Milk fever, post parturient hypocalcaemia or parturient paresis is a disease, usually seen in dairy cows, characterized by reduced blood calcium levels. Low blood calcium levels lead to decreased muscle function throughout the body, causing general weakness, loss of appetite, and eventually heart failure. Low phosphorus levels are often seen in cows with milk fever. Phosphorus has a variety of important biological functions that makes it essential for animal health and well-being. It is a major component of bone as well as a buffer contributing to acid-base balance. Phosphorus is necessary for generation of adenosine triphosphate (ATP), without which many physiologic processes could not occur. A significant increase in serum calcium can be obtained very quickly after oral administration.