basal values were recorded 30 min post exercise for T(3) (P < 0.001), T(4) and fT(4) (P < 0.01) in Session 2 and for T(4) (P < 0.05) and fT(4) (P < 0.01) in Session 3. The interaction fence height/time results were significant on T(3) (P < 0.03) and fT(4) (P < 0.03); sampling time on T(3) (P < 0.0007), T(4) (P < 0.001) and fT(4) (P < 0.002) post exercise changes. CONCLUSION Showjumping over the highest fences induced a release of T(3) from skeletal muscle, probably due to 5'-desiodase activity and increase of fT(4), due to thyroid stimulation and/or changes in capacity to bind iodothyronines.

Summary Reasons for performing study: Limited knowledge exists about the differentiated effects of competitive and noncompetitive showjumping on thyroid function and relationships with hypothalamic-hypophysis-corticoadrenal hormones. Objectives: To obtain preliminary data about differentiated effects of competitive and noncompetitive showjumping on total and free iodothyronines, b-endorphin, ACTH and cortisol of horses. Material and methods: Five trained healthy jumper horses were studied during competitive and noncompetitive showjumping, performed in the same circuit design over 10 fences of 1.10 m. Hormone levels before, 5 and 30 min post exercise were recorded. Serum iodothyronines and cortisol concentrations were measured in duplicate utilising EIA kits. Serum ACTH and plasma b-endorphin concentrations were analysed in duplicate utilising RIA kits. Two-way RM ANOVA was applied to test for effects of interaction between different type of session and time. Significant differences between post exercise and basal values were established using Bonferroni’s multiple comparison test. A linear correlation analysis (Pearson’s method) was performed to analyse the relationships between total and free iodothyronines and between iodothyronines and b-endorphin, ACTH and cortisol. Results: In sampling times adopted no statistical different effects of type of session were recorded on hormone variables. Sampling time affected ACTH (F = 4.25; P

Background: Shearing is considered as a stressful factor in sheep, capable of causing some behavioural changes including variations of body condition and hormonal and haematochemical parameters. On these basis, circulating ACTH and cortisol concentrations were determined in sheep before and after exposure to aversive stimuli in order to evaluate the potential use of these hormones to objectively measure physical and mental stress responses to isolation, restraint and shearing.Materials, Methods & Results: Forty Pinzirita sheep, used as experimental group, were evaluated in baseline conditions, 24 h before isolation, restraint and shearing (T0), after isolation (T1), after restraint and shearing (T2), by taking into account the influence of previous shearing experience (just shorn). A control group of forty sheep (intact) was evaluated in baseline condition (T0). According to previous experience the experimental subjects were divided in two groups, respectively group A represented by 20 sheep (10 males and 10 females), aged 1-2 years, without previous shearing experience (intact); and group B represented by 20 sheep (10 males and 10 females), aged older than 2 years, previously exposed to shearing (just shorn). A control group C of 40 sheep splitted into two sub-groups represented by 10 intact males and 10 intact females, aged 1-2 years, and 10 males and 10 females just shorn, aged older than 2 years, was evaluated in baseline conditions (T0). Blood samples were collected 24 h before experimental practices (T0: 08:00 h), after 1 h after of isolation (T1) and after restraint and shearing, around an average of 5 min (T2). All samples were taken in quiet conditions by the same operator. Serum ACTH concentrations were assayed by a commercial radioimmunoassay (RIA). Serum cortisol concentrations were assayed by amplified Enzyme Immunoassay (EIA). Two-way RM ANOVA showed a significant effect of husbandry procedures on ACTH changes, with higher ACTH and cortisol concentrations of just shorn than intact males (F = 15.76; P < 0.0001) and females (F = 17.34; P < 0.0005), and on cortisol changes, with higher cortisol concentrations of just shorn than intact males (F = 6.54; P < 0.01) and females (F = 22.66; P < 0.0001).Discussion: The highest ACTH and cortisol values after isolation, with an appreciable increase especially after restraint and shearing in just shorn sheep, showed that the previous shearing exposure could not induce a habituation to the stimulus, probably promoting a larger release of ACTH and cortisol hormones, so inducing an early and marked coping response to stress in just shorn specimens. Thus, it would appear that different ACTH and cortisol responses of sheep with or without previous shearing experience over the study period resulted in some significant differences when exposed to isolation, restraint and shearing, probably due to changes in pituitary-adrenal axis reactivity. Nevertheless, it is possible to interpret the increase in ACTH and cortisol concentrations related to intrinsic endocrine control mechanisms as an increase due to a rise in the stressful stimulus or coping response. The magnitude of ACTH and cortisol changes following isolation, restraint and shearing suggests that measurements of both hormones are useful in assessing husbandry procedures stress in sheep, with marked elevations in just shorn sheep, indicating that experience can induce an early much larger coping response to stressful practice of shearing.

The present investigation was focalized to explore the circulating β-endorphin, adrenocorticotrophic hormone, and cortisol patterns as tool to compare the effects of simulated transportation (ST) and conventional transportation (CT) of 18 healthy Sanfratellano stallions accustomed to this procedure. Three different time points of duration (1, 2, and 3 hours) during STs were compared to three different time points of distance (50, 150, and 250 km) during CTs. Blood samples were taken 1 week before the experimental treatment, at rest in baseline conditions; at the first, the second, and the third week during STs, before loading, and after 1, 2, and 3 hours of duration, immediately after unloading; at the fourth, the fifth, and the sixth week during CTs, before loading, and after 50, 150, and 250 km, immediately after unloading. Compared to three different time points of distance (50, 150, and 250 km) of CTs, results showed lower β-endorphin concentrations after 1 hour ( P P P P P

The aim of this study was investigate the effect of growing associated with different gender on circulating total and free iodothyronine concentrations during the first 13 mo of age in foals. In addition, we investigated the evolution of circulating concentrations of thyroid hormones during the first 3 d of weaning. Blood was collected from 13 clinically healthy Thoroughbred foals every month. All foals were weaned at the 4 mo and blood samples were taken also at 24, 48 and 72 h after weaning. The results obtained showed growing effects for tri-iodothyronine (T 3 ), thyroxine (T 4 ), free tri-iodothyronine (fT 3 ) and free thyroxine (fT 4 ) values ( P Serum T 3 concentrations averaged respectively 2.89 and 0.29 nmol/L at 7 and 9 mo. Serum T 4 concentrations averaged respectively 100.17 and 21.77 nmol/L at 1 and at 10 mo. Serum fT 3 concentrations averaged respectively 6.96 and 1.50 pmol/L at 1 and 4 mo. Serum fT 4 concentrations averaged respectively 31.40 and 4.93 pmol/L at 1 and 9 mo. Significant correlations between T 3 , T 4 , fT 3 and fT 4 with body weight (BW) and between T 3 , T 4 and fT 4 with age were observed. Weaning effects ( P 3 and fT 4 levels. No differences ( P > .05) in T 4 and fT 3 levels were observed over the 3-day period. Gender effects ( P 3 , T 4 , fT 3 , and fT 4 levels. Significant correlations between T 4 and fT 4 with BW and age were observed in colts and fillies. T 3 concentrations were correlated with age only in colts and fT 3 with BW only in colts. The results obtained seem to lend support to the recognized effects of growing and weaning in modulating the thyroid function of Thoroughbred foals. In fact, significant and differentiated effects of growing and weaning on total and free iodothyronine levels have been demonstrated.

The aim of the research was to study the total and free iodothyronine (T3, T4, fT3, fT4) changes of trained horses transported before and/or after competition, and performing in show jumping competition, respectively. Six horses were studied in four different sessions during four consecutive weeks. During the first week, horses were submitted to transport before competition (sessions: t0 = before transport, T0 = after transport). Then, during the second week, horses were submitted to transport after competition (sessions: t1 = before transport, T1 = after transport). During the third week, horses participated in a competitive show jumping event (sessions: t2 = before competition, T2 = after competition). During the fourth week, horses were submitted to transport and to a competitive show jumping event (sessions: t3 = after transport and before exercise, T3 = after exercise). Compared with t0 session, t1 showed higher T3 (P < .01) and lower fT4 (P < .01) concentrations. Compared with t2 session, t3 showed higher T3 (P < .01) and lower fT3 (P < .01) concentrations. A significant effect of competition on fT3 changes (F = 4.227; P < .05) was recorded. The results obtained showed that transport and show jumping competition differently influenced the thyroid responses of trained sport horses to physiological and psychological stress, also according to the individual experimental sessions.

AIM The present study was undertaken with the objective to obtain insight into the dynamics of the release of β-endorphin, adrenocorticotrophic hormone (ACTH) and cortisol in response to machine milking in dairy cows. MATERIALS AND METHODS A total of 10 healthy multiparous lactating Italian Friesian dairy cows were used in the study. Animals were at the 4(th)-5(th) month of pregnancy and were submitted to machine milking 2 times daily. Blood samples were collected in the morning: In baseline conditions, immediately before milking and after milking; and in the early afternoon: In baseline conditions, before milking and after milking, for 2 consecutive days. Endocrine variables were measured in duplicate, using a commercial radioimmunoassay for circulating β-endorphin and ACTH concentrations and a competitive enzyme-linked immunoassay for cortisol concentration. RESULTS Data obtained showed a similar biphasic cortisol secretion of lactating dairy cows, with a significant increase of cortisol concentration after morning machine milking, at both the 1(st) and the 2(nd) day (p

Gymkhana is an equestrian event consisting of speed pattern racing and timed games for riders on horses. The aim of the study was to evaluate the effects of gymkhana competition on total cortisol and total and free iodothyronine changes in 23 Arabian purebred horses, by taking into account the effects of previous sport experience on gymkhana riding events. Compared with pre-competition values, an increase of total cortisol concentration has been observed in experienced horses at 30 minutes (P < .001) after exercise and in inexperienced horses both at 5 minutes (P < .05) and at 30 minutes (P < .01) after exercise. Compared with pre-competition values, an increase of total triiodothyronine (T3) concentration has been observed in experienced horses at 5 minutes (P < .05) after exercise. Data obtained showed that gymkhana riding events induced differential adrenocortical and thyroid responsiveness according to previous experience of sport horses. Hence, cortisol and iodothyronine patterns may provide additional information for the monitoring of gymkhana riding performance.

This is an observational study on the adaptive responses of circulating cortisol levels to milking stress evaluated in 34 mature lactating jennies (No = 16 non-milked; No = 18 milked), aged 4–18 years, in the 5th–6th month of pregnancy. The subjects not submitted to milking were divided in two groups on the basis of different times of basal blood sampling (group I: 08:00 a.m. and group II: 04:00 p.m.). These subjects were designated as control groups. The subjects submitted to milking were divided in two other groups on the basis of different times of blood sampling and the method of milking carried out, either at 08:00 a.m. (group III: hand milking) or at 04:00 p.m. (group IV: machine milking). These subjects were designated as observational groups. The median age of jennies ranged between 5 years for groups I and III and 11 years for groups II and IV. Blood samples were collected once a day from the jugular vein, in basal conditions, at 08:00 a.m. for groups I and III, and at 04:00 p.m. for groups II and IV; blood samples were also collected 5 and 15 min after milking in groups III and IV. RM-ANOVA showed a significant effect on the cortisol changes of hand milking only (P

The aim of this study was to investigate thyroid hormone levels in horses stabled in two different locations on the island of Sicily. The study was carried out on a total of 72 clinically healthy Sanfratellano horses ranging in age from 5 to 9 years and weighing 585 ± 40 kg. The results showed higher thyroxine values (P0.02) in horses stabled in an endemic goitre area (group II) than those observed in horses in a non-endemic area (group I). Unexpectedly, the T(4)/T(3) and the fT(4)/fT(3) rations were both lower in group I than in group II. The percentages of fT(4) to T(4) and of fT(3) to T(3) were both higher in group I than the percentages for group II. On the basis of gender, comparison between the two groups showed higher T(4) (P0.01) and fT(4) levels (P0.001) in males, and lower fT(3) (P0.001) and fT(4) levels (P0.005) in females stabled in the goitre endemic area. On the basis of age, younger horses (7 years old) showed the highest thyroid hormone levels in both groups. Results suggest a physiological adaptive response of the equine species to an endemic goitre environment. The possibility that hypothyroidism is present in these horses is thus excluded and is supported not only by the lack of clinical signs, but also by the rarity of cases previously reported.

Background: The hypothalamic-pituitary-adrenal (HPA) axis and functional systems undergo the assessment of stress levels throughout living environments, contributing to avoid side effects to well-being in domestic animals, including pets. Cortisol represents the most important glucocorticoid found in felis and it is frequently used as standard marker in stress research. The purpose of the present study was to compare the adrenal and haematological patterns of cats, by taking into account the effects of different housing’s systems. The hypothesis was to find a different coping strategies, according to different housings.Materials, Methods & Results: For this study a total of 50 cats were selected on the basis of the breed: European domestic short hair cats, age ranged between 22 and 30 months and housing’s systems, represented by cattery and/or households, respectively. On these basis, cats were distinguished into two groups, represented by group A: 22 cats living in cattery, and group B: 28 cats living in households. Blood samples were collected twice a week, for two consecutive days, during one month and subsequently analysed for haematological analysis and cortisol concentrations. Group B showed higher cortisol concentrations (P < 0.01), Red Blood Cell (P < 0.05), Packed Cell Volume (P < 0.001), Platelets (P < 0.01), Heart Rate and Respiratory Rate (P < 0.05) values, and lower White Blood Cell (P < 0.001) than group A.Discussion: This observational study showed that cats housed in the households group showed higher cortisol, RBC, PCV, Plt, HR and RR values, and lower WBC rather than cattery’s cats. Another point is that males showed higher RBC, PCV, WBC and Plt than females, irrespective of different housing’s systems. The significant lower threshold of cortisol levels in cattery’s cats than household’s cats could suggest that these subjects were probably totally accustomed to cattery’s environment; though these animals were daily stimulated by predictable stimuli and manipulations, characterized by handling and husbandry routine, regular feeding and cleaning times, standard caretaking. On the other hand, the higher cortisol concentrations observed in household’s cats could be due to the different environmental stimuli, characterized by unpredictable handling, modified caretaking, presence of irregular talking, petting and manipulations by owners, which promote probably the expression of species and appropriate behaviour with stimulating activities. The significant highest RBC and PCV values in subjects of group B could be explained on the basis of the more intense activity of these subjects, according to the access to outdoor area. These concomitant higher values were corroborated in the present study by the not surprising positive and significant correlation observed between corresponding RBC and PCV values. The higher PCV values observed in cats of group B could be suggest that their daily frequent activity induced a physiological erythrocytosis, compared to sedentary cattery’s cats. The hypothesis that the home represented more rousing than cattery setting was assessed by the physiological and consistent higher cortisol, RBC, PCV, Plt, HR and RR displayed in the home environment; The only difference between the two groups was that environmental stimulus (chronic stress) was cattery for group A, whereas household for group B. Obtained data indicate that there was a marked benefit in to establish a personnel-cat relationship in addition to the traditionally owner-cat relationship, providing physiological coping strategies in both cattery and home cats; this was corroborate in the present study by the wide but physiological cortisol range. This study indicates that predictability, familiarity and unpredictability are significantly associated with environmental stimuli and with quality of pets’ life.

The secretion of circulating prolactin levels in response to sulpiride treatment was evaluated in eight mature cyclic barren jennies divided into two groups on the basis of different treatments. The experimental group A was submitted to the sulpiride treatment twice a day for nine consecutive days, up to 14 days after ovulation, and the control group B was submitted to the equivalent saline placebo administration. Milking was started at 8 days after ovulation, at 3 days after the beginning of sulpiride treatment, to 28 days after ovulation, and performed five times per day between 09:00 AM and 11:00 PM by hand; the oxytocin treatment was performed (5 IU/head per intramuscular injection) 5 minutes before milking, to facilitate the udder contraction. Blood samples were collected in baseline conditions (the day before the onset of the treatments) from day 0, during all treatment periods, until day 28 after ovulation, from the jugular vein from the each subject, twice a day, at 08:00 AM and at 08:00 PM. Both pluriparous experimental ( P P P P P P r = −0.67) was observed only in experimental pluriparous jennies. The present pilot study demonstrates the PRL profiles during and after induction of lactation in barren pluriparous and nulliparous Ragusana jennies.