Project Number: 3602-32000-009-05
Project Type: Reimbursable

Start Date: Jan 01, 2007
End Date: Dec 31, 2010

Objective:
The primary goal of this work is to investigate and model autonomic regulation of cardiac activity in pigs with the ultimate goal of applying HRV analysis to the assessment of stress and well-being. To achieve this we will: 1) Model sympatho-vagal regulation of cardiac activity in male (barrow) and female pigs under normal conditions, during selective autonomic blockade (atropine and propranolol) and controlled activity to determine the exact location of the spectral frequency bands used to assess HRV; 2) Evaluate any age related changes in sympatho-vagal balance that may influence homeostatic HRV profiles and autonomic reactivity to stressful challenges; 3) Examine sympatho-vagal balance in response to acute and chronic stress and finally; and 4) Establish if any specificity exists in sympatho-vagal response to different acute and chronic stressors. Data obtained in this study will greatly contribute to our ability to assess well-being and stress in pigs. Information gained will also be applicable to other animal species.

Approach:
The objectives of this work are directly allied to Objective 4 of our CRIS: 'To develop a relative ranking of animal well-being of sows in gestation stalls compared to pens, based on three factors: physical, physiological, and mental state'. In general, objective assessment of stress and well-being is difficult, particularly when trying to distinguish between physical and psychological components of stress responses and their impact on acute and chronic well-being status. The work proposed in this grant proposal has considerable potential to contribute to our understanding of the underlying mechanisms of stress in pigs. Moreover, preliminary work indicates that there is certain specificity in autonomic nervous system regulation of cardiac activity during stressful challenges that relates to the nature (e.g. physical versus psychological or acute versus chronic) of the stressor itself. The development of heart rate variability assessment proposed in this research will enable us to not only evaluate overall well-being status in sows, but will also assist us in identifying acute and chronic deviations from acceptable levels of well-being, and to determine if these deviations are due to physical (e.g., lameness, disease, etc) and/or psychological (e.g., fear, social stress, etc) stressors. Actually identifying the source of significant stressors in sow housing and management constitutes a key component of our ability to improve well-being. It will allow us to assign a ranking system to the different factors that can potentially influence well-being, thereby enabling us to generate a cumulative score that represents definite well-being status.