Hypocalcaemia / Milk fever
Hypocalcaemia, or milk fever, occurs in cattle, sheep and goats. It is most common in high producing or dairy-cross cows and in milking goats. Clinical signs develop when serum calcium levels fall below a critical level (hypocalcaemia).
Affected animals are initially excited or agitated with muscle tremors, then go down and are unable to rise.
Conditions when hypocalcaemia is likely to occur
- property history of hypocalcaemia
- in cows greater than five years old, in does greater than four 4 years old and in ewes
- late pregnancy and also after calving in dairy cows
- high producing and dairy-cross cows
- cows with a history of hypocalcaemia
- alkaline diets high in sodium and potassium, and low in sulphate and chloride
- low calcium intake after calving and high intake before
- low roughage intake
- heavy grain feeding of sheep
- fat cows with a fat score of 3.5 or greater.
Identification and diagnosis
Clinical signs that would lead you to suspect hypocalcaemia include:
- tetany, unable to rise, dry muzzle
- ewes cast after handling, often with hind legs behind
- response to treatment with calcium borogluconate
- blood samples can also be collected to determine serum calcium levels
An integrated approach to prevent hypocalcaemia should consider the following:
- avoiding over-fattening cows
- ensuring constant access to feed during calving
- avoiding grazing high-risk pastures as per grass tetany
- feeding hay before calving. Using the Health Cost Benefit Calculator to determine the cost-benefit of the this option
- keeping calcium intake to less than 50g/day before calving
- feeding as much calcium as possible after calving. Clover-dominant pasture is one way to do this
- avoiding handling of heavily pregnant ewes
- lowering the herd/flock age structure as older cows, does and ewes are higher risk.