Phosphorus and Other Nutrient Disappearance from Plants Containing Condensed Tannins Using In Situ and Mobile Nylon Bag Techniques

Plants containing condensed tannins (CT) represent an alternative feed resource for ruminants. However, limited information regarding nutrient disappearance from these plants is available. Two experiments were conducted to evaluate phosphorus (P) and other nutrient disappearance from plants containing CT. In the first experiment, nutrient disappearance from three native Texas species (Acacia angustissima var. hirta, Desmodium paniculatum, Smilax bona-nox, and Medicago sativa as control) were evaluated using the mobile nylon bag technique. For the second experiment, ruminal degradation parameters, ruminal and post-ruminal disappearance of P and other nutrients from a browse containing CT (Quercus virginiana) were compared to species without CT (Cynodon dactylon cv. Tifton 85, and Medicago sativa).

Results from the first experiment indicate that the proportion of nutrient that disappeared during rumen, pepsin/HCl, or intestinal incubation differed among plant species and nutrient evaluated (P<0.05) and did not appear to be directly related to relative CT concentrations. Dry matter (DM), inorganic matter (IM), and organic matter (OM) disappearance were greater (P