Topics:
Animal Nutrition, Animal Refresher
Limitations of Chromic Oxide in Digestion Trials
Chromic oxide is not commonly used in ______ because it does not give accurate results:
- Herbivores — Correct Answer
- Carnivores
- Birds
- None
Explanation:
Correct Answer: Herbivores
Chromic oxide is avoided in herbivores (ruminants) because it does not pass through the rumen at a uniform rate — it segregates with different particle sizes and densities, giving inaccurate digestibility estimates. Internal markers like Acid Insoluble Ash (AIA) or lignin are preferred for ruminants.
Digestibility Markers — Comparison
| Marker Type | Examples | Best Suited For |
|---|---|---|
| External — accurate in non-ruminants | Chromic oxide (Cr₂O₃), Ferric oxide | Swine, poultry, carnivores |
| Internal — preferred for ruminants | AIA, Lignin, Silica | Ruminants (cattle, sheep, goat) |
| Radioisotope markers | Cr-EDTA, ⁵¹Cr, Cerium | Liquid vs solid phase in ruminants |
Why Chromic Oxide Fails in Ruminants
- Rumen has differential passage rates for fine vs coarse particles — chromic oxide settles with heavy particles, overestimating faecal output of some fractions.
- Results in overestimation of digestibility in some periods and underestimation in others.
- AIA (endogenous silicates in feed) is a more reliable internal marker for ruminants.
Why Other Options Are Wrong
- Carnivores → chromic oxide works well in carnivores; no segregation issue in simple stomachs.
- Birds → used in poultry; though cloaca presents challenges, chromic oxide itself is accurate.
- None → herbivores IS the correct exclusion group.
📚 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.
