Environmental pollution plays an important role in affecting the internal milieu of animals and humans. The amount of trace elements in the environment is generally low, but these chemicals can interfere with physiological systems. Thus, the health and welfare of individuals could be compromised by exposure to environmental levels of pollutants. In order to understand risk and effects of carious chemicals on the animal and human organism, the input of pollutants into biological systems has to be defined. Trace elements, mainly the toxic ones, can adversely affect animal health and reproductive system and its functions, through either direct or indirect effects on numerous organs and systems.