Stress-Induced Immunomodulation in Low and High Reactive Sheep

Area of Science:

• Animal Science
• Immunology
• Veterinary Medicine

Background:

• Temperament and stress are known to influence physiological responses in livestock.
• Humoral immune responses, particularly immunoglobulin A (IgA), play a crucial role in mucosal immunity.

Purpose of the Study:

• To investigate the relationship between stress and temperament on the humoral immune response in ewes.
• To determine the effects of acute stress on cortisol, CarLA IgA, and total IgA concentrations.

Main Methods:

• Eighty ewes were divided into four groups based on reactivity (low/high) and stress exposure (control/stress).
• Physiological data (heart rate, cortisol, CarLA IgA, total IgA) were collected over 23 hours.
• A 2x2 factorial design was employed to analyze stress and temperament effects.

Main Results:

• Ewes exposed to stress exhibited elevated heart rate and cortisol levels, with decreased CarLA IgA concentrations.
• High reactive ewes showed lower CarLA IgA concentrations compared to low reactive ewes.
• Total IgA concentrations were not significantly affected by stress or temperament.

Conclusions:

• Acute stress has an immunosuppressive effect on salivary CarLA IgA in ewes.
• Temperament influences baseline CarLA IgA levels, but does not interact with stress effects.
• These findings highlight the impact of stress on specific components of the humoral immune system in sheep.