Vol. 10, No. 4, 2004 Page 2


Exposing sheep to environmental pollutants during early development can alter their behavior and emotional reactivity later in life, according to new research.

Hans Erhard and Stewart Rhind studied the behavior of five-month-old lambs exposed before and after birth to slightly elevated levels of pollutants, due to the application of sewage sludge to the pastures on which they and their mothers grazed. Comparing these sheep to sheep raised on minimally polluted pastures, the researchers found that the exposed lambs exhibited less activity—an indication of reduced emotional reactivity— when placed in a crate. When allowed to explore, control females showed a normal pattern of greater exploratory behavior than males; in contrast, both males and females in the pollution-exposed group exhibited a high rate of exploratory behavior. This finding, the researchers say, suggests a selective "demasculinizing effect" on behavior in the exposed males.

"The observation of changes in behavioral patterns in response to low levels of exposure to environmental pollutants suggests that exposure to pollutants at even slightly increased concentrations can alter the development of the neuroendocrine system of mammals," the researchers conclude.


"Prenatal and postnatal exposure to environmental pollutants in sewage sludge alters emotional reactivity and exploratory behaviour in sheep," Hans Erhard and Stewart Rhind, Science of the Total Environment, Vol. 332, 2004, 101-8. Address: h.erhard@macaulay.ac.uk.

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