These information sheets are provided for your interest. They should not replace veterinary advice from your veterinary surgeon.

Whilst every effort is taken to ensure the accuracy and completeness of the information provided at the time of writing, your specific circumstances must be discussed before advice can be given.

Milk fever (hypocalcaemia)

Milk Fever, also known as hypocalcaemia or parturient paresis, is the most common metabolic disease affecting dairy cattle, affecting around  5-10% cows annually. It usually presents as a down cow around calving. However this presentation could be many other diseases so a thorough history and clinical exam is essential. 


Around calving the cow has a huge increase in demand for calcium for colostrum production. Cows with milk fever cannot mobilise calcium from bone or increase absorption from the gut quick enough. This means the cow cannot perform it's normal functions involving calcium such as muscle contraction. Therefore you see signs of weakness, ataxia, recumbency, dystocia or bloat.

Risk Factors:

  • 3rd lactation or more
  • Breed e.g. Jerseys
  • Previous history of milk fever
  • Complete milking after calving
  • High calcium diet during dry period
  • Low magnesium diet during the dry period
  • Over fat cows
  • Stress at calving

Clinical Signs

90% cases occur 24 hours before to 48 hours after calving

Stage 1: refusing concentrates, aggression/apprehension, ataxia, tremors, bloat

Stage 2: sternal recumbency, full udder, rectum distended with faeces, dry muzzle

Stage 3: lateral recumbency, bloat, reduced temperature, respiratory and heart rates

Treat as emergency! Prognosis is good if treated within 6 hours.


Intravenous calcium into the jugular vein, given slowly to avoid cardiac arrhythmias

- If cardiac arrhythmias do occur STOP calcium administration, then give at a lower rate.

Subcutaneous calcium can be given in less severe cases.

Recovery: usually a rapid response 

Heart rate falls and becomes louder, cow tries to stand, looks brighter

(Make sure cow has a room to stand and is on a non-slip surface)

If she doesn't respond to the treatment look for another cause, or may be secondary muscle ischaemia. See Down Cow Syndrome for a discussion of these.


Dry cows off at body condition score 2.5-3 and maintain until calving

Dry period nutrition - Low concentrates and high fibre

Low calcium diet

Dietary Cation Anion Balance (DCAB) - acidifies the diet

Calcium boluses e.g. Bovikalc - administered at first signs of calving, immediately after calving and     12 hours later if necessary. Contains calcium chloride and calcium sulphate, so may also have a DCAB affect

Sub-Clinical Milk Fever

Most often presents as a cow showing signs of calving but doesn't go into second stage labour.

Give calcium IV and she should go into labour.