Milk fever, also known as hypocalcemia, is a metabolic disorder caused by insufficient calcium in the blood of dairy cows. It generally occurs within the first 24 hours post-calving, but can still occur two to three days post-calving. There are two types of hypocalcemia: clinical and subclinical. Clinical milk fever is characterized by the development of clinical signs such as down cow, lethargy, cold extremities, and rumen atony. On the other hand, subclinical hypocalcemia has no clinical signs, making it much harder to detect. Subclinical cases have been reported to affect as many as 73 percent of animals of third and greater lactation. The negative consequences of subclinical hypocalcemia include decreased milk production, decreased immune function, increased risk of ketosis, decreased reproductive performance, and increased risk of early removal from the herd. The cost of the direct and indirect effects of hypocalcemia on animal health and production can be substantial in a 250-cow herd. Therefore, prevention of hypocalcemia is extremely important not only for animal health but also for the profitability of dairy farms.