Greater Cortisol Concentrations Research Articles

140 Effects of ɷ-3 PUFA supplementation during late gestation to first-calf beef heifers on physiological and performance responses of offspring

Abstract The objectives of this experiment were to evaluate the effects of ɷ-3 PUFA supplementation to late gestation first-calf beef heifers on milk and immunoglobulin production and performance and physiological responses of the offspring. Non-lactating, pregnant Angus heifers (n = 44) were ranked by age, body weight (BW), and body condition score (BCS) and allocated to receive DDG + 1 of the 2 treatments: 1) 234 g/heifer per feeding of Ca salts of PUFA based on eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids (OMG, Strata; Virtus Nutrition LLC, Corcoran, CA; n = 22), 2) 234 g/heifer per feeding of Ca salts of saturated and monosaturated fatty acids based on palmitic and oleic acids (CON; EnerGII, Virtus Nutrition, LLC; n = 22; Table 1). The animals were gathered each week on Mondays, Wednesdays, and Fridays and individually fed DDG + treatments. Immediately after calving, heifer-calf pairs were removed from their respective treatments and assigned to the general management of the research herd until weaning, which did not include fatty acid supplementation. Calves were transported to a feedyard for a 90-d preconditioning and feedlot receiving period. Initial cow BW and BCS were similar (P ≥ 0.49) among treatments. No differences were also detected (P ≥ 0.33) for BW or BCS change, and at calving BW or BCS (Table 3). No differences were observed between groups for average colostrum composition (P > 0.37). However, there was an increase in colostrum fat percentage (P = 0.03) and a tendency of greater concentration of colostrum IgG (P = 0.08) in OMG heifers compared with the control group. No significant differences were observed among treatments at calving results (P > 0.83; Table 3). However, a tendency was observed for crown to rump measure (P = 0.07). During the preconditioning period, there was a difference among groups for final BW (P = 0.04) and average daily gain (ADG; P = 0.05), remaining throughout the receiving phase among treatments for initial BW (P = 0.04), final BW (P = 0.04) and ADG (P = 0.05). A tendency (P = 0.09) for greater NEFA concentration and greater cortisol concentrations (P = 0.05) was observed in OMG vs. CON cohorts (Table 4, Table 5). Supplementation during late gestating first-calf beef heifers yielded similar outcomes on cow and offspring performance from birth to weaning; however, OMG calves were 6 kg heavier when compared with CON after being fed a high-energy feedlot diet, meaning that ɷ-3 PUFAs supplemented during late gestation might be an alternative to optimize feedlot responses of the offspring.

Using virtual reality to study the impact of audience size on cortisol responses to the Trier Social Stress Test

Virtual Reality Trier Social Stress Test (VR-TSST) protocols have been shown to effectively elicit psychophysiological stress by having participants perform a speech and math task while viewing a virtual (non-present) audience. However, few studies have utilized VR technology to examine variables that would otherwise be difficult to manipulate in the lab. This study examined the impact of a large VR audience (i.e., 200 members) on the physiological (i.e., cortisol) and psychological responses of 140 individuals. Participants were randomly assigned to one of three conditions: an in-person (2-person) audience, VR 2-person audience, or a VR 200-person audience condition. Salivary cortisol was collected to assess physiological reactivity and recovery. Participants self-reported psychological responses to the TSST including stress, arousal, emotions, and perceptions of the audience. Results revealed that all conditions elicited stress reactivity. The VR 200-person condition resulted in greater cortisol concentrations and more negative affect than the small VR 2-person audience. Thus the effectiveness of a VR-TSST may be enhanced by the use of a larger virtual audience stimulus.

Effects of temperament on reproductive performance of Bos taurus heifers enrolled in the 7-day CO-Synch + controlled internal drug release protocol.

Cattle temperament significantly impacts production traits such as reproduction. The objective of this study was to assess the effects of temperament on pregnancy rates to fixed-timed artificial insemination (TAI) in Bos taurus beef heifers. A total of 297 Angus influenced heifers from 3 different locations were evaluated for temperament based on chute score and exit velocity on the first day of the estrus synchronization protocol (d-9) and classified by temperament type based on temperament score (calm ≤ 3 < excitable). Pregnancy status was determined by transrectal ultrasonography approximately 40 d after TAI. Hair from the tail switch was collected at d-9 and at d0 (TAI) for cumulative cortisol evaluation. A subset of 43 heifers from location 3 had blood samples collected at all handling events and evaluated for cortisol concentrations. Overall, 71% of heifers were classified as calm whereas 29% as excitable. Pregnancy rates to TAI were reduced (P = 0.042) in excitable heifers compared to calm heifers (36% vs. 55%, respectively). Mean concentration of cortisol in the hair was reduced over time (P < 0.001) from d-9 (3.5 ± 0.3 pg/mg) to d0 (1.74 ± 0.3 pg/mg) in all heifers, regardless of temperament. In addition, excitable heifers had increased circulating concentrations of cortisol when compared to calm heifers in all handling events (P = 0.015). More interestingly, despite of temperament, concentrations of circulating cortisol were reduced as the protocol events progressed, with greater cortisol concentrations on d-9, intermediate on d-3, and lesser on d0 (P = 0.031). Therefore, the present study demonstrates that heifer temperament has negative effects in pregnancy rates to TAI programs. However, according to blood cortisol concentrations, no chronic stress response was detected due to cattle handling for the TAI protocol. In fact, blood cortisol concentration was reduced between the initiation and completion of the protocol, indicating that heifers were acclimated to handing. These results support the adoption of acclimation protocols and proper cattle handling as a strategy to increase fertility of heifers that are exposed to TAI.

PSXVI-21 The effect of enhancing the thermal environment of piglets on physiology, behavior and productivity

Abstract To determine if increasing the heated area provided to piglets may improve their welfare; Sows (n = 27) were assigned to stalls using a traditional heat lamp (Control), or stalls using 2, 0.4 x 2.4 m heated mats (Heat). The mat temperature was maintained at approximately 39 °C until the 3rd d post-farrowing when they were replaced with a traditional heat lamp. At 1 d of age, piglets’ temperature was recorded, and blood samples were taken from 4 piglets per litter to measure cortisol, lactate, and glucose. Of these piglets, 2 were females and 2 males, 1 each weighing above average (thrifty) and 1 each below average (unthrifty). ADG of all piglets and mortality were recorded on d 3, when the heated mats were replaced with heat lamps, as well as at weaning. There were no treatment differences (P &amp;gt; 0.10) for cortisol (4.52 ± 0.22 ug/dL), glucose (102.84 ± 2.11 mg/dL), or lactate (2.42 ± 94.77 mmol/L). Unthrifty piglets had greater cortisol concentrations (5.45 ± 0.34 vs. 3.64 ± 0.24 ug/dL, P &amp;lt; 0.0001) and lower glucose (97.3 ± 3.06 vs. 108.37 ± 2.76 mg/dL; P &amp;lt; 0.0014) than thrifty. ADG was not different (P &amp;gt; 0.10) on d 3 (0.12 ± 0.01 kg) or at weaning (0.24 ± 0.003 kg). There was no difference in body temperature between treatments (39.23 ± 0.03 °F, P &amp;gt; 0.10). Day 3 mortality was lower in Heat crates than Control (0.04 ± 0.02 vs. 0.12 ± 0.03, P &amp;lt; 0.02); however, mortality at weaning did not differ (11 ± 0.02%, P &amp;gt; 0.10). In conclusion, increasing the warm area in farrowing crates with heated mats over the length of the piglet area may increase survivability while provided.

Daily variation of the cortisol and insulin concentration, glycemia, surface temperature, and behavior patterns due the administration of equine Chorionic Gonadotropin in rams

Sex steroids can modulate the circadian rhythmicity of some physiological and behavioral functions of sheep. During the non-breeding season, Corriedale rams have a low testosterone concentration, but the administration of equine Chorionic Gonadotropin (eCG) stimulates its secretion. Therefore, the daily variation of cortisol and insulin concentrations, glycemia, behavioral pattern (eating, ruminating, standing, lying, and sleeping), and rostral and eye surface temperatures were compared in rams treated or not treated with eCG during the non-breeding season [between August (late winter) and September (early spring)]. Twenty Corriedale adult rams (BW 63.4 ± 7.3 kg; BCS: 3.5 ± 0.5; mean ± SD; age: 2-3 years old) were randomly assigned to 1 of 2 treatments: a) Treated: administration of 1000 IU of eCG intramuscularly and b) Control: control, without application of eCG. All the rams were managed under the same feeding and environmental conditions (individual pens outdoors). All variables were measured each hour for 26 h, except testosterone and insulin that were measured at 09:00, 10:00, 12:00, 15:00, 18:00, 21:00, 22:00, 24:00, 03:00, 06:00, 09:00 and 11:00 h. Testosterone and cortisol concentration were greater in Treated than Control rams (testosterone: 32.7 ± 0.7 nmol/L vs 5.8 ± 0.7 nmol/L; P <0.0001; cortisol: 11.3 ± 0.6 nmol/L vs 9.9 ± 0.6 nmol/L; P =0.02). The eye surface temperature was 0.9°C lower in the Treated than in the Control rams (P =0.004). The characteristics of the daily variation pattern of cortisol, glycemia, glycemia:insulin ratio, and surface temperature were not affected by the treatment, the acrophases being at ∼06:00 h, ∼18:00 h, ∼08:00 h, and ∼11:00 h, respectively. The acrophase of insulin concentration was observed earlier in Treated than in Control rams (13:02 ± 0:56 vs 15:47 ± 0:53; P =0.04). Additionally, the acrophase of the time spent eating was advanced in Treated rams (09:48 ± 00:16 vs 10:20 ± 00:16; P =0.04) and sleeping (21:39 ± 00:57 vs 02:02 ± 01:06; P <0.0001). Treated rams slept less time than Control rams (P =0.04). In conclusion, the administration of eCG modulated the daily variation pattern of insulin concentration and the behavioral pattern (period in which rams were observed eating and sleeping). Nevertheless, although there was a greater cortisol concentration and reduced eye surface temperature, the administration of eCG did not modify their daily variation pattern, suggesting that this is robust, limiting the effect of testosterone on their basal pattern.

Heat stress affects the expression of key genes in the placenta, placental characteristics, and efficiency of Saanen goats and the survival and growth of their kids

Heat stress is detrimental during gestation; however, the effects of heat stress on goat placental characteristics and kid survival remain unclear. The objective of this study was to evaluate the effects of heat stress at final gestation on cortisol concentration, placenta characteristics, and the expression of genes related to placenta. Forty-six primiparous and multiparous Saanen goats were subjected to control (CT; under a thermoneutral environment: air temperature between 12°C and 25°C and the relative humidity from 45 to 73%, n = 23) or heat stress (HS; under a climatic chamber: air temperature at 37°C and the relative humidity at 60 to 70% from 0800 to 1600 h, n = 23) from the last 60 d of pregnancy until the first colostrum suckling. The heat challenge imposed on HS goats during the prepartum period increased their rectal temperature, respiratory frequency, and cortisol levels in plasma and amniotic fluid versus CT goats. In the placenta, HS treatment also increased the expression of the HSPA1A gene. Heat-stressed goats also showed significantly lower expression of HSD11B2 and greater expression of MC2R and NR3C1 than CT goats, suggesting that heat stress decreased the effectiveness by which the HSD11B2 enzyme converts cortisol to cortisone and increased placental responsiveness to cortisol. The HS goats took longer to release the placenta with lighter placental cotyledons, and HS goats had a lower ratio between the kid's weight at birth and placenta weight than CT goats. There was no treatment effect on the kids' survival or weights at birth, but the kids from goats subjected to HS presented lesser cortisol concentration and greater mortality rates at weaning than kids from CT goats. Finally, the overexpression of HSPA1A by HS goats suggests a protective response of placenta. However, the heat stress negatively affected the placenta's expulsion length, placental cotyledons number, weight and area, the ratio between kid's weight and placenta weight, and cortisol signaling. Indeed, the upregulation of MC2R and NR3C1 and downregulation of HSD11B2 on placenta caused by heat stress were associated with greater cortisol concentrations in the amniotic fluid of HS goats. Although HS and CT kids had adequate weights and survival rate during the first weeks of life, the heat stress increased the mortality at weaning of HS kids versus CT kids, suggesting that the heat stress effect persists and can change the ability of kids to respond to weaning challenge.

Characterization and assessment of vocalization responses of cows to different physiological states

ABSTRACT The objective of our study was to characterize and assess the vocalization responses of cows in four different physiological states using different measurements and relate those to salivary cortisol concentrations as a possible indicator of stress. We characterized and assessed the vocalization responses of cows in four different physiological states: feed anticipation, estrus, communication between or among individuals, and parturition. We used video camera recordings of the calls made by the cattle during these four states. We measured the duration of the calls, intensity and pitch of vocalizations, and the formant, using vocalization analysis software. Two hundred and ninety calls were recorded from 32 cows during the study. Cortisol increased from the least values in communications and feed anticipation, to two-fold concentrations in estrus, and three-fold concentrations in parturition. All the formants tended to increase in the same order with the stress concentrations, whereas low intensity and lower pitched vocalizations were associated with greater cortisol concentrations during parturition. These results indicate that acoustic parameters of calls in each of the physiological states may reflect the stress level in cattle, and thus, the vocalization of animals could be an important behavioural indicator of their stress level.

Short- and long-term effects of temporary early cow–calf separation or restricted suckling on well-being and performance in zebu cattle

Information on weaning techniques in the tropics is scarce, particularly regarding the long-term effect of temporary early cow–calf separation or restricted suckling. Therefore, we studied the effects of these two handling practices on well-being and performance at 150 days postpartum in fifteen zebu cow–calf pairs randomly assigned to three treatments. Continuous suckling (CS) where calves remained with their dams from birth to weaning; restricted suckling (RS) calves were allowed to suckle 30 min/day from Day 34 until weaning at Day 150 and kept separated the rest of the time; temporary separation (TS) calves were separated for 72 h from their dams from Day 33 to 36 but remained with their dams the rest of the time. Blood samples and behavioral data were collected on Days 32–36 (1st period) and 149–153 (2nd period). In the 1st period, a greater percentage of RS and TS calves were observed close to the fence line (<10 m) that separated them from their dams (P < 0.0001) and vocalized more than CS calves (P < 0.0001), while in the 2nd period, RS calves had the highest cortisol concentration and vocalization rate (P < 0.05). Similarly, during the 1st period, a greater percentage of RS and TS cows were observed close to the fence line than CS cows (P < 0.0001), with TS cows vocalizing the most (P = 0.001). In the 2nd period, RS cows had greater cortisol concentration than TS (P = 0.037) and CS cows (P = 0.003). More TS and CS cows than RS were observed close to the fence line (P = 0.03 and P = 0.05). On Day 150, TS calves and cows vocalized more than RS and CS animals (P < 0.0001). Before calf–cow separation, 27 out of 45 cows were cycling (CS = 10; RS = 6; TS = 11). After separation, 12 of the remaining 18 cows resumed ovarian activity (CS = 3; RS = 5; TS = 4), and all cows were cycling after estrous synchronization treatment. The pregnancy rate was similar between CS, RS, and TS (60, 53, and 60% respectively). In conclusion, temporary separation increased calf distress response to definitive weaning even four months later, while restricted suckling seemed to reduce it.

PSI-4 Changes in serum cortisol concentrations and cytokine profiles of growing pigs subjected to low-intensity heat stress

Abstract This study was to determine the impact of low-intensity heat stress on inflammatory biomarkers in serum, ileum, jejunum and lung lavage samples. Pigs (n = 64; 24.6 ± 3.7 kg BW) were housed four per pen in thermoneutral conditions (CON; 23.9°C ± 2.5°C) or constant high ambient temperatures (HS; 28.7°C ± 1.3°C) for 16 d, followed by thermoneutral conditions (24.4°C ± 1.8°C) for both groups through d 21, and subsequent heat stress (28.0°C ± 3.0°C) for both groups through d 30. Respiration rate (P &amp;lt; 0.01) was greater in HS than CON pigs from d 2 through d 15 (mean: 82.54 breaths/min vs. 59.26 breaths/min). HS pigs had greater cortisol concentration (40.1 ng/mL vs. 27.3 ng/mL) than CON on d 2, but lower concentrations on d 22 (32.9 ng/mL vs. 48.9 ng/mL) and d 25 (25.4 ng/mL vs. 42.0 ng/mL; treatment x day: P &amp;lt; 0.001). HS pigs tended to have greater serum IL1β (190.1 vs. 143.4 pg/mL; P = 0.06) and greater serum IL12 concentrations (914.9 vs. 785.4 pg/mL; P &amp;lt; 0.01) than CON pigs. HS pigs tended to have greater ileal mucosa IL6 concentrations than CON pigs (50.4 vs. 30.9 pg/mL; P = 0.08). Jejunal mucosa IL1α concentrations tended (P = 0.10) to be greater for CON than HS pigs (13.5 vs. 9.0 pg/mL) and CON pigs had greater jejunal IL12 concentrations (18.1 vs. 11.8 pg/mL) than HS pigs (P = 0.02). Bronchioalveolar lavage from HS pigs tended (P = 0.10) to have a greater granulocyte-macrophage colony-stimulating factor concentration (6.9 vs. 5.3 pg/mL) than CON pigs and had greater IL4 (7.7 vs. 4.2 pg/mL) and IL12 concentrations (34.8 vs. 24.5 pg/mL) than CON pigs (P = 0.01). Increased inflammatory activity and endocrine stress response occurred during low-intensity heat stress, indicating it may be more detrimental than previously accepted.

The relationship between sleep problems and cortisol in people with type 2 diabetes

BackgroundSleep problems are linked with negative health outcomes, including coronary heart disease. Neuroendocrine dysfunction has been associated with sleep problems and may be a pathway linking sleep and ill health. Dysregulated cortisol output has observed in people with type 2 diabetes (T2D), though little is known about the links between sleep and cortisol in this population at high risk of coronary disease. MethodThis study investigated the association between sleep problems and cortisol over the course of an ordinary day and in response to acute laboratory stress in a sample of 129 individuals with T2D. Sleep problems were assessed using the Jenkins sleep problems questionnaire. Mental stress was induced using two five-minute laboratory stress tasks: a mirror-tracing task and the Stroop color-word interference task. ResultsSleep problems were positively associated with daily cortisol area under the curve (B = 17.051, C.I. = 6.547 to 27.554, p = 0.002) adjusting for age, sex, marital status, education, household income, body mass index and smoking; suggesting that those with greater sleep problems had greater cortisol concentrations over the course of an ordinary day. Participants reporting greater sleep problems also had raised evening cortisol levels (B = 0.96, C.I. = 0.176 to 1.746, p = 0.017) in adjusted models. In the laboratory sleep problems were negatively associated with cortisol immediately post-task (B = -0.030, C.I. = -0.059 to 0.000, p = 0.048) and 45 minutes post-task (B = -0.037, C.I. = -0.072 to -0.002, p = 0.039) in fully adjusted models; indicating that those who experienced greater sleep problems had lower cortisol concentrations after stress. ConclusionsSleep problems were associated with disturbances in cortisol responses to stress, as well as changes diurnal cortisol output in people with T2D. Further research is needed to assess if neuroendocrine disturbance increases the risk of cardiovascular disease in this population.

Effect of different housing systems (single and group penning) on the health and welfare of commercial female rabbits

In recent decades, concern about rabbit welfare and sustainability has increased. The housing system is a very important factor for animal welfare. However, information about how different available housing types for female rabbits affect their health status is scarce, but this is an important factor for their welfare. Hence, the objective of this study was to evaluate the health status of female rabbits in five common housing systems: three different single-housing systems with distinct available surfaces and heights; a single-housing system with a platform; a collective system. Female rabbits in the collective and platform cages had greater cortisol concentrations in hair than those in the single-housing system with no platform. Haptoglobin concentrations and kit mortality rates during lactation were greater for the collective-cage female rabbits. The collective group had more culled females and more lesions than in the other groups. The main reasons for culling in all the groups were reproduction problems and presence of abscesses, and the collective group of females was the most affected. In conclusion, it appears that keeping females together in collective systems negatively affects their health status and welfare, while single-housing systems imply lower kit mortality rates during lactation and cortisol concentrations, and fewer lesions in female rabbits.

Stress and behavioural responses to winter shearing differ between pregnant and non-pregnant ewes

High progesterone concentrations reduce the stress responses in several mammals. Therefore, it may be expected that pregnant ewes have lower responses to stressors than anoestrous ewes. Our aims were to compare the stress response and the behavioural changes of pregnant and non-pregnant ewes sheared during winter. Two trials were with 20 were pregnant (group PR) and 17 non-pregnant ewes (group NP). In the first trial blood samples were collected immediately before and during the first 180 min after shearing, and cortisol, total protein, and albumin concentrations were measured, and globulin concentrations were calculated. In the second trial, the frequency in which each ewe was observed standing, lying down, walking and grazing were recorded from Day −3 to Day −1 (Day 0 = shearing), from Day 1 to Day 5, on Days 13 and 20–21 during 8 h/day. Scan observations were done every 10 min from 8:00 h to 12:00 h and from 14:00 h to 18:00 h (total = 50 recordings.day). Non-pregnant ewes had greater cortisol concentrations than PR ewes (P = .007). Non-pregnant ewes also had greater total protein concentrations than PR ewes (P = .029). Albumin concentration tended to be greater in NP than PR ewes (P = .064). Globulin concentration 30 min after shearing was greater in PR than in NP ewes (P = .047). Pregnant ewes were observed more frequently standing than NP ewes (P = .013). Non-pregnant ewes were observed more frequently lying down and walking than PR ewes (P = .039 and P = .009, respectively). Before shearing, on Day 2 and Day 4, NP ewes walked more frequently than P ewes (P = .007, P < .0001, P = .007 respectively). Pregnant ewes were observed grazing more frequently than NP ewes (P = .009). Pregnant ewes grazed more than NP ewes on Days 1 and 5 (P = .005 and P < .0001 respectively). Overall, we concluded that shearing was a strong stressor that provoked sustained changes in the behavioural pattern, physiological status and gregariousness intensity despite being or not pregnant. Some responses, as cortisol concentration, changes in the time walking and grazing and the decrease of the cohesiveness after shearing seem to be less pronounced in pregnant than in non-pregnant ewes.

Socioeconomic status and central adiposity as determinants of stress-related biological responses relevant to cardiovascular disease risk

Stress-related processes have been implicated in the associations between lower socioeconomic status (SES), central adiposity, and cardiovascular disease risk. This study analysed the impact of SES and central adiposity on cardiovascular, inflammatory and neuroendocrine stress responses, and associations with cytomegalovirus (CMV) infection in a sample of 537 men and women aged 53–76 years (mean 62.89 years). SES was defined by grade of employment (higher, intermediate, and lower categories), and central adiposity was indexed by waist-hip ratio (WHR). Cardiovascular, inflammatory and cortisol responses were monitored during administration of a standardized mental stress testing protocol and salivary cortisol was measured repeatedly over the day. Lower SES was associated with raised systolic and diastolic blood pressure (BP), plasma interleukin (IL-6), fibrinogen, C-reactive protein, and salivary cortisol, and a large WHR accentuated SES differences in fibrinogen, C-reactive protein, and likelihood of CMV seropositivity, independently of general adiposity indexed by body mass index. During mental stress testing, return to resting levels (recovery) following behavioural challenge in systolic and diastolic BP and heart rate was impaired among lower SES participants, particularly those with large WHR. Lower SES participants had greater cortisol concentrations across the day, but this pattern did not vary with WHR. These findings extend the evidence relating lower SES to stress-related biological risk factors for cardiovascular disease, and indicate that central adiposity may augment these effects.

Growing without a mother during rearing affects the response to stressors in rams

Early maternal care contributes to the normal development of the physiological, social and emotional functions of the offspring. As sheep are a strongly gregarious species, separation and isolation of an individual from the flock provokes fear and, consequently a stress response. The first aim of this study was to compare the stress response to social isolation of rams that were reared by their mothers or artificially reared. A complementary objective was to compare the cortisol response to an ACTH challenge in both groups of rams. Rams were: 1) separated from their dams 24–36 h after birth (Week 0) and artificially fed with sheep milk until Week 10 (group AR, n = 14); or 2) reared by their dams until Week 10 (group DR, n = 13). The rams were then kept in separate, adjacent paddocks for the rest of the study. When they were 8 months old, 10 animals randomly selected from each group were isolated from the group in an unfamiliar pen during 10 min. Behavioural (the number of lines crossed, frequencies of vocalizations, eliminations, sniffing, escape attempts and freezing), physiological (heart and respiratory rate, and rectal temperature), biochemical (total blood proteins, globulins and albumin), and endocrine (serum cortisol concentrations) variables were recorded. Dam-reared rams eliminated (defecations + urinations) more times and crossed more lines during the social isolation test than AR lambs (P < 0.05). The increase in total proteins and albumin concentration after the social isolation test was also greater in DR than AR rams (P = 0.01 and P < 0.01 respectively). Artificially-reared rams had greater globulin concentration than DR rams after the test (P = 0.04). When rams were 2 years old, ACTH was administered to 10 rams randomly selected from each group, and the cortisol response was measured. Dam-reared rams had greater cortisol concentrations than AR rams at 150 and 180 min after the administration of ACTH (P < 0.05). In conclusion, artificially reared rams were less affected by social isolation and had lower adrenal response to an ACTH challenge than rams reared by their mothers. This study suggests that the relationship with the mother plays a key role in the development of rams’ social behaviour.

Effect of anti-gonadotropin-releasing factor vaccine and band castration on indicators of welfare in beef cattle.

Angus crossbred bulls (n = 60; 257 ± 5.4 d of age; initial BW 358.8 ± 3.78 kg) were used to study the effect of a vaccine against gonadotropin-releasing factor (GnRF) and band castration on behavioral and physiological indicators of pain. Cattle were randomly assigned to 1 of 3 treatments: bulls, band-castrated calves without pain mitigation (castrated), and immune-vaccinated animals administered an anti-GnRF vaccine (vaccinated). All animals were fitted with a radio frequency ear tag so that individual animal feed intake and feeding behavior were recorded daily over the entire trial using an electronic feed bunk monitoring system. Two doses of anti-GnRF vaccine were administrated on d -35 and 0 and band castration was performed on d 0. Animal BW was recorded weekly starting on d -36 until d 56. Visual analog scores (VAS) were measured on d -36 -35, -1, and 0, and salivary cortisol concentration was measured at -30, 0, 30, 60, 120, and 270 min on d -35 and 0 after castration. Saliva and blood were obtained on d 1, 2, 5, and 7 and weekly until d 56 for determination of cortisol and complete blood cell count. Video data were collected for pain, sexual, and aggressive behavior daily the first week and once a week until d 56. Data were analyzed with a mixed-effect model with castration, time, and their interactions as main effects. Vaccinated calves had reduced ADG and intake (P < 0.05 and P < 0.001, respectively) during the first week after vaccination. Band-castrated calves had reduced ADG and intake (P < 0.001) until the end of the study. No differences in salivary cortisol and VAS were observed among groups at d -35 after the first vaccination and before band castration. However, on d 0, castrated cattle had greater cortisol concentrations and VAS (P < 0.05 and P < 0.01, respectively) than bulls and vaccinated animals. Complete blood cell count did not differ (P > 0.05) between treatments on d 0, 1, and 2. At d 56, vaccinated calves had greater (P < 0.05) final BW than band-castrated calves and both had less final BW than bulls. There was no indication that vaccination caused any physiological or behavioral changes indicative of pain. In contrast, band castration resulted in elevated cortisol scores and VAS indicative of a pain response and behavior related to pain (P < 0.001) until d 42 of the study. The present study demonstrates that anti-GnRF vaccine is a viable animal welfare-friendly alternative to traditional band castration in beef cattle under North American feedlot practices.

Grouping previously unknown bucks is a stressor with negative effects on reproduction.

Grouping previously unknown animals produces social stress, which might have negative effects on reproduction. The aims of the experiment were to determine if grouping unknown bucks (1) triggers a stress response and produces changes in body weight; (2) affects scrotal circumference, testosterone concentration, and semen quality; and (3) has differential effects between resident and introduced bucks. One group of nine Saanen bucks was transported and introduced (introduced bucks, group IG) to a group of eight Saanen bucks (resident bucks, group RG). On day 0, cortisol concentration and rectal temperature were determined, and from day -7 to day 29, body weight, scrotal circumference, and testosterone concentration were recorded and semen quality was determined. The stress response was different between groups: on several moments on day 0, resident bucks had greater cortisol concentration (P < 0.0001), while introduced bucks had higher rectal temperature (P = 0.02). Body weight decreased similarly in both groups from day -7 to day 2 (P < 0.0001), but on day 29, IG bucks were lighter than RG bucks (P = 0.05). Also, the reproductive response differed between groups: introduced bucks had lower scrotal circumference (P < 0.01), lower testosterone concentration (P = 0.02), and lower percentage of motile spermatozoa in the ejaculate (P = 0.05). It was concluded that grouping unknown bucks was stressful and negatively affected the reproduction, being more serious for the introduced than the resident bucks.

Hypothalamic-pituitary-adrenal axis activation and immune regulation in heat-stressed sheep after supplementation with polyunsaturated fatty acids

The aim of this study was to assess the effects of supplementation with polyunsaturated fatty acids from different sources on immune regulation and hypothalamic-pituitary-adrenal (HPA) axis activation in heat-stressed sheep. The experiment was carried out during the summer 2012. Thirty-two Comisana ewes were divided into 4 groups (8 sheep/group): (1) supplemented with whole flaxseed (FS); (2) supplemented with Ascophyllum nodosum (AG); (3) supplemented with a combination of flaxseed and A. nodosum (FS+AG); and (4) control (C; no supplementation). On d 22 of the experiment, cortisol concentrations in sheep blood were measured after an injection of ACTH. Cellular immune response was evaluated by intradermic injection of phytohemagglutinin (PHA) at 0, 15, and 30d of the trial. Humoral response to ovalbumin (OVA) was measured at 0, 15, and 30d. At 0, 15, and 30d of the experiment, blood samples were collected from each ewe to determine production of T-helper (Th)1 cytokines (IL-12 and IFN-γ), and Th2 cytokines (IL-10, IL-4, IL-13), and concentrations of heat shock proteins (HSP) 70 and 90. Ewes supplemented with flaxseed alone had greater cortisol concentrations and a longer-lasting cell-mediated immune response compared with ewes in the control and other groups. Anti-OVA IgG concentrations increased in all groups throughout the trial, even though ewes in the FS+AG group had the lowest anti-OVA IgG concentrations at 15d. The level of IL-10 increased in all groups throughout the experiment; the FS+AG group had the lowest IL-13 concentration at 15 and 30d. The concentration of HSP 70 increased in AG ewes at the end of the experiment and decreased in FS ewes, whereas that of HSP 90 increased in FS ewes compared with FS+AG ewes. Flaxseed supplementation was found to influence in vivo HPA activation in heat-stressed sheep, resulting in increased cortisol concentrations, probably to meet increased energy demand for thermoregulation. Flaxseed supplementation also supported Th1 response via a complex cross-talk between IL-10, IL-12, and IFN-γ production.

Effects of distillers‘ dried grains with solubles on behavior of sows kept in a group-housed system with electronic sow feeders or individual stalls

Li, Y. Z., Phillips, C. E., Wang, L. H., Xie, X. L., Baidoo, S. K., Shurson, G. C. and Johnston, L. J. 2013. Effects of distillers’ dried grains with solubles on behavior of sows kept in a group-housed system with electronic sow feeders or individual stalls. Can. J. Anim. Sci. 93: 57–66. A study was conducted to investigate the effects of diets that contained distillers’ dried grains with solubles (DDGS) on stereotypic behaviors of gestating sows housed in stalls and aggression in a group-housed system. Sows were fed corn–soybean-based control (CON) or treatment (DDGS) diets starting from their previous breeding cycle (40% and 20% DDGS as-fed basis during gestation and lactation, respectively). Group-housed sows were mixed in pens with an electronic sow feeder within 1 wk after mating. Behaviors of focal sows (n=27 in stalls, n=40 in pens) were video-recorded for a period of 24 h between 4 and 8 d after mating. Salivary cortisol levels were measured on 32 focal sows (n=16 in stalls, n=16 in pens) during the week before mating (week 0), 1 wk and 12 wk after mating. In pens, DDGS sows fought for longer periods (P=0.05), tended to fight more frequently (P=0.06), and had greater cortisol concentrations (P&lt;0.001) at mixing compared with CON sows. In stalls, DDGS sows spent more time resting (P=0.02), less time performing stereotypies (P=0.05), and had lower cortisol concentrations (P=0.03) in week 12 compared with CON sows. These results indicate that DDGS diets may compromise the welfare of sows in pens, but improve the welfare of sows in stalls.

Repeated intranasal oxytocin administration in early life dysregulates the HPA axis and alters social behavior

Agonistic interactions are a powerful stressor. Conversely, positive social interactions can reduce the adverse effects of social stress. This possibly occurs through the action of oxytocin (OT), a neuropeptide able to reduce activation of the hypothalamo–pituitary–adrenal (HPA) axis. We hypothesized that repeated OT intranasal administration to neonatal pigs could provide long-lasting protective effects against social stress. In each of six litters, two pigs per litter received 0.5mL of saline containing 24IU (or 50μg) of OT intranasally and two control littermates received 0.5mL of saline as a control at 1, 2 and 3days of age. Contrary to our predictions, when socially mixed after weaning at 17days of age, neonatally OT-administered pigs received more aggressive interactions and performed more aggressive interactions in return, showed greater locomotion, spent less time in social contact, and had greater cortisol concentrations than control pigs. When this social mixing was repeated at 8weeks of age, OT pigs still performed more aggressive interactions and had greater adrenocorticotropic hormone concentrations than control pigs. A dexamethasone suppression test and corticotropic releasing hormone administration challenge at 11weeks of age revealed that OT pigs were less responsive to dexamethasone than control pigs, suggesting a deficient HPA axis' negative feedback control. Postnatal repeated OT administration altered social behavior and resulted in a long-term dysregulation of the HPA axis. These findings highlight the complex, fine-tuning of the neurobiological mechanisms regulating the development of social behavior and suggest caution in the application of neonatal peptide treatments during early development.

Evaluation of the endocrine response of cattle during the relocation process

To evaluate the endocrine responses associated with the relocation process, 22 Holstein heifers (326.4±46.8kg BW) were randomly assigned to control (CON) or relocation (RELOC) treatment groups. On d 0, heifers were weighed and fitted with indwelling rectal temperature (RT) monitoring devices and jugular catheters. On d 1, baseline blood samples were collected from all heifers for 2h prior to the transportation event, then weighed. Controls were returned to tie stalls and RELOC were loaded into a modified stock trailer (12 individual stanchions) for a 4h transportation event. Simultaneous blood samples were obtained at 30-min intervals from both groups throughout the 4h transport event (TE-I). After transport, RELOC were unloaded at an unfamiliar location, weighed, and placed in tie stalls for a 2h post-transportation period. All heifers were then placed into two separate holding paddocks with access to water and hay for 4h. After 4h, hay and water was withdrawn for 20h. On d 2 RELOC heifers were exposed to a second transport event (TE-II); the timeline and procedures of TE-II were identical to those of TE-I (except for the starting point for RELOC heifers). All serum samples were analyzed for concentrations of cortisol, growth hormone (GH), and insulin-like growth factor-I (IGF-I). A 6% reduction in BW for the RELOC as compared to 2.5% reduction in BW for CON (P<0.001) was observed during TE-I. Overall BW loss was 2% greater (P<0.02) for RELOC heifers compared to CON heifers. During TE-I, RELOC heifers had greater RT (P<0.05) compared to CON heifers. There was treatment×time interaction observed for cortisol (P<0.003); RELOC had greater cortisol concentrations at multiple time points throughout TE-I and -II. No differences (P>0.05) in area under the curve (AUC) for cortisol were observed during TE-I. However, AUC for total cortisol during TE-II was greater (P<0.01) in the RELOC group compared to CON. There were no differences in AUC for GH between treatment groups for TE-I or -II, but a transient decline (P<0.05) within each group was observed from d 1 to d 2. There were no differences (P>0.05) in IGF-I concentrations or in AUC between the treatment groups during TE-I and -II or from d 1 to d 2. Results provide evidence that the actual processes surrounding the transportation of cattle, can elicit a stress response, as defined by increased concentrations of cortisol, RT, and BW losses.