Rational treatments for mineral disorders in fresh cows
Hypocalcemia, hypophosphatemia, hypomagnesemia, and hypokalemia are important metabolic diseases of fresh dairy cows. Many dairy practitioners and dairy producers may need to update their approaches to these diseases based on current scientific information. Hypocalcemia in standing cows is best treated orally; intravenous calcium should be reserved for recumbent cases of milk fever because it may cause cardiac toxicity and rebound hypocalcemia. Glucose or additional electrolytes should not be included in intravenous solutions administered to cows with hypocalcemia. Hypophosphatemia is a less common mineral disorder that is usually secondary to hypocalcemia. Mild to moderate cases of hypophosphatemia are best treated with oral phosphorus; intravenous phosphorus should be reserved for severe cases. Hypomagnesemia may be a clinical problem in grazing herds or a subclinical problem in confinement dairies with cows fed stored feeds. Clinical hypomagnesemia may be treated intravenously or via rectal enema; subclinical cases are best managed by oral magnesium supplementation. Hypokalemia may follow prolonged periods of anorexia in early lactation cows and typically presents as severe, flaccid paralysis. Oral potassium supplementation is the preferred means for treating and preventing hypokalemia.