Milk Fever 

By: Peter Lester © 2003

Milk fever (Hypocalcemia) the symptoms are as a result of low blood calcium concentrations. The term milk fever is a misnomer as the animal will not have a fever. The animal has been asked to call on all her body reserves as the demand for calcium increases dramatically at calving. Like phosphorus, calcium’s demand has increased however its supply has not. These two elements are linked along with potassium and sodium. The ratio required is well defined and well established. For animals this is as follows:

In the animals’ diet there should be:-


1 part


1.5 parts


0.75 part


0.5 part


3.0 parts

Our spring feeds contain up to 5% potassium, throwing the rest out of kilter. That’s not due to too much potassium in the soil, but an insufficiency of the other elements. RE-ESTABLISH THE RIGHT RATIOS IN THE SOIL AND THE PROBLEM OF EXCESS POTASSIUM WILL DISAPPEAR. Grazing animals on high calcium feeds or giving them access to licks laced with calcium up to calving will result in the parathyroid becoming lethargic as it assumes all in the animal is in order. It is not until the animal drops her offspring that the demand comes on and the parathyroid gets the message that the demand has exceeded the supply. It takes about 7 days for the glands to strike up and that’s when the animals demand exceeds the supply. Withdraw all calcium from the diet for 10 days prior to calving to frustrate these glands and they will become active and hyperactive. Now immediately at parturition supply calcium and the blood supply will be met.