From ketosis to milk fever
When discussing animal health in livestock systems, attention often focuses on infectious diseases. However, some of the most significant productivity losses are not caused by viruses or bacteria, but by metabolic imbalances related to the animal’s physiology and herd management.
Among these, ketosis and milk fever are two of the most common conditions in high-producing dairy herds. Unlike infectious diseases, they are not transmissible: they develop when the cow’s metabolic balance is challenged by high physiological and production demands.
These disorders are therefore not caused by pathogens, but by a combination of nutritional, environmental, and management factors that place pressure on the animal’s physiological system.
The transition period: the most critical phase
The time when these issues most commonly arise is the transition period, which includes the weeks before and after calving.
During this phase, the cow must simultaneously cope with:
- calving
- the onset of lactation
- a sudden increase in energy and mineral requirements
As a result, metabolic balance becomes particularly fragile. If feed intake, nutrition, and physiological adaptation are not sufficient to support these demands, metabolic disorders can develop.
Among the most common are ketosis and milk fever, two conditions with different mechanisms but both linked to metabolic imbalance in the postpartum period.
Ketosis: when energy demand exceeds intake
Ketosis occurs when the cow enters a negative energy balance, a situation that frequently develops during the first weeks of lactation.
Milk production increases rapidly, but dry matter intake does not rise at the same pace. To compensate for this energy deficit, the cow mobilizes body fat reserves, producing ketone bodies as an alternative energy source.
When these compounds accumulate beyond certain thresholds, clinical symptoms may appear.
Clinical ketosis may involve:
- reduced appetite
- decreased milk production
- lethargy
- behavioral or neurological alterations
However, subclinical ketosis is far more common. Although it may not show obvious symptoms, it still negatively affects performance. In these cases, cows often experience:
- reduced milk yield
- poorer reproductive performance
- increased susceptibility to secondary diseases such as mastitis or metritis.
Milk fever: calcium imbalance after calving
Milk fever, also known as puerperal hypocalcemia, is caused by a rapid drop in blood calcium levels immediately after calving.
With the onset of lactation, calcium demand for colostrum and milk production increases sharply. If the cow cannot activate calcium mobilization from bones and intestinal absorption quickly enough, a deficiency develops that affects muscle and nerve function.
Clinical signs may include:
- muscle weakness
- difficulty standing
- muscle tremors
- recumbency in severe cases.
As with ketosis, subclinical hypocalcemia is much more prevalent than the clinical form and often goes unnoticed. Nevertheless, it can impair muscle contractility, delay placental expulsion, and increase the risk of uterine infections and mastitis.
The role of nutrition and herd management
The causes of metabolic diseases are multifactorial.
Nutrition plays a central role: rations that are not properly balanced in energy, protein, or minerals can predispose animals to metabolic disorders.
Other management factors also influence risk, including:
- dry period management
- body condition at calving
- feed quality
- stability and consistency of the total mixed ration (TMR).
Properly preparing cows for lactation by maintaining adequate body condition and balanced mineral nutrition is one of the most effective preventive strategies.
When the environment triggers imbalance
An often underestimated factor is the barn microclimate.
High temperatures, poor ventilation, overcrowding, or sudden changes in routine can reduce feed intake precisely when the animal needs to consume more nutrients.
Even small but persistent reductions in daily intake can intensify metabolic stress.
Examples include:
- heat stress, which suppresses appetite and alters digestion
- overcrowding, limiting access to feed
- continuous lighting, which may disrupt biological rhythms
- ration instability, which reduces feeding consistency.
Scientific assessments, including reports from EFSA, highlight that environmental welfare conditions play a key role in preventing metabolic disorders in high-producing dairy cows.
Monitoring and prevention: an integrated approach
Preventing metabolic diseases requires an integrated strategy combining nutrition, environmental management, and monitoring.
Useful tools include:
- monitoring feed intake during the first weeks postpartum
- testing ketone bodies in blood or milk
- observing feeding behavior
- analyzing time spent at the feed bunk and rumination patterns.
Data analysis allows farmers and advisors to detect early signs of metabolic imbalance, often before visible clinical symptoms appear.
This approach enables timely intervention, reducing indirect costs associated with reduced productivity, reproductive issues, and secondary diseases.
Conclusion
Metabolic diseases clearly demonstrate that animal health and productivity are not opposing goals, but rather depend on the balance between nutrition, environment, and herd management.
In high-producing dairy systems, physiological balance becomes more delicate and requires increasingly precise management practices. Continuous monitoring and preventive strategies help reduce the incidence of metabolic disorders and improve overall herd stability.
The real challenge is not treating ketosis or milk fever once they appear in clinical form.
The real challenge is designing farming systems where these conditions occur as rarely as possible.
