Rosales et al., 1989. Livest. Res. Rural Dev., 1 (1): 79

To take advantage of the increases in productivity brought about by defaunation in ruminants fed diets rich in soluble sugars and/or alkali-treated straws, a simple and economical method is needed to remove rumen protozoa. This experiment aimed to provide preliminary data as to the efficacy of tropical tree foliages, on the basis of their known content of phenolic substances, as a means of reducing rumen protozoal numbers. Three weaned calves (about 150kg liveweight) were grazed on Kikuyu pasture and received for three days, at 8am, 400g/day of a 50/50 mixture of rice oil polishings and sun-dried foliage (leaves and pecioles; mean N content about 3.5% in dry matter) from each of the following trees (Trichantera gigantea, Erythrina poeppigiana and Enterolobium cyclocarpum). None of the foliages reduced protozoal numbers, which were relatively low (1-2 x10^5/ml) in all animals throughout the trial. This may partly explain the lack of effect.