Hypocalcemia Symptoms and Treatment in Cattle

Hypocalcemia (Milk Fever) in Cattle

Hypocalcemia, or milk fever, is a frequently occurring and potentially fatal metabolic disease in dairy cows during the post-calving period. It is characterized by a drop in blood calcium levels.

What Is Hypocalcemia?#

Normal blood calcium levels range between 8.5-10.5 mg/dL. When this value drops:

• Below 8.0 mg/dL: Subclinical hypocalcemia
• Below 5.5 mg/dL: Clinical hypocalcemia (milk fever)

The intensive use of calcium for colostrum and milk production during and after calving causes blood calcium levels to drop rapidly.

Risk Factors#

High-Risk Groups#

• Cows with 3 or more calvings
• High-yielding dairy cows
• Cows with a previous history of milk fever
• Overconditioned (obese) cows
• Jersey and Guernsey breeds
• Cows carrying twins

Predisposing Factors#

• High-calcium ration during the dry period
• Low magnesium intake
• Vitamin D deficiency
• Metabolic alkalosis

Clinical Signs#

Hypocalcemia progresses through three stages:

Stage 1 (Mild)#

Blood Ca: 5.5-7.5 mg/dL

Signs:

• Restlessness, nervousness
• Loss of appetite
• Stiffness in the legs
• Trembling (especially in muscle groups)
• Hypersensitivity
• Drooping ears
• Dryness of the nose tip

Intervention at this stage is most effective!

Stage 2 (Moderate)#

Blood Ca: 4.0-5.5 mg/dL

Signs:

• Recumbency, unable to stand
• Head turned to the side or backward (S-shaped neck)
• Cold ears and nose
• Low body temperature (hypothermia)
• Irregular heartbeat
• Decreased rumen motility
• Loose feces
• Dilated pupils
• Chewed feed in the mouth

Stage 3 (Severe)#

Blood Ca: Below 4.0 mg/dL

Signs:

• Complete recumbency (lateral recumbency)
• Loss of consciousness
• Severe bloating (tympany)
• Heart failure
• Coma
• Death (in untreated cases)

Diagnosis#

Clinical Examination#

• Post-calving period + typical signs
• Heart rhythm check
• Body temperature measurement
• Rumen motility assessment

Laboratory Tests#

• Blood calcium level (gold standard)
• Magnesium level
• Phosphorus level

Treatment#

Emergency Treatment (Veterinarian)#

Intravenous Calcium#

• Calcium borogluconate solution
• Slow infusion (5-10 minutes)
• Under heart rhythm monitoring
• 500 mL of 23% solution (40-50 g Ca)

Subcutaneous Calcium#

• In addition to intravenous treatment
• For prolonged effect
• 500 mL distributed across several injection sites

Supportive Treatment#

Oral Calcium Bolus#

• After intravenous treatment
• To prevent relapses
• Repeat at 12-24 hour intervals

Magnesium Support#

• Enhances calcium absorption
• Usually added to calcium solutions

Phosphorus Support#

• In non-ambulatory cases
• Oral phosphorus bolus

Patient Care#

• Provide a soft surface
• Regular turning (every 4-6 hours)
• Access to water and feed
• Keep warm
• Bladder monitoring

Complications#

In untreated or late-treated cases:

• Aspiration pneumonia: Due to bloating
• Muscle damage: Due to prolonged recumbency
• Mastitis: Due to inadequate milking
• Metritis: Due to immune suppression
• Ketosis: Due to decreased feed intake
• Downer cow syndrome: Nerve and muscle damage

Prevention#

Dry Period Management#

• Low-calcium ration (<100 g/day)
• Anionic salt use (negative DCAD)
• Adequate magnesium (30-40 g/day)
• Vitamin D supplementation

Calving Period Protocol#

• Prophylactic oral calcium bolus
  • 1 bolus at signs of calving
  • 1 bolus 12 hours after calving
  • 1 additional bolus at 24 hours for high-risk cows

Ration Adjustment#

• Pre-calving potassium restriction
• Gradual ration transition after calving
• Adequate roughage fiber

Subclinical Hypocalcemia#

Calcium deficiency occurring without clinical signs:

Effects#

• Immune suppression
• Increased metritis risk
• Increased ketosis risk
• Impaired udder health
• Decreased reproductive performance
• Milk yield loss

Importance#

Subclinical hypocalcemia is far more common than clinical cases and significantly impacts herd economics.

Prognosis#

• Treatment at Stage 1: 95%+ recovery
• Treatment at Stage 2: 80-90% recovery
• Treatment at Stage 3: 50-70% recovery
• Untreated: High mortality risk

Early intervention is lifesaving!

Conclusion#

Hypocalcemia is a preventable and treatable disease. Losses can be minimized through dry period nutrition management, prophylactic bolus use, and early detection of signs.

Call your veterinarian immediately when milk fever symptoms are observed.