Nutritional and metabolic disorders

1. Introduction

Nutritional and metabolic disorders in ruminants occur when the balance of nutrients, energy, or metabolic processes is disrupted due to poor feeding practices, imbalanced rations, or physiological stresses (e.g., calving, peak lactation). These disorders not only reduce productivity (milk, meat, reproduction) but also lead to health complications and economic losses.

2. Common Nutritional and Metabolic Disorders

A. Ruminal Acidosis

Cause: Excessive intake of rapidly fermentable carbohydrates (e.g., grains) with insufficient fiber

Mechanism: Rapid fermentation → Accumulation of lactic acid → Drop in rumen pH (<5.5)

Signs:

Decreased feed intake
Diarrhea (often foamy)
Lethargy and dehydration
Poor milk production
Laminitis (chronic cases)

Prevention & Management:

Include adequate fiber (forage) in the diet
Avoid sudden diet changes
Use buffers (e.g., sodium bicarbonate)
Feed ionophores (e.g., monensin) to regulate fermentation

B. Ketosis (Acetonemia)

Cause: Negative energy balance during early lactation → Mobilization of body fat

Mechanism: Excess fat mobilization → Liver converts fat to ketone bodies → Ketone accumulation in blood

Signs:

Reduced milk yield
Loss of appetite, especially for concentrates
Sweet or acetone smell in breath, milk, or urine
Nervous signs (in advanced cases)

Prevention & Management:

Provide high-energy diets during transition and early lactation
Use propylene glycol as a glucose precursor
Monitor body condition score (BCS)
Avoid overconditioning during late pregnancy

C. Milk Fever (Hypocalcemia)

Cause: Sudden drop in blood calcium levels around calving due to high demand for milk production

Mechanism: Inadequate calcium mobilization from bones

Signs:

Muscle tremors
Cold ears, dullness
Recumbency (lying down, unable to rise)
Coma and death if untreated

Prevention & Management:

Feed low-calcium diets 2–3 weeks before calving
Supplement anionic salts to improve calcium mobilization
Give oral or intravenous calcium around calving
Monitor high-risk cows closely

D. Grass Tetany (Hypomagnesemia)

Cause: Low magnesium intake or absorption, especially in lush, fast-growing pasture

Mechanism: Magnesium is essential for nerve and muscle function

Signs:

Muscle twitching
Nervousness or aggression
Collapse, convulsions
Sudden death (in severe cases)

Prevention & Management:

Supplement magnesium (Mg oxide) in feed or mineral blocks
Avoid grazing cows on lush pastures without magnesium supplementation
Monitor weather changes (cold, wet weather increases risk)

E. Bloat (Ruminal Tympany)

Types:

Frothy Bloat – gas trapped in stable foam (often from lush legumes like alfalfa)
Free Gas Bloat – gas trapped due to esophageal blockage or motility issues

Signs:

Swollen left abdomen
Discomfort and kicking at belly
Difficulty breathing
Collapse and death (if untreated)

Prevention & Management:

Avoid sudden access to lush legumes or high-concentrate diets
Use anti-foaming agents (e.g., poloxalene)
Provide roughage with legumes
In emergencies: stomach tube or trocarization

F. Nutritional Diarrhea

Cause: Poor-quality feed, abrupt diet changes, high-fat or high-protein feed

Signs:

Loose, watery feces
Dehydration
Poor growth

Prevention & Management:

Introduce new feeds gradually
Provide clean water and electrolytes
Use probiotics and good-quality feed ingredients

G. White Muscle Disease (Nutritional Myopathy)

Cause: Selenium and/or Vitamin E deficiency

Primarily affects: Young calves and lambs

Signs:

Muscle weakness or stiffness
Inability to stand or suckle
Sudden death (heart muscle involvement)

Prevention & Management:

Supplement selenium and vitamin E in pregnant dam’s diet
Inject vitamin E–selenium to newborns in deficient areas
Monitor selenium levels in soil and feed

H. Urinary Calculi (Urolithiasis)

Cause: Imbalance in calcium to phosphorus ratio; high-concentrate diets in males (especially goats, sheep)

Signs:

Straining to urinate
Dribbling urine or blood-tinged urine
Restlessness and abdominal discomfort

Prevention & Management:

Maintain Ca:P ratio of 2:1
Provide access to clean water
Add ammonium chloride to acidify urine
Ensure salt intake to increase water consumption

I. Copper Toxicity or Deficiency

Cause: Imbalance in copper intake, interactions with molybdenum or sulfur

Signs (Deficiency):

Anemia, dull coat, infertility, bone disorders

Signs (Toxicity):

Liver damage, jaundice, hemoglobinuria

Prevention:

Monitor and adjust trace mineral supplementation carefully
Avoid feeding feeds high in antagonistic minerals (e.g., high sulfur)

J. Lactic Acidosis in Calves

Cause: Overfeeding milk or milk replacer; carbohydrate-rich starter

Signs:

Diarrhea with undigested milk
Lethargy, dehydration

Prevention & Management:

Feed appropriate volumes of milk
Ensure access to clean starter and water
Use probiotics to stabilize gut flora

3. General Prevention Strategies for Nutritional Disorders

Balanced feeding: Follow NRC or region-specific guidelines for nutrient requirements.
Gradual feed changes: Prevent rumen upset from sudden dietary transitions.
Regular monitoring: Body condition scoring, milk yield, blood/urine tests.
Feed testing: Analyze forages and TMR for nutrient composition and mycotoxins.
Supplementation: Provide minerals and vitamins tailored to the production stage.
Training of staff and farmers: Nutrition awareness, early detection, and proper management.

4. Economic Impact

Reduced milk/meat yield
Higher treatment and veterinary costs
Reproductive failures and increased culling
Mortality in severe cases

Preventing these disorders through sound nutritional planning and management is far more economical and sustainable than treating them after they occur.

5. Conclusion

Nutritional and metabolic disorders are a major concern in modern ruminant production systems. They can be largely prevented by:

Formulating balanced rations
Monitoring animal health and behavior
Adjusting feed as per physiological stage and environmental stress

With routine veterinary oversight, nutritional audits, and farmer education, the incidence of these disorders can be minimized, ensuring better animal welfare and profitability.