Due to the intense

use of P fertilizers and livestock manure in modern day

agriculture, P has become an accelerator of fresh water

eutrophication, resulting in reduced oxygen availability

because of growth of algae and their decomposition. Recent

research indicates that dietary P management is a key strategy

to reduce P imports and accumulation on dairy farms. Thus,

a more precise formulation of dairy rations can lead to

substantial reduction in fecal P excretion without impairing

animal productivity. Some mathematical equations are

presented in order to estimate P excretion by dairy cows.

These equations would be very useful when developing

nutrient management programs. The objective of the study

was to make a brief commentary of the importance of P in the

body, understand that excess P can be an important threat to

surface waters, and to find the easiest and most economic

ways to reduce P excretion in dairy farm systems.

Keywords: phosphorus, animal nutrition, dairy cattle, environment pollution, phosphorus excretion.