Milk fever and subclinical milk fever are the most important macromineral disorders that affect transition dairy cows. The occurrence of milk fever or subclinical hypocalcaemia is related to increased incidence rates of several other transition cow problems. The cows with low blood level of calcium have a higher likelihood of having immunosupression, an assisted calving (2-3x), retained placenta, uterine prolapse, endometritis, mastitis (8x), displaced abomasum (2-4x) ketosis and fertility problems. Therefore, it very important that both milk fever and subclinical milk fever are prevented.
The main strategies to avoid milk fever and subclinical hypocalcaemia at calving are:
- Ensuring the correct BCS at calving (BCS 3.0)
- Providing adequate Mg supplementation pre-calving (min 20 g per cow per day)
- Achieving negative DCAB (dietary cation anion balance)
- Reducing dietary K intake
*It is very important to have your silage analysed to know the mineral content and the nutritional value.
Cows who have gone down with milk fever should be treated by a vet with IV calcium. High risk cows (over-conditioned, high-yielding, lame cows and cows with a previous history of milk fever) would benefit receiving an oral calcium bolus at the point of calving and the second one 12 hours later in aid of lowering the chance of the cow getting milk fever.
Consider milk fever as a gateway disease to other illnesses and work towards identifying the specific strategy for milk fever control in the enterprise. All farms should have some pre-determined strategy for milk fever prevention. If you have an increased number of transition cow problems or more than 5% of your cows get milk fever an investigation into the issue would be advisory.
Contact Glasslyn Vets for further information on milk fever prevention and testing.