The spring-calving season is underway on many farms, and a common issue seen around this time, is milk fever..
Milk fever is an issue that dairy farmers would prefer not to deal with when calving cows, as it often results in a ‘down cow’.
A case will also often happen when you are busy or in an area that is not ideal for treatment, including places such as the collecting yard or cubicle shed.
At a time of year when you are already busy, cases can increase stress levels on farms.
Milk fever
Milk fever is caused by reduced blood calcium levels and is most commonly seen in the first few days of lactation.
This is when the demand for calcium is high for milk production and it exceeds the body’s ability to mobilise calcium.
But, it can also be seen in the days ahead of calving, right up to the point of calving.
Left untreated, it can result in death, but generally after treatment cows are quick to recover.
Cows of concern
In the lead up to the calving season it is important that cows are fed minerals. Magnesium has a vital role in calcium metabolism and body calcium mobilisation.
The risk of milk fever is reduced if dietary calcium levels can be maintained below 0.5% of dry matter (DM) before calving.
Some cows that should be monitored closely are older cows within the herd and cows that are not in the correct body condition score (BCS). Over-conditioned cows are four times more likely to develop milk fever.
This is most likely due to reduced intakes after calving and having higher concentrations of calcium in the body.
Because of this, later-calving cows should be monitored. These cows are likely to be drier for longer and have more time to put on excess condition.
Metabolic disorders act as a gateway disease, with cows that develop milk fever likely to develop mastitis later in lactation – so cases should be avoided where possible.