Dry Matter and Crude Protein Degradability of Four Parasitic Plants (Mistletoes) Associated with Browse Trees in Botswana

Four parasitic plants (Tapinanthus lugardii, Erianthenum ngamicum, Viscum rotundifolium and Viscum verrucosum) associated with browse trees in Botswana were evaluated for the degradability of their dry matter (DM) and crude protein (CP). All these plants have high levels of crude protein, ranging from 144.5 to 163.4 g/kg DM, with a significant (p<0.001) difference in crude protein content between the plants. The rate of degradation of DM was highest for V. rotundifolium (0.197 h⁻¹) and lowest for E. ngamicum (0.031 h⁻¹). The two Viscum species had the highest effective DM degradability at an outflow rate of 0.05%. The rate of degradation of crude protein was highest for V. rotundifolium (0.144 h⁻¹) and lowest for T. lugardii (0.0346 h⁻¹). The effective degradability (ED) of crude protein was highest for V. rotundifolium at 0.03 and 0.05 h⁻¹ outflow rates. T. lugardii and E. ngamicum had an apparently low effective degradability, but this may result from an association of their protein with tannins, which would be able to supply amino acids in the small intestine after dissociation due to the abomasal pH. This revised version was published online in July 2006 with corrections to the Cover Date.