18/08/2026
🌱Preventing Milk Fever in Fresh cows at grass
Each lactation the risk of milk fever increases by 9%.
This is a combination of factors including
🩺increased milk production
🩺 less ability to mobilise calcium from bones as they get older.
🩺Body condition is also a factor, with cows BCS >4 at a 3 times higher risk of developing milk fever.
High Mg pre-calving helps get the body used to mobilising calcium before the significant increase in demand.
❗️Keep in mind that a period of rain and flush of grass will reduce Mg levels and increase risk❗️
So what can you do to reduce the risk of milk fever?
🐮Regular BCS. Cows should be 2.5-3 at calving
🐮Potassium locks up Magnesium in the soil. If you can, avoid grazing dry cows on fields that have had slurry or fertiliser applied
🐮Supplementing minerals at grazing
🐮High Mg lick buckets
🐮Rumbol boluses give 3 weeks of Mg supplementation
🐮Calcium boluses at calving for higher risk (older/fitter cows)