ABSTRACT
Different commercial lines of laying hens may show varying levels of fearfulness in response to stressful events or situations. It is important to understand the differences in fear response and stress susceptibility. In this study, four commercial laying hen lines reared from hatch to 32 weeks of age in a cage free system Strains consisted of a brown egg laying line (Hyline Brown; HB) and three white egg laying lines (W36, W80, and LSL). Sixty hens from each strain were used. Each hen was assessed for fearfulness using the following tests: isolation (ISO), emergence (EMG), inversion (INV), and tonic immobility (TI). Stress was assessed based on physical asymmetry (ASYM), corticosterone (CORT) concentrations, and heterophil:lymphocyte ratio (HL). At 3 weeks of age, the W80 birds exhibited more vocalizations during ISO and a shorter duration to emerge than other lines except the HB birds during EMG. Conversely the W36 birds had fewer vocalizations during ISO and emerged quicker than other birds except the LSL during EMG. At 16 weeks of age, the LSL and the W36 bird demonstrated greater fear in TI than the HB. At 30 weeks of age, the observed fear response strategies of each strain changed from previous age and differences were observed between lines (p < 0.05). At both 16 and 30 weeks of age the HB birds had the highest (p < 0.05) stress indicators (CORT, HL, and ASYM). Furthermore, they had a higher CORT after acute stressor (p < 0.05). Commercial lines of laying hens show clear variation in their stress response strategy and stress susceptibility. Brown egg laying hens tend to actively avoid perceived threats whereas white egg laying hens use passive avoidance. Brown egg laying hens also have higher levels in the measures of stress susceptibility than white egg laying hens. Understanding of individual strain response to fearful stimuli and other stressors is important knowledge to appropriately determine welfare differences between strains of layers as the baseline measures are often different.
ABSTRACT
INTRODUCTION: Few evidence-based options exist for outpatient treatment of patients at risk of suicide, and to-date almost all research has focused on individually delivered psychotherapy. Group therapy for veterans at risk of suicide is a promising alternative. METHODS: Thirty veterans receiving care at an urban Veterans Affairs Medical Center in the southern United States were randomized to either care as usual (CAU) or to CAU plus the Collaborative Assessment and Management of Suicide-Group (CAMS-G). Veterans were assessed prior to randomization to condition and at 1, 3, and 6 months post-randomization on a range of suicide-specific measures, burdensomeness, belonging, treatment satisfaction, and group cohesion. RESULTS: Across measures and follow-up assessments, veterans in CAMS-G reported good satisfaction with the intervention, a sense of cohesion with other members of the group, and reduced symptom distress. Veterans in both conditions reported decreases in suicidal ideation and behavior, with CAMS-G participants potentially improving slightly faster. CONCLUSION: This description of CAMS-G for veterans adds to the growing literature on suicide-specific interventions and supports the need for additional research to determine if wide-spread rollout is justifiable.
