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Technical note: mineral deposits on Dacron bags during ruminal incubation
J van Milgen1, M L Roach, L L Berger
1Department of Animal Sciences, University of Illinois, Urbana 61801.
Journal of Animal Science
|August 1, 1992
Summary
Extensive dry matter (DM) contamination occurred on Dacron bags incubated in steer rumens, particularly with alfalfa hay diets. This mineral contamination, identified as hydroxylapatite and whitlockite, may necessitate corrections in long-term digestion studies.
Area of Science:
- Animal Nutrition
- Rumen Microbiology
- Analytical Chemistry
Background:
- Dacron bags are commonly used to study feed digestion in ruminants.
- Accurate assessment of feed degradation requires minimizing external contamination.
- Mineral contamination in rumen incubation studies is a potential confounding factor.
Purpose of the Study:
- To investigate the extent and nature of dry matter (DM) contamination on Dacron bags.
- To identify the composition of the contaminant.
- To determine the influence of diet and incubation time on contamination.
Main Methods:
- Incubation of Dacron bags containing feed (alfalfa hay, orchardgrass) in steer rumens for up to 42 days.
- Analysis of contaminant ash content and solubility.
- X-ray analysis to identify mineral composition of the contaminant.
Main Results:
- Significant DM contamination was observed on Dacron bags, especially with alfalfa hay.
- The contaminant was rich in acid-soluble ash, identified as hydroxylapatite and whitlockite.
- Contamination increased exponentially over time and appeared as a smooth coating on fibers.
Conclusions:
- Mineral contamination of Dacron bags is a significant issue in long-term rumen incubation studies.
- Diet composition (alfalfa hay vs. orchardgrass) influences the extent of contamination.
- Corrections for DM contamination may be necessary for accurate interpretation of digestion and mineral balance studies.