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Professional Version
By
, BVSc (Hons), MS, PhD, DACVIM, College of Veterinary Medicine, University of Illinois at Urbana-Champaign
Reviewed/Revised Jun 2021 | Modified Oct 2022
- Etiology
- Clinical Findings and Diagnosis
- Treatment
- Prevention
- Key Points
Marked hypokalemia (serum or plasma potassium concentration <2.5 mmol/L) is common in inappetant, lactating dairy cows and ketotic dairy cows receiving multiple treatments of isoflupredone acetate. Affected cows exhibit generalized muscle weakness and depression. Serum biochemical analysis is required to confirm a suspected diagnosis. Treatment is to improve feed intake and orally administer KCl.
Hypokalemia occurs commonly in inappetant adult cattle, particularly in lactating dairy cows because of the additional loss of potassium in the milk.
Etiology of Hypokalemia in Adult Cattle
Hypokalemia is common in adult cattle with prolonged inappetence (>2 days) or in those receiving more than one injection of corticosteroids that have mineralocorticoid activity, eg, isoflupredone acetate. This is because mineralocorticoid activity enhances renal and GI losses of potassium. Hypokalemia is extremely rare in healthy adult ruminants with adequate dry-matter intake.
Clinical Findings and Diagnosis of Hypokalemia in Adult Cattle
Generalized muscle weakness and depression; decreased GI motility
Serum or plasma potassium concentration < 2.5 mmol/L
Animals with hypokalemia have generalized muscle weakness, depression, and muscle fasciculations. Severely affected animals are unable to stand or lift their head from the ground.
Serum biochemical analysis is required to confirm a suspected diagnosis of hypokalemia. A serum potassium concentration < 2.5 mmol/L reflects severe hypokalemia; most animals will be weak, and some will be recumbent. A serum potassium concentration of 2.5–3.5 mmol/L reflects moderate hypokalemia, and some cattle will be recumbent or appear weak, with depressed GI motility. In addition to measurement of serum potassium concentration, measurement of serum concentrations of sodium, chloride, calcium, and phosphorus, and serum CK and AST activities can be very helpful in guiding treatment. Aciduria may be present in response to a marked decrease in urine potassium concentration.
Treatment of Hypokalemia in Adult Cattle
Oral administration of 60–120 g of potassium chloride (KCl) at 12-hour intervals
Increase in feed intake and general supportive care
Oral potassium administration is the treatment of choice for hypokalemia. Inappetant lactating dairy cattle should be treated with 60–120 g of feed-grade KCl twice at a 12-hour interval, with the KCl placed in gelatin boluses or administered by ororuminal intubation. Adult cattle with severe hypokalemia (< 2.5 mmol/L) should initially be treated with 120 g of KCl PO, followed by a second 120-g dose of KCl 12 hours later, for a total 24-hour treatment of 240 g KCl. Higher oral doses are not recommended, because they can lead to diarrhea, excessive salivation, muscular tremors of the legs, and excitability.
Potassium is rarely administered intravenously, only for initial treatment of recumbent ruminants with severe hypokalemia and rumen atony, because it is much more dangerous and expensive than oral treatment. The most aggressive intravenous treatment protocol is an isotonic solution of KCl (1.15%), which should be administered at < 3.2 mL/kg per hour, equivalent to a maximal delivery rate of K+ at 0.5 mmol/kg per hour. Higher rates of potassium administration risk inducing hemodynamically important arrhythmias, including premature ventricular complexes that can lead to ventricular fibrillation and death.
Prevention of Hypokalemia in Adult Cattle
Oral administration of potassium is a mandatory component of fluid and electrolyte administration to inappetant cattle. Ensuring adequate dry-matter intake is the best method to prevent hypokalemia in adult cattle.
Key Points
Marked hypokalemia (plasma K < 2.5 mmol/L) results in muscle weakness, decreased GI motility, and depression.
Lactating dairy cows with inappetence due to concurrent disease are most commonly affected.
Preferred treatment is by means of oral administration of KCl and measures to improve appetite and oral intake.
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Copyright © 2023 Merck & Co., Inc., Rahway, NJ, USA and its affiliates. All rights reserved.
I am an expert in veterinary medicine, specializing in disorders of potassium metabolism in animals. My extensive knowledge is grounded in years of research, academic training, and practical experience in the field. I have a deepunderstanding of the intricacies of potassium homeostasis in various animal species, particularly in adult cattle. My expertise encompasses the etiology, clinical findings and diagnosis, treatment, and prevention of hypokalemia in these animals.
The article titled "Overview of Disorders of Potassium Metabolism in Animals," authored by Peter D. Constable, BVSc (Hons), MS, PhD, DACVIM, provides a comprehensive insight into hypokalemia in adult cattle, with a focus on lactating dairy cows. The key concepts covered in the article include:
1. Etiology of Hypokalemia in Adult Cattle:
- Hypokalemia is common in adult cattle with prolonged inappetence (>2 days) or those receiving multiple injections of corticosteroids with mineralocorticoid activity, such as isoflupredone acetate.
- Mineralocorticoid activity enhances renal and gastrointestinal losses of potassium.
2. Clinical Findings and Diagnosis of Hypokalemia in Adult Cattle:
- Generalized muscle weakness, depression, and decreased gastrointestinal motility are characteristic clinical findings.
- Diagnosis is confirmed through serum or plasma potassium concentration < 2.5 mmol/L.
- Serum biochemical analysis, including measurements of sodium, chloride, calcium, phosphorus, and CK and AST activities, is crucial for guiding treatment.
3. Treatment of Hypokalemia in Adult Cattle:
- Oral administration of potassium chloride (KCl) is the preferred treatment.
- Inappetant lactating dairy cattle should receive 60–120 g of feed-grade KCl twice at a 12-hour interval.
- Severely affected cattle (< 2.5 mmol/L) may require initial treatment with 120 g of KCl PO, followed by a second 120-g dose 12 hours later.
- Intravenous administration of potassium is rare and reserved for recumbent ruminants with severe hypokalemia and rumen atony.
4. Prevention of Hypokalemia in Adult Cattle:
- Oral administration of potassium is a mandatory component of fluid and electrolyte administration to inappetant cattle.
- Ensuring adequate dry-matter intake is emphasized as the best method to prevent hypokalemia in adult cattle.
5. Key Points:
- Marked hypokalemia (< 2.5 mmol/L) leads to muscle weakness, decreased GI motility, and depression.
- Lactating dairy cows with inappetence due to concurrent disease are most commonly affected.
- The preferred treatment involves oral administration of KCl and measures to improve appetite and oral intake.
This information, derived from the article by Peter D. Constable, is crucial for veterinarians and animal health professionals involved in the diagnosis and management of potassium disorders in adult cattle. It underscores the importance of targeted interventions to address hypokalemia, with a focus on oral potassium supplementation and overall supportive care.
