Water is a central constituent of the body of the pig, fulfi lling many
critical functions essential to life. Its unique chemical structure makes it
particularly effective in fulfi lling these roles. Because intake can be affected
by a number of pig and nonpig factors, and because intake is not
always a satisfactory refl ection of need, defi ning the water requirement of
the pig is particularly challenging. The quality of drinking water can be
a serious problem, but it tends to be isolated in regions known to possess
aquifers containing problematic minerals such as sulfates, iron, manganese,
or nitrates. Although water is abundant and inexpensive in many
parts of the world where pigs are raised, the prospect of greater agricultural
and nonagricultural demand on water resources suggests that both
cost and availability could become issues in many more parts of the world.
Therefore, the most effi cient use of this valuable resource is essential as
we move further into the 21st century.