Rumen VFA Production Ratio

Question

The ratio of production of Acetate : Propionate : Butyrate in the rumen is:

Select an answer

The ratio of production of Acetate : Propionate : Butyrate in the rumen is:

  1. 65 : 10 : 20
  2. 65 : 20 : 10 — Correct Answer
  3. 10 : 20 : 65
  4. 70 : 15 : 10
Explanation:
Correct Answer: 65 : 20 : 10

Under normal feeding conditions (mixed diet of roughage and concentrate), the rumen VFA profile is:

  • Acetate: 65% — predominant VFA; used for milk fat synthesis
  • Propionate: 20% — gluconeogenic; used for milk sugar (lactose) and body glucose
  • Butyrate: 10% — used by ruminal epithelial cells; precursor to ketone bodies
Dietary Effects on VFA Ratio
  • High roughage diet: ↑ Acetate → ↑ Milk fat% (A:P ratio increases)
  • High grain/concentrate diet: ↑ Propionate → ↑ Milk yield, ↓ Milk fat% (A:P ratio decreases)
Total VFA Facts
  • Total VFA concentration: 80–120 mEq/L of rumen liquor
  • Total VFA produced by adult cow: ~4 kg/day
  • VFAs provide 70% of ruminant energy needs

📚 About this Topic — Animal Nutrition

This multiple choice question is from Animal Nutrition, Animal Refresher. It has 4 options with a detailed explanation of the correct answer. Practice more MCQs from Animal Nutrition to strengthen your preparation.

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