Energy deficiency in Cats (Felis) | Vetlexicon
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Energy deficiency

ISSN 2398-2950

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Introduction

  • Each individual animal has unique energy requirement.
  • Energy is derived from dietary fat, carbohydrate and protein.
  • Cause: (often) young animal fed homemade diet.
  • Signs: weight loss +/- failure to grow.
  • Diagnosis: must rule out weight loss due to concurrent disease (because of legal welfare considerations).

Presenting signs

  • Weight = less than optimum for breed (see individual breed data for exact figures).
  • Failure to grow (of young animal).
  • Reproductive failure.
  • Lactation failure.
  • Decreased physical performance.
  • Poor coat condition.

Age predisposition

  • Growing animal: fed inappropriate diet.
  • Adult: very active cat fed inappropriate, bulky, low-energy diet.
  • Adult: fed a poor quality low-digestible diet.
  • Older animal: decreased appetite due to ageing.
  • Older animal: reduced efficiency of digestion with increasing age.

Cost considerations

  • Higher quality balanced diet, if uncomplicated underweight (ie undernutrition) and not due to underlying disease.

Special risks

  • General anesthesia: if poor physical condition .
  • Surgical procedures: may be impaired healing due to poor physical condition.
  • Vaccination: may be immuno-incompetent.

Pathogenesis

Etiology

  • Homemade diet: especially if based on vegetarian foods.
  • Inappropriate commercial diet: eg adult food fed to kitten; adult food to queen at peak lactation.
  • Feeding too few calories for individual's requirements:
  • Competitive feeding: dominant cat(s) fed simultaneously pushing out affected animal.

Specific

  • Diet is bulk-limited: if its energy density is low   →   gastrointestinal capacity will limit intake before animal's energy needs are met.

Pathophysiology

  • Correct amount of a balanced diet = animal's energy requirement + correct amounts of all other nutrients.
  • Underfed animal  →   uses liver glycogen stores   →   provides glucose essential for brain, blood, kidneys   →   if fasting for >36 hours   →   gluconeogenesis occurs using amino acids   →   mobilization of fat stores   →   supplies energy for other cells.
  • Starved animal  →   uses fat and protein as energy source (not carbohydrate)   →   decreasing fat stores noticeable over ribs/lumbar area   →   muscle atrophy over skull/lumbar region/limbs.

Timecourse

  • Gradual: if uncomplicated starvation.
  • Within days: if disease-induced, eg hypermetabolism and catabolism of amino acids providing energy and also maintaining antibody production, tissue repair etc.

Diagnosis

Presenting problems

  • Weight loss.
  • Reproductive failure.
  • Lactation failure.
  • Abdominal distension.

Client history

  • Gradual weight loss in otherwise healthy cat.
  • Failure of litter to thrive.
  • Lactation failure.
  • Reproductive failure: conception or to sustain pregnancy.
    Must obtain dietary history: consider current diet and previous diets fed (brand, varieties, feeding regime, treats, titbits). Examine product labels.

Diagnostic investigation

Diet calculator

  • Calculate energy requirement compared to energy fed:
  • MER = 1.4 x (30 x bodyweight in kg + 70) or 110 x bodyweight (kg) ^0.75.
    This is accurate for cats weighing more than 2kg.
  • MER must then be multiplied by appropriate factor to take into consideration animal's unique needs, eg daily energy requirement for peak lactation = (1 + 0.25 x number in litter) x MER.

Hematology

  • Normal if simple underfeeding.
  • Anemic.

Biochemistry

If severe starvation:

  • Hypoglycemia Blood biochemistry: glucose.
  • Increased free fatty acids.
  • Increased branched chain amino acids/decreased gluconeogenic amino acids.

Ultrasonography

  • To determine body composition.
  • To calculate proportion of fat to lean body tissue.

Gross autopsy findings

  • Fat depletion especially perirenal/subcutaneous.
  • Muscle wastage: if more severe/longstanding energy deficiency.

Differential diagnosis

Treatment

Initial symptomatic treatment

Diet change

  • Calculate required energy intake.
  • Select appropriate balanced diet Dietetic diet: for convalescence.
    Choose highly palatable, highly digestible diet containing protein of high biological value
  • Avoid sudden change in diet, gradually increase amount fed over 2-4 days.

Monitoring


Consider tube-feeding enteral diet Dietetic diet: for convalescence if failure to gain weight at desired rate.
  • Aim for animal to consume >85% of calculated energy requirement within 2 weeks.

Subsequent management

Treatment

  • Regular weight check.

Prevention

Prophylaxis

Owner education

Outcomes

Prognosis

  • Good: if uncomplicated starvation and detected early.
  • Guarded: if concurrent disease - depends on primary cause.

Expected response to treatment

  • Gradual return to optimum body weight: time taken depends on animal's initial weight.
  • Improving activity level and general demeanor.

Reasons for treatment failure

Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Burger I H (1994) Energy needs of companion animals: matching food intakes to requirements throughout the life cycle. Journal of Nutrition 124 (12 Suppl), 2584S-2593S PubMed.