Older cows have a less active bone metabolism, so they have problems with low blood calcium levels more often. This is why clinical milk fever is mostly seen in multiparous dairy cows.
Most of the cows with low calcium levels in their blood immediately after calving don’t develop visible signs of milk fever but are suffering from subclinical milk fever. For every cow in the herd with clinical milk fever, there are usually 4 cows with subclinical milk fever35.
The poor metabolic and immune adaptation that comes with subclinical milk fever in dairy cows results in:
- A decrease in dry matter intake
- An increased risk of ketosis
- Low milk production
- An increased incidence of retained placenta and infections of the reproductive tract, resulting in poor fertility36
- An increase in the incidence of mastitis38
- An increased incidence of displaced abomasum
- An increase of the involuntary culling rate
Reduce systemic immune activation to reduce the risk of subclinical hypocalcaemia and manage the transition to lactation in such a way that stress is minimal. If this transition to lactation is not managed properly, a high rate of involuntary culling in the first 100 days after calving occurs7,27,28, resulting in a serious negative impact on dairy farm profitability32,33.