Stress & its Effects on Livestock

Stress is a mental or bodily tension produced by external or internal stressors. All animals experience stress as necessary and normal occurrences in their lives. However, when stressors become so aversive that an animal is unable to adapt, it enters a state of distress, where its physiology and behavior become maladaptive.

Stress and distress can be caused by:

• Psychological factors (e.g., inability to exhibit natural behavior patterns, fear);
• Physiological factors (e.g., disease, physical abnormalities, poor nutrition, pain);
• Environmental factors (e.g., overcrowding, rough handling, excessive heat or cold);
• Physical factors (e.g., poor facility design).

When livestock have difficulty coping with stress their productivity is affected:

• Weight gains and meat quality may not be optimal;
• Immune systems may be compromised, making animals vulnerable to disease;
• Behaviors may become maladaptive, e.g., excessive aggression, harmful stereotypy’s, or other behaviors that negatively impact the animal or its pen mates;
• Lower survival rates in young animals.

Pain is one cause of stress or distress. It is difficult to quantify, but researchers have used behavioral techniques and biochemical and endocrine measures to determine pain levels. This research has shown that animals feel significant levels of acute pain from many normal farm management practices (e.g., dehorning, castration, beak trimming, tail-docking). Poorly designed flooring and physical abnormalities can contribute to chronic pain in livestock.

Research is showing that mitigating stress and distress in livestock can improve productivity through:

• Environmental enrichment, to aid in the display of natural behaviors;
• Gentle handling and positive conditioning to people, to reduce fear;
• Appropriate pain control for painful management procedures, and;
• Appropriate facility design and environmental controls.

Productivity and livestock well-being is enhanced by addressing the causes of stress in livestock.