Stress is a condition which occurs in all pigs when confronted with adverse management and environments. Better management of the environment has a beneficial effect on the health and the biological efficiency of the pig.

What does the pig do when stressed?

• It increases the leucocytes in the blood.
• It increases output of hormones (cortisol) from the adrenal gland and this depresses immunity.
• It becomes more susceptible to disease.
• It eats and drinks less.
• The growth rate and feed efficiency get worse for a period.
• It requires an increase in environmental temperature.

Major factors that may cause stress

• Shortage of water supply.
• Shortage of trough space.
• Excessive stocking density.
• Low, high or variable temperatures.
• Draughts.
• Movement, mixing, fighting.
• Verbal or physical abuse.
• Poor light.
• Low levels of selenium or vitamin E may increase the susceptibility to stress.
• High levels of vitamin A.
• Inadequate or poor nutrition.
• The act of farrowing or weaning.
• Transport.
• Changes in the environment e.g. changes in housing.
• Exposure to disease.