Cases of milk fever have been quite common this autumn. Milk fever is a calcium deficiency triggered by the increased secretion of calcium as a result of the production of colostrum and milk in the first days of lactation.

The sudden decrease in calcium levels affect the strength of muscle contractions and the cow may initially be unsteady on her feet but eventually she will go down completely.

Prevention is the preferred option as for every case of clinical milk fever up to five cows may have subclinical milk fever and associated decreased muscle contraction.

This can possibly lead to left displacement of the abomasum, it may also cause uterine contraction after calving to be delayed resulting in womb infections and retained afterbirth and eventually sub-fertility.

Steps to preventing milk fever
  1. Have cows in the correct BCS at calving (3 to 3.25).
  2. Reduce calcium intake before calving and avoid any added oral calcium. This will allow the cow to mobilise her own calcium from bone or blood immediately after giving birth.
  3. Avoid lush pasture for autumn calving cows as this grass is low in magnesium.
  4. Feed a good quality dry cow mineral that is high in magnesium and has no added calcium or low added levels.
  5. Feed forages that are low in potassium and have not received potassium fertiliser or slurry.
  6. Use DCAD (Dietary cation-anion difference) diets that have been formulated by the nutritionist.

Treating a cow with milk fever

Treatment of this case involved giving IV calcium together with an oral bolus of calcium.

A second bottle of calcium was given under the skin for a prolonged release. The response to treatment of this cow was excellent and she was up and about looking for her calf within 10 minutes after treatment.

Frank O’Sullivan works in Patrick Farrelly & Partners Veterinary Practice in Co. Meath. The UCD graduate is also a member of Animal Health Ireland’s Technical Working Group and is the current Chair of the One Health Committee with Veterinary Ireland.