Topics:
Animal Nutrition, Animal Refresher
Optimum Rumen Ammonia Concentration
Optimum concentration of rumen $NH_{3}$ is:
- 10-15 mg/dl
- 15-20 mg/dl
- 5-8 mg/dl — Correct Answer
- None
Explanation:
Correct Answer: 5–8 mg/dl
The optimum (minimum threshold) rumen NH₃ concentration for effective microbial protein synthesis is 5–8 mg/100 ml (mg/dl). Below this level, rumen bacteria cannot effectively use ammonia for growth.
Rumen NH₃ Thresholds
| Condition | NH₃ Level |
|---|---|
| Optimum for microbial synthesis | 5–8 mg/100 ml |
| Rumen bacteria unable to use NH₃ | <5–8 mg/100 ml (too low) |
| Toxicity threshold (rumen) | >80 mg/100 ml |
| Toxicity threshold (blood) | >1 mg/100 ml |
Urea Utilisation Factors
- N:S ratio should be 10:1 for optimum urea use
- Starch:Urea ratio should be 10:1
- Rumen bacteria cannot use NH₃ effectively if: diet CP >13% OR rumen NH₃ >5–8 mg/100 ml
- Adaptation period for rumen microbes to dietary urea: 2–4 weeks
Why Other Options Are Wrong
- 10–15 mg/dl → too high; above this level, bacteria cannot use NH₃ effectively and toxicity risk increases
- 15–20 mg/dl → dangerously high; approaches toxic levels
- None → incorrect; 5–8 mg/100 ml is the standard optimum value
📚 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.
