General Definition: A common metabolic disorder in adult cattle characterized by a deficiency of potassium in the blood.
Severity Levels:
Severe Hypokalemia: Serum or plasma potassium concentration < 2.5 mmol/L.
Moderate Hypokalemia: Serum potassium concentration between 2.5–3.5 mmol/L.
Primary Targets: Early-lactation dairy cows and inappetent animals.
Etiology
Nutritional Factors: Prolonged inappetence (> 2 days); the condition is extremely rare in healthy cattle with adequate dry-matter intake.
Production Factors: Additional loss of potassium through milk in lactating dairy cows.
Pharmacological Factors: Multiple injections of corticosteroids with mineralocorticoid effects (e.g., isoflupredone acetate), which enhance renal and GI potassium losses.
Clinical Findings
Neuromuscular Signs:
Generalized muscle weakness and depression.
Muscle fasciculations (twitching).
Severe cases: Recumbency (inability to stand) or inability to lift the head off the ground.
Gastrointestinal Signs: Decreased GI motility and rumen atony.
Diagnosis
Confirmation: Required via serum biochemical analysis.
Supporting Diagnostics:
Measuring other electrolytes: Sodium, chloride, calcium, and phosphorus.
Enzyme activity: Checking CK and AST activities to guide treatment.
Urinalysis: Aciduria may be present due to a marked decrease in urine potassium.
Treatment Strategies
Oral Administration (Treatment of Choice):
Agent: Feed-grade Potassium Chloride (KCl).
Protocol: 100–150 g twice daily for 3–5 days.
Methods: Administered via gelatin boluses or ororuminal intubation.
Precaution: High doses (> 1 g/kg) can cause diarrhea, tremors, and excitability.
Intravenous (IV) Therapy:
Indication: Rare; reserved for severe, recumbent cases with rumen atony.
Protocol: Isotonic KCl (1.15%) at a maximum delivery rate of 0.5 mmol/kg/h.
Risk: Rapid infusion can trigger fatal cardiac arrhythmias.
Supportive Care: Offering highly palatable feed to restore dry-matter intake.
Prevention
Appetite Management: Ensuring adequate and consistent dry-matter intake is the most effective prevention.
Proactive Care: Oral potassium should be a mandatory component of fluid therapy for any inappetent cattle.