Milk fever in dairy cows:Strategies for preventing& It’s Measures

Milk fever

Milk fever arises when cows are unable to mobilise sufficient calcium at calving. This website is intended to provide a better understanding of the challenge of controlling (sub)clinical milk fever for dairy farmers.

What is milk fever?

Milk fever, or hypocalcemia, is a calcium deficiency.

The disease has a clinical and a subclinical form and affects when cows they are at their most vulnerable – during the transition period. Cows need a large amount of calcium immediately after calving: initially they take the calcium from their blood and later from their diet and bones. If unable to mobilise sufficient calcium the affected animal won’t be able to stand properly and will have a reduced appetite resulting in poor health and performance. 


There are two forms of hypocalcemia: clinical and subclinical.

-Clinical milk fever

A cow that is struck by clinical milk fever will shows signs of severe calcium deficiency: she won’t be able to stand and will feel cold to the touch.

-Subclinical milk fever

Despite having a much higher incidence than clinical hypocalcemia, the effects of subclinical hypocalcemia are often severely underestimated. While an affected cow will be able to stand and function largely as normal, she will perform much less efficiently as a result of the underlying calcium deficiency and will be much more susceptible to diseases. The incidence of problems such as mastitis, uterine infections, endometritis and placenta retention will increase. 

How to prevent milk fever?

A cow’s demand for calcium increases significantly as she gets closer to calving. A large amount of calcium is required for the increased bone growth in the unborn calf and the production of colostrum.

To meet this demand, the cow first takes calcium from its blood. Because this doesn’t suffice, the cow has to mobilise more calcium from its diet and its bones. Most of the time, cows can’t get enough available calcium, leading to (sub)clinical milk fever. In general, older cows are more susceptible to (sub)clinical milk fever than younger ones.

Consequences of milk fever

While clinical milk fever can be fatal, subclinical cases can also have a serious impact as a result of lost milk production and the costs and time involved in bringing the cow back to full health. While obvious symptoms are absent, subclinical cases of milk fever can be the gateway to an increase in mastitis, retained placenta, endometritis, uterine infections and other diseases as a result of the immune system being weakened immune system. This will have an obvious detrimental effect on milk output and can incur significant time, energy and financial costs to return the cow to full health.

How to Reduce cases of milk fever

Start by testing the macromineral content of all the forages which will be fed to the dry cows. Select forages with low potassium content. Formulate the ration to minimize potassium content of the ration as much as possible and use palatable ingredients.

AniStart helps to reduce (sub)clinical milk fever. An optimised calcium metabolism around calving results in healthier, more productive dairy cows.
By adding AniStart to the dry cow ration, your cows can mobilise more calcium and can start their subsequent lactation with more milk and fewer health events.

How to treat milk fever

Typically treated with intravenous calcium. Subcutaneous application, and oral calcium formulations, are available to address milder and suspected cases. Note these different forms of calcium are not equivalent to each other. There is more to calcium treatments than meets the eye; as any other treatment, they should only be administered under the guidance of a veterinarian.

Providing dairy cows with enough clean water is very important if you want them to consume enough dry matter

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