Preventing Subclinical Milk Fever In Cows

Subclinical milk fever, though often overlooked, is a subtle yet costly threat, with potential losses exceeding €150 per cow per lactation. At Specialist Nutrition, we recognise the gravity of this condition and pledge our expertise to assist farmers in averting and managing subclinical milk fever through tailored nutritional solutions and on-farm consultations.

Quick Facts

Even though it is practically impossible to entirely eliminate hypocalcemia from a dairy herd, adopting preventive strategies is paramount for the success of any transition cow program.

Nutritional and management strategies play a vital role in decreasing the losses caused by hypocalcemia, ultimately optimising post-calving health, milk production, and reproductive performance.

What is Clinical Milk Fever?

Milk fever, or hypocalcaemia, is a metabolic disorder caused by insufficient calcium, frequently manifesting around calving. This condition, whether clinical or subclinical, poses a heightened risk during the transition period, a crucial phase for cows. In need of substantial calcium post-calving, cows initially draw from their blood, later turning to their diet and bones. Insufficient calcium mobilisation results in weakened mobility, reduced appetite, and compromised health and performance.

Understanding the nuances of milk fever is paramount, considering its prevalence of 5–10% in dairy cattle and significant economic implications. Clinical cases lead to notable losses from deaths (approximately 8% of affected cows), premature culling (about 12% of affected cows), treatment costs, and decreased milk production in subsequent lactations. Additionally, each episode heightens the risk of other parturient diseases, such as ketosis, displaced abomasum, and coliform mastitis.

Subclinical hypocalcaemia, affecting about 50% of adult dairy cattle around calving, often surpasses clinical cases in economic impact. This form may result in decreased dry matter intake post-calving, heightened risk of secondary diseases, reduced milk production, and compromised fertility later in lactation. Regardless of breed, risk factors include age, milk production level, and parity, with Jerseys being the most susceptible.

Efforts to enhance calcium metabolism in fresh cows prove financially rewarding, even in herds with lower clinical milk fever rates. A strategic nutritional approach, considering breed-specific factors and calcium-rich supplementation, plays a pivotal role in preventing subclinical milk fever and ensuring the sustained health and productivity of dairy herds.

Quick Facts

Traditionally, milk fever has been linked to a higher risk of dystocia, uterine prolapse, retained placenta, mastitis, and displaced abomasum.

The negative consequences of subclinical hypocalcemia include decreased milk production, impaired immune function, heightened risk of ketosis, reduced reproductive performance, and an increased likelihood of early removal from the herd.

Considering both direct and indirect effects, the costs associated with hypocalcemia on animal health and production can be substantial, particularly in a 250-cow herd. Therefore, the prevention of hypocalcemia is crucial not only for animal health but also for the profitability of dairy farms.

What are the Three Stages of Milk Fever?

Parturient hypocalcemia, commonly known as milk fever, primarily occurs within 24 hours after calving, with the majority of cases surfacing within this critical window. Traditionally categorised into three stages, the first stage is characterised by the cow's ability to stand, the second by recumbency, and the third by coma and unresponsiveness.

Stage One

In the initial phase, cows may exhibit signs such as muscle tremors, restlessness, a stiff gait, and a slightly elevated temperature. The restlessness often manifests as protruding tongues, a displacement activity indicative of internal distress. As hypocalcemia progresses, the cow's ability to regulate core temperature diminishes, with a normal rectal temperature in this stage.

Stage Two

As milk fever advances to the second stage, cows typically lie on their stomachs with an extended neck or the head resting on the flank. Early symptoms of paralysis become evident, including a fast, flat pulse, cold body surface, dilated pupils, and flatulence. Recognising these clear symptoms is crucial for timely intervention.

Stage Three

The final phase of milk fever sees the cow lying on its side, losing consciousness, and entering a coma. This stage poses the highest risk of mortality, averaging between 2% to 5%. Death can occur within 12 hours of the onset of signs, resulting from suffocation due to bloat or cardiovascular collapse.

While the overt symptoms of the second stage are easily identifiable, the consequences of a seemingly "slight" calcium deficiency in the first stage are often underestimated. Diminished feed intake, increased negative energy and protein balance, and reduced movement can lead to complications in the udder (mastitis) or the gastrointestinal tract.

Prevention and Treatment of Milk Fever

Effectively managing and preventing milk fever requires a comprehensive approach. Specialist Nutrition advocates for the following strategies to mitigate the risk and impact of hypocalcemia in dairy cows:

Low Calcium Dry Cow Diet: Implementing a dry cow diet with calcium levels below 60g/head is a fundamental preventive measure. This approach helps maintain an adequate balance of calcium during the critical transition period.

High Magnesium Dry Cow Mineral: Providing a dry cow mineral with elevated magnesium content (above 30g/head) supports overall metabolic health and aids in the prevention of milk fever.

Managing Dry Cow Body Condition: Maintaining an optimal body condition in dry cows within the range of 3.0-3.25 is crucial. This ensures that cows enter the calving period with the necessary reserves for a smooth transition.

Addressing High Potash Silage: In cases where silage exhibits high potash levels (>2.5%), additional measures are recommended. Supplementing extra magnesium, vitamin D, and anionic salts 21 days pre-calving aids in mobilising calcium. Diluting the Dietary Cation-Anion Difference (DCAD) of grass silage with low DCAD forages, such as straw, contributes to a balanced nutritional profile.

Optimising Feed Space and Forage Intakes: Reevaluating feed space for cows at calving is essential. Ensuring optimum forage intakes promotes a steady nutritional supply during this critical period.

Introducing Dietary Calcium at Calving: Providing supplementary calcium at calving is crucial. Options such as calcium/electrolyte drinks, calcium boluses, and post-calver minerals can be tailored to individual farm requirements, with an recommended intake of >120g/head.

Specialist Nutrition takes a proactive stance in preventing milk fever, offering expert advice, personalised consultations, and precise nutritional solutions. Our commitment extends beyond conventional approaches, ensuring the sustained health and productivity of dairy herds. For tailored nutritional guidance and comprehensive support, connect with our team of experts at Specialist Nutrition.